handle antialiased rendering as premultiplied

core/fpdfapi/render/cpdf_renderstatus.cpp

 // Copyright 2016 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/render/cpdf_renderstatus.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 875 matching lines @@
   mtPattern2Bitmap.Concat(mtAdjust);
   CPDF_RenderOptions options;
   if (!pPattern->colored())
     options.m_ColorMode = RENDER_COLOR_ALPHA;
 
   flags |= RENDER_FORCE_HALFTONE;
   options.m_Flags = flags;
   CPDF_RenderContext context(pDoc, pCache);
   context.AppendLayer(pPattern->form(), &mtPattern2Bitmap);
   context.Render(&bitmap_device, &options, nullptr);
+#if defined _SKIA_SUPPORT_PATHS_
+  pBitmap->UnPreMultiply();
+#endif
   return pBitmap;
 }
 
 bool IsAvailableMatrix(const CFX_Matrix& matrix) {
   if (matrix.a == 0 || matrix.d == 0)
     return matrix.b != 0 && matrix.c != 0;
 
   if (matrix.b == 0 || matrix.c == 0)
     return matrix.a != 0 && matrix.d != 0;
 
@@ skipping 223 matching lines @@
       return;
     case CPDF_PageObject::FORM:
       bRet = ProcessForm(pObj->AsForm(), pObj2Device);
       break;
   }
   if (!bRet)
     DrawObjWithBackground(pObj, pObj2Device);
 #if defined _SKIA_SUPPORT_
   DebugVerifyDeviceIsPreMultiplied();
 #endif
-#if defined _SKIA_SUPPORT_PATHS_
-  UnPreMultiplyDevice();
-#endif
 }
 
 bool CPDF_RenderStatus::DrawObjWithBlend(CPDF_PageObject* pObj,
                                          const CFX_Matrix* pObj2Device) {
   bool bRet = false;
   switch (pObj->GetType()) {
     case CPDF_PageObject::PATH:
       bRet = ProcessPath(pObj->AsPath(), pObj2Device);
       break;
     case CPDF_PageObject::IMAGE:
@@ skipping 388 matching lines @@
           textobj->m_pCharPos, textobj->m_TextState.GetFont(),
           textobj->m_TextState.GetFontSize(), &text_matrix, &new_matrix,
           textobj->m_GraphState.GetObject(), (FX_ARGB)-1, 0, nullptr, 0);
     }
   }
   CPDF_RenderStatus bitmap_render;
   bitmap_render.Initialize(m_pContext, &bitmap_device, nullptr, m_pStopObj,
                            nullptr, nullptr, &m_Options, 0, m_bDropObjects,
                            pFormResource, true);
   bitmap_render.ProcessObjectNoClip(pPageObj, &new_matrix);
+#if defined _SKIA_SUPPORT_PATHS_
+  bitmap->UnPreMultiply();
+#endif
   m_bStopped = bitmap_render.m_bStopped;
   if (pSMaskDict) {
     CFX_Matrix smask_matrix = *pPageObj->m_GeneralState.GetSMaskMatrix();
     smask_matrix.Concat(*pObj2Device);
     std::unique_ptr<CFX_DIBSource> pSMaskSource(
         LoadSMask(pSMaskDict, &rect, &smask_matrix));
     if (pSMaskSource)
       bitmap->MultiplyAlpha(pSMaskSource.get());
   }
   if (pTextMask) {
@@ skipping 83 matching lines @@
   }
   return pStates;
 }
 
 #if defined _SKIA_SUPPORT_
 void CPDF_RenderStatus::DebugVerifyDeviceIsPreMultiplied() const {
   m_pDevice->DebugVerifyBitmapIsPreMultiplied();
 }
 #endif
 
-#if defined _SKIA_SUPPORT_PATHS_
-void CPDF_RenderStatus::UnPreMultiplyDevice() {
-  m_pDevice->UnPreMultiplyDevice();
-}
-#endif
-
 bool CPDF_RenderStatus::ProcessText(CPDF_TextObject* textobj,
                                     const CFX_Matrix* pObj2Device,
                                     CFX_PathData* pClippingPath) {
   if (textobj->m_nChars == 0)
     return true;
 
   const TextRenderingMode text_render_mode = textobj->m_TextState.GetTextMode();
   if (text_render_mode == TextRenderingMode::MODE_INVISIBLE)
     return true;
 
@@ skipping 958 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();
 }