SDL_surface.h File Reference

#include "SDL_stdinc.h"
#include "SDL_pixels.h"
#include "SDL_rect.h"
#include "SDL_blendmode.h"
#include "SDL_rwops.h"
#include "begin_code.h"
#include "close_code.h"

Include dependency graph for SDL_surface.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	SDL_Surface
	A collection of pixels used in software blitting. More...

Surface flags
These are the currently supported flags for the SDL_Surface. Used internally (read-only).
#define	SDL_SWSURFACE   0
#define	SDL_PREALLOC   0x00000001
#define	SDL_RLEACCEL   0x00000002
#define	SDL_DONTFREE   0x00000004
#define	SDL_SIMD_ALIGNED   0x00000008
#define	SDL_MUSTLOCK(S)   (((S)->flags & SDL_RLEACCEL) != 0)
#define	SDL_LoadBMP(file)   SDL_LoadBMP_RW(SDL_RWFromFile(file, "rb"), 1)
#define	SDL_SaveBMP(surface, file)    SDL_SaveBMP_RW(surface, SDL_RWFromFile(file, "wb"), 1)
#define	SDL_BlitSurface   SDL_UpperBlit
#define	SDL_BlitScaled   SDL_UpperBlitScaled
enum	SDL_YUV_CONVERSION_MODE {   SDL_YUV_CONVERSION_JPEG ,   SDL_YUV_CONVERSION_BT601 ,   SDL_YUV_CONVERSION_BT709 ,   SDL_YUV_CONVERSION_AUTOMATIC }
	The formula used for converting between YUV and RGB. More...
typedef int(*	SDL_blit) (struct SDL_Surface *src, SDL_Rect *srcrect, struct SDL_Surface *dst, SDL_Rect *dstrect)
	The type of function used for surface blitting functions. More...
SDL_Surface *	SDL_CreateRGBSurface (Uint32 flags, int width, int height, int depth, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
SDL_Surface *	SDL_CreateRGBSurfaceWithFormat (Uint32 flags, int width, int height, int depth, Uint32 format)
SDL_Surface *	SDL_CreateRGBSurfaceFrom (void *pixels, int width, int height, int depth, int pitch, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
SDL_Surface *	SDL_CreateRGBSurfaceWithFormatFrom (void *pixels, int width, int height, int depth, int pitch, Uint32 format)
void	SDL_FreeSurface (SDL_Surface *surface)
int	SDL_SetSurfacePalette (SDL_Surface *surface, SDL_Palette *palette)
	Set the palette used by a surface. More...
int	SDL_LockSurface (SDL_Surface *surface)
	Sets up a surface for directly accessing the pixels. More...
void	SDL_UnlockSurface (SDL_Surface *surface)
SDL_Surface *	SDL_LoadBMP_RW (SDL_RWops *src, int freesrc)
int	SDL_SaveBMP_RW (SDL_Surface *surface, SDL_RWops *dst, int freedst)
int	SDL_SetSurfaceRLE (SDL_Surface *surface, int flag)
	Sets the RLE acceleration hint for a surface. More...
SDL_bool	SDL_HasSurfaceRLE (SDL_Surface *surface)
	Returns whether the surface is RLE enabled. More...
int	SDL_SetColorKey (SDL_Surface *surface, int flag, Uint32 key)
	Sets the color key (transparent pixel) in a blittable surface. More...
SDL_bool	SDL_HasColorKey (SDL_Surface *surface)
	Returns whether the surface has a color key. More...
int	SDL_GetColorKey (SDL_Surface *surface, Uint32 *key)
	Gets the color key (transparent pixel) in a blittable surface. More...
int	SDL_SetSurfaceColorMod (SDL_Surface *surface, Uint8 r, Uint8 g, Uint8 b)
	Set an additional color value used in blit operations. More...
int	SDL_GetSurfaceColorMod (SDL_Surface *surface, Uint8 *r, Uint8 *g, Uint8 *b)
	Get the additional color value used in blit operations. More...
int	SDL_SetSurfaceAlphaMod (SDL_Surface *surface, Uint8 alpha)
	Set an additional alpha value used in blit operations. More...
int	SDL_GetSurfaceAlphaMod (SDL_Surface *surface, Uint8 *alpha)
	Get the additional alpha value used in blit operations. More...
int	SDL_SetSurfaceBlendMode (SDL_Surface *surface, SDL_BlendMode blendMode)
	Set the blend mode used for blit operations. More...
int	SDL_GetSurfaceBlendMode (SDL_Surface *surface, SDL_BlendMode *blendMode)
	Get the blend mode used for blit operations. More...
SDL_bool	SDL_SetClipRect (SDL_Surface *surface, const SDL_Rect *rect)
void	SDL_GetClipRect (SDL_Surface *surface, SDL_Rect *rect)
SDL_Surface *	SDL_DuplicateSurface (SDL_Surface *surface)
SDL_Surface *	SDL_ConvertSurface (SDL_Surface *src, const SDL_PixelFormat *fmt, Uint32 flags)
SDL_Surface *	SDL_ConvertSurfaceFormat (SDL_Surface *src, Uint32 pixel_format, Uint32 flags)
int	SDL_ConvertPixels (int width, int height, Uint32 src_format, const void *src, int src_pitch, Uint32 dst_format, void *dst, int dst_pitch)
	Copy a block of pixels of one format to another format. More...
int	SDL_FillRect (SDL_Surface *dst, const SDL_Rect *rect, Uint32 color)
int	SDL_FillRects (SDL_Surface *dst, const SDL_Rect *rects, int count, Uint32 color)
int	SDL_UpperBlit (SDL_Surface *src, const SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect)
int	SDL_LowerBlit (SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect)
int	SDL_SoftStretch (SDL_Surface *src, const SDL_Rect *srcrect, SDL_Surface *dst, const SDL_Rect *dstrect)
	Perform a fast, low quality, stretch blit between two surfaces of the same pixel format. More...
int	SDL_UpperBlitScaled (SDL_Surface *src, const SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect)
int	SDL_LowerBlitScaled (SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect)
void	SDL_SetYUVConversionMode (SDL_YUV_CONVERSION_MODE mode)
	Set the YUV conversion mode. More...
SDL_YUV_CONVERSION_MODE	SDL_GetYUVConversionMode (void)
	Get the YUV conversion mode. More...
SDL_YUV_CONVERSION_MODE	SDL_GetYUVConversionModeForResolution (int width, int height)
	Get the YUV conversion mode, returning the correct mode for the resolution when the current conversion mode is SDL_YUV_CONVERSION_AUTOMATIC. More...

Detailed Description

Header file for SDL_Surface definition and management functions.

Definition in file SDL_surface.h.

Macro Definition Documentation

SDL_BlitScaled

#define SDL_BlitScaled   SDL_UpperBlitScaled

Definition at line 522 of file SDL_surface.h.

SDL_BlitSurface

#define SDL_BlitSurface   SDL_UpperBlit

Performs a fast blit from the source surface to the destination surface.

This assumes that the source and destination rectangles are the same size. If either srcrect or dstrect are NULL, the entire surface (src or dst) is copied. The final blit rectangles are saved in srcrect and dstrect after all clipping is performed.

Returns

If the blit is successful, it returns 0, otherwise it returns -1.

The blit function should not be called on a locked surface.

The blit semantics for surfaces with and without blending and colorkey are defined as follows:

RGBA->RGB:
  Source surface blend mode set to SDL_BLENDMODE_BLEND:
    alpha-blend (using the source alpha-channel and per-surface alpha)
    SDL_SRCCOLORKEY ignored.
  Source surface blend mode set to SDL_BLENDMODE_NONE:
    copy RGB.
    if SDL_SRCCOLORKEY set, only copy the pixels matching the
    RGB values of the source color key, ignoring alpha in the
    comparison.

RGB->RGBA:
  Source surface blend mode set to SDL_BLENDMODE_BLEND:
    alpha-blend (using the source per-surface alpha)
  Source surface blend mode set to SDL_BLENDMODE_NONE:
    copy RGB, set destination alpha to source per-surface alpha value.
  both:
    if SDL_SRCCOLORKEY set, only copy the pixels matching the
    source color key.

RGBA->RGBA:
  Source surface blend mode set to SDL_BLENDMODE_BLEND:
    alpha-blend (using the source alpha-channel and per-surface alpha)
    SDL_SRCCOLORKEY ignored.
  Source surface blend mode set to SDL_BLENDMODE_NONE:
    copy all of RGBA to the destination.
    if SDL_SRCCOLORKEY set, only copy the pixels matching the
    RGB values of the source color key, ignoring alpha in the
    comparison.

RGB->RGB:
  Source surface blend mode set to SDL_BLENDMODE_BLEND:
    alpha-blend (using the source per-surface alpha)
  Source surface blend mode set to SDL_BLENDMODE_NONE:
    copy RGB.
  both:
    if SDL_SRCCOLORKEY set, only copy the pixels matching the
    source color key.

You should call SDL_BlitSurface() unless you know exactly how SDL blitting works internally and how to use the other blit functions.

Definition at line 493 of file SDL_surface.h.

SDL_DONTFREE

#define SDL_DONTFREE   0x00000004

Surface is referenced internally

Definition at line 55 of file SDL_surface.h.

SDL_LoadBMP

#define SDL_LoadBMP

(

file

)

SDL_LoadBMP_RW(SDL_RWFromFile(file, "rb"), 1)

Load a surface from a file.

Convenience macro.

Definition at line 203 of file SDL_surface.h.

SDL_MUSTLOCK

#define SDL_MUSTLOCK

(

S

)

(((S)->flags & SDL_RLEACCEL) != 0)

Evaluates to true if the surface needs to be locked before access.

Definition at line 62 of file SDL_surface.h.

SDL_PREALLOC

#define SDL_PREALLOC   0x00000001

Surface uses preallocated memory

Definition at line 53 of file SDL_surface.h.

SDL_RLEACCEL

#define SDL_RLEACCEL   0x00000002

Surface is RLE encoded

Definition at line 54 of file SDL_surface.h.

SDL_SaveBMP

#define SDL_SaveBMP	(		surface,
			file
	)		SDL_SaveBMP_RW(surface, SDL_RWFromFile(file, "wb"), 1)

Save a surface to a file.

Convenience macro.

Definition at line 226 of file SDL_surface.h.

SDL_SIMD_ALIGNED

#define SDL_SIMD_ALIGNED   0x00000008

Surface uses aligned memory

Definition at line 56 of file SDL_surface.h.

SDL_SWSURFACE

#define SDL_SWSURFACE   0

Just here for compatibility

Definition at line 52 of file SDL_surface.h.

Typedef Documentation

SDL_blit

typedef int( * SDL_blit) (struct SDL_Surface *src, SDL_Rect *srcrect, struct SDL_Surface *dst, SDL_Rect *dstrect)

The type of function used for surface blitting functions.

Definition at line 100 of file SDL_surface.h.

Enumeration Type Documentation

SDL_YUV_CONVERSION_MODE

enum SDL_YUV_CONVERSION_MODE

The formula used for converting between YUV and RGB.

Enumerator
SDL_YUV_CONVERSION_JPEG	Full range JPEG
SDL_YUV_CONVERSION_BT601	BT.601 (the default)
SDL_YUV_CONVERSION_BT709	BT.709
SDL_YUV_CONVERSION_AUTOMATIC	BT.601 for SD content, BT.709 for HD content

Definition at line 106 of file SDL_surface.h.

{
    SDL_YUV_CONVERSION_JPEG,        /**< Full range JPEG */
    SDL_YUV_CONVERSION_BT601,       /**< BT.601 (the default) */
    SDL_YUV_CONVERSION_BT709,       /**< BT.709 */
    SDL_YUV_CONVERSION_AUTOMATIC    /**< BT.601 for SD content, BT.709 for HD content */
} SDL_YUV_CONVERSION_MODE;

Function Documentation

SDL_ConvertPixels()

int SDL_ConvertPixels	(	int	width,
		int	height,
		Uint32	src_format,
		const void *	src,
		int	src_pitch,
		Uint32	dst_format,
		void *	dst,
		int	dst_pitch
	)

Copy a block of pixels of one format to another format.

Returns

0 on success, or -1 if there was an error

Definition at line 1267 of file SDL_surface.c.

