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Made SDL_ReadSurfacePixel a public function

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Fixes https://github.com/libsdl-org/SDL/issues/8320
This commit is contained in:
Sam Lantinga
2024-01-18 04:36:37 -08:00
parent f7ba340999
commit f8dfee01bb
9 changed files with 93 additions and 118 deletions
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68
src/video/SDL_surface.c
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@@ -24,7 +24,6 @@
#include "SDL_video_c.h"
#include "SDL_blit.h"
#include "SDL_RLEaccel_c.h"
#include "SDL_surface_pixel_impl.h"
#include "SDL_pixels_c.h"
#include "SDL_yuv_c.h"
#include "../render/SDL_sysrender.h"
@@ -36,11 +35,6 @@ SDL_COMPILE_TIME_ASSERT(surface_size_assumptions,
SDL_COMPILE_TIME_ASSERT(can_indicate_overflow, SDL_SIZE_MAX > SDL_MAX_SINT32);
int SDL_ReadSurfacePixel(SDL_Surface *surface, int x, int y, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a)
{
return SDL_ReadSurfacePixel_impl(surface, x, y, r, g, b, a);
}
/* Public routines */
/*
@@ -1560,6 +1554,68 @@ int SDL_PremultiplyAlpha(int width, int height,
return 0;
}
/* This function Copyright 2023 Collabora Ltd., contributed to SDL under the ZLib license */
int SDL_ReadSurfacePixel(SDL_Surface *surface, int x, int y, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a)
{
Uint32 pixel = 0;
size_t bytes_per_pixel;
Uint8 unused;
Uint8 *p;
if (!surface || !surface->format || !surface->pixels) {
return SDL_InvalidParamError("surface");
}
if (x < 0 || x >= surface->w) {
return SDL_InvalidParamError("x");
}
if (y < 0 || y >= surface->h) {
return SDL_InvalidParamError("y");
}
if (!r) {
r = &unused;
}
if (!g) {
g = &unused;
}
if (!b) {
b = &unused;
}
if (!a) {
a = &unused;
}
bytes_per_pixel = surface->format->BytesPerPixel;
if (bytes_per_pixel > sizeof(pixel)) {
return SDL_InvalidParamError("surface->format->BytesPerPixel");
}
if (SDL_MUSTLOCK(surface)) {
SDL_LockSurface(surface);
}
p = (Uint8 *)surface->pixels + y * surface->pitch + x * bytes_per_pixel;
/* Fill the appropriate number of least-significant bytes of pixel,
* leaving the most-significant bytes set to zero */
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
SDL_memcpy(((Uint8 *) &pixel) + (sizeof(pixel) - bytes_per_pixel), p, bytes_per_pixel);
#else
SDL_memcpy(&pixel, p, bytes_per_pixel);
#endif
SDL_GetRGBA(pixel, surface->format, r, g, b, a);
if (SDL_MUSTLOCK(surface)) {
SDL_UnlockSurface(surface);
}
return 0;
}
/*
* Free a surface created by the above function.
*/