Added tiled 9-grid texture rendering function

* New function SDL_RenderTexture9GridTiled, borders and center is tiled instead of stretched

include/SDL3/SDL_render.h

@@ -2235,6 +2235,42 @@ extern SDL_DECLSPEC bool SDLCALL SDL_RenderTextureTiled(SDL_Renderer *renderer,
  */
 extern SDL_DECLSPEC bool SDLCALL SDL_RenderTexture9Grid(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float left_width, float right_width, float top_height, float bottom_height, 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 different
+ * corner sizes 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
+ * tiled 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 left_width the width, in pixels, of the left corners in `srcrect`.
+ * \param right_width the width, in pixels, of the right corners in `srcrect`.
+ * \param top_height the height, in pixels, of the top corners in `srcrect`.
+ * \param bottom_height the height, in pixels, of the bottom corners 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.
+ * \param tileScale the scale used to transform the borders and center of `srcrect` into the
+ *              borders and middle of `dstrect`, or 1.0f for an unscaled copy.
+ * \returns true on success or false on failure; call SDL_GetError() for more
+ *          information.
+ *
+ * \threadsafety This function should only be called on the main thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_RenderTexture
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_RenderTexture9GridTiled(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float left_width, float right_width, float top_height, float bottom_height, float scale, const SDL_FRect *dstrect, float tileScale);
+
 /**
  * Render a list of triangles, optionally using a texture and indices into the
  * vertex array Color and alpha modulation is done per vertex

src/render/SDL_render.c

@@ -4525,6 +4525,141 @@ bool SDL_RenderTexture9Grid(SDL_Renderer *renderer, SDL_Texture *texture, const
     return true;
 }
 
+bool SDL_RenderTexture9GridTiled(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_FRect *srcrect, float left_width, float right_width, float top_height, float bottom_height, float scale, const SDL_FRect *dstrect, float tileScale)
+{
+    SDL_FRect full_src, full_dst;
+    SDL_FRect curr_src, curr_dst;
+    float dst_left_width;
+    float dst_right_width;
+    float dst_top_height;
+    float dst_bottom_height;
+
+    CHECK_RENDERER_MAGIC(renderer, false);
+    CHECK_TEXTURE_MAGIC(texture, false);
+
+    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_left_width = SDL_ceilf(left_width);
+        dst_right_width = SDL_ceilf(right_width);
+        dst_top_height = SDL_ceilf(top_height);
+        dst_bottom_height = SDL_ceilf(bottom_height);
+    } else {
+        dst_left_width = SDL_ceilf(left_width * scale);
+        dst_right_width = SDL_ceilf(right_width * scale);
+        dst_top_height = SDL_ceilf(top_height * scale);
+        dst_bottom_height = SDL_ceilf(bottom_height * scale);
+    }
+
+    // Center
+    curr_src.x = srcrect->x + left_width;
+    curr_src.y = srcrect->y + top_height;