{
    SDL_Surface src_surface, dst_surface;
    SDL_PixelFormat src_fmt, dst_fmt;
    SDL_BlitMap src_blitmap, dst_blitmap;
    SDL_Rect rect;
    void *nonconst_src = (void *) src;
    int ret;
 
    /* Check to make sure we are blitting somewhere, so we don't crash */
    if (!dst) {
        return SDL_InvalidParamError("dst");
    }
    if (!dst_pitch) {
        return SDL_InvalidParamError("dst_pitch");
    }
 
#if SDL_HAVE_YUV
    if (SDL_ISPIXELFORMAT_FOURCC(src_format) && SDL_ISPIXELFORMAT_FOURCC(dst_format)) {
        return SDL_ConvertPixels_YUV_to_YUV(width, height, src_format, src, src_pitch, dst_format, dst, dst_pitch);
    } else if (SDL_ISPIXELFORMAT_FOURCC(src_format)) {
        return SDL_ConvertPixels_YUV_to_RGB(width, height, src_format, src, src_pitch, dst_format, dst, dst_pitch);
    } else if (SDL_ISPIXELFORMAT_FOURCC(dst_format)) {
        return SDL_ConvertPixels_RGB_to_YUV(width, height, src_format, src, src_pitch, dst_format, dst, dst_pitch);
    }
#else
    if (SDL_ISPIXELFORMAT_FOURCC(src_format) || SDL_ISPIXELFORMAT_FOURCC(dst_format)) {
        SDL_SetError("SDL not built with YUV support");
        return -1;
    }
#endif
 
    /* Fast path for same format copy */
    if (src_format == dst_format) {
        int i;
        const int bpp = SDL_BYTESPERPIXEL(src_format);
        width *= bpp;
        for (i = height; i--;) {
            SDL_memcpy(dst, src, width);
            src = (const Uint8*)src + src_pitch;
            dst = (Uint8*)dst + dst_pitch;
        }
        return 0;
    }
 
    if (!SDL_CreateSurfaceOnStack(width, height, src_format, nonconst_src,
                                  src_pitch,
                                  &src_surface, &src_fmt, &src_blitmap)) {
        return -1;
    }
    if (!SDL_CreateSurfaceOnStack(width, height, dst_format, dst, dst_pitch,
                                  &dst_surface, &dst_fmt, &dst_blitmap)) {
        return -1;
    }
 
    /* Set up the rect and go! */
    rect.x = 0;
    rect.y = 0;
    rect.w = width;
    rect.h = height;
    ret = SDL_LowerBlit(&src_surface, &rect, &dst_surface, &rect);
 
    /* Free blitmap reference, after blitting between stack'ed surfaces */
    SDL_InvalidateMap(src_surface.map);
 
    return ret;
}

References bpp, SDL_Rect::h, i, SDL_Surface::map, rect, SDL_BYTESPERPIXEL, SDL_ConvertPixels_RGB_to_YUV(), SDL_ConvertPixels_YUV_to_RGB(), SDL_ConvertPixels_YUV_to_YUV(), SDL_CreateSurfaceOnStack(), SDL_InvalidateMap(), SDL_InvalidParamError, SDL_ISPIXELFORMAT_FOURCC, SDL_LowerBlit(), SDL_memcpy, SDL_SetError, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

SDL_ConvertSurface()

SDL_Surface* SDL_ConvertSurface	(	SDL_Surface *	src,
		const SDL_PixelFormat *	fmt,
		Uint32	flags
	)

Creates a new surface of the specified format, and then copies and maps the given surface to it so the blit of the converted surface will be as fast as possible. If this function fails, it returns NULL.

The flags parameter is passed to SDL_CreateRGBSurface() and has those semantics. You can also pass SDL_RLEACCEL in the flags parameter and SDL will try to RLE accelerate colorkey and alpha blits in the resulting surface.

Definition at line 979 of file SDL_surface.c.

{
    SDL_Surface *convert;
    Uint32 copy_flags;
    SDL_Color copy_color;
    SDL_Rect bounds;
    int ret;
    SDL_bool palette_ck_transform = SDL_FALSE;
    int palette_ck_value = 0;
    SDL_bool palette_has_alpha = SDL_FALSE;
    Uint8 *palette_saved_alpha = NULL;
 
    if (!surface) {
        SDL_InvalidParamError("surface");
        return NULL;
    }
    if (!format) {
        SDL_InvalidParamError("format");
        return NULL;
    }
 
    /* Check for empty destination palette! (results in empty image) */
    if (format->palette != NULL) {
        int i;
        for (i = 0; i < format->palette->ncolors; ++i) {
            if ((format->palette->colors[i].r != 0xFF) ||
                (format->palette->colors[i].g != 0xFF) ||
                (format->palette->colors[i].b != 0xFF))
                break;
        }
        if (i == format->palette->ncolors) {
            SDL_SetError("Empty destination palette");
            return (NULL);
        }
    }
 
    /* Create a new surface with the desired format */
    convert = SDL_CreateRGBSurface(flags, surface->w, surface->h,
                                   format->BitsPerPixel, format->Rmask,
                                   format->Gmask, format->Bmask,
                                   format->Amask);
    if (convert == NULL) {
        return (NULL);
    }
 
    /* Copy the palette if any */
    if (format->palette && convert->format->palette) {
        SDL_memcpy(convert->format->palette->colors,
                   format->palette->colors,
                   format->palette->ncolors * sizeof(SDL_Color));
        convert->format->palette->ncolors = format->palette->ncolors;
    }
 
    /* Save the original copy flags */
    copy_flags = surface->map->info.flags;
    copy_color.r = surface->map->info.r;
    copy_color.g = surface->map->info.g;
    copy_color.b = surface->map->info.b;
    copy_color.a = surface->map->info.a;
    surface->map->info.r = 0xFF;
    surface->map->info.g = 0xFF;
    surface->map->info.b = 0xFF;
    surface->map->info.a = 0xFF;
    surface->map->info.flags = (copy_flags & (SDL_COPY_RLE_COLORKEY | SDL_COPY_RLE_ALPHAKEY));
    SDL_InvalidateMap(surface->map);
 
    /* Copy over the image data */
    bounds.x = 0;
    bounds.y = 0;
    bounds.w = surface->w;
    bounds.h = surface->h;
 
    /* Source surface has a palette with no real alpha (0 or OPAQUE).
     * Destination format has alpha.
     * -> set alpha channel to be opaque */
    if (surface->format->palette && format->Amask) {
        SDL_bool set_opaque = SDL_FALSE;
 
        SDL_bool is_opaque, has_alpha_channel;
        SDL_DetectPalette(surface->format->palette, &is_opaque, &has_alpha_channel);
 
        if (is_opaque) {
            if (!has_alpha_channel) {
                set_opaque = SDL_TRUE;
            }
        } else {
            palette_has_alpha = SDL_TRUE;
        }
 
        /* Set opaque and backup palette alpha values */
        if (set_opaque) {
            int i;
            palette_saved_alpha = SDL_stack_alloc(Uint8, surface->format->palette->ncolors);
            for (i = 0; i < surface->format->palette->ncolors; i++) {
                palette_saved_alpha[i] = surface->format->palette->colors[i].a;
                surface->format->palette->colors[i].a = SDL_ALPHA_OPAQUE;
            }
        }
    }
 
    /* Transform colorkey to alpha. for cases where source palette has duplicate values, and colorkey is one of them */
    if (copy_flags & SDL_COPY_COLORKEY) {
        if (surface->format->palette && !format->palette) {
            palette_ck_transform = SDL_TRUE;
            palette_has_alpha = SDL_TRUE;
            palette_ck_value = surface->format->palette->colors[surface->map->info.colorkey].a;
            surface->format->palette->colors[surface->map->info.colorkey].a = SDL_ALPHA_TRANSPARENT;
        }
    }
 
    ret = SDL_LowerBlit(surface, &bounds, convert, &bounds);
 
    /* Restore colorkey alpha value */
    if (palette_ck_transform) {
        surface->format->palette->colors[surface->map->info.colorkey].a = palette_ck_value;
    }
 
    /* Restore palette alpha values */
    if (palette_saved_alpha) {
        int i;
        for (i = 0; i < surface->format->palette->ncolors; i++) {
            surface->format->palette->colors[i].a = palette_saved_alpha[i];
        }
        SDL_stack_free(palette_saved_alpha);
    }
 
    /* Clean up the original surface, and update converted surface */
    convert->map->info.r = copy_color.r;
    convert->map->info.g = copy_color.g;
    convert->map->info.b = copy_color.b;
    convert->map->info.a = copy_color.a;
    convert->map->info.flags =
        (copy_flags &
         ~(SDL_COPY_COLORKEY | SDL_COPY_BLEND
           | SDL_COPY_RLE_DESIRED | SDL_COPY_RLE_COLORKEY |
           SDL_COPY_RLE_ALPHAKEY));
    surface->map->info.r = copy_color.r;
    surface->map->info.g = copy_color.g;
    surface->map->info.b = copy_color.b;
    surface->map->info.a = copy_color.a;
    surface->map->info.flags = copy_flags;
    SDL_InvalidateMap(surface->map);
 
    /* SDL_LowerBlit failed, and so the conversion */
    if (ret < 0) {
        SDL_FreeSurface(convert);
        return NULL;
    }
 
    if (copy_flags & SDL_COPY_COLORKEY) {
        SDL_bool set_colorkey_by_color = SDL_FALSE;
        SDL_bool convert_colorkey = SDL_TRUE;
 
        if (surface->format->palette) {
            if (format->palette &&
                surface->format->palette->ncolors <= format->palette->ncolors &&
                (SDL_memcmp(surface->format->palette->colors, format->palette->colors,
                  surface->format->palette->ncolors * sizeof(SDL_Color)) == 0)) {
                /* The palette is identical, just set the same colorkey */
                SDL_SetColorKey(convert, 1, surface->map->info.colorkey);
            } else if (!format->palette) {
                if (format->Amask) {
                    /* No need to add the colorkey, transparency is in the alpha channel*/
                } else {
                    /* Only set the colorkey information */
                    set_colorkey_by_color = SDL_TRUE;
                    convert_colorkey = SDL_FALSE;
                }
            } else {
                set_colorkey_by_color = SDL_TRUE;
            }
        } else {
            set_colorkey_by_color = SDL_TRUE;
        }
 
        if (set_colorkey_by_color) {
            SDL_Surface *tmp;
            SDL_Surface *tmp2;
            int converted_colorkey = 0;
 
            /* Create a dummy surface to get the colorkey converted */
            tmp = SDL_CreateRGBSurface(0, 1, 1,
                                   surface->format->BitsPerPixel, surface->format->Rmask,
                                   surface->format->Gmask, surface->format->Bmask,
                                   surface->format->Amask);
 
            /* Share the palette, if any */
            if (surface->format->palette) {
                SDL_SetSurfacePalette(tmp, surface->format->palette);
            }
 
            SDL_FillRect(tmp, NULL, surface->map->info.colorkey);
 
            tmp->map->info.flags &= ~SDL_COPY_COLORKEY;
 
            /* Convertion of the colorkey */
            tmp2 = SDL_ConvertSurface(tmp, format, 0);
 
            /* Get the converted colorkey */
            SDL_memcpy(&converted_colorkey, tmp2->pixels, tmp2->format->BytesPerPixel);
 
            SDL_FreeSurface(tmp);
            SDL_FreeSurface(tmp2);
 
            /* Set the converted colorkey on the new surface */
            SDL_SetColorKey(convert, 1, converted_colorkey);
 
            /* This is needed when converting for 3D texture upload */
            if (convert_colorkey) {
                SDL_ConvertColorkeyToAlpha(convert, SDL_TRUE);
            }
        }
    }
    SDL_SetClipRect(convert, &surface->clip_rect);
 
    /* Enable alpha blending by default if the new surface has an
     * alpha channel or alpha modulation */
    if ((surface->format->Amask && format->Amask) ||
        (palette_has_alpha && format->Amask) ||
        (copy_flags & SDL_COPY_MODULATE_ALPHA)) {
        SDL_SetSurfaceBlendMode(convert, SDL_BLENDMODE_BLEND);
    }
    if ((copy_flags & SDL_COPY_RLE_DESIRED) || (flags & SDL_RLEACCEL)) {
        SDL_SetSurfaceRLE(convert, SDL_RLEACCEL);
    }
 
    /* We're ready to go! */
    return (convert);
}

References SDL_Color::a, SDL_BlitInfo::a, SDL_Color::b, SDL_BlitInfo::b, SDL_PixelFormat::BytesPerPixel, SDL_Surface::clip_rect, SDL_BlitInfo::colorkey, SDL_Palette::colors, SDL_BlitInfo::flags, SDL_Surface::format, SDL_Color::g, SDL_BlitInfo::g, SDL_Rect::h, i, SDL_BlitMap::info, SDL_Surface::map, SDL_Palette::ncolors, NULL, SDL_PixelFormat::palette, SDL_Surface::pixels, SDL_Color::r, SDL_BlitInfo::r, SDL_ALPHA_OPAQUE, SDL_ALPHA_TRANSPARENT, SDL_BLENDMODE_BLEND, SDL_ConvertColorkeyToAlpha(), SDL_ConvertSurface(), SDL_COPY_BLEND, SDL_COPY_COLORKEY, SDL_COPY_MODULATE_ALPHA, SDL_COPY_RLE_ALPHAKEY, SDL_COPY_RLE_COLORKEY, SDL_COPY_RLE_DESIRED, SDL_CreateRGBSurface(), SDL_DetectPalette(), SDL_FALSE, SDL_FillRect, SDL_FreeSurface(), SDL_InvalidateMap(), SDL_InvalidParamError, SDL_LowerBlit(), SDL_memcmp, SDL_memcpy, SDL_RLEACCEL, SDL_SetClipRect(), SDL_SetColorKey(), SDL_SetError, SDL_SetSurfaceBlendMode(), SDL_SetSurfacePalette(), SDL_SetSurfaceRLE(), SDL_stack_alloc, SDL_stack_free, SDL_TRUE, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

Referenced by SDL_ConvertSurface(), SDL_ConvertSurfaceFormat(), and SDL_DuplicateSurface().

