[tkreuzer] 48463: [SHELL32] When creating a shortcut icon and we have 32 bpp, use GdiAlphaBlend to create the final bitmap. This is neccessary, since we want to support alpha channels and those are destroyed when using SRCPAINT or any similar ROPs on the alpha bitmap (not a bug, Windows works like that, too). We could use MaskBlt, if it would work correctly, but on reactos it destroys the alpha channel as well (bug!), it's also most likely slower then the current solution. Fixes broken overlay i

Author: tkreuzer
Date: Thu Aug  5 14:42:56 2010
New Revision: 48463

URL: http://svn.reactos.org/svn/reactos?rev=48463&view=rev
Log:
[SHELL32]
When creating a shortcut icon and we have 32 bpp, use GdiAlphaBlend to create the final
bitmap. This is neccessary, since we want to support alpha channels and those are
destroyed when using SRCPAINT or any similar ROPs on the alpha bitmap (not a bug, Windows
works like that, too). We could use MaskBlt, if it would work correctly, but on reactos it
destroys the alpha channel as well (bug!), it's also most likely slower then the
current solution.
Fixes broken overlay icons.
See issue #5455 for more details.

Modified:
    trunk/reactos/dll/win32/shell32/iconcache.c

Modified: trunk/reactos/dll/win32/shell32/iconcache.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/dll/win32/shell32/iconcach…
==============================================================================
--- trunk/reactos/dll/win32/shell32/iconcache.c [iso-8859-1] (original)
+++ trunk/reactos/dll/win32/shell32/iconcache.c [iso-8859-1] Thu Aug  5 14:42:56 2010
@@ -171,25 +171,40 @@
 	  goto fail;
 	}
 
-	/* Copy the source xor bitmap to the target and clear out part of it by using
-	   the shortcut mask */
+	/* Copy the source color bitmap to the target */
 	if (! BitBlt(TargetDC, 0, 0, SourceBitmapInfo.bmWidth, SourceBitmapInfo.bmHeight,
-	             SourceDC, 0, 0, SRCCOPY) ||
-	    ! BitBlt(TargetDC, 0, SourceBitmapInfo.bmHeight - ShortcutBitmapInfo.bmHeight,
-	             ShortcutBitmapInfo.bmWidth, ShortcutBitmapInfo.bmHeight,
-	             ShortcutDC, 0, 0, SRCAND))
-	{
-	  goto fail;
-	}
-
-	if (NULL == SelectObject(ShortcutDC, ShortcutIconInfo.hbmColor)) goto fail;
-
-	/* Now put in the shortcut xor mask */
-	if (! BitBlt(TargetDC, 0, SourceBitmapInfo.bmHeight - ShortcutBitmapInfo.bmHeight,
-	             ShortcutBitmapInfo.bmWidth, ShortcutBitmapInfo.bmHeight,
-	             ShortcutDC, 0, 0, SRCINVERT))
-	{
-	  goto fail;
+	             SourceDC, 0, 0, SRCCOPY)) goto fail;
+
+	/* Check if we can use alpha blending */
+	if (ShortcutBitmapInfo.bmBitsPixel == 32)
+	{
+		/* Use alpha blending to make sure the target alpha channel stays valid */
+		if (NULL == SelectObject(ShortcutDC, ShortcutIconInfo.hbmColor)) goto fail;
+		if (!GdiAlphaBlend(TargetDC, 0, SourceBitmapInfo.bmHeight -
ShortcutBitmapInfo.bmHeight,
+		                ShortcutBitmapInfo.bmWidth, ShortcutBitmapInfo.bmHeight,
+		                ShortcutDC, 0, 0, ShortcutBitmapInfo.bmWidth,
ShortcutBitmapInfo.bmHeight,
+		                (BLENDFUNCTION){AC_SRC_OVER, 0, 255, AC_SRC_ALPHA})) goto fail;
+	}
+	else
+	{
+		/* Copy the source xor bitmap to the target and clear out part of it by using
+		   the shortcut mask */
+		if (! BitBlt(TargetDC, 0, SourceBitmapInfo.bmHeight - ShortcutBitmapInfo.bmHeight,
+		             ShortcutBitmapInfo.bmWidth, ShortcutBitmapInfo.bmHeight,
+		         ShortcutDC, 0, 0, SRCAND))
+		{
+			goto fail;
+		}
+
+		if (NULL == SelectObject(ShortcutDC, ShortcutIconInfo.hbmColor)) goto fail;
+
+		/* Now put in the shortcut xor mask */
+		if (! BitBlt(TargetDC, 0, SourceBitmapInfo.bmHeight - ShortcutBitmapInfo.bmHeight,
+		             ShortcutBitmapInfo.bmWidth, ShortcutBitmapInfo.bmHeight,
+		         ShortcutDC, 0, 0, SRCINVERT))
+		{
+			goto fail;
+		}
 	}
 
 	/* Clean up, we're not goto'ing to 'fail' after this so we can be lazy
and not set
@@ -387,14 +402,14 @@
     if (sic_hdpa)
     {
         TRACE("Icon cache already initialized\n");
-        return TRUE;
+	  return TRUE;
     }
 
-    sic_hdpa = DPA_Create(16);
-    if (!sic_hdpa)
-    {
+	sic_hdpa = DPA_Create(16);
+	if (!sic_hdpa)
+	{
         return FALSE;
-    }
+	}
 
     hDC = CreateICW(L"DISPLAY", NULL, NULL, NULL);
     if (!hDC)
@@ -439,7 +454,7 @@
                                         100);
     if (ShellSmallIconList)
     {
-         /* Load the document icon, which is used as the default if an icon isn't
found. */
+        /* Load the document icon, which is used as the default if an icon isn't
found. */
         hSm = (HICON)LoadImageW(shell32_hInstance,
                                 MAKEINTRESOURCEW(IDI_SHELL_DOCUMENT),
                                 IMAGE_ICON,
@@ -459,7 +474,7 @@
     }
 
     if (ShellBigIconList)
-    {
+        {
         hLg = (HICON)LoadImageW(shell32_hInstance,
                                 MAKEINTRESOURCEW(IDI_SHELL_DOCUMENT),
                                 IMAGE_ICON,
@@ -470,7 +485,7 @@
         {
             ERR("Failed to load IDI_SHELL_DOCUMENT icon2!\n");
             DestroyIcon(hSm);
-            return FALSE;
+          return FALSE;
         }
     }
     else
@@ -482,9 +497,9 @@
     SIC_IconAppend(swShell32Name, IDI_SHELL_DOCUMENT-1, hSm, hLg, 0);
     SIC_IconAppend(swShell32Name, -IDI_SHELL_DOCUMENT, hSm, hLg, 0);
 
-    TRACE("hIconSmall=%p hIconBig=%p\n",ShellSmallIconList, ShellBigIconList);
-
-    return TRUE;
+	TRACE("hIconSmall=%p hIconBig=%p\n",ShellSmallIconList, ShellBigIconList);
+
+	return TRUE;
 }
 /*************************************************************************
  * SIC_Destroy
@@ -550,7 +565,7 @@
 		LPWSTR p = wcschr(buffer, ',');
 
 		if (p)
-		    *p++ = 0;
+		*p++ = 0;
 
 		iconPath = buffer;
 		iconIdx = _wtoi(p);