+    curr_src.w = srcrect->w - left_width - right_width;
+    curr_src.h = srcrect->h - top_height - bottom_height;
+    curr_dst.x = dstrect->x + dst_left_width;
+    curr_dst.y = dstrect->y + dst_top_height;
+    curr_dst.w = dstrect->w - dst_left_width - dst_right_width;
+    curr_dst.h = dstrect->h - dst_top_height - dst_bottom_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, tileScale, &curr_dst)) {
+        return false;
+    }
+
+    // Upper-left corner
+    curr_src.x = srcrect->x;
+    curr_src.y = srcrect->y;
+    curr_src.w = left_width;
+    curr_src.h = top_height;
+    curr_dst.x = dstrect->x;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dst_left_width;
+    curr_dst.h = dst_top_height;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Upper-right corner
+    curr_src.x = srcrect->x + srcrect->w - right_width;
+    curr_src.w = right_width;
+    curr_dst.x = dstrect->x + dstrect->w - dst_right_width;
+    curr_dst.w = dst_right_width;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Lower-right corner
+    curr_src.y = srcrect->y + srcrect->h - bottom_height;
+    curr_dst.y = dstrect->y + dstrect->h - dst_bottom_height;
+    curr_dst.h = dst_bottom_height;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Lower-left corner
+    curr_src.x = srcrect->x;
+    curr_src.w = left_width;
+    curr_dst.x = dstrect->x;
+    curr_dst.w = dst_left_width;
+    if (!SDL_RenderTexture(renderer, texture, &curr_src, &curr_dst)) {
+        return false;
+    }
+
+    // Left
+    curr_src.y = srcrect->y + top_height;
+    curr_src.h = srcrect->h - top_height - bottom_height;
+    curr_dst.y = dstrect->y + dst_top_height;
+    curr_dst.h = dstrect->h - dst_top_height - dst_bottom_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, tileScale, &curr_dst)) {
+        return false;
+    }
+
+    // Right
+    curr_src.x = srcrect->x + srcrect->w - right_width;
+    curr_src.w = right_width;
+    curr_dst.x = dstrect->x + dstrect->w - dst_right_width;
+    curr_dst.w = dst_right_width;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, tileScale, &curr_dst)) {
+        return false;
+    }
+
+    // Top
+    curr_src.x = srcrect->x + left_width;
+    curr_src.y = srcrect->y;
+    curr_src.w = srcrect->w - left_width - right_width;
+    curr_src.h = top_height;
+    curr_dst.x = dstrect->x + dst_left_width;
+    curr_dst.y = dstrect->y;
+    curr_dst.w = dstrect->w - dst_left_width - dst_right_width;
+    curr_dst.h = dst_top_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, tileScale, &curr_dst)) {
+        return false;
+    }
+
+    // Bottom
+    curr_src.y = srcrect->y + srcrect->h - bottom_height;
+    curr_dst.y = dstrect->y + dstrect->h - dst_bottom_height;
+    curr_dst.h = dst_bottom_height;
+    if (!SDL_RenderTextureTiled(renderer, texture, &curr_src, tileScale, &curr_dst)) {
+        return false;
+    }
+
+    return true;
+}
+
 bool SDL_RenderGeometry(SDL_Renderer *renderer,
                        SDL_Texture *texture,
                        const SDL_Vertex *vertices, int num_vertices,

