From 3871c9a943cb9e64abd6efa4d9743d867c3e8142 Mon Sep 17 00:00:00 2001
From: Jonathan Watt <jwatt@jwatt.org>
Date: Tue, 15 Nov 2011 13:11:43 +0000
Subject: [PATCH] Bug 702477 - Change the names of nsSVGPathElement::GetScale
 and nsSVGTextPathFrame::GetPathScale, and add documenting comments.
 r=longsonr.

---
 content/svg/content/src/nsSVGPathElement.cpp |  2 +-
 content/svg/content/src/nsSVGPathElement.h   |  7 ++++++-
 layout/svg/base/src/nsSVGGeometryFrame.cpp   |  3 ++-
 layout/svg/base/src/nsSVGGlyphFrame.cpp      |  6 +++---
 layout/svg/base/src/nsSVGTextPathFrame.cpp   |  7 ++++---
 layout/svg/base/src/nsSVGTextPathFrame.h     | 14 +++++++++++++-
 6 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/content/svg/content/src/nsSVGPathElement.cpp b/content/svg/content/src/nsSVGPathElement.cpp
index 8b1e258d173..d0063d50355 100644
--- a/content/svg/content/src/nsSVGPathElement.cpp
+++ b/content/svg/content/src/nsSVGPathElement.cpp
@@ -427,7 +427,7 @@ nsSVGPathElement::ConstructPath(gfxContext *aCtx)
 }
 
 gfxFloat
-nsSVGPathElement::GetScale()
+nsSVGPathElement::GetPathLengthScale()
 {
   if (mPathLength.IsExplicitlySet()) {
 
diff --git a/content/svg/content/src/nsSVGPathElement.h b/content/svg/content/src/nsSVGPathElement.h
index 742f6206000..e5c011d8a7a 100644
--- a/content/svg/content/src/nsSVGPathElement.h
+++ b/content/svg/content/src/nsSVGPathElement.h
@@ -98,7 +98,12 @@ public:
     return nsGkAtoms::d;
   }
 
-  gfxFloat GetScale();
+  /**
+   * Gets the ratio of the actual path length to the content author's estimated
+   * length (as provided by the <path> element's 'pathLength' attribute). This
+   * is used to scale stroke dashing, and to scale offsets along a textPath.
+   */
+  gfxFloat GetPathLengthScale();
 
 protected:
 
diff --git a/layout/svg/base/src/nsSVGGeometryFrame.cpp b/layout/svg/base/src/nsSVGGeometryFrame.cpp
index 53d130335b6..c40254f66c1 100644
--- a/layout/svg/base/src/nsSVGGeometryFrame.cpp
+++ b/layout/svg/base/src/nsSVGGeometryFrame.cpp
@@ -120,7 +120,8 @@ nsSVGGeometryFrame::GetStrokeDashArray(gfxFloat **aDashes, PRUint32 *aCount)
     gfxFloat pathScale = 1.0;
 
     if (mContent->Tag() == nsGkAtoms::path) {
-      pathScale = static_cast<nsSVGPathElement*>(mContent)->GetScale();
+      pathScale =
+        static_cast<nsSVGPathElement*>(mContent)->GetPathLengthScale();
       if (pathScale <= 0) {
         return NS_OK;
       }
diff --git a/layout/svg/base/src/nsSVGGlyphFrame.cpp b/layout/svg/base/src/nsSVGGlyphFrame.cpp
index f661a3c16a6..bc75a44b90f 100644
--- a/layout/svg/base/src/nsSVGGlyphFrame.cpp
+++ b/layout/svg/base/src/nsSVGGlyphFrame.cpp
@@ -751,7 +751,7 @@ nsSVGGlyphFrame::GetCharacterPositions(nsTArray<CharacterPosition>* aCharacterPo
     if (!aCharacterPositions->SetLength(strLength))
       return false;
 
-    gfxFloat pathScale = textPath->GetPathScale();
+    gfxFloat pathScale = textPath->GetOffsetScale();
 
     CharacterPosition *cp = aCharacterPositions->Elements();
 
@@ -877,7 +877,7 @@ nsSVGGlyphFrame::GetSubStringAdvance(PRUint32 aCharnum,
     gfxFloat pathScale = 1.0;
     nsSVGTextPathFrame *textPath = FindTextPathParent();
     if (textPath)
-      pathScale = textPath->GetPathScale();
+      pathScale = textPath->GetOffsetScale();
     if (dxcount > aFragmentChars) 
       dxcount = aFragmentChars;
     for (PRUint32 i = aCharnum; i < dxcount; i++) {
@@ -1101,7 +1101,7 @@ nsSVGGlyphFrame::SetGlyphPosition(gfxPoint *aPosition, bool aForceGlobalTransfor
 
   gfxFloat pathScale = 1.0;
   if (textPath)
-    pathScale = textPath->GetPathScale();
+    pathScale = textPath->GetOffsetScale();
 
   nsTArray<float> dxList, dyList;
   GetEffectiveDxDy(strLength, dxList, dyList);
diff --git a/layout/svg/base/src/nsSVGTextPathFrame.cpp b/layout/svg/base/src/nsSVGTextPathFrame.cpp
index e5649d8b7eb..eaf00e10841 100644
--- a/layout/svg/base/src/nsSVGTextPathFrame.cpp
+++ b/layout/svg/base/src/nsSVGTextPathFrame.cpp
@@ -166,17 +166,18 @@ nsSVGTextPathFrame::GetStartOffset()
     nsRefPtr<gfxFlattenedPath> data = GetFlattenedPath();
     return data ? (val * data->GetLength() / 100.0) : 0.0;
   }
-  return val * GetPathScale();
+  return val * GetOffsetScale();
 }
 
 gfxFloat
-nsSVGTextPathFrame::GetPathScale() 
+nsSVGTextPathFrame::GetOffsetScale()
 {
   nsIFrame *pathFrame = GetPathFrame();
   if (!pathFrame)
     return 1.0;
 
-  return static_cast<nsSVGPathElement*>(pathFrame->GetContent())->GetScale();
+  return static_cast<nsSVGPathElement*>(pathFrame->GetContent())->
+    GetPathLengthScale();
 }
 
 //----------------------------------------------------------------------
diff --git a/layout/svg/base/src/nsSVGTextPathFrame.h b/layout/svg/base/src/nsSVGTextPathFrame.h
index 992817aebe1..94ce2ae51e7 100644
--- a/layout/svg/base/src/nsSVGTextPathFrame.h
+++ b/layout/svg/base/src/nsSVGTextPathFrame.h
@@ -84,8 +84,20 @@ public:
   already_AddRefed<gfxFlattenedPath> GetFlattenedPath();
   nsIFrame *GetPathFrame();
 
+  /**
+   * Gets the scale by which offsets along this textPath must be scaled. This
+   * scaling is due to the user provided 'pathLength' attribute on the <path>
+   * element, which is a user provided estimate of the path length.
+   */
+  gfxFloat GetOffsetScale();
+
+  /**
+   * Gets the offset from the start of the path at which the first character
+   * should be positioned. The value returned already takes GetOffsetScale
+   * into account.
+   */
   gfxFloat GetStartOffset();
-  gfxFloat GetPathScale();
+
 protected:
 
   virtual void GetXY(SVGUserUnitList *aX, SVGUserUnitList *aY);