SDL_ConvertSurfaceFormat()

SDL_Surface* SDL_ConvertSurfaceFormat	(	SDL_Surface *	src,
		Uint32	pixel_format,
		Uint32	flags
	)

Definition at line 1211 of file SDL_surface.c.

{
    SDL_PixelFormat *fmt;
    SDL_Surface *convert = NULL;
 
    fmt = SDL_AllocFormat(pixel_format);
    if (fmt) {
        convert = SDL_ConvertSurface(surface, fmt, flags);
        SDL_FreeFormat(fmt);
    }
    return convert;
}

References NULL, pixel_format, SDL_AllocFormat, SDL_ConvertSurface(), and SDL_FreeFormat.

SDL_CreateRGBSurface()

SDL_Surface* SDL_CreateRGBSurface	(	Uint32	flags,
		int	width,
		int	height,
		int	depth,
		Uint32	Rmask,
		Uint32	Gmask,
		Uint32	Bmask,
		Uint32	Amask
	)

Allocate and free an RGB surface.

If the depth is 4 or 8 bits, an empty palette is allocated for the surface. If the depth is greater than 8 bits, the pixel format is set using the flags '[RGB]mask'.

If the function runs out of memory, it will return NULL.

Parameters

flags	The flags are obsolete and should be set to 0.
width	The width in pixels of the surface to create.
height	The height in pixels of the surface to create.
depth	The depth in bits of the surface to create.
Rmask	The red mask of the surface to create.
Gmask	The green mask of the surface to create.
Bmask	The blue mask of the surface to create.
Amask	The alpha mask of the surface to create.

Definition at line 155 of file SDL_surface.c.

{
    Uint32 format;
 
    /* Get the pixel format */
    format = SDL_MasksToPixelFormatEnum(depth, Rmask, Gmask, Bmask, Amask);
    if (format == SDL_PIXELFORMAT_UNKNOWN) {
        SDL_SetError("Unknown pixel format");
        return NULL;
    }
 
    return SDL_CreateRGBSurfaceWithFormat(flags, width, height, depth, format);
}

References NULL, SDL_CreateRGBSurfaceWithFormat(), SDL_MasksToPixelFormatEnum, SDL_PIXELFORMAT_UNKNOWN, and SDL_SetError.

Referenced by SDL_ConvertSurface(), and SDL_CreateRGBSurfaceFrom().

SDL_CreateRGBSurfaceFrom()

SDL_Surface* SDL_CreateRGBSurfaceFrom	(	void *	pixels,
		int	width,
		int	height,
		int	depth,
		int	pitch,
		Uint32	Rmask,
		Uint32	Gmask,
		Uint32	Bmask,
		Uint32	Amask
	)

Definition at line 175 of file SDL_surface.c.

{
    SDL_Surface *surface;
 
    surface = SDL_CreateRGBSurface(0, 0, 0, depth, Rmask, Gmask, Bmask, Amask);
    if (surface != NULL) {
        surface->flags |= SDL_PREALLOC;
        surface->pixels = pixels;
        surface->w = width;
        surface->h = height;
        surface->pitch = pitch;
        SDL_SetClipRect(surface, NULL);
    }
    return surface;
}

References NULL, SDL_CreateRGBSurface(), SDL_PREALLOC, and SDL_SetClipRect().

SDL_CreateRGBSurfaceWithFormat()

SDL_Surface* SDL_CreateRGBSurfaceWithFormat	(	Uint32	flags,
		int	width,
		int	height,
		int	depth,
		Uint32	format
	)

Definition at line 59 of file SDL_surface.c.

{
    Sint64 pitch;
    SDL_Surface *surface;
 
    /* The flags are no longer used, make the compiler happy */
    (void)flags;
 
    pitch = SDL_CalculatePitch(format, width);
    if (pitch < 0 || pitch > SDL_MAX_SINT32) {
        /* Overflow... */
        SDL_OutOfMemory();
        return NULL;
    }
 
    /* Allocate the surface */
    surface = (SDL_Surface *) SDL_calloc(1, sizeof(*surface));
    if (surface == NULL) {
        SDL_OutOfMemory();
        return NULL;
    }
 
    surface->format = SDL_AllocFormat(format);
    if (!surface->format) {
        SDL_FreeSurface(surface);
        return NULL;
    }
    surface->w = width;
    surface->h = height;
    surface->pitch = (int)pitch;
    SDL_SetClipRect(surface, NULL);
 
    if (SDL_ISPIXELFORMAT_INDEXED(surface->format->format)) {
        SDL_Palette *palette =
            SDL_AllocPalette((1 << surface->format->BitsPerPixel));
        if (!palette) {
            SDL_FreeSurface(surface);
            return NULL;
        }
        if (palette->ncolors == 2) {
            /* Create a black and white bitmap palette */
            palette->colors[0].r = 0xFF;
            palette->colors[0].g = 0xFF;
            palette->colors[0].b = 0xFF;
            palette->colors[1].r = 0x00;
            palette->colors[1].g = 0x00;
            palette->colors[1].b = 0x00;
        }
        SDL_SetSurfacePalette(surface, palette);
        SDL_FreePalette(palette);
    }
 
    /* Get the pixels */
    if (surface->w && surface->h) {
        /* Assumptions checked in surface_size_assumptions assert above */
        Sint64 size = ((Sint64)surface->h * surface->pitch);
        if (size < 0 || size > SDL_MAX_SINT32) {
            /* Overflow... */
            SDL_FreeSurface(surface);
            SDL_OutOfMemory();
            return NULL;
        }
 
        surface->pixels = SDL_SIMDAlloc((size_t)size);
        if (!surface->pixels) {
            SDL_FreeSurface(surface);
            SDL_OutOfMemory();
            return NULL;
        }
        surface->flags |= SDL_SIMD_ALIGNED;
        /* This is important for bitmaps */
        SDL_memset(surface->pixels, 0, surface->h * surface->pitch);
    }
 
    /* Allocate an empty mapping */
    surface->map = SDL_AllocBlitMap();
    if (!surface->map) {
        SDL_FreeSurface(surface);
        return NULL;
    }
 
    /* By default surface with an alpha mask are set up for blending */
    if (surface->format->Amask) {
        SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);
    }
 
    /* The surface is ready to go */
    surface->refcount = 1;
    return surface;
}

References SDL_Color::b, SDL_Palette::colors, SDL_Color::g, int(), SDL_Palette::ncolors, NULL, SDL_Color::r, SDL_AllocBlitMap(), SDL_AllocFormat, SDL_AllocPalette, SDL_BLENDMODE_BLEND, SDL_CalculatePitch(), SDL_calloc, SDL_FreePalette, SDL_FreeSurface(), SDL_ISPIXELFORMAT_INDEXED, SDL_MAX_SINT32, SDL_memset, SDL_OutOfMemory, SDL_SetClipRect(), SDL_SetSurfaceBlendMode(), SDL_SetSurfacePalette(), SDL_SIMD_ALIGNED, SDL_SIMDAlloc, and void.

Referenced by SDL_CreateRGBSurface(), and SDL_CreateRGBSurfaceWithFormatFrom().

SDL_CreateRGBSurfaceWithFormatFrom()

SDL_Surface* SDL_CreateRGBSurfaceWithFormatFrom	(	void *	pixels,
		int	width,
		int	height,
		int	depth,
		int	pitch,
		Uint32	format
	)

Definition at line 199 of file SDL_surface.c.

{
    SDL_Surface *surface;
 
    surface = SDL_CreateRGBSurfaceWithFormat(0, 0, 0, depth, format);
    if (surface != NULL) {
        surface->flags |= SDL_PREALLOC;
        surface->pixels = pixels;
        surface->w = width;
        surface->h = height;
        surface->pitch = pitch;
        SDL_SetClipRect(surface, NULL);
    }
    return surface;
}

References NULL, SDL_CreateRGBSurfaceWithFormat(), SDL_PREALLOC, and SDL_SetClipRect().

SDL_DuplicateSurface()

SDL_Surface* SDL_DuplicateSurface

(

SDL_Surface *

surface

)

Definition at line 970 of file SDL_surface.c.

{
    return SDL_ConvertSurface(surface, surface->format, surface->flags);
}

References SDL_ConvertSurface().

SDL_FillRect()

int SDL_FillRect	(	SDL_Surface *	dst,
		const SDL_Rect *	rect,
		Uint32	color
	)

Performs a fast fill of the given rectangle with color.

If rect is NULL, the whole surface will be filled with color.

The color should be a pixel of the format used by the surface, and can be generated by the SDL_MapRGB() function.

Returns

0 on success, or -1 on error.

Definition at line 238 of file SDL_fillrect.c.

{
    if (!dst) {
        return SDL_SetError("Passed NULL destination surface");
    }
 
    /* If 'rect' == NULL, then fill the whole surface */
    if (!rect) {
        rect = &dst->clip_rect;
        /* Don't attempt to fill if the surface's clip_rect is empty */
        if (SDL_RectEmpty(rect)) {
            return 0;
        }
    }
 
    return SDL_FillRects(dst, rect, 1, color);
}

References rect, SDL_FillRects(), SDL_RectEmpty(), and SDL_SetError.

SDL_FillRects()

int SDL_FillRects	(	SDL_Surface *	dst,
		const SDL_Rect *	rects,
		int	count,
		Uint32	color
	)

Definition at line 299 of file SDL_fillrect.c.

{
    SDL_Rect clipped;
    Uint8 *pixels;
    const SDL_Rect* rect;
    void (*fill_function)(Uint8 * pixels, int pitch, Uint32 color, int w, int h) = NULL;
    int i;
 
    if (!dst) {
        return SDL_SetError("Passed NULL destination surface");
    }
 
    /* This function doesn't work on surfaces < 8 bpp */
    if (dst->format->BitsPerPixel < 8) {
        return SDL_SetError("SDL_FillRect(): Unsupported surface format");
    }
 
    /* Nothing to do */
    if (dst->w == 0 || dst->h == 0) {
        return 0;
    }
 
    /* Perform software fill */
    if (!dst->pixels) {
        return SDL_SetError("SDL_FillRect(): You must lock the surface");
    }
 
    if (!rects) {
        return SDL_SetError("SDL_FillRects() passed NULL rects");
    }
 
#if SDL_ARM_NEON_BLITTERS
    if (SDL_HasNEON() && dst->format->BytesPerPixel != 3 && fill_function == NULL) {
        switch (dst->format->BytesPerPixel) {
        case 1:
            fill_function = fill_8_neon;
            break;
        case 2:
            fill_function = fill_16_neon;
            break;
        case 4:
            fill_function = fill_32_neon;
            break;
        }
    }
#endif
#if SDL_ARM_SIMD_BLITTERS
    if (SDL_HasARMSIMD() && dst->format->BytesPerPixel != 3 && fill_function == NULL) {
        switch (dst->format->BytesPerPixel) {
        case 1:
            fill_function = fill_8_simd;
            break;
        case 2:
            fill_function = fill_16_simd;
            break;
        case 4:
            fill_function = fill_32_simd;
            break;
        }
    }
#endif
 
    if (fill_function == NULL) {
        switch (dst->format->BytesPerPixel) {
        case 1:
            {
                color |= (color << 8);
                color |= (color << 16);
#ifdef __SSE__
                if (SDL_HasSSE()) {
                    fill_function = SDL_FillRect1SSE;
                    break;
                }
#endif
                fill_function = SDL_FillRect1;
                break;
            }
 
        case 2:
            {
                color |= (color << 16);
#ifdef __SSE__
                if (SDL_HasSSE()) {
                    fill_function = SDL_FillRect2SSE;
                    break;
                }
#endif
                fill_function = SDL_FillRect2;
                break;
            }
 
        case 3:
            /* 24-bit RGB is a slow path, at least for now. */
            {
                fill_function = SDL_FillRect3;
                break;
            }
 
        case 4:
            {
#ifdef __SSE__
                if (SDL_HasSSE()) {
                    fill_function = SDL_FillRect4SSE;
                    break;
                }
#endif
                fill_function = SDL_FillRect4;
                break;
            }
 
        default:
            return SDL_SetError("Unsupported pixel format");
        }
    }
 
    for (i = 0; i < count; ++i) {
        rect = &rects[i];
        /* Perform clipping */
        if (!SDL_IntersectRect(rect, &dst->clip_rect, &clipped)) {
            continue;
        }
        rect = &clipped;
 
        pixels = (Uint8 *) dst->pixels + rect->y * dst->pitch +
                                         rect->x * dst->format->BytesPerPixel;
 
        fill_function(pixels, dst->pitch, color, rect->w, rect->h);
    }
 
    /* We're done! */
    return 0;
}

References SDL_Rect::h, i, NULL, rect, SDL_FillRect1(), SDL_FillRect2(), SDL_FillRect3(), SDL_FillRect4(), SDL_HasARMSIMD, SDL_HasNEON, SDL_HasSSE, SDL_IntersectRect, SDL_SetError, void, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

Referenced by SDL_FillRect().

