Added SDL_BlitSurface9Grid() and SDL_RenderTexture9Grid()

include/SDL3/SDL_render.h

@@ -1898,6 +1898,28 @@ extern SDL_DECLSPEC int SDLCALL SDL_RenderTextureRotated(SDL_Renderer *renderer,
  */
 extern SDL_DECLSPEC int SDLCALL SDL_RenderTextureTiled(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float scale, const SDL_FRect *dstrect);
 
+/**
+ * Perform a scaled copy using the 9-grid algorithm to the current rendering target at subpixel precision.
+ *
+ * The pixels in the texture are split into a 3x3 grid, using the corner size for each corner, and the sides and center making up the remaining pixels. The corners are then scaled using `scale` and fit into the corners of the destination rectangle. The sides and center are then stretched into place to cover the remaining destination rectangle.
+ *
+ * \param renderer the renderer which should copy parts of a texture.
+ * \param texture the source texture.
+ * \param srcrect the SDL_Rect structure representing the rectangle to be
+ *                used for the 9-grid, or NULL to use the entire texture.
+ * \param corner_size the size, in pixels, of the corner in `srcrect`.
+ * \param scale the scale used to transform the corner of `srcrect` into the corner of `dstrect`, or 0.0f for an unscaled copy.
+ * \param dstrect a pointer to the destination rectangle, or NULL for the
+ *                entire rendering target.
+ * \returns 0 on success or a negative error code on failure; call
+ *          SDL_GetError() for more information.
+ *
+ * \since This function is available since SDL 3.0.0.
+ *
+ * \sa SDL_RenderTexture
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_RenderTexture9Grid(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float corner_size, float scale, const SDL_FRect *dstrect);
+
 /**
  * Render a list of triangles, optionally using a texture and indices into the
  * vertex array Color and alpha modulation is done per vertex

include/SDL3/SDL_surface.h

@@ -1099,6 +1099,34 @@ extern SDL_DECLSPEC int SDLCALL SDL_BlitSurfaceTiled(SDL_Surface *src, const SDL
  */
 extern SDL_DECLSPEC int SDLCALL SDL_BlitSurfaceTiledWithScale(SDL_Surface *src, const SDL_Rect *srcrect, float scale, SDL_ScaleMode scaleMode, SDL_Surface *dst, const SDL_Rect *dstrect);
 
+/**
+ * Perform a scaled blit using the 9-grid algorithm to a destination surface, which may be of a different
+ * format.
+ *
+ * The pixels in the source surface are split into a 3x3 grid, using the corner size for each corner, and the sides and center making up the remaining pixels. The corners are then scaled using `scale` and fit into the corners of the destination rectangle. The sides and center are then stretched into place to cover the remaining destination rectangle.
+ *
+ * \param src the SDL_Surface structure to be copied from.
+ * \param srcrect the SDL_Rect structure representing the rectangle to be
+ *                used for the 9-grid, or NULL to use the entire surface.
+ * \param corner_size the size, in pixels, of the corner in `srcrect`.
+ * \param scale the scale used to transform the corner of `srcrect` into the corner of `dstrect`, or 0.0f for an unscaled blit.
+ * \param scaleMode scale algorithm to be used.
+ * \param dst the SDL_Surface structure that is the blit target.
+ * \param dstrect the SDL_Rect structure representing the target rectangle in
+ *                the destination surface, or NULL to fill the entire surface.
+ * \returns 0 on success or a negative error code on failure; call
+ *          SDL_GetError() for more information.
+ *
+ * \threadsafety The same destination surface should not be used from two
+ *               threads at once. It is safe to use the same source surface
+ *               from multiple threads.
+ *
+ * \since This function is available since SDL 3.0.0.
+ *
+ * \sa SDL_BlitSurface
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_BlitSurface9Grid(SDL_Surface *src, const SDL_Rect *srcrect, int corner_size, float scale, SDL_ScaleMode scaleMode, SDL_Surface *dst, const SDL_Rect *dstrect);
+
 /**
  * Map an RGB triple to an opaque pixel value for a surface.
  *

