Fix content generation to only generate dirty page objects.

BUG=pdfium:717
R=dsinclair@chromium.org,thestig@chromium.org

Change-Id: I7e0e6fd301d40f9b5341d40cf11167b7748af243
Reviewed-on: https://pdfium-review.googlesource.com/6071
Reviewed-by: dsinclair <dsinclair@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

4 files changed, 132 insertions, 31 deletions

diff --git a/fpdfsdk/fpdfedit_embeddertest.cpp b/fpdfsdk/fpdfedit_embeddertest.cpp
index 6045618411..f52848c81d 100644
--- a/fpdfsdk/fpdfedit_embeddertest.cpp
+++ b/fpdfsdk/fpdfedit_embeddertest.cpp
@@ -368,6 +368,90 @@ TEST_F(FPDFEditEmbeddertest, PathOnTopOfText) {
   UnloadPage(page);
 }
 
+TEST_F(FPDFEditEmbeddertest, EditOverExistingContent) {
+  // Load document with existing content
+  EXPECT_TRUE(OpenDocument("bug_717.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  EXPECT_NE(nullptr, page);
+
+  // Add a transparent rectangle on top of the existing content
+  FPDF_PAGEOBJECT red_rect2 = FPDFPageObj_CreateNewRect(90, 700, 25, 50);
+  EXPECT_TRUE(FPDFPath_SetFillColor(red_rect2, 255, 0, 0, 100));
+  EXPECT_TRUE(FPDFPath_SetDrawMode(red_rect2, FPDF_FILLMODE_ALTERNATE, 0));
+  FPDFPage_InsertObject(page, red_rect2);
+
+  // Add an opaque rectangle on top of the existing content
+  FPDF_PAGEOBJECT red_rect = FPDFPageObj_CreateNewRect(115, 700, 25, 50);
+  EXPECT_TRUE(FPDFPath_SetFillColor(red_rect, 255, 0, 0, 255));
+  EXPECT_TRUE(FPDFPath_SetDrawMode(red_rect, FPDF_FILLMODE_ALTERNATE, 0));
+  FPDFPage_InsertObject(page, red_rect);
+
+  FPDF_BITMAP bitmap = RenderPage(page);
+  CompareBitmap(bitmap, 612, 792, "ad04e5bd0f471a9a564fb034bd0fb073");
+  FPDFBitmap_Destroy(bitmap);
+  EXPECT_TRUE(FPDFPage_GenerateContent(page));
+
+  // Now save the result, closing the page and document
+  EXPECT_TRUE(FPDF_SaveAsCopy(document(), this, 0));
+  FPDF_ClosePage(page);
+
+  // Render the saved result
+  std::string new_file = GetString();
+  FPDF_FILEACCESS file_access;
+  memset(&file_access, 0, sizeof(file_access));
+  file_access.m_FileLen = new_file.size();
+  file_access.m_GetBlock = GetBlockFromString;
+  file_access.m_Param = &new_file;
+  FPDF_DOCUMENT new_doc = FPDF_LoadCustomDocument(&file_access, nullptr);
+  ASSERT_NE(nullptr, new_doc);
+  EXPECT_EQ(1, FPDF_GetPageCount(new_doc));
+  FPDF_PAGE new_page = FPDF_LoadPage(new_doc, 0);
+  ASSERT_NE(nullptr, new_page);
+  FPDF_BITMAP new_bitmap = RenderPage(new_page);
+  CompareBitmap(new_bitmap, 612, 792, "ad04e5bd0f471a9a564fb034bd0fb073");
+  FPDFBitmap_Destroy(new_bitmap);
+
+  ClearString();
+  // Add another opaque rectangle on top of the existing content
+  FPDF_PAGEOBJECT green_rect = FPDFPageObj_CreateNewRect(150, 700, 25, 50);
+  EXPECT_TRUE(FPDFPath_SetFillColor(green_rect, 0, 255, 0, 255));
+  EXPECT_TRUE(FPDFPath_SetDrawMode(green_rect, FPDF_FILLMODE_ALTERNATE, 0));
+  FPDFPage_InsertObject(new_page, green_rect);
+
+  // Add another transparent rectangle on top of existing content
+  FPDF_PAGEOBJECT green_rect2 = FPDFPageObj_CreateNewRect(175, 700, 25, 50);
+  EXPECT_TRUE(FPDFPath_SetFillColor(green_rect2, 0, 255, 0, 100));
+  EXPECT_TRUE(FPDFPath_SetDrawMode(green_rect2, FPDF_FILLMODE_ALTERNATE, 0));
+  FPDFPage_InsertObject(new_page, green_rect2);
+  new_bitmap = RenderPage(new_page);
+  CompareBitmap(new_bitmap, 612, 792, "4b5b00f824620f8c9b8801ebb98e1cdd");
+  FPDFBitmap_Destroy(new_bitmap);
+  EXPECT_TRUE(FPDFPage_GenerateContent(new_page));
+
+  // Now save the result, closing the page and document
+  EXPECT_TRUE(FPDF_SaveAsCopy(new_doc, this, 0));
+  FPDF_ClosePage(new_page);
+  FPDF_CloseDocument(new_doc);
+
+  // Render the saved result
+  new_file = GetString();
+  memset(&file_access, 0, sizeof(file_access));
+  file_access.m_FileLen = new_file.size();
+  file_access.m_GetBlock = GetBlockFromString;
+  file_access.m_Param = &new_file;
+  new_doc = FPDF_LoadCustomDocument(&file_access, nullptr);
+  ASSERT_NE(nullptr, new_doc);
+  EXPECT_EQ(1, FPDF_GetPageCount(new_doc));
+  new_page = FPDF_LoadPage(new_doc, 0);
+  ASSERT_NE(nullptr, new_page);
+  new_bitmap = RenderPage(new_page);
+  CompareBitmap(new_bitmap, 612, 792, "4b5b00f824620f8c9b8801ebb98e1cdd");
+  FPDFBitmap_Destroy(new_bitmap);
+
+  FPDF_ClosePage(new_page);
+  FPDF_CloseDocument(new_doc);
+}
+
 TEST_F(FPDFEditEmbeddertest, AddStrokedPaths) {
   // Start with a blank page
   FPDF_PAGE page = FPDFPage_New(CreateNewDocument(), 0, 612, 792);
diff --git a/fpdfsdk/fpdfeditimg.cpp b/fpdfsdk/fpdfeditimg.cpp
index 9f4b2968ee..fdc98e06e9 100644
--- a/fpdfsdk/fpdfeditimg.cpp
+++ b/fpdfsdk/fpdfeditimg.cpp
@@ -39,7 +39,7 @@ bool LoadJpegHelper(FPDF_PAGE* pages,
     pImgObj->GetImage()->SetJpegImageInline(pFile);
   else
     pImgObj->GetImage()->SetJpegImage(pFile);
-
+  pImgObj->SetDirty(true);
   return true;
 }
 