test/testautomation_render.c

@@ -616,6 +616,189 @@ static int SDLCALL render_testBlit9Grid(void *arg)
     return TEST_COMPLETED;
 }
 
+/**
+ *  Tests tiled 9-grid blitting.
+ */
+static int SDLCALL render_testBlit9GridTiled(void *arg)
+{
+    SDL_Surface *referenceSurface = NULL;
+    SDL_Surface *source = NULL;
+    SDL_Texture *texture;
+    int x, y;
+    SDL_FRect rect;
+    int ret = 0;
+
+    /* Create source surface */
+    source = SDL_CreateSurface(3, 3, SDL_PIXELFORMAT_RGBA32);
+    SDLTest_AssertCheck(source != NULL, "Verify source surface is not NULL");
+    for (y = 0; y < 3; ++y) {
+        for (x = 0; x < 3; ++x) {
+            SDL_WriteSurfacePixel(source, x, y, (Uint8)((1 + x) * COLOR_SEPARATION), (Uint8)((1 + y) * COLOR_SEPARATION), 0, 255);
+        }
+    }
+    texture = SDL_CreateTextureFromSurface(renderer, source);
+    SDLTest_AssertCheck(texture != NULL, "Verify source texture is not NULL");
+    ret = SDL_SetTextureScaleMode(texture, SDL_SCALEMODE_NEAREST);
+    SDLTest_AssertCheck(ret == true, "Validate results from call to SDL_SetTextureScaleMode, expected: true, got: %i", ret);
+
+    /* Tiled 9-grid blit - 1.0 scale */
+    {
+        SDLTest_Log("tiled 9-grid blit - 1.0 scale");
+        /* Create reference surface */
+        SDL_DestroySurface(referenceSurface);
+        referenceSurface = SDL_CreateSurface(TESTRENDER_SCREEN_W, TESTRENDER_SCREEN_H, SDL_PIXELFORMAT_RGBA32);
+        SDLTest_AssertCheck(referenceSurface != NULL, "Verify reference surface is not NULL");
+        Fill9GridReferenceSurface(referenceSurface, 1, 1, 1, 1);
+
+        /* Clear surface. */
+        clearScreen();
+
+        /* Tiled blit. */
+        rect.x = 0.0f;
+        rect.y = 0.0f;
+        rect.w = (float)TESTRENDER_SCREEN_W;
+        rect.h = (float)TESTRENDER_SCREEN_H;
+        ret = SDL_RenderTexture9GridTiled(renderer, texture, NULL, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, &rect, 1.0f);
+        SDLTest_AssertCheck(ret == true, "Validate results from call to SDL_RenderTexture9GridTiled, expected: true, got: %i", ret);
+
+        /* See if it's the same */
+        compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE);
+
+        /* Make current */
+        SDL_RenderPresent(renderer);
+    }
+
+    /* Tiled 9-grid blit - 2.0 scale */
+    {
+        SDLTest_Log("tiled 9-grid blit - 2.0 scale");
+        /* Create reference surface */
+        SDL_DestroySurface(referenceSurface);
+        referenceSurface = SDL_CreateSurface(TESTRENDER_SCREEN_W, TESTRENDER_SCREEN_H, SDL_PIXELFORMAT_RGBA32);
+        SDLTest_AssertCheck(referenceSurface != NULL, "Verify reference surface is not NULL");
+        Fill9GridReferenceSurface(referenceSurface, 2, 2, 2, 2);
+
+        /* Clear surface. */
+        clearScreen();
+
+        /* Tiled blit. */
+        rect.x = 0.0f;
+        rect.y = 0.0f;
+        rect.w = (float)TESTRENDER_SCREEN_W;
+        rect.h = (float)TESTRENDER_SCREEN_H;
+        ret = SDL_RenderTexture9GridTiled(renderer, texture, NULL, 1.0f, 1.0f, 1.0f, 1.0f, 2.0f, &rect, 2.0f);
+        SDLTest_AssertCheck(ret == true, "Validate results from call to SDL_RenderTexture9GridTiled, expected: true, got: %i", ret);
+
+        /* See if it's the same */
+        compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE);
+
+        /* Make current */
+        SDL_RenderPresent(renderer);
+    }
+
+    /* Clean up. */
+    SDL_DestroySurface(source);
+    SDL_DestroyTexture(texture);
+
+    /* Create complex source surface */
+    source = SDL_CreateSurface(5, 5, SDL_PIXELFORMAT_RGBA32);
+    SDLTest_AssertCheck(source != NULL, "Verify source surface is not NULL");
+    SDL_WriteSurfacePixel(source, 0, 0, (Uint8)((1) * COLOR_SEPARATION), (Uint8)((1) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 1, 0, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((1) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 2, 0, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((1) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 3, 0, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((1) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 4, 0, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((1) * COLOR_SEPARATION), 0, 255);
+
+    SDL_WriteSurfacePixel(source, 0, 1, (Uint8)((1) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 1, 1, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 2, 1, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 3, 1, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 4, 1, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+
