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Size: 3353
Comment: add remark that pixel data is not copied and must be freed *after* freeing the surface
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Size: 3347
Comment: pitch is the length of a row of pixels in bytes (like in SDL_CreateRGBSurfaceFrom()), *not* the number of pixels
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DRAFT |
SDL_CreateRGBSurfaceWithFormatFrom
Use this function to allocate an RGB surface from provided pixel data.
Contents
Syntax
SDL_Surface* SDL_CreateRGBSurfaceWithFormatFrom(void* pixels,
int width,
int height,
int depth,
int pitch,
Uint32 format)
Function Parameters
pixels |
the pixel data to create the surface from |
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 |
pitch |
the length of a row of pixels in bytes |
format |
the pixel format of the surface to create |
Return Value
Returns a new SDL_Surface on success or NULL on failure; call SDL_GetError() for more information.
Code Examples
// This example shows how to create a SDL_Surface* with the data loaded
// from an image file with stb_image.h (https://github.com/nothings/stb/)
// the color format you request stb_image to output,
// use STBI_rgb if you don't want/need the alpha channel
int req_format = STBI_rgb_alpha;
int width, height, orig_format;
unsigned char* data = stbi_load("./test.png", &width, &height, &orig_format, req_format);
if(data == NULL) {
fprintf(stderr, "Loading image failed: %s\n", stbi_failure_reason());
exit(1);
}
int depth, pitch;
Uint32 pixel_format;
if(req_format == STBI_rgb) {
depth = 24;
pitch = 3*width; // 3 bytes per pixel * pixels per row
pixel_format = SDL_PIXELFORMAT_RGB24;
} else { // STBI_rgb_alpha (RGBA)
depth = 32;
pitch = 4*width;
pixel_format = SDL_PIXELFORMAT_RGBA32;
}
SDL_Surface* surf = SDL_CreateRGBSurfaceWithFormatFrom((void*)data, width, height,
depth, pitch, pixel_format);
if(surf == NULL) {
fprintf(stderr, "Creating surface failed: %s\n", SDL_GetError());
stbi_image_free(data);
exit(1);
}
// ... do something useful with the surface ...
// ...
// when you don't need the surface anymore, free it..
SDL_FreeSurface(surf);
// .. *and* the data used by the surface!
stbi_image_free(data);
Remarks
If the function runs out of memory, it will return NULL.
No copy is made of the pixel data. Pixel data is not managed automatically; you must free the surface before you free the pixel data.
Version
This function is available since SDL 2.0.5.
