From 95c7a6f6e7dca23199da895bdc837fb6b9965fbe Mon Sep 17 00:00:00 2001
From: Jonathan Watt <jwatt@jwatt.org>
Date: Tue, 28 Oct 2014 14:40:51 +0000
Subject: [PATCH] Bug 1089397 - Port the code that uses
 gfxContextPathAutoSaveRestore to Moz2D. r=mattwoodrow

---
 gfx/thebes/gfxContext.h   | 61 ---------------------------------------
 gfx/thebes/gfxTextRun.cpp | 31 +++++++-------------
 2 files changed, 11 insertions(+), 81 deletions(-)

diff --git a/gfx/thebes/gfxContext.h b/gfx/thebes/gfxContext.h
index 5a514412baea..3ac8f3160ca6 100644
--- a/gfx/thebes/gfxContext.h
+++ b/gfx/thebes/gfxContext.h
@@ -710,67 +710,6 @@ private:
   gfxContext *mContext;
 };
 
-/**
- * Sentry helper class for functions with multiple return points that need to
- * back up the current path of a context and have it automatically restored
- * before they return. This class assumes that the transformation matrix will
- * be the same when Save and Restore are called. The calling function must
- * ensure that this is the case or the path will be copied incorrectly.
- */
-class gfxContextPathAutoSaveRestore
-{
-    typedef mozilla::gfx::Path Path;
-
-public:
-    gfxContextPathAutoSaveRestore() : mContext(nullptr) {}
-
-    explicit gfxContextPathAutoSaveRestore(gfxContext *aContext, bool aSave = true) : mContext(aContext)
-    {
-        if (aSave)
-            Save();       
-    }
-
-    ~gfxContextPathAutoSaveRestore()
-    {
-        Restore();
-    }
-
-    void SetContext(gfxContext *aContext, bool aSave = true)
-    {
-        mContext = aContext;
-        if (aSave)
-            Save();
-    }
-
-    /**
-     * If a path is already saved, does nothing. Else copies the current path
-     * so that it may be restored.
-     */
-    void Save()
-    {
-        if (!mPath && mContext) {
-            mPath = mContext->GetPath();
-        }
-    }
-
-    /**
-     * If no path is saved, does nothing. Else replaces the context's path with
-     * a copy of the saved one, and clears the saved path.
-     */
-    void Restore()
-    {
-        if (mPath) {
-            mContext->SetPath(mPath);
-            mPath = nullptr;
-        }
-    }
-
-private:
-    gfxContext *mContext;
-
-    mozilla::RefPtr<Path> mPath;
-};
-
 /**
  * Sentry helper class for functions with multiple return points that need to
  * back up the current matrix of a context and have it automatically restored
diff --git a/gfx/thebes/gfxTextRun.cpp b/gfx/thebes/gfxTextRun.cpp
index d1ba492841d5..a09d9f172328 100644
--- a/gfx/thebes/gfxTextRun.cpp
+++ b/gfx/thebes/gfxTextRun.cpp
@@ -7,6 +7,8 @@
 #include "gfxGlyphExtents.h"
 #include "gfxPlatformFontList.h"
 #include "gfxUserFontSet.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/PathHelpers.h"
 #include "nsGkAtoms.h"
 #include "nsILanguageAtomService.h"
 #include "nsServiceManagerUtils.h"
@@ -24,6 +26,7 @@
 #include "cairo.h"
 
 using namespace mozilla;
+using namespace mozilla::gfx;
 using namespace mozilla::unicode;
 
 static const char16_t kEllipsisChar[] = { 0x2026, 0x0 };
@@ -454,30 +457,18 @@ gfxTextRun::DrawPartialLigature(gfxFont *aFont, uint32_t aStart, uint32_t aEnd,
     }
 
     {
-      // Need to preserve the path, otherwise this can break canvas text-on-path;
-      // in general it seems like a good thing, as naive callers probably won't
-      // expect gfxTextRun::Draw to implicitly destroy the current path.
-      gfxContextPathAutoSaveRestore savePath(aParams.context);
-
       // use division here to ensure that when the rect is aligned on multiples
       // of mAppUnitsPerDevUnit, we clip to true device unit boundaries.
       // Also, make sure we snap the rectangle to device pixels.
+      Rect clipRect = aParams.isVerticalRun ?
+          Rect(clipExtents.X(), start / mAppUnitsPerDevUnit,
+               clipExtents.Width(), (end - start) / mAppUnitsPerDevUnit) :
+          Rect(start / mAppUnitsPerDevUnit, clipExtents.Y(),
+               (end - start) / mAppUnitsPerDevUnit, clipExtents.Height());
+      MaybeSnapToDevicePixels(clipRect, *aParams.dt, true);
+
       aParams.context->Save();
-      aParams.context->NewPath();
-      if (aParams.isVerticalRun) {
-          aParams.context->Rectangle(gfxRect(clipExtents.X(),
-                                             start / mAppUnitsPerDevUnit,
-                                             clipExtents.Width(),
-                                             (end - start) / mAppUnitsPerDevUnit),
-                                     true);
-      } else {
-          aParams.context->Rectangle(gfxRect(start / mAppUnitsPerDevUnit,
-                                             clipExtents.Y(),
-                                             (end - start) / mAppUnitsPerDevUnit,
-                                             clipExtents.Height()),
-                                     true);
-      }
-      aParams.context->Clip();
+      aParams.context->Clip(clipRect);
     }
 
     gfxPoint pt;