+    SDL_WriteSurfacePixel(source, 0, 2, (Uint8)((1) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 1, 2, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 2, 2, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 3, 2, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 4, 2, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((2) * COLOR_SEPARATION), 0, 255);
+
+    SDL_WriteSurfacePixel(source, 0, 3, (Uint8)((1) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 1, 3, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 2, 3, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 3, 3, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 4, 3, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+
+    SDL_WriteSurfacePixel(source, 0, 4, (Uint8)((1) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 1, 4, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 2, 4, (Uint8)((2) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 3, 4, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+    SDL_WriteSurfacePixel(source, 4, 4, (Uint8)((3) * COLOR_SEPARATION), (Uint8)((3) * COLOR_SEPARATION), 0, 255);
+
+    texture = SDL_CreateTextureFromSurface(renderer, source);
+    SDLTest_AssertCheck(texture != NULL, "Verify source texture is not NULL");
+    ret = SDL_SetTextureScaleMode(texture, SDL_SCALEMODE_NEAREST);
+    SDLTest_AssertCheck(ret == true, "Validate results from call to SDL_SetTextureScaleMode, expected: true, got: %i", ret);
+
+    /* complex tiled 9-grid blit - 1.0 scale */
+    {
+        SDLTest_Log("complex tiled 9-grid blit - 1.0 scale");
+        /* Create reference surface */
+        SDL_DestroySurface(referenceSurface);
+        referenceSurface = SDL_CreateSurface(TESTRENDER_SCREEN_W, TESTRENDER_SCREEN_H, SDL_PIXELFORMAT_RGBA32);
+        SDLTest_AssertCheck(referenceSurface != NULL, "Verify reference surface is not NULL");
+        Fill9GridReferenceSurface(referenceSurface, 1, 2, 1, 2);
+
+        /* Clear surface. */
+        clearScreen();
+
+        /* Tiled blit. */
+        rect.x = 0.0f;
+        rect.y = 0.0f;
+        rect.w = (float)TESTRENDER_SCREEN_W;
+        rect.h = (float)TESTRENDER_SCREEN_H;
+        ret = SDL_RenderTexture9GridTiled(renderer, texture, NULL, 1.0f, 2.0f, 1.0f, 2.0f, 1.0f, &rect, 1.0f);
+        SDLTest_AssertCheck(ret == true, "Validate results from call to SDL_RenderTexture9GridTiled, expected: true, got: %i", ret);
+
+        /* See if it's the same */
+        compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE);
+
+        /* Make current */
+        SDL_RenderPresent(renderer);
+    }
+
+    /* complex tiled 9-grid blit - 2.0 scale */
+    {
+        SDLTest_Log("complex tiled 9-grid blit - 2.0 scale");
+        /* Create reference surface */
+        SDL_DestroySurface(referenceSurface);
+        referenceSurface = SDL_CreateSurface(TESTRENDER_SCREEN_W, TESTRENDER_SCREEN_H, SDL_PIXELFORMAT_RGBA32);
+        SDLTest_AssertCheck(referenceSurface != NULL, "Verify reference surface is not NULL");
+        Fill9GridReferenceSurface(referenceSurface, 2, 4, 2, 4);
+
+        /* Clear surface. */
+        clearScreen();
+
+        /* Tiled blit. */
+        rect.x = 0.0f;
+        rect.y = 0.0f;
+        rect.w = (float)TESTRENDER_SCREEN_W;
+        rect.h = (float)TESTRENDER_SCREEN_H;
+        ret = SDL_RenderTexture9GridTiled(renderer, texture, NULL, 1.0f, 2.0f, 1.0f, 2.0f, 2.0f, &rect, 2.0f);
+        SDLTest_AssertCheck(ret == true, "Validate results from call to SDL_RenderTexture9GridTiled, expected: true, got: %i", ret);
+
+        /* See if it's the same */
+        compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE);
+
+        /* Make current */
+        SDL_RenderPresent(renderer);
+    }
+
+    /* Clean up. */
+    SDL_DestroySurface(referenceSurface);
+    SDL_DestroySurface(source);
+    SDL_DestroyTexture(texture);
+
+    return TEST_COMPLETED;
+}
+
 /**
  * Blits doing color tests.
  *
@@ -1539,6 +1722,10 @@ static const SDLTest_TestCaseReference renderTestBlit9Grid = {
     render_testBlit9Grid, "render_testBlit9Grid", "Tests 9-grid blitting", TEST_ENABLED
 };
 
+static const SDLTest_TestCaseReference renderTestBlit9GridTiled = {
+    render_testBlit9GridTiled, "render_testBlit9GridTiled", "Tests tiled 9-grid blitting", TEST_ENABLED
+};
+
 static const SDLTest_TestCaseReference renderTestBlitColor = {
     render_testBlitColor, "render_testBlitColor", "Tests blitting with color", TEST_ENABLED
 };
@@ -1571,6 +1758,7 @@ static const SDLTest_TestCaseReference *renderTests[] = {
     &renderTestBlit,
     &renderTestBlitTiled,
     &renderTestBlit9Grid,
+    &renderTestBlit9GridTiled,
     &renderTestBlitColor,
     &renderTestBlendModes,
     &renderTestViewport,