src/dynapi/SDL_dynapi.sym

@@ -23,6 +23,7 @@ SDL3_0.0.0 {
     SDL_AudioDevicePaused;
     SDL_BindAudioStream;
     SDL_BindAudioStreams;
+    SDL_BlitSurface9Grid;
     SDL_BlitSurface;
     SDL_BlitSurfaceScaled;
     SDL_BlitSurfaceTiled;
@@ -662,6 +663,7 @@ SDL3_0.0.0 {
     SDL_RenderReadPixels;
     SDL_RenderRect;
     SDL_RenderRects;
+    SDL_RenderTexture9Grid;
     SDL_RenderTexture;
     SDL_RenderTextureRotated;
     SDL_RenderTextureTiled;

src/dynapi/SDL_dynapi_overrides.h

@@ -49,6 +49,7 @@
 #define SDL_BindAudioStream SDL_BindAudioStream_REAL
 #define SDL_BindAudioStreams SDL_BindAudioStreams_REAL
 #define SDL_BlitSurface SDL_BlitSurface_REAL
+#define SDL_BlitSurface9Grid SDL_BlitSurface9Grid_REAL
 #define SDL_BlitSurfaceScaled SDL_BlitSurfaceScaled_REAL
 #define SDL_BlitSurfaceTiled SDL_BlitSurfaceTiled_REAL
 #define SDL_BlitSurfaceTiledWithScale SDL_BlitSurfaceTiledWithScale_REAL
@@ -688,6 +689,7 @@
 #define SDL_RenderRect SDL_RenderRect_REAL
 #define SDL_RenderRects SDL_RenderRects_REAL
 #define SDL_RenderTexture SDL_RenderTexture_REAL
+#define SDL_RenderTexture9Grid SDL_RenderTexture9Grid_REAL
 #define SDL_RenderTextureRotated SDL_RenderTextureRotated_REAL
 #define SDL_RenderTextureTiled SDL_RenderTextureTiled_REAL
 #define SDL_RenderViewportSet SDL_RenderViewportSet_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -69,6 +69,7 @@ SDL_DYNAPI_PROC(SDL_bool,SDL_AudioDevicePaused,(SDL_AudioDeviceID a),(a),return)
 SDL_DYNAPI_PROC(int,SDL_BindAudioStream,(SDL_AudioDeviceID a, SDL_AudioStream *b),(a,b),return)
 SDL_DYNAPI_PROC(int,SDL_BindAudioStreams,(SDL_AudioDeviceID a, SDL_AudioStream **b, int c),(a,b,c),return)
 SDL_DYNAPI_PROC(int,SDL_BlitSurface,(SDL_Surface *a, const SDL_Rect *b, SDL_Surface *c, const SDL_Rect *d),(a,b,c,d),return)
+SDL_DYNAPI_PROC(int,SDL_BlitSurface9Grid,(SDL_Surface *a, const SDL_Rect *b, int c, float d, SDL_ScaleMode e, SDL_Surface *f, const SDL_Rect *g),(a,b,c,d,e,f,g),return)
 SDL_DYNAPI_PROC(int,SDL_BlitSurfaceScaled,(SDL_Surface *a, const SDL_Rect *b, SDL_Surface *c, const SDL_Rect *d, SDL_ScaleMode e),(a,b,c,d,e),return)
 SDL_DYNAPI_PROC(int,SDL_BlitSurfaceTiled,(SDL_Surface *a, const SDL_Rect *b, SDL_Surface *c, const SDL_Rect *d),(a,b,c,d),return)
 SDL_DYNAPI_PROC(int,SDL_BlitSurfaceTiledWithScale,(SDL_Surface *a, const SDL_Rect *b, float c, SDL_ScaleMode d, SDL_Surface *e, const SDL_Rect *f),(a,b,c,d,e,f),return)
@@ -699,6 +700,7 @@ SDL_DYNAPI_PROC(SDL_Surface*,SDL_RenderReadPixels,(SDL_Renderer *a, const SDL_Re
 SDL_DYNAPI_PROC(int,SDL_RenderRect,(SDL_Renderer *a, const SDL_FRect *b),(a,b),return)
 SDL_DYNAPI_PROC(int,SDL_RenderRects,(SDL_Renderer *a, const SDL_FRect *b, int c),(a,b,c),return)
 SDL_DYNAPI_PROC(int,SDL_RenderTexture,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, const SDL_FRect *d),(a,b,c,d),return)
+SDL_DYNAPI_PROC(int,SDL_RenderTexture9Grid,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, float d, float e, const SDL_FRect *f),(a,b,c,d,e,f),return)
 SDL_DYNAPI_PROC(int,SDL_RenderTextureRotated,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, const SDL_FRect *d, const double e, const SDL_FPoint *f, const SDL_FlipMode g),(a,b,c,d,e,f,g),return)
 SDL_DYNAPI_PROC(int,SDL_RenderTextureTiled,(SDL_Renderer *a, SDL_Texture *b, const SDL_FRect *c, float d, const SDL_FRect *e),(a,b,c,d,e),return)
 SDL_DYNAPI_PROC(SDL_bool,SDL_RenderViewportSet,(SDL_Renderer *a),(a),return)