SDL_FreeSurface()

void SDL_FreeSurface

(

SDL_Surface *

surface

)

Definition at line 1341 of file SDL_surface.c.

{
    if (surface == NULL) {
        return;
    }
    if (surface->flags & SDL_DONTFREE) {
        return;
    }
    SDL_InvalidateMap(surface->map);
 
    SDL_InvalidateAllBlitMap(surface);
 
    if (--surface->refcount > 0) {
        return;
    }
    while (surface->locked > 0) {
        SDL_UnlockSurface(surface);
    }
#if SDL_HAVE_RLE
    if (surface->flags & SDL_RLEACCEL) {
        SDL_UnRLESurface(surface, 0);
    }
#endif
    if (surface->format) {
        SDL_SetSurfacePalette(surface, NULL);
        SDL_FreeFormat(surface->format);
        surface->format = NULL;
    }
    if (surface->flags & SDL_PREALLOC) {
        /* Don't free */
    } else if (surface->flags & SDL_SIMD_ALIGNED) {
        /* Free aligned */
        SDL_SIMDFree(surface->pixels);
    } else {
        /* Normal */
        SDL_free(surface->pixels);
    }
    if (surface->map) {
        SDL_FreeBlitMap(surface->map);
    }
    SDL_free(surface);
}

References NULL, SDL_DONTFREE, SDL_free, SDL_FreeBlitMap(), SDL_FreeFormat, SDL_InvalidateAllBlitMap(), SDL_InvalidateMap(), SDL_PREALLOC, SDL_RLEACCEL, SDL_SetSurfacePalette(), SDL_SIMD_ALIGNED, SDL_SIMDFree, SDL_UnlockSurface(), and SDL_UnRLESurface().

Referenced by SDL_ConvertSurface(), and SDL_CreateRGBSurfaceWithFormat().

SDL_GetClipRect()

void SDL_GetClipRect	(	SDL_Surface *	surface,
		SDL_Rect *	rect
	)

Gets the clipping rectangle for the destination surface in a blit.

rect must be a pointer to a valid rectangle which will be filled with the correct values.

Definition at line 605 of file SDL_surface.c.

{
    if (surface && rect) {
        *rect = surface->clip_rect;
    }
}

References rect.

SDL_GetColorKey()

int SDL_GetColorKey	(	SDL_Surface *	surface,
		Uint32 *	key
	)

Gets the color key (transparent pixel) in a blittable surface.

Parameters

surface	The surface to update
key	A pointer filled in with the transparent pixel in the native surface format

Returns

0 on success, or -1 if the surface is not valid or colorkey is not enabled.

Definition at line 312 of file SDL_surface.c.

{
    if (!surface) {
        return SDL_InvalidParamError("surface");
    }
 
    if (!(surface->map->info.flags & SDL_COPY_COLORKEY)) {
        return SDL_SetError("Surface doesn't have a colorkey");
    }
 
    if (key) {
        *key = surface->map->info.colorkey;
    }
    return 0;
}

References SDL_COPY_COLORKEY, SDL_InvalidParamError, and SDL_SetError.

SDL_GetSurfaceAlphaMod()

int SDL_GetSurfaceAlphaMod	(	SDL_Surface *	surface,
		Uint8 *	alpha
	)

Get the additional alpha value used in blit operations.

Parameters

surface	The surface to query.
alpha	A pointer filled in with the current alpha value.

Returns

0 on success, or -1 if the surface is not valid.

See also

SDL_SetSurfaceAlphaMod()

Definition at line 496 of file SDL_surface.c.

{
    if (!surface) {
        return -1;
    }
 
    if (alpha) {
        *alpha = surface->map->info.a;
    }
    return 0;
}

SDL_GetSurfaceBlendMode()

int SDL_GetSurfaceBlendMode	(	SDL_Surface *	surface,
		SDL_BlendMode *	blendMode
	)

Get the blend mode used for blit operations.

Parameters

surface	The surface to query.
blendMode	A pointer filled in with the current blend mode.

Returns

0 on success, or -1 if the surface is not valid.

See also

SDL_SetSurfaceBlendMode()

Definition at line 549 of file SDL_surface.c.

{
    if (!surface) {
        return -1;
    }
 
    if (!blendMode) {
        return 0;
    }
 
    switch (surface->map->
            info.flags & (SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD | SDL_COPY_MUL)) {
    case SDL_COPY_BLEND:
        *blendMode = SDL_BLENDMODE_BLEND;
        break;
    case SDL_COPY_ADD:
        *blendMode = SDL_BLENDMODE_ADD;
        break;
    case SDL_COPY_MOD:
        *blendMode = SDL_BLENDMODE_MOD;
        break;
    case SDL_COPY_MUL:
        *blendMode = SDL_BLENDMODE_MUL;
        break;
    default:
        *blendMode = SDL_BLENDMODE_NONE;
        break;
    }
    return 0;
}

References blendMode, SDL_BLENDMODE_ADD, SDL_BLENDMODE_BLEND, SDL_BLENDMODE_MOD, SDL_BLENDMODE_MUL, SDL_BLENDMODE_NONE, SDL_COPY_ADD, SDL_COPY_BLEND, SDL_COPY_MOD, and SDL_COPY_MUL.

SDL_GetSurfaceColorMod()

int SDL_GetSurfaceColorMod	(	SDL_Surface *	surface,
		Uint8 *	r,
		Uint8 *	g,
		Uint8 *	b
	)

Get the additional color value used in blit operations.

Parameters

surface	The surface to query.
r	A pointer filled in with the current red color value.
g	A pointer filled in with the current green color value.
b	A pointer filled in with the current blue color value.

Returns

0 on success, or -1 if the surface is not valid.

See also

SDL_SetSurfaceColorMod()

Definition at line 454 of file SDL_surface.c.

{
    if (!surface) {
        return -1;
    }
 
    if (r) {
        *r = surface->map->info.r;
    }
    if (g) {
        *g = surface->map->info.g;
    }
    if (b) {
        *b = surface->map->info.b;
    }
    return 0;
}

SDL_GetYUVConversionMode()

SDL_YUV_CONVERSION_MODE SDL_GetYUVConversionMode

(

void

)

Get the YUV conversion mode.

Definition at line 698 of file SDL_dynapi_procs.h.

References SDL_YUV_ConversionMode.

Referenced by SDL_GetYUVConversionModeForResolution().

SDL_GetYUVConversionModeForResolution()

SDL_YUV_CONVERSION_MODE SDL_GetYUVConversionModeForResolution	(	int	width,
		int	height
	)

Get the YUV conversion mode, returning the correct mode for the resolution when the current conversion mode is SDL_YUV_CONVERSION_AUTOMATIC.

Definition at line 46 of file SDL_yuv.c.

{
    SDL_YUV_CONVERSION_MODE mode = SDL_GetYUVConversionMode();
    if (mode == SDL_YUV_CONVERSION_AUTOMATIC) {
        if (height <= SDL_YUV_SD_THRESHOLD) {
            mode = SDL_YUV_CONVERSION_BT601;
        } else {
            mode = SDL_YUV_CONVERSION_BT709;
        }
    }
    return mode;
}

References SDL_GetYUVConversionMode(), SDL_YUV_CONVERSION_AUTOMATIC, SDL_YUV_CONVERSION_BT601, SDL_YUV_CONVERSION_BT709, and SDL_YUV_SD_THRESHOLD.

Referenced by GetYUVConversionType(), and SDL_ConvertPixels_ARGB8888_to_YUV().

SDL_HasColorKey()

SDL_bool SDL_HasColorKey

(

SDL_Surface *

surface

)

Returns whether the surface has a color key.

Returns

SDL_TRUE if the surface has a color key, or SDL_FALSE if the surface is NULL or has no color key

Definition at line 298 of file SDL_surface.c.

{
    if (!surface) {
        return SDL_FALSE;
    }
 
    if (!(surface->map->info.flags & SDL_COPY_COLORKEY)) {
        return SDL_FALSE;
    }
 
    return SDL_TRUE;
}

References SDL_COPY_COLORKEY, SDL_FALSE, and SDL_TRUE.

SDL_HasSurfaceRLE()

SDL_bool SDL_HasSurfaceRLE

(

SDL_Surface *

surface

)

Returns whether the surface is RLE enabled.

Returns

SDL_TRUE if the surface is RLE enabled, or SDL_FALSE if the surface is NULL or not RLE enabled

Definition at line 253 of file SDL_surface.c.

{
    if (!surface) {
        return SDL_FALSE;
    }
 
    if (!(surface->map->info.flags & SDL_COPY_RLE_DESIRED)) {
        return SDL_FALSE;
    }
 
    return SDL_TRUE;
}

References SDL_COPY_RLE_DESIRED, SDL_FALSE, and SDL_TRUE.

SDL_LoadBMP_RW()

SDL_Surface* SDL_LoadBMP_RW	(	SDL_RWops *	src,
		int	freesrc
	)

Load a surface from a seekable SDL data stream (memory or file).

If freesrc is non-zero, the stream will be closed after being read.

The new surface should be freed with SDL_FreeSurface().

Returns

the new surface, or NULL if there was an error.

Definition at line 172 of file SDL_bmp.c.

{
    SDL_bool was_error;
    Sint64 fp_offset = 0;
    int bmpPitch;
    int i, pad;
    SDL_Surface *surface;
    Uint32 Rmask = 0;
    Uint32 Gmask = 0;
    Uint32 Bmask = 0;
    Uint32 Amask = 0;
    SDL_Palette *palette;
    Uint8 *bits;
    Uint8 *top, *end;
    SDL_bool topDown;
    int ExpandBMP;
    SDL_bool haveRGBMasks = SDL_FALSE;
    SDL_bool haveAlphaMask = SDL_FALSE;
    SDL_bool correctAlpha = SDL_FALSE;
 
    /* The Win32 BMP file header (14 bytes) */
    char magic[2];
    /* Uint32 bfSize; */
    /* Uint16 bfReserved1; */
    /* Uint16 bfReserved2; */
    Uint32 bfOffBits;
 
    /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
    Uint32 biSize;
    Sint32 biWidth = 0;
    Sint32 biHeight = 0;
    /* Uint16 biPlanes; */
    Uint16 biBitCount = 0;
    Uint32 biCompression = 0;
    /* Uint32 biSizeImage; */
    /* Sint32 biXPelsPerMeter; */
    /* Sint32 biYPelsPerMeter; */
    Uint32 biClrUsed = 0;
    /* Uint32 biClrImportant; */
 
    /* Make sure we are passed a valid data source */
    surface = NULL;
    was_error = SDL_FALSE;
    if (src == NULL) {
        was_error = SDL_TRUE;
        goto done;
    }
 
    /* Read in the BMP file header */
    fp_offset = SDL_RWtell(src);
    SDL_ClearError();
    if (SDL_RWread(src, magic, 1, 2) != 2) {
        SDL_Error(SDL_EFREAD);
        was_error = SDL_TRUE;
        goto done;
    }
    if (SDL_strncmp(magic, "BM", 2) != 0) {
        SDL_SetError("File is not a Windows BMP file");
        was_error = SDL_TRUE;
        goto done;
    }
    /* bfSize      = */ SDL_ReadLE32(src);
    /* bfReserved1 = */ SDL_ReadLE16(src);
    /* bfReserved2 = */ SDL_ReadLE16(src);
    bfOffBits   = SDL_ReadLE32(src);
 
