Implement canvas2d direction attribute

Source/core/html/canvas/CanvasRenderingContext2D.cpp

Index: Source/core/html/canvas/CanvasRenderingContext2D.cpp
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.cpp b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
index 4eea12475e641bce52e6482f6efa3b73d6060b7e..4caa2a2f2d77e98b9ffe011f557af5cb27bf165c 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.cpp
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
@@ -83,6 +83,12 @@ static bool contextLostRestoredEventsEnabled()
     return RuntimeEnabledFeatures::experimentalCanvasFeaturesEnabled();
 }
 
+static inline TextDirection inheritedDirection(HTMLCanvasElement& canvasElement)
+{
+    RenderStyle* computedStyle = canvasElement.computedStyle();
+    return computedStyle ? computedStyle->direction() : LTR;
+}
+
 CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement* canvas, const Canvas2DContextAttributes* attrs, bool usesCSSCompatibilityParseMode)
     : CanvasRenderingContext(canvas)
     , m_usesCSSCompatibilityParseMode(usesCSSCompatibilityParseMode)
@@ -96,6 +102,7 @@ CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement* canvas, co
     , m_tryRestoreContextEventTimer(this, &CanvasRenderingContext2D::tryRestoreContextEvent)
 {
     m_stateStack.append(adoptPtrWillBeNoop(new State()));
+    m_stateStack.first()->m_direction = inheritedDirection(*canvas);
     ScriptWrappable::init(this);
 }
 
@@ -231,6 +238,7 @@ void CanvasRenderingContext2D::reset()
     unwindStateStack();
     m_stateStack.resize(1);
     m_stateStack.first() = adoptPtrWillBeNoop(new State());
+    m_stateStack.first()->m_direction = inheritedDirection(*canvas());
     m_path.clear();
     validateStateStack();
 }
@@ -257,6 +265,7 @@ CanvasRenderingContext2D::State::State()
     , m_imageSmoothingEnabled(true)
     , m_textAlign(StartTextAlign)
     , m_textBaseline(AlphabeticTextBaseline)
+    , m_direction(LTR)
     , m_unparsedFont(defaultFont)
     , m_realizedFont(false)
     , m_hasClip(false)
@@ -286,6 +295,7 @@ CanvasRenderingContext2D::State::State(const State& other)
     , m_imageSmoothingEnabled(other.m_imageSmoothingEnabled)
     , m_textAlign(other.m_textAlign)
     , m_textBaseline(other.m_textBaseline)
+    , m_direction(other.m_direction)
     , m_unparsedFont(other.m_unparsedFont)
     , m_font(other.m_font)
     , m_realizedFont(other.m_realizedFont)
@@ -325,6 +335,7 @@ CanvasRenderingContext2D::State& CanvasRenderingContext2D::State::operator=(cons
     m_imageSmoothingEnabled = other.m_imageSmoothingEnabled;
     m_textAlign = other.m_textAlign;
     m_textBaseline = other.m_textBaseline;
+    m_direction = other.m_direction;
     m_unparsedFont = other.m_unparsedFont;
     m_font = other.m_font;
     m_realizedFont = other.m_realizedFont;
@@ -2016,6 +2027,24 @@ void CanvasRenderingContext2D::setTextBaseline(const String& s)
     modifiableState().m_textBaseline = baseline;
 }
 
+String CanvasRenderingContext2D::direction() const
+{
+    return (state().m_direction == RTL) ? "rtl" : "ltr";

[esprehn, 2014/08/18 19:22:44]

no parens

+}
+
+void CanvasRenderingContext2D::setDirection(const String& s)

[esprehn, 2014/08/18 19:22:44]

Don't use single letter variable bames.

+{
+    if (s != "inherit" && s != "rtl" && s != "ltr")
+        return;
+
+    TextDirection direction = (s == "inherit") ? inheritedDirection(*canvas()) : (s == "rtl") ? RTL : LTR;

[esprehn, 2014/08/18 19:22:44]

Don't nest ternaries.

+    if (state().m_direction == direction)
+        return;
+
+    realizeSaves();
+    modifiableState().m_direction = direction;
+}
+
 void CanvasRenderingContext2D::fillText(const String& text, float x, float y)
 {
     drawTextInternal(text, x, y, true);
@@ -2143,15 +2172,14 @@ void CanvasRenderingContext2D::drawTextInternal(const String& text, float x, flo
     // FIXME: Need to turn off font smoothing.
 
     RenderStyle* computedStyle = canvas()->computedStyle();
-    TextDirection direction = computedStyle ? computedStyle->direction() : LTR;
-    bool isRTL = direction == RTL;
+    bool isRTL = state().m_direction == RTL;
     bool override = computedStyle ? isOverride(computedStyle->unicodeBidi()) : false;
 
-    TextRun textRun(normalizedText, 0, 0, TextRun::AllowTrailingExpansion, direction, override, true);
+    TextRun textRun(normalizedText, 0, 0, TextRun::AllowTrailingExpansion, state().m_direction, override, true);
     // Draw the item text at the correct point.
     FloatPoint location(x, y + getFontBaseline(fontMetrics));
 
-    float fontWidth = font.width(TextRun(normalizedText, 0, 0, TextRun::AllowTrailingExpansion, direction, override));
+    float fontWidth = font.width(TextRun(normalizedText, 0, 0, TextRun::AllowTrailingExpansion, state().m_direction, override));
 
     useMaxWidth = (useMaxWidth && maxWidth < fontWidth);
     float width = useMaxWidth ? maxWidth : fontWidth;