src/render/SDL_render.c

@@ -4160,6 +4160,123 @@ int SDL_RenderTextureTiled(SDL_Renderer *renderer, SDL_Texture *texture, const S
     }
 }
 
+int SDL_RenderTexture9Grid(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float corner_size, float scale, const SDL_FRect *dstrect)
+{
+    SDL_FRect full_src, full_dst;
+    SDL_FRect curr_src, curr_dst;
+    float dst_corner_size;
+
+    CHECK_RENDERER_MAGIC(renderer, -1);
+    CHECK_TEXTURE_MAGIC(texture, -1);
+
+    if (renderer != texture->renderer) {
+        return SDL_SetError("Texture was not created with this renderer");
+    }
+
+    if (!srcrect) {
+        full_src.x = 0;
+        full_src.y = 0;
+        full_src.w = (float)texture->w;
+        full_src.h = (float)texture->h;
+        srcrect = &full_src;
+    }
+
+    if (!dstrect) {
+        GetRenderViewportSize(renderer, &full_dst);
+        dstrect = &full_dst;
+    }
+
+    if (scale <= 0.0f || scale == 1.0f) {
+        dst_corner_size = corner_size;
+    } else {
+        dst_corner_size = (corner_size * scale);
+    }
+
+    // Upper-left corner
+    curr_src.x = srcrect->x;
+    curr_src.y = srcrect->y;
+    curr_src.w = corner_size;
+    curr_src.h = corner_size;
+    curr_dst.x = dstrect->x;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dst_corner_size;
+    curr_dst.h = dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Upper-right corner
+    curr_src.x = srcrect->x + srcrect->w - corner_size;
+    curr_dst.x = dstrect->x + dstrect->w - dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Lower-right corner
+    curr_src.y = srcrect->y + srcrect->h - corner_size;
+    curr_dst.y = dstrect->y + dstrect->h - dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Lower-left corner
+    curr_src.x = srcrect->x;
+    curr_dst.x = dstrect->x;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Left
+    curr_src.y = srcrect->y + corner_size;
+    curr_src.h = srcrect->h - 2 * corner_size;
+    curr_dst.y = dstrect->y + dst_corner_size;
+    curr_dst.h = dstrect->h - 2 * dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Right
+    curr_src.x = srcrect->x + srcrect->w - corner_size;
+    curr_dst.x = dstrect->x + dstrect->w - dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Top
+    curr_src.x = srcrect->x + corner_size;
+    curr_src.y = srcrect->y;
+    curr_src.w = srcrect->w - 2 * corner_size;
+    curr_src.h = corner_size;
+    curr_dst.x = dstrect->x + dst_corner_size;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dstrect->w - 2 * dst_corner_size;
+    curr_dst.h = dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Bottom
+    curr_src.y = srcrect->y + srcrect->h - corner_size;
+    curr_dst.y = dstrect->y + dstrect->h - dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    // Center
+    curr_src.x = srcrect->x + corner_size;
+    curr_src.y = srcrect->y + corner_size;
+    curr_src.w = srcrect->w - 2 * corner_size;
+    curr_src.h = srcrect->h - 2 * corner_size;
+    curr_dst.x = dstrect->x + dst_corner_size;
+    curr_dst.y = dstrect->y + dst_corner_size;
+    curr_dst.w = dstrect->w - 2 * dst_corner_size;
+    curr_dst.h = dstrect->h - 2 * dst_corner_size;
+    if (SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst) < 0) {
+        return -1;
+    }
+
+    return 0;
+}
 int SDL_RenderGeometry(SDL_Renderer *renderer,
                        SDL_Texture *texture,
                        const SDL_Vertex *vertices, int num_vertices,

src/video/SDL_surface.c

@@ -1444,6 +1444,127 @@ int SDL_BlitSurfaceTiledWithScale(SDL_Surface *src, const SDL_Rect *srcrect, flo
     return 0;
 }
 
