X-Git-Url: http://git.asbjorn.it/?a=blobdiff_plain;f=lib%2Fpdf%2FFullBitmapOutputDev.cc;h=d35956db8ef1916e7e738c3d62c5ca57b7e87fa3;hb=838a4e38a059c610ad7da822e036ca8d917afcf8;hp=f19fd25e9f0e3d33519175d42788d762c776737a;hpb=2e91122327d95b7a6751eba98be50487a18a3d56;p=swftools.git

diff --git a/lib/pdf/FullBitmapOutputDev.cc b/lib/pdf/FullBitmapOutputDev.cc
index f19fd25..d35956d 100644
--- a/lib/pdf/FullBitmapOutputDev.cc
+++ b/lib/pdf/FullBitmapOutputDev.cc
@@ -167,11 +167,13 @@ void FullBitmapOutputDev::flushBitmap()
 	gfxcolor_t*out = &img->data[y*rangex];
 	Guchar*ain = &alpha[(y+ymin)*width+xmin];
 	for(x=0;x<rangex;x++) {
-	    // blend against a white background
-	    out[x].r = (in[x*3+0]*ain[x])/255 + 255-ain[x];
-	    out[x].g = (in[x*3+1]*ain[x])/255 + 255-ain[x];
-	    out[x].b = (in[x*3+2]*ain[x])/255 + 255-ain[x];
-	    out[x].a = 255;//ain[x];
+	    /* according to endPage()/compositeBackground() in xpdf/SplashOutputDev.cc, we
+	       have to premultiply alpha (mix background and pixel according to the alpha channel).
+	    */
+	    out[x].r = (in[x*3+0]*ain[x])/255;
+	    out[x].g = (in[x*3+1]*ain[x])/255;
+	    out[x].b = (in[x*3+2]*ain[x])/255;
+	    out[x].a = ain[x];
 	}
     }
     /* transform bitmap rectangle to "device space" */
@@ -190,6 +192,9 @@ void FullBitmapOutputDev::flushBitmap()
     dev->fillbitmap(dev, line, img, &m, 0);
     gfxline_free(line);
 
+    memset(rgbdev->getBitmap()->getAlphaPtr(), 0, rgbdev->getBitmap()->getWidth()*rgbdev->getBitmap()->getHeight());
+    memset(rgbdev->getBitmap()->getDataPtr(), 0, rgbdev->getBitmap()->getRowSize()*rgbdev->getBitmap()->getHeight());
+
     free(img->data);img->data=0;free(img);img=0;
 }