Generate default AP stream for highlight annotation.

core/fpdfdoc/cpvt_generateap.cpp

Index: core/fpdfdoc/cpvt_generateap.cpp
diff --git a/core/fpdfdoc/cpvt_generateap.cpp b/core/fpdfdoc/cpvt_generateap.cpp
index 7eb6188c94baeba8c2e58c2f5f88abf9b953b1ff..dedd412a746e56929b7c7b101ca9ae8c462a3866 100644
--- a/core/fpdfdoc/cpvt_generateap.cpp
+++ b/core/fpdfdoc/cpvt_generateap.cpp
@@ -493,6 +493,66 @@ FX_BOOL CPVT_GenerateAP::GenerateListBoxAP(CPDF_Document* pDoc,
   return GenerateWidgetAP(pDoc, pAnnotDict, 2);
 }
 
+FX_BOOL CPVT_GenerateAP::GenerateHighlightAP(CPDF_Document* pDoc,
+                                             CPDF_Dictionary* pAnnotDict) {
+  // If AP dictionary exists, we use the appearance defined in the
+  // existing AP dictionary.
+  if (pAnnotDict->KeyExist("AP"))
+    return FALSE;
+
+  CFX_ByteTextBuf sAppStream;
+  sAppStream << "/TransGs gs ";
+
+  if (pAnnotDict->KeyExist("C")) {
+    CPDF_Array* pColor = pAnnotDict->GetArrayBy("C");
+    CPVT_Color color = CPVT_Color::ParseColor(*pColor);
+    sAppStream << CPVT_GenerateAP::GenerateColorAP(color, TRUE);
+  } else {
+    // Defaults to 0xFFFF0 color for highlight.

[Lei Zhang, 2016/07/29 22:20:50]

0xFFFF00 ?

[jaepark, 2016/07/29 23:32:26]

Done.

+    sAppStream << "1 1 0 rg \n";
+  }
+
+  CFX_FloatRect rect = pAnnotDict->GetRectBy("Rect");
+  rect.Normalize();
+
+  sAppStream << rect.left << " " << rect.top << " m " << rect.right << " "
+             << rect.top << " l " << rect.right << " " << rect.bottom << " l "
+             << rect.left << " " << rect.bottom << " l "
+             << "h f\n";
+
+  CPDF_Dictionary* pAPDict = new CPDF_Dictionary;
+  pAnnotDict->SetAt("AP", pAPDict);
+
+  CPDF_Stream* pNormalStream = new CPDF_Stream(nullptr, 0, nullptr);
+  int32_t objnum = pDoc->AddIndirectObject(pNormalStream);
+  pAnnotDict->GetDictBy("AP")->SetAtReference("N", pDoc, objnum);
+
+  pNormalStream->SetData((uint8_t*)sAppStream.GetBuffer(), sAppStream.GetSize(),

[Lei Zhang, 2016/07/29 22:20:50]

No C-style casting. Use static_cast or reinterpret_cast.

[jaepark, 2016/07/29 23:32:26]

Done.

+                         FALSE, FALSE);
+
+  CPDF_Dictionary* pStreamDict = pNormalStream->GetDict();
+  pStreamDict->SetAtInteger("FormType", 1);
+  pStreamDict->SetAtString("Subtype", "Form");
+  pStreamDict->SetAtMatrix("Matrix", CFX_Matrix());
+  pStreamDict->SetAtRect("BBox", rect);
+
+  CPDF_Dictionary* pTransGsDict = new CPDF_Dictionary;
+  pTransGsDict->SetAtString("Type", "ExtGState");
+  pTransGsDict->SetAtInteger("ca", 1);
+  pTransGsDict->SetAtString("CA", 1);
+  pTransGsDict->SetAtBoolean("AIS", false);
+  pTransGsDict->SetAtString("BM", "Multiply");
+
+  CPDF_Dictionary* pExtGStateDict = new CPDF_Dictionary;
+  pExtGStateDict->SetAt("TransGs", pTransGsDict);

[Lei Zhang, 2016/07/29 22:20:50]

So if we have multiple highlight annotations, can we reuse "TransGs" or do the
other annotations need unique names for their dictionaries? I've seen other PDFs
that have /GS1 /GS2, etc.

[jaepark, 2016/07/29 23:32:26]

We can reuse "TransGs" because the scope of a named resources, like "TransGs",
is local to a particular content stream.

[Lei Zhang, 2016/07/30 00:56:44]

How about just "GS" then?

[jaepark, 2016/07/30 01:28:27]

Done.

+
+  CPDF_Dictionary* pResourceDict = new CPDF_Dictionary;
+  pResourceDict->SetAt("ExtGState", pExtGStateDict);
+
+  pStreamDict->SetAt("Resources", pResourceDict);
+  return TRUE;
+}
+
 // Static.
 CFX_ByteString CPVT_GenerateAP::GenerateEditAP(
     IPVT_FontMap* pFontMap,