+int SDL_BlitSurface9Grid(SDL_Surface *src, const SDL_Rect *srcrect, int corner_size, float scale, SDL_ScaleMode scaleMode, SDL_Surface *dst, const SDL_Rect *dstrect)
+{
+    SDL_Rect full_src, full_dst;
+    SDL_Rect curr_src, curr_dst;
+    int dst_corner_size;
+
+    /* Make sure the surfaces aren't locked */
+    if (!SDL_SurfaceValid(src)) {
+        return SDL_InvalidParamError("src");
+    } else if (!SDL_SurfaceValid(dst)) {
+        return SDL_InvalidParamError("dst");
+    }
+
+    if (!srcrect) {
+        full_src.x = 0;
+        full_src.y = 0;
+        full_src.w = src->w;
+        full_src.h = src->h;
+        srcrect = &full_src;
+    }
+
+    if (!dstrect) {
+        full_dst.x = 0;
+        full_dst.y = 0;
+        full_dst.w = dst->w;
+        full_dst.h = dst->h;
+        dstrect = &full_dst;
+    }
+
+    if (scale <= 0.0f || scale == 1.0f) {
+        dst_corner_size = corner_size;
+    } else {
+        dst_corner_size = (int)SDL_roundf(corner_size * scale);
+    }
+
+    // Upper-left corner
+    curr_src.x = srcrect->x;
+    curr_src.y = srcrect->y;
+    curr_src.w = corner_size;
+    curr_src.h = corner_size;
+    curr_dst.x = dstrect->x;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dst_corner_size;
+    curr_dst.h = dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Upper-right corner
+    curr_src.x = srcrect->x + srcrect->w - corner_size;
+    curr_dst.x = dstrect->x + dstrect->w - dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Lower-right corner
+    curr_src.y = srcrect->y + srcrect->h - corner_size;
+    curr_dst.y = dstrect->y + dstrect->h - dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Lower-left corner
+    curr_src.x = srcrect->x;
+    curr_dst.x = dstrect->x;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Left
+    curr_src.y = srcrect->y + corner_size;
+    curr_src.h = srcrect->h - 2 * corner_size;
+    curr_dst.y = dstrect->y + dst_corner_size;
+    curr_dst.h = dstrect->h - 2 * dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Right
+    curr_src.x = srcrect->x + srcrect->w - corner_size;
+    curr_dst.x = dstrect->x + dstrect->w - dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Top
+    curr_src.x = srcrect->x + corner_size;
+    curr_src.y = srcrect->y;
+    curr_src.w = srcrect->w - 2 * corner_size;
+    curr_src.h = corner_size;
+    curr_dst.x = dstrect->x + dst_corner_size;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dstrect->w - 2 * dst_corner_size;
+    curr_dst.h = dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Bottom
+    curr_src.y = srcrect->y + srcrect->h - corner_size;
+    curr_dst.y = dstrect->y + dstrect->h - dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    // Center
+    curr_src.x = srcrect->x + corner_size;
+    curr_src.y = srcrect->y + corner_size;
+    curr_src.w = srcrect->w - 2 * corner_size;
+    curr_src.h = srcrect->h - 2 * corner_size;
+    curr_dst.x = dstrect->x + dst_corner_size;
+    curr_dst.y = dstrect->y + dst_corner_size;
+    curr_dst.w = dstrect->w - 2 * dst_corner_size;
+    curr_dst.h = dstrect->h - 2 * dst_corner_size;
+    if (SDL_BlitSurfaceScaled(src, &curr_src, dst, &curr_dst, scaleMode) < 0) {
+        return -1;
+    }
+
+    return 0;
+}
+
 /*
  * Lock a surface to directly access the pixels
  */