    /* Read the Win32 BITMAPINFOHEADER */
    biSize = SDL_ReadLE32(src);
    if (biSize == 12) {   /* really old BITMAPCOREHEADER */
        biWidth = (Uint32) SDL_ReadLE16(src);
        biHeight = (Uint32) SDL_ReadLE16(src);
        /* biPlanes = */ SDL_ReadLE16(src);
        biBitCount = SDL_ReadLE16(src);
        biCompression = BI_RGB;
        /* biSizeImage = 0; */
        /* biXPelsPerMeter = 0; */
        /* biYPelsPerMeter = 0; */
        biClrUsed = 0;
        /* biClrImportant = 0; */
    } else if (biSize >= 40) {  /* some version of BITMAPINFOHEADER */
        Uint32 headerSize;
        biWidth = SDL_ReadLE32(src);
        biHeight = SDL_ReadLE32(src);
        /* biPlanes = */ SDL_ReadLE16(src);
        biBitCount = SDL_ReadLE16(src);
        biCompression = SDL_ReadLE32(src);
        /* biSizeImage = */ SDL_ReadLE32(src);
        /* biXPelsPerMeter = */ SDL_ReadLE32(src);
        /* biYPelsPerMeter = */ SDL_ReadLE32(src);
        biClrUsed = SDL_ReadLE32(src);
        /* biClrImportant = */ SDL_ReadLE32(src);
 
        /* 64 == BITMAPCOREHEADER2, an incompatible OS/2 2.x extension. Skip this stuff for now. */
        if (biSize != 64) {
            /* This is complicated. If compression is BI_BITFIELDS, then
               we have 3 DWORDS that specify the RGB masks. This is either
               stored here in an BITMAPV2INFOHEADER (which only differs in
               that it adds these RGB masks) and biSize >= 52, or we've got
               these masks stored in the exact same place, but strictly
               speaking, this is the bmiColors field in BITMAPINFO immediately
               following the legacy v1 info header, just past biSize. */
            if (biCompression == BI_BITFIELDS) {
                haveRGBMasks = SDL_TRUE;
                Rmask = SDL_ReadLE32(src);
                Gmask = SDL_ReadLE32(src);
                Bmask = SDL_ReadLE32(src);
 
                /* ...v3 adds an alpha mask. */
                if (biSize >= 56) {  /* BITMAPV3INFOHEADER; adds alpha mask */
                    haveAlphaMask = SDL_TRUE;
                    Amask = SDL_ReadLE32(src);
                }
            } else {
                /* the mask fields are ignored for v2+ headers if not BI_BITFIELD. */
                if (biSize >= 52) {  /* BITMAPV2INFOHEADER; adds RGB masks */
                    /*Rmask = */ SDL_ReadLE32(src);
                    /*Gmask = */ SDL_ReadLE32(src);
                    /*Bmask = */ SDL_ReadLE32(src);
                }
                if (biSize >= 56) {  /* BITMAPV3INFOHEADER; adds alpha mask */
                    /*Amask = */ SDL_ReadLE32(src);
                }
            }
 
            /* Insert other fields here; Wikipedia and MSDN say we're up to
               v5 of this header, but we ignore those for now (they add gamma,
               color spaces, etc). Ignoring the weird OS/2 2.x format, we
               currently parse up to v3 correctly (hopefully!). */
        }
 
        /* skip any header bytes we didn't handle... */
        headerSize = (Uint32) (SDL_RWtell(src) - (fp_offset + 14));
        if (biSize > headerSize) {
            SDL_RWseek(src, (biSize - headerSize), RW_SEEK_CUR);
        }
    }
    if (biWidth <= 0 || biHeight == 0) {
        SDL_SetError("BMP file with bad dimensions (%dx%d)", biWidth, biHeight);
        was_error = SDL_TRUE;
        goto done;
    }
    if (biHeight < 0) {
        topDown = SDL_TRUE;
        biHeight = -biHeight;
    } else {
        topDown = SDL_FALSE;
    }
 
    /* Check for read error */
    if (SDL_strcmp(SDL_GetError(), "") != 0) {
        was_error = SDL_TRUE;
        goto done;
    }
 
    /* Expand 1 and 4 bit bitmaps to 8 bits per pixel */
    switch (biBitCount) {
    case 1:
    case 4:
        ExpandBMP = biBitCount;
        biBitCount = 8;
        break;
    case 0:
    case 2:
    case 3:
    case 5:
    case 6:
    case 7:
        SDL_SetError("%d-bpp BMP images are not supported", biBitCount);
        was_error = SDL_TRUE;
        goto done;
    default:
        ExpandBMP = 0;
        break;
    }
 
    /* RLE4 and RLE8 BMP compression is supported */
    switch (biCompression) {
    case BI_RGB:
        /* If there are no masks, use the defaults */
        SDL_assert(!haveRGBMasks);
        SDL_assert(!haveAlphaMask);
        /* Default values for the BMP format */
        switch (biBitCount) {
        case 15:
        case 16:
            Rmask = 0x7C00;
            Gmask = 0x03E0;
            Bmask = 0x001F;
            break;
        case 24:
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
            Rmask = 0x000000FF;
            Gmask = 0x0000FF00;
            Bmask = 0x00FF0000;
#else
            Rmask = 0x00FF0000;
            Gmask = 0x0000FF00;
            Bmask = 0x000000FF;
#endif
            break;
        case 32:
            /* We don't know if this has alpha channel or not */
            correctAlpha = SDL_TRUE;
            Amask = 0xFF000000;
            Rmask = 0x00FF0000;
            Gmask = 0x0000FF00;
            Bmask = 0x000000FF;
            break;
        default:
            break;
        }
        break;
 
    case BI_BITFIELDS:
        break;  /* we handled this in the info header. */
 
    default:
        break;
    }
 
    /* Create a compatible surface, note that the colors are RGB ordered */
    surface =
        SDL_CreateRGBSurface(0, biWidth, biHeight, biBitCount, Rmask, Gmask,
                             Bmask, Amask);
    if (surface == NULL) {
        was_error = SDL_TRUE;
        goto done;
    }
 
    /* Load the palette, if any */
    palette = (surface->format)->palette;
    if (palette) {
        if (SDL_RWseek(src, fp_offset+14+biSize, RW_SEEK_SET) < 0) {
            SDL_Error(SDL_EFSEEK);
            was_error = SDL_TRUE;
            goto done;
        }
 
        /*
        | guich: always use 1<<bpp b/c some bitmaps can bring wrong information
        | for colorsUsed
        */
        /* if (biClrUsed == 0) {  */
        biClrUsed = 1 << biBitCount;
        /* } */
        if (biSize == 12) {
            for (i = 0; i < (int) biClrUsed; ++i) {
                SDL_RWread(src, &palette->colors[i].b, 1, 1);
                SDL_RWread(src, &palette->colors[i].g, 1, 1);
                SDL_RWread(src, &palette->colors[i].r, 1, 1);
                palette->colors[i].a = SDL_ALPHA_OPAQUE;
            }
        } else {
            for (i = 0; i < (int) biClrUsed; ++i) {
                SDL_RWread(src, &palette->colors[i].b, 1, 1);
                SDL_RWread(src, &palette->colors[i].g, 1, 1);
                SDL_RWread(src, &palette->colors[i].r, 1, 1);
                SDL_RWread(src, &palette->colors[i].a, 1, 1);
 
                /* According to Microsoft documentation, the fourth element
                   is reserved and must be zero, so we shouldn't treat it as
                   alpha.
                */
                palette->colors[i].a = SDL_ALPHA_OPAQUE;
            }
        }
        palette->ncolors = biClrUsed;
    }
 
    /* Read the surface pixels.  Note that the bmp image is upside down */
    if (SDL_RWseek(src, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
        SDL_Error(SDL_EFSEEK);
        was_error = SDL_TRUE;
        goto done;
    }
    if ((biCompression == BI_RLE4) || (biCompression == BI_RLE8)) {
        was_error = (SDL_bool)readRlePixels(surface, src, biCompression == BI_RLE8);
        if (was_error) SDL_SetError("Error reading from BMP");
        goto done;
    }
    top = (Uint8 *)surface->pixels;
    end = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
    switch (ExpandBMP) {
    case 1:
        bmpPitch = (biWidth + 7) >> 3;
        pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
        break;
    case 4:
        bmpPitch = (biWidth + 1) >> 1;
        pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
        break;
    default:
        pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0);
        break;
    }
    if (topDown) {
        bits = top;
    } else {
        bits = end - surface->pitch;
    }
    while (bits >= top && bits < end) {
        switch (ExpandBMP) {
        case 1:
        case 4:{
                Uint8 pixel = 0;
                int shift = (8 - ExpandBMP);
                for (i = 0; i < surface->w; ++i) {
                    if (i % (8 / ExpandBMP) == 0) {
                        if (!SDL_RWread(src, &pixel, 1, 1)) {
                            SDL_SetError("Error reading from BMP");
                            was_error = SDL_TRUE;
                            goto done;
                        }
                    }
                    bits[i] = (pixel >> shift);
                    if (bits[i] >= biClrUsed) {
                        SDL_SetError("A BMP image contains a pixel with a color out of the palette");
                        was_error = SDL_TRUE;
                        goto done;
                    }
                    pixel <<= ExpandBMP;
                }
            }
            break;
 
        default:
            if (SDL_RWread(src, bits, 1, surface->pitch) != surface->pitch) {
                SDL_Error(SDL_EFREAD);
                was_error = SDL_TRUE;
                goto done;
            }
            if (biBitCount == 8 && palette && biClrUsed < (1u << biBitCount)) {
                for (i = 0; i < surface->w; ++i) {
                    if (bits[i] >= biClrUsed) {
                        SDL_SetError("A BMP image contains a pixel with a color out of the palette");
                        was_error = SDL_TRUE;
                        goto done;
                    }
                }
            }
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
            /* Byte-swap the pixels if needed. Note that the 24bpp
               case has already been taken care of above. */
            switch (biBitCount) {
            case 15:
            case 16:{
                    Uint16 *pix = (Uint16 *) bits;
                    for (i = 0; i < surface->w; i++)
                        pix[i] = SDL_Swap16(pix[i]);
                    break;
                }
 
            case 32:{
                    Uint32 *pix = (Uint32 *) bits;
                    for (i = 0; i < surface->w; i++)
                        pix[i] = SDL_Swap32(pix[i]);
                    break;
                }
            }
#endif
            break;
        }
        /* Skip padding bytes, ugh */
        if (pad) {
            Uint8 padbyte;
            for (i = 0; i < pad; ++i) {
                SDL_RWread(src, &padbyte, 1, 1);
            }
        }
        if (topDown) {
            bits += surface->pitch;
        } else {
            bits -= surface->pitch;
        }
    }
    if (correctAlpha) {
        CorrectAlphaChannel(surface);
    }
  done:
    if (was_error) {
        if (src) {
            SDL_RWseek(src, fp_offset, RW_SEEK_SET);
        }
        if (surface) {
            SDL_FreeSurface(surface);
        }
        surface = NULL;
    }
    if (freesrc && src) {
        SDL_RWclose(src);
    }
    return (surface);
}

References SDL_Color::a, SDL_Color::b, BI_BITFIELDS, BI_RGB, BI_RLE4, BI_RLE8, SDL_Palette::colors, CorrectAlphaChannel(), done, SDL_Color::g, i, int(), SDL_Palette::ncolors, NULL, SDL_Color::r, readRlePixels(), RW_SEEK_CUR, RW_SEEK_SET, SDL_ALPHA_OPAQUE, SDL_assert, SDL_ClearError, SDL_CreateRGBSurface, SDL_EFREAD, SDL_EFSEEK, SDL_Error, SDL_FALSE, SDL_FreeSurface, SDL_GetError, SDL_ReadLE16, SDL_ReadLE32, SDL_RWclose, SDL_RWread, SDL_RWseek, SDL_RWtell, SDL_SetError, SDL_strcmp, SDL_strncmp, SDL_Swap16(), SDL_Swap32(), and SDL_TRUE.

SDL_LockSurface()

int SDL_LockSurface

(

SDL_Surface *

surface

)

Sets up a surface for directly accessing the pixels.

Between calls to SDL_LockSurface() / SDL_UnlockSurface(), you can write to and read from surface->pixels, using the pixel format stored in surface->format. Once you are done accessing the surface, you should use SDL_UnlockSurface() to release it.

Not all surfaces require locking. If SDL_MUSTLOCK(surface) evaluates to 0, then you can read and write to the surface at any time, and the pixel format of the surface will not change.

No operating system or library calls should be made between lock/unlock pairs, as critical system locks may be held during this time.

SDL_LockSurface() returns 0, or -1 if the surface couldn't be locked.

See also

SDL_UnlockSurface()

Definition at line 927 of file SDL_surface.c.

