Render image masks individually instead of rendering the entire page as

a bitmap in order to reduce spool sizes.

BUG=682156, 674771

Change-Id: Ic743ba729a7b9609be18fb620a5eb6bc440aed6a
Reviewed-on: https://pdfium-review.googlesource.com/2916
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

3 files changed, 18 insertions, 8 deletions

diff --git a/core/fpdfapi/page/cpdf_pageobjectholder.cpp b/core/fpdfapi/page/cpdf_pageobjectholder.cpp
index 974baa65a0..5f5597e5ac 100644
--- a/core/fpdfapi/page/cpdf_pageobjectholder.cpp
+++ b/core/fpdfapi/page/cpdf_pageobjectholder.cpp
@@ -21,7 +21,6 @@ CPDF_PageObjectHolder::CPDF_PageObjectHolder()
       m_pResources(nullptr),
       m_Transparency(0),
       m_bBackgroundAlphaNeeded(false),
-      m_bHasImageMask(false),
       m_ParseState(CONTENT_NOT_PARSED) {}
 
 CPDF_PageObjectHolder::~CPDF_PageObjectHolder() {}
@@ -37,6 +36,10 @@ void CPDF_PageObjectHolder::ContinueParse(IFX_Pause* pPause) {
   }
 }
 
+void CPDF_PageObjectHolder::AddImageMaskBoundingBox(const CFX_FloatRect& box) {
+  m_MaskBoundingBoxes.push_back(box);
+}
+
 void CPDF_PageObjectHolder::Transform(const CFX_Matrix& matrix) {
   for (auto& pObj : m_PageObjectList)
     pObj->Transform(matrix);
diff --git a/core/fpdfapi/page/cpdf_pageobjectholder.h b/core/fpdfapi/page/cpdf_pageobjectholder.h
index aee7617c1f..0b88a86518 100644
--- a/core/fpdfapi/page/cpdf_pageobjectholder.h
+++ b/core/fpdfapi/page/cpdf_pageobjectholder.h
@@ -8,6 +8,7 @@
 #define CORE_FPDFAPI_PAGE_CPDF_PAGEOBJECTHOLDER_H_
 
 #include <memory>
+#include <vector>
 
 #include "core/fpdfapi/page/cpdf_pageobjectlist.h"
 #include "core/fxcrt/fx_coordinates.h"
@@ -41,9 +42,11 @@ class CPDF_PageObjectHolder {
     m_bBackgroundAlphaNeeded = needed;
   }
 
-  bool HasImageMask() const { return m_bHasImageMask; }
-  void SetHasImageMask(bool value) { m_bHasImageMask = value; }
-
+  bool HasImageMask() const { return !m_MaskBoundingBoxes.empty(); }
+  const std::vector<CFX_FloatRect>& GetMaskBoundingBoxes() const {
+    return m_MaskBoundingBoxes;
+  }
+  void AddImageMaskBoundingBox(const CFX_FloatRect& box);
   void Transform(const CFX_Matrix& matrix);
   CFX_FloatRect CalcBoundingBox() const;
 
@@ -61,7 +64,7 @@ class CPDF_PageObjectHolder {
   void LoadTransInfo();
 
   bool m_bBackgroundAlphaNeeded;
-  bool m_bHasImageMask;
+  std::vector<CFX_FloatRect> m_MaskBoundingBoxes;
   ParseState m_ParseState;
   std::unique_ptr<CPDF_ContentParser> m_pParser;
   CPDF_PageObjectList m_PageObjectList;
diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.cpp b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
index 30686133c2..d9f12f121b 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -735,7 +735,11 @@ void CPDF_StreamContentParser::Handle_ExecuteXObject() {
   CFX_ByteString name = GetString(0);
   if (name == m_LastImageName && m_pLastImage && m_pLastImage->GetStream() &&
       m_pLastImage->GetStream()->GetObjNum()) {
-    AddImage(m_pLastImage);
+    CPDF_ImageObject* pObj = AddImage(m_pLastImage);
+    // Record the bounding box of this image, so rendering code can draw it
+    // properly.
+    if (pObj->GetImage()->IsMask())
+      m_pObjectHolder->AddImageMaskBoundingBox(pObj->GetRect());
     return;
   }
 
@@ -757,8 +761,8 @@ void CPDF_StreamContentParser::Handle_ExecuteXObject() {
 
     m_LastImageName = name;
     m_pLastImage = pObj->GetImage();
-    if (!m_pObjectHolder->HasImageMask())
-      m_pObjectHolder->SetHasImageMask(m_pLastImage->IsMask());
+    if (m_pLastImage->IsMask())
+      m_pObjectHolder->AddImageMaskBoundingBox(pObj->GetRect());
   } else if (type == "Form") {
     AddForm(pXObject);
   }