BUG Fix strip_alpha for RGBA PNGs

luispedro · Sep 19, 2016 · 0869ce1 · 0869ce1
1 parent 4bc08a7
commit 0869ce1
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Showing 3 changed files with 7 additions and 1 deletion.
diff --git a/imread/lib/_png.cpp b/imread/lib/_png.cpp
@@ -121,7 +121,7 @@ std::auto_ptr<Image> PNGFormat::read(byte_source* src, ImageFactory* factory, co
             d = 3;
             break;
         case PNG_COLOR_TYPE_RGB_ALPHA:
-            d = 4;
+            d = 4 - int(strip_alpha);
             break;
         case PNG_COLOR_TYPE_GRAY:
             d = -1;

diff --git a/imread/tests/data/rgba.png b/imread/tests/data/rgba.png
diff --git a/imread/tests/test_png.py b/imread/tests/test_png.py
@@ -80,3 +80,9 @@ def test_write_16bit():
     imsave(_filename, f)
     f2 = imread(_filename)
     assert np.all(f == f2)
+
+
+def test_strip_alpha():
+    w_alpha = imread(file_path('rgba.png'))
+    wno_alpha = imread(file_path('rgba.png'), opts={'strip_alpha':True})
+    assert np.all(w_alpha[:,:,:3] == wno_alpha)
-Original file line number
+Diff line change
@@ Expand Up @@
                 d = 3;
                 break;
             case PNG_COLOR_TYPE_RGB_ALPHA:
-                d = 4;
+                d = 4 - int(strip_alpha);
                 break;
             case PNG_COLOR_TYPE_GRAY:
                 d = -1;
@@ Expand Down @@