@@ -87,6 +87,7 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFImageObj_SetMatrix(FPDF_PAGEOBJECT image_object,
                                  static_cast<float>(c), static_cast<float>(d),
                                  static_cast<float>(e), static_cast<float>(f)));
   pImgObj->CalcBoundingBox();
+  pImgObj->SetDirty(true);
   return true;
 }
 
@@ -106,5 +107,6 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFImageObj_SetBitmap(FPDF_PAGE* pages,
   CFX_RetainPtr<CFX_DIBitmap> holder(CFXBitmapFromFPDFBitmap(bitmap));
   pImgObj->GetImage()->SetImage(holder);
   pImgObj->CalcBoundingBox();
+  pImgObj->SetDirty(true);
   return true;
 }
diff --git a/fpdfsdk/fpdfeditpage.cpp b/fpdfsdk/fpdfeditpage.cpp
index a474414435..da156cd790 100644
--- a/fpdfsdk/fpdfeditpage.cpp
+++ b/fpdfsdk/fpdfeditpage.cpp
@@ -61,6 +61,38 @@ bool IsPageObject(CPDF_Page* pPage) {
   return pObject && !pObject->GetString().Compare("Page");
 }
 
+void CalcBoundingBox(CPDF_PageObject* pPageObj) {
+  switch (pPageObj->GetType()) {
+    case CPDF_PageObject::TEXT: {
+      break;
+    }
+    case CPDF_PageObject::PATH: {
+      CPDF_PathObject* pPathObj = pPageObj->AsPath();
+      pPathObj->CalcBoundingBox();
+      break;
+    }
+    case CPDF_PageObject::IMAGE: {
+      CPDF_ImageObject* pImageObj = pPageObj->AsImage();
+      pImageObj->CalcBoundingBox();
+      break;
+    }
+    case CPDF_PageObject::SHADING: {
+      CPDF_ShadingObject* pShadingObj = pPageObj->AsShading();
+      pShadingObj->CalcBoundingBox();
+      break;
+    }
+    case CPDF_PageObject::FORM: {
+      CPDF_FormObject* pFormObj = pPageObj->AsForm();
+      pFormObj->CalcBoundingBox();
+      break;
+    }
+    default: {
+      NOTREACHED();
+      break;
+    }
+  }
+}
+
 }  // namespace
 
 DLLEXPORT FPDF_DOCUMENT STDCALL FPDF_CreateNewDocument() {
@@ -144,37 +176,9 @@ DLLEXPORT void STDCALL FPDFPage_InsertObject(FPDF_PAGE page,
   CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
   if (!IsPageObject(pPage))
     return;
-
+  pPageObj->SetDirty(true);
   pPage->GetPageObjectList()->push_back(std::move(pPageObjHolder));
-  switch (pPageObj->GetType()) {
-    case CPDF_PageObject::TEXT: {
-      break;
-    }
-    case CPDF_PageObject::PATH: {
-      CPDF_PathObject* pPathObj = pPageObj->AsPath();
-      pPathObj->CalcBoundingBox();
-      break;
-    }
-    case CPDF_PageObject::IMAGE: {
-      CPDF_ImageObject* pImageObj = pPageObj->AsImage();
-      pImageObj->CalcBoundingBox();
-      break;
-    }
-    case CPDF_PageObject::SHADING: {
-      CPDF_ShadingObject* pShadingObj = pPageObj->AsShading();
-      pShadingObj->CalcBoundingBox();
-      break;
-    }
-    case CPDF_PageObject::FORM: {
-      CPDF_FormObject* pFormObj = pPageObj->AsForm();
-      pFormObj->CalcBoundingBox();
-      break;
-    }
-    default: {
-      NOTREACHED();
-      break;
-    }
-  }
+  CalcBoundingBox(pPageObj);
 }
 