{
    if (!surface->locked) {
#if SDL_HAVE_RLE
        /* Perform the lock */
        if (surface->flags & SDL_RLEACCEL) {
            SDL_UnRLESurface(surface, 1);
            surface->flags |= SDL_RLEACCEL;     /* save accel'd state */
        }
#endif
    }
 
    /* Increment the surface lock count, for recursive locks */
    ++surface->locked;
 
    /* Ready to go.. */
    return (0);
}

References SDL_RLEACCEL, and SDL_UnRLESurface().

Referenced by SDL_ConvertColorkeyToAlpha().

SDL_LowerBlit()

int SDL_LowerBlit	(	SDL_Surface *	src,
		SDL_Rect *	srcrect,
		SDL_Surface *	dst,
		SDL_Rect *	dstrect
	)

This is a semi-private blit function and it performs low-level surface blitting only.

Definition at line 624 of file SDL_surface.c.

{
    /* Check to make sure the blit mapping is valid */
    if ((src->map->dst != dst) ||
        (dst->format->palette &&
         src->map->dst_palette_version != dst->format->palette->version) ||
        (src->format->palette &&
         src->map->src_palette_version != src->format->palette->version)) {
        if (SDL_MapSurface(src, dst) < 0) {
            return (-1);
        }
        /* just here for debugging */
/*         printf */
/*             ("src = 0x%08X src->flags = %08X src->map->info.flags = %08x\ndst = 0x%08X dst->flags = %08X dst->map->info.flags = %08X\nsrc->map->blit = 0x%08x\n", */
/*              src, dst->flags, src->map->info.flags, dst, dst->flags, */
/*              dst->map->info.flags, src->map->blit); */
    }
    return (src->map->blit(src, srcrect, dst, dstrect));
}

References SDL_MapSurface().

Referenced by SDL_ConvertPixels(), SDL_ConvertSurface(), SDL_LowerBlitScaled(), and SDL_UpperBlit().

SDL_LowerBlitScaled()

int SDL_LowerBlitScaled	(	SDL_Surface *	src,
		SDL_Rect *	srcrect,
		SDL_Surface *	dst,
		SDL_Rect *	dstrect
	)

This is a semi-private blit function and it performs low-level surface scaled blitting only.

Definition at line 900 of file SDL_surface.c.

{
    static const Uint32 complex_copy_flags = (
        SDL_COPY_MODULATE_COLOR | SDL_COPY_MODULATE_ALPHA |
        SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD | SDL_COPY_MUL |
        SDL_COPY_COLORKEY
    );
 
    if (!(src->map->info.flags & SDL_COPY_NEAREST)) {
        src->map->info.flags |= SDL_COPY_NEAREST;
        SDL_InvalidateMap(src->map);
    }
 
    if ( !(src->map->info.flags & complex_copy_flags) &&
         src->format->format == dst->format->format &&
         !SDL_ISPIXELFORMAT_INDEXED(src->format->format) ) {
        return SDL_SoftStretch( src, srcrect, dst, dstrect );
    } else {
        return SDL_LowerBlit( src, srcrect, dst, dstrect );
    }
}

References SDL_COPY_ADD, SDL_COPY_BLEND, SDL_COPY_COLORKEY, SDL_COPY_MOD, SDL_COPY_MODULATE_ALPHA, SDL_COPY_MODULATE_COLOR, SDL_COPY_MUL, SDL_COPY_NEAREST, SDL_InvalidateMap(), SDL_ISPIXELFORMAT_INDEXED, SDL_LowerBlit(), and SDL_SoftStretch.

Referenced by SDL_UpperBlitScaled().

SDL_SaveBMP_RW()

int SDL_SaveBMP_RW	(	SDL_Surface *	surface,
		SDL_RWops *	dst,
		int	freedst
	)

Save a surface to a seekable SDL data stream (memory or file).

Surfaces with a 24-bit, 32-bit and paletted 8-bit format get saved in the BMP directly. Other RGB formats with 8-bit or higher get converted to a 24-bit surface or, if they have an alpha mask or a colorkey, to a 32-bit surface before they are saved. YUV and paletted 1-bit and 4-bit formats are not supported.

If freedst is non-zero, the stream will be closed after being written.

Returns

0 if successful or -1 if there was an error.

Definition at line 567 of file SDL_bmp.c.

{
    Sint64 fp_offset;
    int i, pad;
    SDL_Surface *surface;
    Uint8 *bits;
    SDL_bool save32bit = SDL_FALSE;
    SDL_bool saveLegacyBMP = SDL_FALSE;
 
    /* The Win32 BMP file header (14 bytes) */
    char magic[2] = { 'B', 'M' };
    Uint32 bfSize;
    Uint16 bfReserved1;
    Uint16 bfReserved2;
    Uint32 bfOffBits;
 
    /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
    Uint32 biSize;
    Sint32 biWidth;
    Sint32 biHeight;
    Uint16 biPlanes;
    Uint16 biBitCount;
    Uint32 biCompression;
    Uint32 biSizeImage;
    Sint32 biXPelsPerMeter;
    Sint32 biYPelsPerMeter;
    Uint32 biClrUsed;
    Uint32 biClrImportant;
 
    /* The additional header members from the Win32 BITMAPV4HEADER struct (108 bytes in total) */
    Uint32 bV4RedMask = 0;
    Uint32 bV4GreenMask = 0;
    Uint32 bV4BlueMask = 0;
    Uint32 bV4AlphaMask = 0;
    Uint32 bV4CSType = 0;
    Sint32 bV4Endpoints[3 * 3] = {0};
    Uint32 bV4GammaRed = 0;
    Uint32 bV4GammaGreen = 0;
    Uint32 bV4GammaBlue = 0;
 
    /* Make sure we have somewhere to save */
    surface = NULL;
    if (dst) {
#ifdef SAVE_32BIT_BMP
        /* We can save alpha information in a 32-bit BMP */
        if (saveme->format->BitsPerPixel >= 8 && (saveme->format->Amask ||
            saveme->map->info.flags & SDL_COPY_COLORKEY)) {
            save32bit = SDL_TRUE;
        }
#endif /* SAVE_32BIT_BMP */
 
        if (saveme->format->palette && !save32bit) {
            if (saveme->format->BitsPerPixel == 8) {
                surface = saveme;
            } else {
                SDL_SetError("%d bpp BMP files not supported",
                             saveme->format->BitsPerPixel);
            }
        } else if ((saveme->format->BitsPerPixel == 24) && !save32bit &&
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
                   (saveme->format->Rmask == 0x00FF0000) &&
                   (saveme->format->Gmask == 0x0000FF00) &&
                   (saveme->format->Bmask == 0x000000FF)
#else
                   (saveme->format->Rmask == 0x000000FF) &&
                   (saveme->format->Gmask == 0x0000FF00) &&
                   (saveme->format->Bmask == 0x00FF0000)
#endif
            ) {
            surface = saveme;
        } else {
            SDL_PixelFormat format;
 
            /* If the surface has a colorkey or alpha channel we'll save a
               32-bit BMP with alpha channel, otherwise save a 24-bit BMP. */
            if (save32bit) {
                SDL_InitFormat(&format, SDL_PIXELFORMAT_BGRA32);
            } else {
                SDL_InitFormat(&format, SDL_PIXELFORMAT_BGR24);
            }
            surface = SDL_ConvertSurface(saveme, &format, 0);
            if (!surface) {
                SDL_SetError("Couldn't convert image to %d bpp",
                             format.BitsPerPixel);
            }
        }
    } else {
        /* Set no error here because it may overwrite a more useful message from
           SDL_RWFromFile() if SDL_SaveBMP_RW() is called from SDL_SaveBMP(). */
        return -1;
    }
 
    if (save32bit) {
        saveLegacyBMP = SDL_GetHintBoolean(SDL_HINT_BMP_SAVE_LEGACY_FORMAT, SDL_FALSE);
    }
 
    if (surface && (SDL_LockSurface(surface) == 0)) {
        const int bw = surface->w * surface->format->BytesPerPixel;
 
        /* Set the BMP file header values */
        bfSize = 0;             /* We'll write this when we're done */
        bfReserved1 = 0;
        bfReserved2 = 0;
        bfOffBits = 0;          /* We'll write this when we're done */
 
        /* Write the BMP file header values */
        fp_offset = SDL_RWtell(dst);
        SDL_ClearError();
        SDL_RWwrite(dst, magic, 2, 1);
        SDL_WriteLE32(dst, bfSize);
        SDL_WriteLE16(dst, bfReserved1);
        SDL_WriteLE16(dst, bfReserved2);
        SDL_WriteLE32(dst, bfOffBits);
 
        /* Set the BMP info values */
        biSize = 40;
        biWidth = surface->w;
        biHeight = surface->h;
        biPlanes = 1;
        biBitCount = surface->format->BitsPerPixel;
        biCompression = BI_RGB;
        biSizeImage = surface->h * surface->pitch;
        biXPelsPerMeter = 0;
        biYPelsPerMeter = 0;
        if (surface->format->palette) {
            biClrUsed = surface->format->palette->ncolors;
        } else {
            biClrUsed = 0;
        }
        biClrImportant = 0;
 
        /* Set the BMP info values for the version 4 header */
        if (save32bit && !saveLegacyBMP) {
            biSize = 108;
            biCompression = BI_BITFIELDS;
            /* The BMP format is always little endian, these masks stay the same */
            bV4RedMask   = 0x00ff0000;
            bV4GreenMask = 0x0000ff00;
            bV4BlueMask  = 0x000000ff;
            bV4AlphaMask = 0xff000000;
            bV4CSType = LCS_WINDOWS_COLOR_SPACE;
            bV4GammaRed = 0;
            bV4GammaGreen = 0;
            bV4GammaBlue = 0;
        }
 
        /* Write the BMP info values */
        SDL_WriteLE32(dst, biSize);
        SDL_WriteLE32(dst, biWidth);
        SDL_WriteLE32(dst, biHeight);
        SDL_WriteLE16(dst, biPlanes);
        SDL_WriteLE16(dst, biBitCount);
        SDL_WriteLE32(dst, biCompression);
        SDL_WriteLE32(dst, biSizeImage);
        SDL_WriteLE32(dst, biXPelsPerMeter);
        SDL_WriteLE32(dst, biYPelsPerMeter);
        SDL_WriteLE32(dst, biClrUsed);
        SDL_WriteLE32(dst, biClrImportant);
 
        /* Write the BMP info values for the version 4 header */
        if (save32bit && !saveLegacyBMP) {
            SDL_WriteLE32(dst, bV4RedMask);
            SDL_WriteLE32(dst, bV4GreenMask);
            SDL_WriteLE32(dst, bV4BlueMask);
            SDL_WriteLE32(dst, bV4AlphaMask);
            SDL_WriteLE32(dst, bV4CSType);
            for (i = 0; i < 3 * 3; i++) {
                SDL_WriteLE32(dst, bV4Endpoints[i]);
            }
            SDL_WriteLE32(dst, bV4GammaRed);
            SDL_WriteLE32(dst, bV4GammaGreen);
            SDL_WriteLE32(dst, bV4GammaBlue);
        }
 
        /* Write the palette (in BGR color order) */
        if (surface->format->palette) {
            SDL_Color *colors;
            int ncolors;
 
            colors = surface->format->palette->colors;
            ncolors = surface->format->palette->ncolors;
            for (i = 0; i < ncolors; ++i) {
                SDL_RWwrite(dst, &colors[i].b, 1, 1);
                SDL_RWwrite(dst, &colors[i].g, 1, 1);
                SDL_RWwrite(dst, &colors[i].r, 1, 1);
                SDL_RWwrite(dst, &colors[i].a, 1, 1);
            }
        }
 
        /* Write the bitmap offset */
        bfOffBits = (Uint32)(SDL_RWtell(dst) - fp_offset);
        if (SDL_RWseek(dst, fp_offset + 10, RW_SEEK_SET) < 0) {
            SDL_Error(SDL_EFSEEK);
        }
        SDL_WriteLE32(dst, bfOffBits);
        if (SDL_RWseek(dst, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
            SDL_Error(SDL_EFSEEK);
        }
 
        /* Write the bitmap image upside down */
        bits = (Uint8 *) surface->pixels + (surface->h * surface->pitch);
        pad = ((bw % 4) ? (4 - (bw % 4)) : 0);
        while (bits > (Uint8 *) surface->pixels) {
            bits -= surface->pitch;
            if (SDL_RWwrite(dst, bits, 1, bw) != bw) {
                SDL_Error(SDL_EFWRITE);
                break;
            }
            if (pad) {
                const Uint8 padbyte = 0;
                for (i = 0; i < pad; ++i) {
                    SDL_RWwrite(dst, &padbyte, 1, 1);
                }
            }
        }
 
        /* Write the BMP file size */
        bfSize = (Uint32)(SDL_RWtell(dst) - fp_offset);
        if (SDL_RWseek(dst, fp_offset + 2, RW_SEEK_SET) < 0) {
            SDL_Error(SDL_EFSEEK);
        }
        SDL_WriteLE32(dst, bfSize);
        if (SDL_RWseek(dst, fp_offset + bfSize, RW_SEEK_SET) < 0) {
            SDL_Error(SDL_EFSEEK);
        }
 
        /* Close it up.. */
        SDL_UnlockSurface(surface);
        if (surface != saveme) {
            SDL_FreeSurface(surface);
        }
    }
 
    if (freedst && dst) {
        SDL_RWclose(dst);
    }
    return ((SDL_strcmp(SDL_GetError(), "") == 0) ? 0 : -1);
}

References SDL_PixelFormat::Amask, BI_BITFIELDS, BI_RGB, SDL_PixelFormat::BitsPerPixel, SDL_PixelFormat::Bmask, colors, endif, SDL_BlitInfo::flags, SDL_Surface::format, SDL_PixelFormat::Gmask, i, SDL_BlitMap::info, LCS_WINDOWS_COLOR_SPACE, SDL_Surface::map, NULL, SDL_PixelFormat::palette, SDL_PixelFormat::Rmask, RW_SEEK_SET, SDL_BYTEORDER, SDL_ClearError, SDL_ConvertSurface, SDL_COPY_COLORKEY, SDL_EFSEEK, SDL_EFWRITE, SDL_Error, SDL_FALSE, SDL_FreeSurface, SDL_GetError, SDL_GetHintBoolean, SDL_HINT_BMP_SAVE_LEGACY_FORMAT, SDL_InitFormat(), SDL_LIL_ENDIAN, SDL_LockSurface, SDL_PIXELFORMAT_BGR24, SDL_PIXELFORMAT_BGRA32, SDL_RWclose, SDL_RWseek, SDL_RWtell, SDL_RWwrite, SDL_SetError, SDL_strcmp, SDL_TRUE, SDL_UnlockSurface, SDL_WriteLE16, and SDL_WriteLE32.

