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..14b4d274e322c0117e53d536b2ce66da555eaab8 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.cpp
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
@@ -83,6 +83,13 @@ static bool contextLostRestoredEventsEnabled()
     return RuntimeEnabledFeatures::experimentalCanvasFeaturesEnabled();
 }
 
+static inline TextDirection inheritedDirection(HTMLCanvasElement& canvasElement)
+{
+    canvasElement.document().updateRenderTreeIfNeeded();
+    RenderStyle* computedStyle = canvasElement.computedStyle();
+    return computedStyle ? computedStyle->direction() : LTR;
+}
+
 CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement* canvas, const Canvas2DContextAttributes* attrs, bool usesCSSCompatibilityParseMode)
     : CanvasRenderingContext(canvas)
     , m_usesCSSCompatibilityParseMode(usesCSSCompatibilityParseMode)
@@ -95,7 +102,7 @@ CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement* canvas, co
     , m_dispatchContextRestoredEventTimer(this, &CanvasRenderingContext2D::dispatchContextRestoredEvent)
     , m_tryRestoreContextEventTimer(this, &CanvasRenderingContext2D::tryRestoreContextEvent)
 {
-    m_stateStack.append(adoptPtrWillBeNoop(new State()));
+    m_stateStack.append(adoptPtrWillBeNoop(new State(inheritedDirection(*canvas))));
     ScriptWrappable::init(this);
 }
 
@@ -230,7 +237,7 @@ void CanvasRenderingContext2D::reset()
     validateStateStack();
     unwindStateStack();
     m_stateStack.resize(1);
-    m_stateStack.first() = adoptPtrWillBeNoop(new State());
+    m_stateStack.first() = adoptPtrWillBeNoop(new State(inheritedDirection(*canvas())));
     m_path.clear();
     validateStateStack();
 }
@@ -239,7 +246,7 @@ void CanvasRenderingContext2D::reset()
 // StrokeData. The default values that StrokeData uses may not the same values
 // that the canvas 2d spec specifies. Make sure to sync the initial state of the
 // GraphicsContext in HTMLCanvasElement::createImageBuffer()!
-CanvasRenderingContext2D::State::State()
+CanvasRenderingContext2D::State::State(TextDirection direction)
     : m_unrealizedSaveCount(0)
     , m_strokeStyle(CanvasStyle::createFromRGBA(Color::black))
     , m_fillStyle(CanvasStyle::createFromRGBA(Color::black))
@@ -257,6 +264,7 @@ CanvasRenderingContext2D::State::State()
     , m_imageSmoothingEnabled(true)
     , m_textAlign(StartTextAlign)
     , m_textBaseline(AlphabeticTextBaseline)
+    , m_direction(direction)
     , m_unparsedFont(defaultFont)
     , m_realizedFont(false)
     , m_hasClip(false)
@@ -286,6 +294,7 @@ 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 +334,7 @@ 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 +2026,27 @@ void CanvasRenderingContext2D::setTextBaseline(const String& s)
     modifiableState().m_textBaseline = baseline;
 }
 
+String CanvasRenderingContext2D::direction() const
+{
+    return state().m_direction == RTL ? "rtl" : "ltr";
+}
+
+void CanvasRenderingContext2D::setDirection(const String& directionString)
+{
+    TextDirection direction;
+    if (directionString == "inherit")
+        direction = inheritedDirection(*canvas());

[esprehn, 2014/08/19 17:46:53]

This is now how inheritance is supposed to work, it's supposed to be live, so
that if the parent value changes then it changes here too. The getter needs to
resolve inherit into the correct value when reading, not when here in the
setter.

+    else if (directionString == "rtl")
+        direction = RTL;
+    else if (directionString == "ltr")
+        direction = LTR;
+    else
+        return;
+
+    realizeSaves();
+    modifiableState().m_direction = direction;
+}
+
 void CanvasRenderingContext2D::fillText(const String& text, float x, float y)
 {
     drawTextInternal(text, x, y, true);
@@ -2143,15 +2174,14 @@ 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;