Added SDL_GetRenderLogicalPresentationRect()

Fixes https://github.com/libsdl-org/SDL/issues/8815

include/SDL3/SDL_render.h

@@ -1297,6 +1297,7 @@ extern SDL_DECLSPEC SDL_Texture *SDLCALL SDL_GetRenderTarget(SDL_Renderer *rende
  *
  * \sa SDL_ConvertEventToRenderCoordinates
  * \sa SDL_GetRenderLogicalPresentation
+ * \sa SDL_GetRenderLogicalPresentationRect
  */
 extern SDL_DECLSPEC int SDLCALL SDL_SetRenderLogicalPresentation(SDL_Renderer *renderer, int w, int h, SDL_RendererLogicalPresentation mode, SDL_ScaleMode scale_mode);
 
@@ -1320,6 +1321,22 @@ extern SDL_DECLSPEC int SDLCALL SDL_SetRenderLogicalPresentation(SDL_Renderer *r
  */
 extern SDL_DECLSPEC int SDLCALL SDL_GetRenderLogicalPresentation(SDL_Renderer *renderer, int *w, int *h, SDL_RendererLogicalPresentation *mode, SDL_ScaleMode *scale_mode);
 
+/**
+ * Get the final presentation rectangle for rendering.
+ *
+ * This function returns the calculated rectangle used for logical presentation, based on the presentation mode and output size. If logical presentation is disabled, it will fill the rectangle with the output size, in pixels.
+ *
+ * \param renderer the rendering context.
+ * \param rect a pointer filled in with the final presentation rectangle, may be NULL.
+ * \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_SetRenderLogicalPresentation
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_GetRenderLogicalPresentationRect(SDL_Renderer *renderer, SDL_FRect *rect);
+
 /**
  * Get a point in render coordinates when given a point in window coordinates.
  *

src/dynapi/SDL_dynapi.sym

@@ -393,6 +393,7 @@ SDL3_0.0.0 {
     SDL_GetRenderDrawColorFloat;
     SDL_GetRenderDriver;
     SDL_GetRenderLogicalPresentation;
+    SDL_GetRenderLogicalPresentationRect;
     SDL_GetRenderMetalCommandEncoder;
     SDL_GetRenderMetalLayer;
     SDL_GetRenderOutputSize;

src/dynapi/SDL_dynapi_overrides.h

@@ -418,6 +418,7 @@
 #define SDL_GetRenderDrawColorFloat SDL_GetRenderDrawColorFloat_REAL
 #define SDL_GetRenderDriver SDL_GetRenderDriver_REAL
 #define SDL_GetRenderLogicalPresentation SDL_GetRenderLogicalPresentation_REAL
+#define SDL_GetRenderLogicalPresentationRect SDL_GetRenderLogicalPresentationRect_REAL
 #define SDL_GetRenderMetalCommandEncoder SDL_GetRenderMetalCommandEncoder_REAL
 #define SDL_GetRenderMetalLayer SDL_GetRenderMetalLayer_REAL
 #define SDL_GetRenderOutputSize SDL_GetRenderOutputSize_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -438,6 +438,7 @@ SDL_DYNAPI_PROC(int,SDL_GetRenderDrawColor,(SDL_Renderer *a, Uint8 *b, Uint8 *c,
 SDL_DYNAPI_PROC(int,SDL_GetRenderDrawColorFloat,(SDL_Renderer *a, float *b, float *c, float *d, float *e),(a,b,c,d,e),return)
 SDL_DYNAPI_PROC(const char*,SDL_GetRenderDriver,(int a),(a),return)
 SDL_DYNAPI_PROC(int,SDL_GetRenderLogicalPresentation,(SDL_Renderer *a, int *b, int *c, SDL_RendererLogicalPresentation *d, SDL_ScaleMode *e),(a,b,c,d,e),return)
+SDL_DYNAPI_PROC(int,SDL_GetRenderLogicalPresentationRect,(SDL_Renderer *a, SDL_FRect *b),(a,b),return)
 SDL_DYNAPI_PROC(void*,SDL_GetRenderMetalCommandEncoder,(SDL_Renderer *a),(a),return)
 SDL_DYNAPI_PROC(void*,SDL_GetRenderMetalLayer,(SDL_Renderer *a),(a),return)
 SDL_DYNAPI_PROC(int,SDL_GetRenderOutputSize,(SDL_Renderer *a, int *b, int *c),(a,b,c),return)

src/render/SDL_render.c

@@ -2607,6 +2607,33 @@ int SDL_GetRenderLogicalPresentation(SDL_Renderer *renderer, int *w, int *h, SDL
     return 0;
 }
 
