diff --git a/poppler/SplashOutputDev.cc b/poppler/SplashOutputDev.cc
index 2ca42a4..962354f 100644
--- a/poppler/SplashOutputDev.cc
+++ b/poppler/SplashOutputDev.cc
@@ -1195,6 +1195,8 @@ struct SplashTransparencyGroup {
   SplashBitmap *shape;
   GBool knockout;
   SplashCoord knockoutOpacity;
+  GBool useBlendFunc;
+  SplashBlendFunc blendFunc;
 
   //----- saved state
   SplashBitmap *origBitmap;
@@ -3812,6 +3814,8 @@ void SplashOutputDev::beginTransparencyGroup(GfxState *state, double *bbox,
   transpGroup->isolated = isolated;
   transpGroup->shape = (knockout && !isolated) ? SplashBitmap::copy(bitmap) : NULL;
   transpGroup->knockout = gFalse; 
+  transpGroup->useBlendFunc = gFalse;
+  transpGroup->blendFunc = splash->getBlendFunc();
   transpGroup->knockoutOpacity = 1.0;
   transpGroup->next = transpGroupStack;
   transpGroupStack = transpGroup;
@@ -3868,8 +3872,12 @@ void SplashOutputDev::beginTransparencyGroup(GfxState *state, double *bbox,
   } else {
     SplashBitmap *shape = (knockout) ? transpGroup->shape :
                                        (transpGroup->next != NULL && transpGroup->next->shape != NULL) ? transpGroup->next->shape : transpGroup->origBitmap;
+    int shapeTx = (knockout) ? tx :
+      (transpGroup->next != NULL && transpGroup->next->shape != NULL) ? transpGroup->next->tx + tx : tx;
+    int shapeTy = (knockout) ? ty :
+      (transpGroup->next != NULL && transpGroup->next->shape != NULL) ? transpGroup->next->ty + ty : ty;
     splash->blitTransparent(transpGroup->origBitmap, tx, ty, 0, 0, w, h);
-    splash->setInNonIsolatedGroup(shape, tx, ty);
+    splash->setInNonIsolatedGroup(shape, shapeTx, shapeTy);
   }
   transpGroup->tBitmap = bitmap;
   state->shiftCTMAndClip(-tx, -ty);
@@ -3905,9 +3913,39 @@ void SplashOutputDev::paintTransparencyGroup(GfxState *state, double *bbox) {
     SplashCoord knockoutOpacity = (transpGroupStack->next != NULL) ? transpGroupStack->next->knockoutOpacity
                                                                    : transpGroupStack->knockoutOpacity;
     splash->setOverprintMask(0xffffffff, gFalse);
-    splash->composite(tBitmap, 0, 0, tx, ty,
+    if (transpGroupStack->next != NULL && transpGroupStack->next->shape != NULL && splash->getBlendFunc() != NULL) {
+      if (transpGroupStack->next->useBlendFunc && transpGroupStack->next->blendFunc != splash->getBlendFunc()) {
+        // create the temporary bitmap
+        SplashBitmap *tmpBitmap = SplashBitmap::copy(transpGroupStack->next->origBitmap);
+        Splash *tmpSplash = new Splash(tmpBitmap, vectorAntialias,
+		      splash->getScreen());
+        tmpSplash->setInNonIsolatedGroup(transpGroupStack->next->shape, transpGroupStack->next->tx, transpGroupStack->next->ty);
+        tmpSplash->setBlendFunc(transpGroupStack->next->blendFunc);
+        tmpSplash->composite(bitmap, 0, 0, transpGroupStack->next->tx, transpGroupStack->next->ty,
+	        bitmap->getWidth(), bitmap->getHeight(),
+	        gFalse, !isolated, gFalse, knockoutOpacity);
+        splash->blitTransparent(tmpBitmap, transpGroupStack->next->tx, transpGroupStack->next->ty, 0, 0, bitmap->getWidth(), bitmap->getHeight(), gTrue);
+        delete tmpSplash;
+        delete tmpBitmap;
+        splash->composite(tBitmap, 0, 0, tx, ty,
+	        tBitmap->getWidth(), tBitmap->getHeight(),
+	        gFalse, !isolated, gTrue, knockoutOpacity);
+        transpGroupStack->next->useBlendFunc = gFalse;
+      } else {
+        splash->blitTransparent(tBitmap, 0, 0, tx, ty, tBitmap->getWidth(), tBitmap->getHeight(), gTrue);
+        transpGroupStack->next->useBlendFunc = gTrue;        
+        transpGroupStack->next->blendFunc = splash->getBlendFunc();
+      }
+    } else {
+      SplashBlendFunc formerBlendFunc = splash->getBlendFunc();
+      if (transpGroupStack->shape != NULL && transpGroupStack->useBlendFunc) {
+        splash->setBlendFunc(transpGroupStack->blendFunc);
+      }
+      splash->composite(tBitmap, 0, 0, tx, ty,
 	      tBitmap->getWidth(), tBitmap->getHeight(),
 	      gFalse, !isolated, transpGroupStack->next != NULL && transpGroupStack->next->knockout, knockoutOpacity);
+      splash->setBlendFunc(formerBlendFunc);
+    }
     if (transpGroupStack->next != NULL && transpGroupStack->next->shape != NULL) {
       transpGroupStack->next->knockout = gTrue;
     }
diff --git a/splash/Splash.cc b/splash/Splash.cc
index 6bb0dfe..d597bea 100644
--- a/splash/Splash.cc
+++ b/splash/Splash.cc
@@ -446,39 +446,68 @@ void Splash::pipeRun(SplashPipe *pipe) {
 