SDL_SetClipRect()

SDL_bool SDL_SetClipRect	(	SDL_Surface *	surface,
		const SDL_Rect *	rect
	)

Sets the clipping rectangle for the destination surface in a blit.

If the clip rectangle is NULL, clipping will be disabled.

If the clip rectangle doesn't intersect the surface, the function will return SDL_FALSE and blits will be completely clipped. Otherwise the function returns SDL_TRUE and blits to the surface will be clipped to the intersection of the surface area and the clipping rectangle.

Note that blits are automatically clipped to the edges of the source and destination surfaces.

Definition at line 581 of file SDL_surface.c.

{
    SDL_Rect full_rect;
 
    /* Don't do anything if there's no surface to act on */
    if (!surface) {
        return SDL_FALSE;
    }
 
    /* Set up the full surface rectangle */
    full_rect.x = 0;
    full_rect.y = 0;
    full_rect.w = surface->w;
    full_rect.h = surface->h;
 
    /* Set the clipping rectangle */
    if (!rect) {
        surface->clip_rect = full_rect;
        return SDL_TRUE;
    }
    return SDL_IntersectRect(rect, &full_rect, &surface->clip_rect);
}

References SDL_Rect::h, rect, SDL_FALSE, SDL_IntersectRect, SDL_TRUE, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

Referenced by SDL_ConvertSurface(), SDL_CreateRGBSurfaceFrom(), SDL_CreateRGBSurfaceWithFormat(), and SDL_CreateRGBSurfaceWithFormatFrom().

SDL_SetColorKey()

int SDL_SetColorKey	(	SDL_Surface *	surface,
		int	flag,
		Uint32	key
	)

Sets the color key (transparent pixel) in a blittable surface.

Parameters

surface	The surface to update
flag	Non-zero to enable colorkey and 0 to disable colorkey
key	The transparent pixel in the native surface format

Returns

0 on success, or -1 if the surface is not valid

You can pass SDL_RLEACCEL to enable RLE accelerated blits.

Definition at line 267 of file SDL_surface.c.

{
    int flags;
 
    if (!surface) {
        return SDL_InvalidParamError("surface");
    }
 
    if (surface->format->palette && key >= ((Uint32) surface->format->palette->ncolors)) {
        return SDL_InvalidParamError("key");
    }
 
    if (flag & SDL_RLEACCEL) {
        SDL_SetSurfaceRLE(surface, 1);
    }
 
    flags = surface->map->info.flags;
    if (flag) {
        surface->map->info.flags |= SDL_COPY_COLORKEY;
        surface->map->info.colorkey = key;
    } else {
        surface->map->info.flags &= ~SDL_COPY_COLORKEY;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
 
    return 0;
}

References SDL_COPY_COLORKEY, SDL_InvalidateMap(), SDL_InvalidParamError, SDL_RLEACCEL, and SDL_SetSurfaceRLE().

Referenced by SDL_ConvertColorkeyToAlpha(), and SDL_ConvertSurface().

SDL_SetSurfaceAlphaMod()

int SDL_SetSurfaceAlphaMod	(	SDL_Surface *	surface,
		Uint8	alpha
	)

Set an additional alpha value used in blit operations.

Parameters

surface	The surface to update.
alpha	The alpha value multiplied into blit operations.

Returns

0 on success, or -1 if the surface is not valid.

See also

SDL_GetSurfaceAlphaMod()

Definition at line 473 of file SDL_surface.c.

{
    int flags;
 
    if (!surface) {
        return -1;
    }
 
    surface->map->info.a = alpha;
 
    flags = surface->map->info.flags;
    if (alpha != 0xFF) {
        surface->map->info.flags |= SDL_COPY_MODULATE_ALPHA;
    } else {
        surface->map->info.flags &= ~SDL_COPY_MODULATE_ALPHA;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return 0;
}

References SDL_COPY_MODULATE_ALPHA, and SDL_InvalidateMap().

SDL_SetSurfaceBlendMode()

int SDL_SetSurfaceBlendMode	(	SDL_Surface *	surface,
		SDL_BlendMode	blendMode
	)

Set the blend mode used for blit operations.

Parameters

surface	The surface to update.
blendMode	SDL_BlendMode to use for blit blending.

Returns

0 on success, or -1 if the parameters are not valid.

See also

SDL_GetSurfaceBlendMode()

Definition at line 509 of file SDL_surface.c.

{
    int flags, status;
 
    if (!surface) {
        return -1;
    }
 
    status = 0;
    flags = surface->map->info.flags;
    surface->map->info.flags &=
        ~(SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD | SDL_COPY_MUL);
    switch (blendMode) {
    case SDL_BLENDMODE_NONE:
        break;
    case SDL_BLENDMODE_BLEND:
        surface->map->info.flags |= SDL_COPY_BLEND;
        break;
    case SDL_BLENDMODE_ADD:
        surface->map->info.flags |= SDL_COPY_ADD;
        break;
    case SDL_BLENDMODE_MOD:
        surface->map->info.flags |= SDL_COPY_MOD;
        break;
    case SDL_BLENDMODE_MUL:
        surface->map->info.flags |= SDL_COPY_MUL;
        break;
    default:
        status = SDL_Unsupported();
        break;
    }
 
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
 
    return status;
}

References blendMode, SDL_BLENDMODE_ADD, SDL_BLENDMODE_BLEND, SDL_BLENDMODE_MOD, SDL_BLENDMODE_MUL, SDL_BLENDMODE_NONE, SDL_COPY_ADD, SDL_COPY_BLEND, SDL_COPY_MOD, SDL_COPY_MUL, SDL_InvalidateMap(), and SDL_Unsupported.

Referenced by SDL_ConvertColorkeyToAlpha(), SDL_ConvertSurface(), and SDL_CreateRGBSurfaceWithFormat().

SDL_SetSurfaceColorMod()

int SDL_SetSurfaceColorMod	(	SDL_Surface *	surface,
		Uint8	r,
		Uint8	g,
		Uint8	b
	)

Set an additional color value used in blit operations.

Parameters

surface	The surface to update.
r	The red color value multiplied into blit operations.
g	The green color value multiplied into blit operations.
b	The blue color value multiplied into blit operations.

Returns

0 on success, or -1 if the surface is not valid.

See also

SDL_GetSurfaceColorMod()

Definition at line 428 of file SDL_surface.c.

{
    int flags;
 
    if (!surface) {
        return -1;
    }
 
    surface->map->info.r = r;
    surface->map->info.g = g;
    surface->map->info.b = b;
 
    flags = surface->map->info.flags;
    if (r != 0xFF || g != 0xFF || b != 0xFF) {
        surface->map->info.flags |= SDL_COPY_MODULATE_COLOR;
    } else {
        surface->map->info.flags &= ~SDL_COPY_MODULATE_COLOR;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return 0;
}

References SDL_COPY_MODULATE_COLOR, and SDL_InvalidateMap().

SDL_SetSurfacePalette()

int SDL_SetSurfacePalette	(	SDL_Surface *	surface,
		SDL_Palette *	palette
	)

Set the palette used by a surface.

Returns

0, or -1 if the surface format doesn't use a palette.

Note

A single palette can be shared with many surfaces.

Definition at line 218 of file SDL_surface.c.

{
    if (!surface) {
        return SDL_SetError("SDL_SetSurfacePalette() passed a NULL surface");
    }
    if (SDL_SetPixelFormatPalette(surface->format, palette) < 0) {
        return -1;
    }
    SDL_InvalidateMap(surface->map);
 
    return 0;
}

References SDL_InvalidateMap(), SDL_SetError, and SDL_SetPixelFormatPalette.

Referenced by SDL_ConvertSurface(), SDL_CreateRGBSurfaceWithFormat(), and SDL_FreeSurface().

SDL_SetSurfaceRLE()

int SDL_SetSurfaceRLE	(	SDL_Surface *	surface,
		int	flag
	)

Sets the RLE acceleration hint for a surface.

Returns

0 on success, or -1 if the surface is not valid

Note

If RLE is enabled, colorkey and alpha blending blits are much faster, but the surface must be locked before directly accessing the pixels.

Definition at line 232 of file SDL_surface.c.

{
    int flags;
 
    if (!surface) {
        return -1;
    }
 
    flags = surface->map->info.flags;
    if (flag) {
        surface->map->info.flags |= SDL_COPY_RLE_DESIRED;
    } else {
        surface->map->info.flags &= ~SDL_COPY_RLE_DESIRED;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return 0;
}

References SDL_COPY_RLE_DESIRED, and SDL_InvalidateMap().

Referenced by SDL_ConvertSurface(), and SDL_SetColorKey().

SDL_SetYUVConversionMode()

void SDL_SetYUVConversionMode

(

SDL_YUV_CONVERSION_MODE

mode

)

Set the YUV conversion mode.

Definition at line 36 of file SDL_yuv.c.

{
    SDL_YUV_ConversionMode = mode;
}

References SDL_YUV_ConversionMode.

SDL_SoftStretch()

int SDL_SoftStretch	(	SDL_Surface *	src,
		const SDL_Rect *	srcrect,
		SDL_Surface *	dst,
		const SDL_Rect *	dstrect
	)

Perform a fast, low quality, stretch blit between two surfaces of the same pixel format.

Note

This function uses a static buffer, and is not thread-safe.

Definition at line 203 of file SDL_stretch.c.

