CPDF_Document::LoadPattern() and friends always have a valid matrix.

core/fpdfapi/fpdf_page/fpdf_page_parser.cpp

Index: core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
diff --git a/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 1f10b4ea4eecfb0529bb9388370f630b64144f87..93ea93dee76403bb50b8bc83c95ea0dae962b56d 100644
--- a/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -12,6 +12,7 @@
 #include "core/fpdfapi/fpdf_font/cpdf_type3font.h"
 #include "core/fpdfapi/fpdf_font/include/cpdf_font.h"
 #include "core/fpdfapi/fpdf_page/cpdf_allstates.h"
+#include "core/fpdfapi/fpdf_page/cpdf_meshstream.h"
 #include "core/fpdfapi/fpdf_page/cpdf_shadingpattern.h"
 #include "core/fpdfapi/fpdf_page/include/cpdf_form.h"
 #include "core/fpdfapi/fpdf_page/include/cpdf_formobject.h"
@@ -33,6 +34,12 @@
 
 namespace {
 
+const int kSingleCoordinatePair = 1;
+const int kTensorCoordinatePairs = 16;
+const int kCoonsCoordinatePairs = 12;
+const int kSingleColorPerPatch = 1;
+const int kQuadColorsPerPatch = 4;
+
 const char kPathOperatorSubpath = 'm';
 const char kPathOperatorLine = 'l';
 const char kPathOperatorCubicBezier1 = 'c';
@@ -90,6 +97,64 @@ CFX_ByteStringC PDF_FindFullName(const PDF_AbbrPair* table,
                              : CFX_ByteStringC();
 }
 
+CFX_FloatRect GetShadingBBox(CPDF_Stream* pStream,
+                             ShadingType type,
+                             const CFX_Matrix& matrix,
+                             CPDF_Function** pFuncs,
+                             int nFuncs,
+                             CPDF_ColorSpace* pCS) {
+  if (!pStream || !pFuncs || !pCS)
+    return CFX_FloatRect(0, 0, 0, 0);
+
+  CPDF_MeshStream stream;
+  if (!stream.Load(pStream, pFuncs, nFuncs, pCS))
+    return CFX_FloatRect(0, 0, 0, 0);
+
+  CFX_FloatRect rect;
+  bool bStarted = false;
+  bool bGouraud = type == kFreeFormGouraudTriangleMeshShading ||
+                  type == kLatticeFormGouraudTriangleMeshShading;
+
+  int point_count = kSingleCoordinatePair;
+  if (type == kTensorProductPatchMeshShading)
+    point_count = kTensorCoordinatePairs;
+  else if (type == kCoonsPatchMeshShading)
+    point_count = kCoonsCoordinatePairs;
+
+  int color_count = kSingleColorPerPatch;
+  if (type == kCoonsPatchMeshShading || type == kTensorProductPatchMeshShading)
+    color_count = kQuadColorsPerPatch;
+
+  while (!stream.m_BitStream.IsEOF()) {
+    uint32_t flag = 0;
+    if (type != kLatticeFormGouraudTriangleMeshShading)
+      flag = stream.GetFlag();
+
+    if (!bGouraud && flag) {
+      point_count -= 4;
+      color_count -= 2;
+    }
+
+    for (int i = 0; i < point_count; i++) {
+      FX_FLOAT x;
+      FX_FLOAT y;
+      stream.GetCoords(x, y);
+      if (bStarted) {
+        rect.UpdateRect(x, y);
+      } else {
+        rect.InitRect(x, y);
+        bStarted = true;
+      }
+    }
+    stream.m_BitStream.SkipBits(stream.m_nComps * stream.m_nCompBits *
+                                color_count);
+    if (bGouraud)
+      stream.m_BitStream.ByteAlign();
+  }
+  rect.Transform(&matrix);
+  return rect;
+}
+
 }  // namespace
 
 CFX_ByteStringC PDF_FindKeyAbbreviationForTesting(const CFX_ByteStringC& abbr) {
@@ -124,7 +189,7 @@ CPDF_StreamContentParser::CPDF_StreamContentParser(
     CPDF_Document* pDocument,
     CPDF_Dictionary* pPageResources,
     CPDF_Dictionary* pParentResources,
-    CFX_Matrix* pmtContentToUser,
+    const CFX_Matrix* pmtContentToUser,
     CPDF_PageObjectHolder* pObjHolder,
     CPDF_Dictionary* pResources,
     CFX_FloatRect* pBBox,
@@ -985,7 +1050,7 @@ void CPDF_StreamContentParser::Handle_SetColorPS_Fill() {
     }
   }
   if (nvalues != nargs) {
-    CPDF_Pattern* pPattern = FindPattern(GetString(0), FALSE);
+    CPDF_Pattern* pPattern = FindPattern(GetString(0), false);
     if (pPattern) {
       m_pCurStates->m_ColorState.SetFillPattern(pPattern, values, nvalues);
     }
@@ -1013,7 +1078,7 @@ void CPDF_StreamContentParser::Handle_SetColorPS_Stroke() {
     }
   }
   if (nvalues != nargs) {
-    CPDF_Pattern* pPattern = FindPattern(GetString(0), FALSE);
+    CPDF_Pattern* pPattern = FindPattern(GetString(0), false);
     if (pPattern) {
       m_pCurStates->m_ColorState.SetStrokePattern(pPattern, values, nvalues);
     }
@@ -1023,15 +1088,8 @@ void CPDF_StreamContentParser::Handle_SetColorPS_Stroke() {
   FX_Free(values);
 }
 
-CFX_FloatRect GetShadingBBox(CPDF_Stream* pStream,
-                             ShadingType type,
-                             const CFX_Matrix* pMatrix,
-                             CPDF_Function** pFuncs,
-                             int nFuncs,
-                             CPDF_ColorSpace* pCS);
-
 void CPDF_StreamContentParser::Handle_ShadeFill() {
-  CPDF_Pattern* pPattern = FindPattern(GetString(0), TRUE);
+  CPDF_Pattern* pPattern = FindPattern(GetString(0), true);
   if (!pPattern)
     return;
 
@@ -1051,7 +1109,7 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
       pObj->m_ClipPath.IsNull() ? m_BBox : pObj->m_ClipPath.GetClipBox();
   if (pShading->IsMeshShading()) {
     bbox.Intersect(GetShadingBBox(ToStream(pShading->m_pShadingObj),
-                                  pShading->m_ShadingType, &pObj->m_Matrix,
+                                  pShading->m_ShadingType, pObj->m_Matrix,
                                   pShading->m_pFunctions, pShading->m_nFuncs,
                                   pShading->m_pCS));
   }
@@ -1164,15 +1222,15 @@ CPDF_ColorSpace* CPDF_StreamContentParser::FindColorSpace(
 }
 
 CPDF_Pattern* CPDF_StreamContentParser::FindPattern(const CFX_ByteString& name,
-                                                    FX_BOOL bShading) {
+                                                    bool bShading) {
   CPDF_Object* pPattern =
       FindResourceObj(bShading ? "Shading" : "Pattern", name);
   if (!pPattern || (!pPattern->IsDictionary() && !pPattern->IsStream())) {
     m_bResourceMissing = TRUE;
-    return NULL;
+    return nullptr;
   }
   return m_pDocument->LoadPattern(pPattern, bShading,
-                                  &m_pCurStates->m_ParentMatrix);
+                                  m_pCurStates->m_ParentMatrix);
 }
 
 void CPDF_StreamContentParser::ConvertTextSpace(FX_FLOAT& x, FX_FLOAT& y) {