Merge pull request #3432 from pygame-community/ankith26-fix-alpha-tga

Fix SRCALPHA TGA image saving

Author: ankith26

src_c/image.c

@@ -1687,7 +1687,7 @@ SaveTGA_RW(SDL_Surface *surface, SDL_RWops *out, int rle)
     int alpha = 0;
     struct TGAheader h;
     int srcbpp;
-    Uint8 surf_alpha;
+    SDL_BlendMode surf_blendmode;
     int have_surf_colorkey = 0;
     Uint32 surf_colorkey;
     SDL_Rect r;
@@ -1718,7 +1718,10 @@ SaveTGA_RW(SDL_Surface *surface, SDL_RWops *out, int rle)
     SDL_PixelFormatEnum output_format;
 #endif
 
-    SDL_GetSurfaceAlphaMod(surface, &surf_alpha);
+    if (!PG_GetSurfaceBlendMode(surface, &surf_blendmode)) {
+        return -1;
+    }
+
     if ((have_surf_colorkey = SDL_HasColorKey(surface))) {
         SDL_GetColorKey(surface, &surf_colorkey);
     }
@@ -1805,11 +1808,9 @@ SaveTGA_RW(SDL_Surface *surface, SDL_RWops *out, int rle)
         }
     }
 
-    /* Temporarily remove colorkey and alpha from surface so copies are
-       opaque */
-    SDL_SetSurfaceAlphaMod(surface, SDL_ALPHA_OPAQUE);
-    if (have_surf_colorkey) {
-        SDL_SetColorKey(surface, SDL_FALSE, surf_colorkey);
+    /* Temporarily set SDL_BLENDMODE_NONE so that copies are opaque */
+    if (!PG_SetSurfaceBlendMode(surface, SDL_BLENDMODE_NONE)) {
+        goto error;
     }
 
     r.x = 0;
@@ -1841,9 +1842,8 @@ SaveTGA_RW(SDL_Surface *surface, SDL_RWops *out, int rle)
     }
 
     /* restore flags */
-    SDL_SetSurfaceAlphaMod(surface, surf_alpha);
-    if (have_surf_colorkey) {
-        SDL_SetColorKey(surface, SDL_TRUE, surf_colorkey);
+    if (!PG_SetSurfaceBlendMode(surface, surf_blendmode)) {
+        goto error;
     }
 
     free(rlebuf);

test/image_test.py

@@ -4,6 +4,7 @@
 import io
 import os
 import pathlib
+import random
 import tempfile
 import unittest
 from concurrent.futures import ThreadPoolExecutor
@@ -426,6 +427,39 @@ def test_save_tga(self):
             # clean up the temp file, even if test fails
             os.remove(temp_filename)
 
+    def test_save_tga_srcalpha(self):
+        WIDTH = 10
+        HEIGHT = 10
+        s = pygame.Surface((WIDTH, HEIGHT), pygame.SRCALPHA)
+        pixels = [
+            [
+                (
+                    random.randint(0, 255),
+                    random.randint(0, 255),
+                    random.randint(0, 255),
+                    random.randint(0, 255),
+                )
+                for _ in range(WIDTH)
+            ]
+            for _ in range(HEIGHT)
+        ]
+        for y in range(HEIGHT):
+            for x in range(WIDTH):
+                s.set_at((x, y), pixels[y][x])
+
+        with tempfile.NamedTemporaryFile(suffix=".tga", delete=False) as f:
+            temp_filename = f.name
+
+        try:
+            pygame.image.save(s, temp_filename)
+            s2 = pygame.image.load(temp_filename)
+            for y in range(HEIGHT):
+                for x in range(WIDTH):
+                    self.assertEqual(s2.get_at((x, y)), pixels[y][x])
+        finally:
+            # clean up the temp file, even if test fails
+            os.remove(temp_filename)
+
     def test_save_pathlib(self):
         surf = pygame.Surface((1, 1))
         surf.fill((23, 23, 23))