remove some calls to dib

core/fpdfapi/fpdf_render/fpdf_render_image.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_render/render_int.h"
 
 #include <utility>
 #include <vector>
@@ skipping 30 matching lines @@
                                           FX_ARGB mask_argb,
                                           int bitmap_alpha,
                                           int blend_mode,
                                           int Transparency) {
   if (!pDIBitmap) {
     return;
   }
   if (blend_mode == FXDIB_BLEND_NORMAL) {
     if (!pDIBitmap->IsAlphaMask()) {
       if (bitmap_alpha < 255) {
+#ifdef _SKIA_SUPPORT_
+        void* dummy;
+        CFX_Matrix m(pDIBitmap->GetWidth(), 0, 0, -pDIBitmap->GetHeight(), left,
+                     top + pDIBitmap->GetHeight());
+        m_pDevice->StartDIBits(pDIBitmap, bitmap_alpha, 0, &m, 0, dummy);
+        return;
+#else
         pDIBitmap->MultiplyAlpha(bitmap_alpha);
+#endif
       }
       if (m_pDevice->SetDIBits(pDIBitmap, left, top)) {
         return;
       }
     } else {
       uint32_t fill_argb = m_Options.TranslateColor(mask_argb);
       if (bitmap_alpha < 255) {
         ((uint8_t*)&fill_argb)[3] =
             ((uint8_t*)&fill_argb)[3] * bitmap_alpha / 255;
       }
@@ skipping 624 matching lines @@
             *dest_scan++ = orig;
             dest_scan++;
           } else {
             dest_scan += 4;
           }
         }
       }
     }
     bitmap_device2.GetBitmap()->ConvertFormat(FXDIB_8bppMask);
     bitmap_device1.GetBitmap()->MultiplyAlpha(bitmap_device2.GetBitmap());
+#ifdef _SKIA_SUPPORT_
+    bitmap_device1.PreMultiply();  // convert unpremultiplied to premultiplied
+#endif
     if (m_BitmapAlpha < 255) {
       bitmap_device1.GetBitmap()->MultiplyAlpha(m_BitmapAlpha);
     }
   }
   m_pRenderStatus->m_pDevice->SetDIBitsWithBlend(
       bitmap_device1.GetBitmap(), rect.left, rect.top, m_BlendType);
   return FALSE;
 }
 
 FX_BOOL CPDF_ImageRenderer::StartDIBSource() {
@@ skipping 291 matching lines @@
   } else if (pFunc) {
     int size = dest_pitch * height;
     for (int i = 0; i < size; i++) {
       dest_buf[i] = transfers[src_buf[i]];
     }
   } else {
     FXSYS_memcpy(dest_buf, src_buf, dest_pitch * height);
   }
   return pMask.release();
 }