     //----- read destination pixel
 
+    Guchar *destColorPtr;
+    if (pipe->shape && state->blendFunc && pipe->knockout && alpha0Bitmap != NULL) {
+      destColorPtr = alpha0Bitmap->data + (alpha0Y+pipe->y)*alpha0Bitmap->rowSize;
+      switch (bitmap->mode) {
+        case splashModeMono1:
+          destColorPtr += (alpha0X+pipe->x) / 8;
+          break;
+        case splashModeMono8:
+          destColorPtr += (alpha0X+pipe->x);
+          break;
+        case splashModeRGB8:
+        case splashModeBGR8:
+          destColorPtr += (alpha0X+pipe->x) * 3;
+          break;
+        case splashModeXBGR8:
+#if SPLASH_CMYK
+        case splashModeCMYK8:
+#endif
+          destColorPtr += (alpha0X+pipe->x) * 4;
+          break;
+#if SPLASH_CMYK
+        case splashModeDeviceN8:
+          destColorPtr += (alpha0X+pipe->x) * (SPOT_NCOMPS + 4);
+          break;
+#endif
+      }
+    } else {
+      destColorPtr = pipe->destColorPtr;
+    }
     switch (bitmap->mode) {
     case splashModeMono1:
-      cDest[0] = (*pipe->destColorPtr & pipe->destColorMask) ? 0xff : 0x00;
+      cDest[0] = (*destColorPtr & pipe->destColorMask) ? 0xff : 0x00;
       break;
     case splashModeMono8:
-      cDest[0] = *pipe->destColorPtr;
+      cDest[0] = *destColorPtr;
       break;
     case splashModeRGB8:
-      cDest[0] = pipe->destColorPtr[0];
-      cDest[1] = pipe->destColorPtr[1];
-      cDest[2] = pipe->destColorPtr[2];
+      cDest[0] = destColorPtr[0];
+      cDest[1] = destColorPtr[1];
+      cDest[2] = destColorPtr[2];
       break;
     case splashModeXBGR8:
-      cDest[0] = pipe->destColorPtr[2];
-      cDest[1] = pipe->destColorPtr[1];
-      cDest[2] = pipe->destColorPtr[0];
+      cDest[0] = destColorPtr[2];
+      cDest[1] = destColorPtr[1];
+      cDest[2] = destColorPtr[0];
       cDest[3] = 255;
       break;
     case splashModeBGR8:
-      cDest[0] = pipe->destColorPtr[2];
-      cDest[1] = pipe->destColorPtr[1];
-      cDest[2] = pipe->destColorPtr[0];
+      cDest[0] = destColorPtr[2];
+      cDest[1] = destColorPtr[1];
+      cDest[2] = destColorPtr[0];
       break;
 #if SPLASH_CMYK
     case splashModeCMYK8:
-      cDest[0] = pipe->destColorPtr[0];
-      cDest[1] = pipe->destColorPtr[1];
-      cDest[2] = pipe->destColorPtr[2];
-      cDest[3] = pipe->destColorPtr[3];
+      cDest[0] = destColorPtr[0];
+      cDest[1] = destColorPtr[1];
+      cDest[2] = destColorPtr[2];
+      cDest[3] = destColorPtr[3];
       break;
     case splashModeDeviceN8:
       for (cp = 0; cp < SPOT_NCOMPS + 4; cp++)
-        cDest[cp] = pipe->destColorPtr[cp];
+        cDest[cp] = destColorPtr[cp];
       break;
 #endif
     }
@@ -5711,7 +5740,7 @@ GBool Splash::gouraudTriangleShadedFill(SplashGouraudColor *shading)
 }
 
 SplashError Splash::blitTransparent(SplashBitmap *src, int xSrc, int ySrc,
-				    int xDest, int yDest, int w, int h) {
+				    int xDest, int yDest, int w, int h, GBool knockout) {
   SplashColorPtr p, sp;
   Guchar *q;
   int x, y, mask, srcMask;
@@ -5807,7 +5836,16 @@ SplashError Splash::blitTransparent(SplashBitmap *src, int xSrc, int ySrc,
   if (bitmap->alpha) {
     for (y = 0; y < h; ++y) {
       q = &bitmap->alpha[(yDest + y) * bitmap->width + xDest];
-      memset(q, 0x00, w);
+      if (knockout) {
+        p = &src->alpha[(ySrc + y) * src->width + xSrc];
+        for (x = 0; x < w; ++x, ++q, ++p) {
+          if (*p > *q) {
+            *q = *p;
+          }
+        }
+      } else {
+        memset(q, 0x00, w);
+      }
     }
   }
 
diff --git a/splash/Splash.h b/splash/Splash.h
index cf98e6c..491e01e 100644
--- a/splash/Splash.h
+++ b/splash/Splash.h
@@ -231,7 +231,7 @@ public:
   // this Splash object.  The destination alpha values are all set to
   // zero.
   SplashError blitTransparent(SplashBitmap *src, int xSrc, int ySrc,
-			      int xDest, int yDest, int w, int h);
+			      int xDest, int yDest, int w, int h, GBool knockout = gFalse);
   void blitImage(SplashBitmap *src, GBool srcAlpha, int xDest, int yDest);
 
   //----- misc