Make it compile

[wxWidgets.git] / src / common / imagbmp.cpp

diff --git a/src/common/imagbmp.cpp b/src/common/imagbmp.cpp
index 3e7a128d101005f7a473af6a8fe8b66475bc28b8..41edf784b42bd491fdbb768aed602333b5d3910d 100644 (file)
--- a/src/common/imagbmp.cpp
+++ b/src/common/imagbmp.cpp
@@ -684,6 +684,14 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
 
     int linesize = ((width * bpp + 31) / 32) * 4;
 
+    // flag indicating if we have any not fully transparent alpha values: this
+    // is used to account for the bitmaps which use 32bpp format (normally
+    // meaning that they have alpha channel) but have only zeroes in it so that
+    // without this hack they appear fully transparent -- and as this is
+    // unlikely intentional, we consider that they don't have alpha at all in
+    // this case (see #10915)
+    bool hasValidAlpha = false;
+
     /* BMPs are stored upside down */
     for ( int line = (height - 1); line >= 0; line-- )
     {
@@ -895,6 +903,9 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
                 {
                     temp = (unsigned char)((aDword & amask) >> ashift);
                     alpha[line * width + column] = temp;
+
+                    if ( temp != wxALPHA_TRANSPARENT )
+                        hasValidAlpha = true;
                 }
                 column++;
             }
@@ -910,6 +921,13 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
 
     image->SetMask(false);
 
+    // check if we had any valid alpha values in this bitmap
+    if ( alpha && !hasValidAlpha )
+    {
+        // we didn't, so finally discard the alpha channel completely
+        image->ClearAlpha();
+    }
+
     const wxStreamError err = stream.GetLastError();
     return err == wxSTREAM_NO_ERROR || err == wxSTREAM_EOF;
 }