{
    int src_locked;
    int dst_locked;
    int pos, inc;
    int dst_maxrow;
    int src_row, dst_row;
    Uint8 *srcp = NULL;
    Uint8 *dstp;
    SDL_Rect full_src;
    SDL_Rect full_dst;
#ifdef USE_ASM_STRETCH
    SDL_bool use_asm = SDL_TRUE;
#ifdef __GNUC__
    int u1, u2;
#endif
#endif /* USE_ASM_STRETCH */
    const int bpp = dst->format->BytesPerPixel;
 
    if (src->format->format != dst->format->format) {
        return SDL_SetError("Only works with same format surfaces");
    }
 
    /* Verify the blit rectangles */
    if (srcrect) {
        if ((srcrect->x < 0) || (srcrect->y < 0) ||
            ((srcrect->x + srcrect->w) > src->w) ||
            ((srcrect->y + srcrect->h) > src->h)) {
            return SDL_SetError("Invalid source blit rectangle");
        }
    } else {
        full_src.x = 0;
        full_src.y = 0;
        full_src.w = src->w;
        full_src.h = src->h;
        srcrect = &full_src;
    }
    if (dstrect) {
        if ((dstrect->x < 0) || (dstrect->y < 0) ||
            ((dstrect->x + dstrect->w) > dst->w) ||
            ((dstrect->y + dstrect->h) > dst->h)) {
            return SDL_SetError("Invalid destination blit rectangle");
        }
    } else {
        full_dst.x = 0;
        full_dst.y = 0;
        full_dst.w = dst->w;
        full_dst.h = dst->h;
        dstrect = &full_dst;
    }
 
    /* Lock the destination if it's in hardware */
    dst_locked = 0;
    if (SDL_MUSTLOCK(dst)) {
        if (SDL_LockSurface(dst) < 0) {
            return SDL_SetError("Unable to lock destination surface");
        }
        dst_locked = 1;
    }
    /* Lock the source if it's in hardware */
    src_locked = 0;
    if (SDL_MUSTLOCK(src)) {
        if (SDL_LockSurface(src) < 0) {
            if (dst_locked) {
                SDL_UnlockSurface(dst);
            }
            return SDL_SetError("Unable to lock source surface");
        }
        src_locked = 1;
    }
 
    /* Set up the data... */
    pos = 0x10000;
    inc = (srcrect->h << 16) / dstrect->h;
    src_row = srcrect->y;
    dst_row = dstrect->y;
 
#ifdef USE_ASM_STRETCH
    /* Write the opcodes for this stretch */
    if ((bpp == 3) || (generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0)) {
        use_asm = SDL_FALSE;
    }
#endif
 
    /* Perform the stretch blit */
    for (dst_maxrow = dst_row + dstrect->h; dst_row < dst_maxrow; ++dst_row) {
        dstp = (Uint8 *) dst->pixels + (dst_row * dst->pitch)
            + (dstrect->x * bpp);
        while (pos >= 0x10000L) {
            srcp = (Uint8 *) src->pixels + (src_row * src->pitch)
                + (srcrect->x * bpp);
            ++src_row;
            pos -= 0x10000L;
        }
#ifdef USE_ASM_STRETCH
        if (use_asm) {
#ifdef __GNUC__
            __asm__ __volatile__("call *%4":"=&D"(u1), "=&S"(u2)
                                 :"0"(dstp), "1"(srcp), "r"(copy_row)
                                 :"memory");
#elif defined(_MSC_VER) || defined(__WATCOMC__)
            /* *INDENT-OFF* */
            {
                void *code = copy_row;
                __asm {
                    push edi
                    push esi
                    mov edi, dstp
                    mov esi, srcp
                    call dword ptr code
                    pop esi
                    pop edi
                }
            }
            /* *INDENT-ON* */
#else
#error Need inline assembly for this compiler
#endif
        } else
#endif
            switch (bpp) {
            case 1:
                copy_row1(srcp, srcrect->w, dstp, dstrect->w);
                break;
            case 2:
                copy_row2((Uint16 *) srcp, srcrect->w,
                          (Uint16 *) dstp, dstrect->w);
                break;
            case 3:
                copy_row3(srcp, srcrect->w, dstp, dstrect->w);
                break;
            case 4:
                copy_row4((Uint32 *) srcp, srcrect->w,
                          (Uint32 *) dstp, dstrect->w);
                break;
            }
        pos += inc;
    }
 
    /* We need to unlock the surfaces if they're locked */
    if (dst_locked) {
        SDL_UnlockSurface(dst);
    }
    if (src_locked) {
        SDL_UnlockSurface(src);
    }
    return (0);
}

References bpp, copy_row3(), SDL_Rect::h, if, mov, NULL, pop, ptr, SDL_FALSE, SDL_LockSurface, SDL_MUSTLOCK, SDL_SetError, SDL_TRUE, SDL_UnlockSurface, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

SDL_UnlockSurface()

void SDL_UnlockSurface

(

SDL_Surface *

surface

)

See also

SDL_LockSurface()

Definition at line 950 of file SDL_surface.c.

{
    /* Only perform an unlock if we are locked */
    if (!surface->locked || (--surface->locked > 0)) {
        return;
    }
 
#if SDL_HAVE_RLE
    /* Update RLE encoded surface with new data */
    if ((surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL) {
        surface->flags &= ~SDL_RLEACCEL;        /* stop lying */
        SDL_RLESurface(surface);
    }
#endif
}

References SDL_RLEACCEL, and SDL_RLESurface().

Referenced by SDL_ConvertColorkeyToAlpha(), and SDL_FreeSurface().

SDL_UpperBlit()

int SDL_UpperBlit	(	SDL_Surface *	src,
		const SDL_Rect *	srcrect,
		SDL_Surface *	dst,
		SDL_Rect *	dstrect
	)

This is the public blit function, SDL_BlitSurface(), and it performs rectangle validation and clipping before passing it to SDL_LowerBlit()

Definition at line 647 of file SDL_surface.c.

{
    SDL_Rect fulldst;
    int srcx, srcy, w, h;
 
    /* Make sure the surfaces aren't locked */
    if (!src || !dst) {
        return SDL_SetError("SDL_UpperBlit: passed a NULL surface");
    }
    if (src->locked || dst->locked) {
        return SDL_SetError("Surfaces must not be locked during blit");
    }
 
    /* If the destination rectangle is NULL, use the entire dest surface */
    if (dstrect == NULL) {
        fulldst.x = fulldst.y = 0;
        fulldst.w = dst->w;
        fulldst.h = dst->h;
        dstrect = &fulldst;
    }
 
    /* clip the source rectangle to the source surface */
    if (srcrect) {
        int maxw, maxh;
 
        srcx = srcrect->x;
        w = srcrect->w;
        if (srcx < 0) {
            w += srcx;
            dstrect->x -= srcx;
            srcx = 0;
        }
        maxw = src->w - srcx;
        if (maxw < w)
            w = maxw;
 
        srcy = srcrect->y;
        h = srcrect->h;
        if (srcy < 0) {
            h += srcy;
            dstrect->y -= srcy;
            srcy = 0;
        }
        maxh = src->h - srcy;
        if (maxh < h)
            h = maxh;
 
    } else {
        srcx = srcy = 0;
        w = src->w;
        h = src->h;
    }
 
    /* clip the destination rectangle against the clip rectangle */
    {
        SDL_Rect *clip = &dst->clip_rect;
        int dx, dy;
 
        dx = clip->x - dstrect->x;
        if (dx > 0) {
            w -= dx;
            dstrect->x += dx;
            srcx += dx;
        }
        dx = dstrect->x + w - clip->x - clip->w;
        if (dx > 0)
            w -= dx;
 
        dy = clip->y - dstrect->y;
        if (dy > 0) {
            h -= dy;
            dstrect->y += dy;
            srcy += dy;
        }
        dy = dstrect->y + h - clip->y - clip->h;
        if (dy > 0)
            h -= dy;
    }
 
    /* Switch back to a fast blit if we were previously stretching */
    if (src->map->info.flags & SDL_COPY_NEAREST) {
        src->map->info.flags &= ~SDL_COPY_NEAREST;
        SDL_InvalidateMap(src->map);
    }
 
    if (w > 0 && h > 0) {
        SDL_Rect sr;
        sr.x = srcx;
        sr.y = srcy;
        sr.w = dstrect->w = w;
        sr.h = dstrect->h = h;
        return SDL_LowerBlit(src, &sr, dst, dstrect);
    }
    dstrect->w = dstrect->h = 0;
    return 0;
}

References SDL_Rect::h, NULL, SDL_COPY_NEAREST, SDL_InvalidateMap(), SDL_LowerBlit(), SDL_SetError, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.

SDL_UpperBlitScaled()

int SDL_UpperBlitScaled	(	SDL_Surface *	src,
		const SDL_Rect *	srcrect,
		SDL_Surface *	dst,
		SDL_Rect *	dstrect
	)

This is the public scaled blit function, SDL_BlitScaled(), and it performs rectangle validation and clipping before passing it to SDL_LowerBlitScaled()

Definition at line 746 of file SDL_surface.c.

{
    double src_x0, src_y0, src_x1, src_y1;
    double dst_x0, dst_y0, dst_x1, dst_y1;
    SDL_Rect final_src, final_dst;
    double scaling_w, scaling_h;
    int src_w, src_h;
    int dst_w, dst_h;
 
    /* Make sure the surfaces aren't locked */
    if (!src || !dst) {
        return SDL_SetError("SDL_UpperBlitScaled: passed a NULL surface");
    }
    if (src->locked || dst->locked) {
        return SDL_SetError("Surfaces must not be locked during blit");
    }
 
    if (NULL == srcrect) {
        src_w = src->w;
        src_h = src->h;
    } else {
        src_w = srcrect->w;
        src_h = srcrect->h;
    }
 
    if (NULL == dstrect) {
        dst_w = dst->w;
        dst_h = dst->h;
    } else {
        dst_w = dstrect->w;
        dst_h = dstrect->h;
    }
 
    if (dst_w == src_w && dst_h == src_h) {
        /* No scaling, defer to regular blit */
        return SDL_BlitSurface(src, srcrect, dst, dstrect);
    }
 
    scaling_w = (double)dst_w / src_w;
    scaling_h = (double)dst_h / src_h;
 
    if (NULL == dstrect) {
        dst_x0 = 0;
        dst_y0 = 0;
        dst_x1 = dst_w - 1;
        dst_y1 = dst_h - 1;
    } else {
        dst_x0 = dstrect->x;
        dst_y0 = dstrect->y;
        dst_x1 = dst_x0 + dst_w - 1;
        dst_y1 = dst_y0 + dst_h - 1;
    }
 
    if (NULL == srcrect) {
        src_x0 = 0;
        src_y0 = 0;
        src_x1 = src_w - 1;
        src_y1 = src_h - 1;
    } else {
        src_x0 = srcrect->x;
        src_y0 = srcrect->y;
        src_x1 = src_x0 + src_w - 1;
        src_y1 = src_y0 + src_h - 1;
 
        /* Clip source rectangle to the source surface */
 
        if (src_x0 < 0) {
            dst_x0 -= src_x0 * scaling_w;
            src_x0 = 0;
        }
 
        if (src_x1 >= src->w) {
            dst_x1 -= (src_x1 - src->w + 1) * scaling_w;
            src_x1 = src->w - 1;
        }
 
        if (src_y0 < 0) {
            dst_y0 -= src_y0 * scaling_h;
            src_y0 = 0;
        }
 
        if (src_y1 >= src->h) {
            dst_y1 -= (src_y1 - src->h + 1) * scaling_h;
            src_y1 = src->h - 1;
        }
    }
 
    /* Clip destination rectangle to the clip rectangle */
 
    /* Translate to clip space for easier calculations */
    dst_x0 -= dst->clip_rect.x;
    dst_x1 -= dst->clip_rect.x;
    dst_y0 -= dst->clip_rect.y;
    dst_y1 -= dst->clip_rect.y;
 
    if (dst_x0 < 0) {
        src_x0 -= dst_x0 / scaling_w;
        dst_x0 = 0;
    }
 
    if (dst_x1 >= dst->clip_rect.w) {
        src_x1 -= (dst_x1 - dst->clip_rect.w + 1) / scaling_w;
        dst_x1 = dst->clip_rect.w - 1;
    }
 
    if (dst_y0 < 0) {
        src_y0 -= dst_y0 / scaling_h;
        dst_y0 = 0;
    }
 
    if (dst_y1 >= dst->clip_rect.h) {
        src_y1 -= (dst_y1 - dst->clip_rect.h + 1) / scaling_h;
        dst_y1 = dst->clip_rect.h - 1;
    }
 
    /* Translate back to surface coordinates */
    dst_x0 += dst->clip_rect.x;
    dst_x1 += dst->clip_rect.x;
    dst_y0 += dst->clip_rect.y;
    dst_y1 += dst->clip_rect.y;
 
    final_src.x = (int)SDL_floor(src_x0 + 0.5);
    final_src.y = (int)SDL_floor(src_y0 + 0.5);
    final_src.w = (int)SDL_floor(src_x1 + 1 + 0.5) - (int)SDL_floor(src_x0 + 0.5);
    final_src.h = (int)SDL_floor(src_y1 + 1 + 0.5) - (int)SDL_floor(src_y0 + 0.5);
 
    final_dst.x = (int)SDL_floor(dst_x0 + 0.5);
    final_dst.y = (int)SDL_floor(dst_y0 + 0.5);
    final_dst.w = (int)SDL_floor(dst_x1 - dst_x0 + 1.5);
    final_dst.h = (int)SDL_floor(dst_y1 - dst_y0 + 1.5);
 
    if (final_dst.w < 0)
        final_dst.w = 0;
    if (final_dst.h < 0)
        final_dst.h = 0;
 
    if (dstrect)
        *dstrect = final_dst;
 
    if (final_dst.w == 0 || final_dst.h == 0 ||
        final_src.w <= 0 || final_src.h <= 0) {
        /* No-op. */
        return 0;
    }
 
    return SDL_LowerBlitScaled(src, &final_src, dst, &final_dst);
}

References SDL_Rect::h, int(), NULL, SDL_BlitSurface, SDL_floor, SDL_LowerBlitScaled(), SDL_SetError, SDL_Rect::w, SDL_Rect::x, and SDL_Rect::y.