flesh out gradient shaders

core/fpdfapi/fpdf_render/fpdf_render_pattern.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 "core/fpdfapi/fpdf_page/cpdf_graphicstates.h"
 #include "core/fpdfapi/fpdf_page/cpdf_meshstream.h"
@@ skipping 837 matching lines @@
       background = ArgbEncode(255, (int32_t)(R * 255), (int32_t)(G * 255),
                               (int32_t)(B * 255));
     }
   }
   if (pDict->KeyExist("BBox")) {
     CFX_FloatRect rect = pDict->GetRectBy("BBox");
     rect.Transform(pMatrix);
     clip_rect.Intersect(rect.GetOutterRect());
   }
   if (m_pDevice->GetDeviceCaps(FXDC_RENDER_CAPS) & FXRC_SHADING &&
-      m_pDevice->GetDeviceDriver()->DrawShading(pPattern, pMatrix, alpha,
-                                                bAlphaMode)) {
+      m_pDevice->GetDeviceDriver()->DrawShading(pPattern, pMatrix, clip_rect,
+                                                alpha, bAlphaMode)) {
     return;
   }
   CPDF_DeviceBuffer buffer;
   buffer.Initialize(m_pContext, m_pDevice, &clip_rect, m_pCurObj, 150);
   CFX_Matrix FinalMatrix = *pMatrix;
   FinalMatrix.Concat(*buffer.GetMatrix());
   CFX_DIBitmap* pBitmap = buffer.GetBitmap();
   if (!pBitmap->GetBuffer()) {
     return;
   }
@@ skipping 337 matching lines @@
     }
   }
   if (bStroke) {
     CPDF_Color& StrokeColor = *pPathObj->m_ColorState.GetStrokeColor();
     if (StrokeColor.m_pCS && StrokeColor.m_pCS->GetFamily() == PDFCS_PATTERN) {
       DrawPathWithPattern(pPathObj, pObj2Device, &StrokeColor, TRUE);
       bStroke = FALSE;
     }
   }
 }