 DLLEXPORT int STDCALL FPDFPage_CountObject(FPDF_PAGE page) {
@@ -271,6 +275,7 @@ DLLEXPORT void STDCALL FPDFPageObj_SetBlendMode(FPDF_PAGEOBJECT page_object,
     return;
 
   pPageObj->m_GeneralState.SetBlendMode(blend_mode);
+  pPageObj->SetDirty(true);
 }
 
 DLLEXPORT void STDCALL FPDFPage_TransformAnnots(FPDF_PAGE page,
@@ -327,6 +332,7 @@ FPDF_BOOL FPDFPageObj_SetFillColor(FPDF_PAGEOBJECT page_object,
   pPageObj->m_GeneralState.SetFillAlpha(A / 255.f);
   pPageObj->m_ColorState.SetFillColor(
       CPDF_ColorSpace::GetStockCS(PDFCS_DEVICERGB), rgb, 3);
+  pPageObj->SetDirty(true);
   return true;
 }
 
diff --git a/fpdfsdk/fpdfeditpath.cpp b/fpdfsdk/fpdfeditpath.cpp
index ad5ca9433f..f58d1e18a9 100644
--- a/fpdfsdk/fpdfeditpath.cpp
+++ b/fpdfsdk/fpdfeditpath.cpp
@@ -40,6 +40,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_SetStrokeColor(FPDF_PAGEOBJECT path,
   pPathObj->m_GeneralState.SetStrokeAlpha(A / 255.f);
   pPathObj->m_ColorState.SetStrokeColor(
       CPDF_ColorSpace::GetStockCS(PDFCS_DEVICERGB), rgb, 3);
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -49,6 +50,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_SetStrokeWidth(FPDF_PAGEOBJECT path, float width) {
 
   auto* pPathObj = static_cast<CPDF_PathObject*>(path);
   pPathObj->m_GraphState.SetLineWidth(width);
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -84,6 +86,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_MoveTo(FPDF_PAGEOBJECT path, float x, float y) {
 
   auto* pPathObj = static_cast<CPDF_PathObject*>(path);
   pPathObj->m_Path.AppendPoint(CFX_PointF(x, y), FXPT_TYPE::MoveTo, false);
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -93,6 +96,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_LineTo(FPDF_PAGEOBJECT path, float x, float y) {
 
   auto* pPathObj = static_cast<CPDF_PathObject*>(path);
   pPathObj->m_Path.AppendPoint(CFX_PointF(x, y), FXPT_TYPE::LineTo, false);
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -110,6 +114,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_BezierTo(FPDF_PAGEOBJECT path,
   pPathObj->m_Path.AppendPoint(CFX_PointF(x1, y1), FXPT_TYPE::BezierTo, false);
   pPathObj->m_Path.AppendPoint(CFX_PointF(x2, y2), FXPT_TYPE::BezierTo, false);
   pPathObj->m_Path.AppendPoint(CFX_PointF(x3, y3), FXPT_TYPE::BezierTo, false);
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -122,6 +127,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_Close(FPDF_PAGEOBJECT path) {
     return false;
 
   pPathObj->m_Path.ClosePath();
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -140,6 +146,7 @@ DLLEXPORT FPDF_BOOL FPDFPath_SetDrawMode(FPDF_PAGEOBJECT path,
   else
     pPathObj->m_FillType = 0;
   pPathObj->m_bStroke = stroke != 0;
+  pPathObj->SetDirty(true);
   return true;
 }
 
@@ -157,6 +164,7 @@ DLLEXPORT void STDCALL FPDFPath_SetLineJoin(FPDF_PAGEOBJECT path,
   CFX_GraphStateData::LineJoin lineJoin =
       static_cast<CFX_GraphStateData::LineJoin>(line_join);
   pPathObj->m_GraphState.SetLineJoin(lineJoin);
+  pPathObj->SetDirty(true);
 }
 
 DLLEXPORT void STDCALL FPDFPath_SetLineCap(FPDF_PAGEOBJECT path, int line_cap) {
@@ -170,4 +178,5 @@ DLLEXPORT void STDCALL FPDFPath_SetLineCap(FPDF_PAGEOBJECT path, int line_cap) {
   CFX_GraphStateData::LineCap lineCap =
       static_cast<CFX_GraphStateData::LineCap>(line_cap);
   pPathObj->m_GraphState.SetLineCap(lineCap);
+  pPathObj->SetDirty(true);
 }