+int SDL_GetRenderLogicalPresentationRect(SDL_Renderer *renderer, SDL_FRect *rect)
+{
+    if (rect) {
+        SDL_zerop(rect);
+    }
+
+    CHECK_RENDERER_MAGIC(renderer, -1);
+
+    if (rect) {
+        if (renderer->logical_presentation_mode == SDL_LOGICAL_PRESENTATION_DISABLED) {
+            int output_w = 0, output_h = 0;
+
+            if (SDL_GetRenderOutputSize(renderer, &output_w, &output_h) < 0) {
+                return -1;
+            }
+
+            rect->x = 0.0f;
+            rect->y = 0.0f;
+            rect->w = (float)output_w;
+            rect->h = (float)output_h;
+        } else {
+            SDL_copyp(rect, &renderer->logical_dst_rect);
+        }
+    }
+    return 0;
+}
+
 static void SDL_RenderLogicalBorders(SDL_Renderer *renderer)
 {
     const SDL_FRect *dst = &renderer->logical_dst_rect;

test/testautomation_render.c

@@ -920,6 +920,10 @@ static int render_testLogicalSize(void *arg)
     SDL_Rect viewport;
     SDL_FRect rect;
     int w, h;
+    int set_w, set_h;
+    SDL_RendererLogicalPresentation set_presentation_mode;
+    SDL_ScaleMode set_scale_mode;
+    SDL_FRect set_rect;
     const int factor = 2;
 
     viewport.x = ((TESTRENDER_SCREEN_W / 4) / factor) * factor;
@@ -940,6 +944,20 @@ static int render_testLogicalSize(void *arg)
     CHECK_FUNC(SDL_SetRenderLogicalPresentation, (renderer, w / factor, h / factor,
                                            SDL_LOGICAL_PRESENTATION_LETTERBOX,
                                            SDL_SCALEMODE_NEAREST))
+    CHECK_FUNC(SDL_GetRenderLogicalPresentation, (renderer, &set_w, &set_h, &set_presentation_mode, &set_scale_mode))
+    SDLTest_AssertCheck(
+        set_w == (w / factor) &&
+        set_h == (h / factor) &&
+        set_presentation_mode == SDL_LOGICAL_PRESENTATION_LETTERBOX &&
+        set_scale_mode == SDL_SCALEMODE_NEAREST,
+        "Validate result from SDL_GetRenderLogicalPresentation, got %d, %d, %d, %d", set_w, set_h, set_presentation_mode, set_scale_mode);
+    CHECK_FUNC(SDL_GetRenderLogicalPresentationRect, (renderer, &set_rect))
+    SDLTest_AssertCheck(
+        set_rect.x == 0.0f &&
+        set_rect.y == 0.0f &&
+        set_rect.w == 320.0f &&
+        set_rect.h == 240.0f,
+        "Validate result from SDL_GetRenderLogicalPresentationRect, got {%g, %g, %gx%g}", set_rect.x, set_rect.y, set_rect.w, set_rect.h);
     CHECK_FUNC(SDL_SetRenderDrawColor, (renderer, 0, 255, 0, SDL_ALPHA_OPAQUE))
     rect.x = (float)viewport.x / factor;
     rect.y = (float)viewport.y / factor;
@@ -949,6 +967,20 @@ static int render_testLogicalSize(void *arg)
     CHECK_FUNC(SDL_SetRenderLogicalPresentation, (renderer, 0, 0,
                                            SDL_LOGICAL_PRESENTATION_DISABLED,
                                            SDL_SCALEMODE_NEAREST))
+    CHECK_FUNC(SDL_GetRenderLogicalPresentation, (renderer, &set_w, &set_h, &set_presentation_mode, &set_scale_mode))
+    SDLTest_AssertCheck(
+        set_w == 0 &&
+        set_h == 0 &&
+        set_presentation_mode == SDL_LOGICAL_PRESENTATION_DISABLED &&
+        set_scale_mode == SDL_SCALEMODE_NEAREST,
+        "Validate result from SDL_GetRenderLogicalPresentation, got %d, %d, %d, %d", set_w, set_h, set_presentation_mode, set_scale_mode);
+    CHECK_FUNC(SDL_GetRenderLogicalPresentationRect, (renderer, &set_rect))
+    SDLTest_AssertCheck(
+        set_rect.x == 0.0f &&
+        set_rect.y == 0.0f &&
+        set_rect.w == 320.0f &&
+        set_rect.h == 240.0f,
+        "Validate result from SDL_GetRenderLogicalPresentationRect, got {%g, %g, %gx%g}", set_rect.x, set_rect.y, set_rect.w, set_rect.h);
 
