CVS: winex/dlls/msimg32 msimg32_main.c,1.7,1.8

Subject: winex/dlls/msimg32 msimg32_main.c,1.7,1.8Update of /var/lib/cvsd/cvsroot/winex/dlls/msimg32
In directory agravaine:/tmp/cvs-serv31878/dlls/msimg32

Modified Files:
	msimg32_main.c 
Log Message:

Preliminary attempt at doing alpha blending manually for the AlphaBlend
function.  There are a number of issues with this currently, including
the following:
- Use of BITMAPINFOHEADER instead of BITMAPV5HEADER may mean that the DIB
  sections aren't actually being created with alpha
- Our StretchBlt implementation may not be capable of handling alpha



Index: msimg32_main.c
===================================================================
RCS file: /var/lib/cvsd/cvsroot/winex/dlls/msimg32/msimg32_main.c,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -d -r1.7 -r1.8
--- msimg32_main.c	30 Mar 2007 21:33:01 -0000	1.7
+++ msimg32_main.c	27 Apr 2007 13:17:50 -0000	1.8
@@ -100,16 +100,93 @@
 		       int nWidthSrc, int nHeightSrc,
 		       BLENDFUNCTION blendFunction)
 {
-  FIXME("(%d, (%d,%d),(%d,%d), %d, (%d,%d),(%d,%d), (%d,%d,%d,%d)) stub!\n",
+  HDC hdcScratch;
+  BITMAPINFO bmiScratch;
+  HBITMAP hbmSrc, hbmDest;
+  BYTE *src, *dest;
+  int x,y,c;
+  
+  TRACE("(%d, (%d,%d),(%d,%d), %d, (%d,%d),(%d,%d), (%d,%d,%d,%d)) stub!\n",
         hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest,
 	hdcSrc, nXOriginSrc, nYOriginSrc, nWidthSrc, nHeightSrc, 
 	blendFunction.BlendOp, blendFunction.BlendFlags, 
 	blendFunction.SourceConstantAlpha, blendFunction.AlphaFormat);
-  StretchBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest,
+  
+  if ((blendFunction.BlendOp != AC_SRC_OVER) || blendFunction.BlendFlags) {
+    FIXME("Invalid parameters\n");
+    return FALSE;
+  }
+  
+  /* Check for opaque case that doesn't need alpha blending */
+  if ((blendFunction.SourceConstantAlpha == 255) && (blendFunction.AlphaFormat == 0))
+  {
+    StretchBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest,
+               hdcSrc, nXOriginSrc, nYOriginSrc, nWidthSrc, nHeightSrc, SRCCOPY);
+    return TRUE;
+  }
+  
+  /* create scratch dc and prep the dibsection header */
+  /* FIXME: change bmiScratch to a BITMAPV5HEADER to ensure DIB sections have alpha */
+  memset(&bmiScratch.bmiHeader, 0, sizeof(BITMAPINFOHEADER));
+  bmiScratch.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
+  bmiScratch.bmiHeader.biWidth = nWidthDest;
+  bmiScratch.bmiHeader.biHeight = nHeightDest;
+  bmiScratch.bmiHeader.biPlanes = 1;
+  bmiScratch.bmiHeader.biBitCount = 32;
+  bmiScratch.bmiHeader.biCompression = BI_RGB;
+  
+  hdcScratch = CreateCompatibleDC(hdcDest);
+  
+  /* read in src */
+  /* FIXME: Our StretchBlt implementation is likely losing the alpha data during this copy.. */
+  hbmSrc = CreateDIBSection(hdcScratch, &bmiScratch, DIB_RGB_COLORS, (void**)(&src), 0, 0);
+  SelectObject(hdcScratch, hbmSrc);
+  StretchBlt(hdcScratch, 0, 0, nWidthDest, nHeightDest,
              hdcSrc, nXOriginSrc, nYOriginSrc, nWidthSrc, nHeightSrc, SRCCOPY);
+  
+  /* read in dest */
+  hbmDest = CreateDIBSection(hdcScratch, &bmiScratch, DIB_RGB_COLORS, (void**)(&dest), 0, 0);
+  SelectObject(hdcScratch, hbmDest);
+  BitBlt(hdcScratch, 0, 0, nWidthDest, nHeightDest, hdcDest, nXOriginDest, nYOriginDest, SRCCOPY);
+  
+  /* blend them together in dest */
+  if (blendFunction.AlphaFormat == AC_SRC_ALPHA)
+  {
+    FLOAT sca = blendFunction.SourceConstantAlpha / 255.0;
+    for (y=0; y<nHeightDest; y++) {
+      for (x=0; x<nWidthDest; x++) {
+        FLOAT sa = src[(y * 4 * nWidthDest) + (x * 4) + 3] / 255.0;
+        for (c=0; c<4; c++)
+        {
+          BYTE s = src[(y * 4 * nWidthDest) + (x * 4) + c];
+          BYTE d = dest[(y * 4 * nWidthDest) + (x * 4) + c];
+          FLOAT t = (s * sca) + ((1 - sa) * d);
+          dest[(y * 4 * nWidthDest) + (x * 4) + c] = max(0, min(t, 255));
+        }
+      }
+    }
+  } else {
+    FLOAT sca = blendFunction.SourceConstantAlpha / 255.0;
+    for (y=0; y<nHeightDest; y++) {
+      for (x=0; x<nWidthDest; x++) {
+        for (c=0; c<4; c++)
+        {
+          BYTE s = src[(y * 4 * nWidthDest) + (x * 4) + c];
+          BYTE d = dest[(y * 4 * nWidthDest) + (x * 4) + c];
+          FLOAT t = (s * sca) + ((1 - sca) * d);
+          dest[(y * 4 * nWidthDest) + (x * 4) + c] = max(0, min(t, 255));
+        }
+      }
+    }
+  }
+  
+  /* copy to destination dc */
+  BitBlt(hdcDest, nXOriginDest, nYOriginDest, nWidthDest, nHeightDest, hdcScratch, 0, 0, SRCCOPY);
+  
+  /* delete objects */
+  DeleteObject(hbmDest);
+  DeleteObject(hbmSrc);
+  DeleteObject(hdcScratch);
+  
   return TRUE;
-/*
-  SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-  return FALSE;
-*/
 }