Fix issue #2446: rotozoom keeps the colorkey flag.

src_c/_pygame.h

@@ -72,6 +72,8 @@
 #define PG_ConvertSurface SDL_ConvertSurface
 #define PG_ConvertSurfaceFormat SDL_ConvertSurfaceFormat
 
+#define PG_SurfaceHasRLE SDL_SurfaceHasRLE
+
 #else /* ~SDL_VERSION_ATLEAST(3, 0, 0)*/
 #define PG_ShowCursor() SDL_ShowCursor(SDL_ENABLE)
 #define PG_HideCursor() SDL_ShowCursor(SDL_DISABLE)
@@ -100,6 +102,44 @@
 #define PG_ConvertSurface(src, fmt) SDL_ConvertSurface(src, fmt, 0)
 #define PG_ConvertSurfaceFormat(src, pixel_format) \
     SDL_ConvertSurfaceFormat(src, pixel_format, 0)
+#if SDL_VERSION_ATLEAST(2, 0, 14)
+#define PG_SurfaceHasRLE SDL_HasSurfaceRLE
+#else
+// vendored in until our lowest SDL version is 2.0.14
+typedef struct {
+    Uint8 *src;
+    int src_w, src_h;
+    int src_pitch;
+    int src_skip;
+    Uint8 *dst;
+    int dst_w, dst_h;
+    int dst_pitch;
+    int dst_skip;
+    SDL_PixelFormat *src_fmt;
+    SDL_PixelFormat *dst_fmt;
+    Uint8 *table;
+    int flags;
+    Uint32 colorkey;
+    Uint8 r, g, b, a;
+} SDL_InternalBlitInfo;
+
+struct SDL_BlitMap {
+    SDL_Surface *dst;
+    int identity;
+    SDL_blit blit;
+    void *data;
+    SDL_InternalBlitInfo info;
+
+    /* the version count matches the destination; mismatch indicates
+       an invalid mapping */
+    Uint32 dst_palette_version;
+    Uint32 src_palette_version;
+};
+#define SDL_COPY_RLE_DESIRED 0x00001000
+
+SDL_bool
+PG_SurfaceHasRLE(SDL_Surface *surface);
+#endif
 
 #endif
 

src_c/rotozoom.c

@@ -11,6 +11,23 @@
 
 */
 
+#include "_pygame.h"
+
+#if !SDL_VERSION_ATLEAST(2, 0, 14)
+SDL_bool
+PG_SurfaceHasRLE(SDL_Surface *surface)
+{
+    if (surface == NULL) {
+        return SDL_FALSE;
+    }
+
+    if (!(surface->map->info.flags & SDL_COPY_RLE_DESIRED)) {
+        return SDL_FALSE;
+    }
+
+    return SDL_TRUE;
+}
+#endif
 #define NO_PYGAME_C_API
 #include "pygame.h"
 
@@ -511,6 +528,7 @@ rotozoomSurface(SDL_Surface *src, double angle, double zoom, int smooth)
     int dstwidth, dstheight;
     int is32bit;
     int src_converted;
+    Uint32 colorkey;
 
     /*
      * Sanity check
@@ -583,6 +601,17 @@ rotozoomSurface(SDL_Surface *src, double angle, double zoom, int smooth)
          * Target surface is 32bit with source RGBA/ABGR ordering
          */
         rz_dst = PG_CreateSurface(dstwidth, dstheight, rz_src->format->format);
+        if (SDL_GetColorKey(src, &colorkey) == 0) {
+            if (SDL_SetColorKey(rz_dst, SDL_TRUE, colorkey) != 0) {
+                SDL_FreeSurface(rz_dst);
+                return NULL;
+            }
+            if (PG_SurfaceHasRLE(src) &&
+                SDL_SetSurfaceRLE(rz_dst, SDL_TRUE) != 0) {
+                SDL_FreeSurface(rz_dst);
+                return NULL;
+            }
+        }
 
         /*
          * Lock source surface
@@ -628,7 +657,19 @@ rotozoomSurface(SDL_Surface *src, double angle, double zoom, int smooth)
         /*
          * Target surface is 32bit with source RGBA/ABGR ordering
          */
+
         rz_dst = PG_CreateSurface(dstwidth, dstheight, rz_src->format->format);
+        if (SDL_GetColorKey(src, &colorkey) == 0) {
+            if (SDL_SetColorKey(rz_dst, SDL_TRUE, colorkey) != 0) {
+                SDL_FreeSurface(rz_dst);
+                return NULL;
+            }
+            if (PG_SurfaceHasRLE(src) &&
+                SDL_SetSurfaceRLE(rz_dst, SDL_TRUE) != 0) {
+                SDL_FreeSurface(rz_dst);
+                return NULL;
+            }
+        }
 
         /*
          * Lock source surface

src_c/transform.c

@@ -891,6 +891,10 @@ surf_rotozoom(PyObject *self, PyObject *args, PyObject *kwargs)
     Py_BEGIN_ALLOW_THREADS;
     newsurf = rotozoomSurface(surf32, angle, scale, 1);
     Py_END_ALLOW_THREADS;
+    if (newsurf == NULL) {
+        PyErr_SetString(pgExc_SDLError, SDL_GetError());
+        return NULL;
+    }
 
     if (surf32 == surf)
         pgSurface_Unlock(surfobj);

test/transform_test.py

@@ -1287,6 +1287,17 @@ def test_rotozoom(self):
         self.assertEqual(s1.get_rect(), pygame.Rect(0, 0, 0, 0))
         self.assertEqual(s2.get_rect(), pygame.Rect(0, 0, 0, 0))
 
+    def test_rotozoom_keeps_colorkey(self):
+        image = pygame.Surface((64, 64))
+        image.set_colorkey("black")
+        pygame.draw.circle(image, "red", (32, 32), 32, width=0)
+
+        no_rot = pygame.transform.rotozoom(image, 0, 1.1)
+        self.assertEqual(image.get_colorkey(), no_rot.get_colorkey())
+
+        with_rot = pygame.transform.rotozoom(image, 5, 1.1)
+        self.assertEqual(image.get_colorkey(), with_rot.get_colorkey())
+
     def test_invert(self):
         surface = pygame.Surface((10, 10), depth=32)