     /* Check to see if final image matches. */
     compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE);
@@ -999,11 +1031,39 @@ static int render_testLogicalSize(void *arg)
                                            h,
                                            SDL_LOGICAL_PRESENTATION_LETTERBOX,
                                            SDL_SCALEMODE_LINEAR))
+    CHECK_FUNC(SDL_GetRenderLogicalPresentation, (renderer, &set_w, &set_h, &set_presentation_mode, &set_scale_mode))
+    SDLTest_AssertCheck(
+        set_w == w - 2 * (TESTRENDER_SCREEN_W / 4) &&
+        set_h == h &&
+        set_presentation_mode == SDL_LOGICAL_PRESENTATION_LETTERBOX &&
+        set_scale_mode == SDL_SCALEMODE_LINEAR,
+        "Validate result from SDL_GetRenderLogicalPresentation, got %d, %d, %d, %d", set_w, set_h, set_presentation_mode, set_scale_mode);
+    CHECK_FUNC(SDL_GetRenderLogicalPresentationRect, (renderer, &set_rect))
+    SDLTest_AssertCheck(
+        set_rect.x == 20.0f &&
+        set_rect.y == 0.0f &&
+        set_rect.w == 280.0f &&
+        set_rect.h == 240.0f,
+        "Validate result from SDL_GetRenderLogicalPresentationRect, got {%g, %g, %gx%g}", set_rect.x, set_rect.y, set_rect.w, set_rect.h);
     CHECK_FUNC(SDL_SetRenderDrawColor, (renderer, 0, 255, 0, SDL_ALPHA_OPAQUE))
     CHECK_FUNC(SDL_RenderFillRect, (renderer, NULL))
     CHECK_FUNC(SDL_SetRenderLogicalPresentation, (renderer, 0, 0,
                                            SDL_LOGICAL_PRESENTATION_DISABLED,
                                            SDL_SCALEMODE_NEAREST))
+    CHECK_FUNC(SDL_GetRenderLogicalPresentation, (renderer, &set_w, &set_h, &set_presentation_mode, &set_scale_mode))
+    SDLTest_AssertCheck(
+        set_w == 0 &&
+        set_h == 0 &&
+        set_presentation_mode == SDL_LOGICAL_PRESENTATION_DISABLED &&
+        set_scale_mode == SDL_SCALEMODE_NEAREST,
+        "Validate result from SDL_GetRenderLogicalPresentation, got %d, %d, %d, %d", set_w, set_h, set_presentation_mode, set_scale_mode);
+    CHECK_FUNC(SDL_GetRenderLogicalPresentationRect, (renderer, &set_rect))
+    SDLTest_AssertCheck(
+        set_rect.x == 0.0f &&
+        set_rect.y == 0.0f &&
+        set_rect.w == 320.0f &&
+        set_rect.h == 240.0f,
+        "Validate result from SDL_GetRenderLogicalPresentationRect, got {%g, %g, %gx%g}", set_rect.x, set_rect.y, set_rect.w, set_rect.h);
 
     /* Check to see if final image matches. */
     compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE);