From 85f09693e0cd9cb38d390b70ee42afbb2760eb7a Mon Sep 17 00:00:00 2001
From: Nicolas Silva <nsilva@mozilla.com>
Date: Wed, 10 Jun 2015 19:57:08 +0200
Subject: [PATCH] Bug 1083101 - Part 3: Extend DrawCommand storage
 functionality and fix a bug with dashed stroke patterns. r=jrmuizel

---
 gfx/2d/DrawCommand.h | 88 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 87 insertions(+), 1 deletion(-)

diff --git a/gfx/2d/DrawCommand.h b/gfx/2d/DrawCommand.h
index bad569c8b0c0..76ae32f8dfc1 100644
--- a/gfx/2d/DrawCommand.h
+++ b/gfx/2d/DrawCommand.h
@@ -6,6 +6,10 @@
 #ifndef MOZILLA_GFX_DRAWCOMMAND_H_
 #define MOZILLA_GFX_DRAWCOMMAND_H_
 
+
+#define _USE_MATH_DEFINES
+#include <math.h>
+
 #include "2D.h"
 #include "Filters.h"
 #include <vector>
@@ -31,7 +35,8 @@ enum class CommandType : int8_t {
   PUSHCLIP,
   PUSHCLIPRECT,
   POPCLIP,
-  SETTRANSFORM
+  SETTRANSFORM,
+  FLUSH
 };
 
 class DrawingCommand
@@ -41,6 +46,8 @@ public:
 
   virtual void ExecuteOnDT(DrawTarget* aDT, const Matrix* aTransform = nullptr) = 0;
 
+  virtual bool GetAffectedRect(Rect& aDeviceRect, const Matrix& aTransform) { return false; }
+
 protected:
   explicit DrawingCommand(CommandType aType)
     : mType(aType)
@@ -231,6 +238,12 @@ public:
     aDT->FillRect(mRect, mPattern, mOptions);
   }
 
+  bool GetAffectedRect(Rect& aDeviceRect, const Matrix& aTransform)
+  {
+    aDeviceRect = aTransform.TransformBounds(mRect);
+    return true;
+  }
+
 private:
   Rect mRect;
   StoredPattern mPattern;
@@ -250,6 +263,11 @@ public:
     , mStrokeOptions(aStrokeOptions)
     , mOptions(aOptions)
   {
+    if (aStrokeOptions.mDashLength) {
+      mDashes.resize(aStrokeOptions.mDashLength);
+      mStrokeOptions.mDashPattern = &mDashes.front();
+      memcpy(&mDashes.front(), aStrokeOptions.mDashPattern, mStrokeOptions.mDashLength * sizeof(Float));
+    }
   }
 
   virtual void ExecuteOnDT(DrawTarget* aDT, const Matrix*)
@@ -262,6 +280,7 @@ private:
   StoredPattern mPattern;
   StrokeOptions mStrokeOptions;
   DrawOptions mOptions;
+  std::vector<Float> mDashes;
 };
 
 class StrokeLineCommand : public DrawingCommand
@@ -312,12 +331,53 @@ public:
     aDT->Fill(mPath, mPattern, mOptions);
   }
 
+  bool GetAffectedRect(Rect& aDeviceRect, const Matrix& aTransform)
+  {
+    aDeviceRect = mPath->GetBounds(aTransform);
+    return true;
+  }
+
 private:
   RefPtr<Path> mPath;
   StoredPattern mPattern;
   DrawOptions mOptions;
 };
 
+#ifndef M_SQRT2
+#define M_SQRT2 1.41421356237309504880
+#endif
+
+#ifndef M_SQRT1_2
+#define M_SQRT1_2 0.707106781186547524400844362104849039
+#endif
+
+// The logic for this comes from _cairo_stroke_style_max_distance_from_path
+static Rect
+PathExtentsToMaxStrokeExtents(const StrokeOptions &aStrokeOptions,
+                              const Rect &aRect,
+                              const Matrix &aTransform)
+{
+  double styleExpansionFactor = 0.5f;
+
+  if (aStrokeOptions.mLineCap == CapStyle::SQUARE) {
+    styleExpansionFactor = M_SQRT1_2;
+  }
+
+  if (aStrokeOptions.mLineJoin == JoinStyle::MITER &&
+      styleExpansionFactor < M_SQRT2 * aStrokeOptions.mMiterLimit) {
+    styleExpansionFactor = M_SQRT2 * aStrokeOptions.mMiterLimit;
+  }
+
+  styleExpansionFactor *= aStrokeOptions.mLineWidth;
+
+  double dx = styleExpansionFactor * hypot(aTransform._11, aTransform._21);
+  double dy = styleExpansionFactor * hypot(aTransform._22, aTransform._12);
+
+  Rect result = aRect;
+  result.Inflate(dx, dy);
+  return result;
+}
+
 class StrokeCommand : public DrawingCommand
 {
 public:
@@ -331,6 +391,11 @@ public:
     , mStrokeOptions(aStrokeOptions)
     , mOptions(aOptions)
   {
+    if (aStrokeOptions.mDashLength) {
+      mDashes.resize(aStrokeOptions.mDashLength);
+      mStrokeOptions.mDashPattern = &mDashes.front();
+      memcpy(&mDashes.front(), aStrokeOptions.mDashPattern, mStrokeOptions.mDashLength * sizeof(Float));
+    }
   }
 
   virtual void ExecuteOnDT(DrawTarget* aDT, const Matrix*)
@@ -338,11 +403,18 @@ public:
     aDT->Stroke(mPath, mPattern, mStrokeOptions, mOptions);
   }
 
+  bool GetAffectedRect(Rect& aDeviceRect, const Matrix& aTransform)
+  {
+    aDeviceRect = PathExtentsToMaxStrokeExtents(mStrokeOptions, mPath->GetBounds(aTransform), aTransform);
+    return true;
+  }
+
 private:
   RefPtr<Path> mPath;
   StoredPattern mPattern;
   StrokeOptions mStrokeOptions;
   DrawOptions mOptions;
+  std::vector<Float> mDashes;
 };
 
 class FillGlyphsCommand : public DrawingCommand
@@ -502,6 +574,20 @@ private:
   Matrix mTransform;
 };
 
+class FlushCommand : public DrawingCommand
+{
+public:
+  explicit FlushCommand()
+    : DrawingCommand(CommandType::FLUSH)
+  {
+  }
+
+  virtual void ExecuteOnDT(DrawTarget* aDT, const Matrix*)
+  {
+    aDT->Flush();
+  }
+};
+
 } // namespace gfx
 
 } // namespace mozilla