Implement CRC2D.scrollPathIntoView() on Canvas

Source/core/html/canvas/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 1091 matching lines @@
 
     StrokeData strokeData;
     strokeData.setThickness(lineWidth());
     strokeData.setLineCap(getLineCap());
     strokeData.setLineJoin(getLineJoin());
     strokeData.setMiterLimit(miterLimit());
     strokeData.setLineDash(getLineDash(), lineDashOffset());
     return path.strokeContains(transformedPoint, strokeData);
 }
 
+void CanvasRenderingContext2D::scrollPathIntoView()
+{
+    scrollPathIntoViewInternal(m_path);
+}
+
+void CanvasRenderingContext2D::scrollPathIntoView(Path2D* path2d, ExceptionState& exceptionState)
+{
+    if (!path2d) {
+        exceptionState.throwDOMException(TypeMismatchError, ExceptionMessages::argumentNullOrIncorrectType(1, "Path2D"));
+        return;
+    }
+
+    scrollPathIntoViewInternal(path2d->path());
+}
+
+void CanvasRenderingContext2D::scrollPathIntoViewInternal(const Path& path)
+{
+    if (!state().m_invertibleCTM || path.isEmpty())
+        return;
+
+    canvas()->document().updateLayoutIgnorePendingStylesheets();
+
+    // Apply transformation and get the bounding rect
+    Path transformedPath = path;
+    transformedPath.transform(state().m_transform);

[Justin Novosad, 2014/03/27 21:26:21]

I am fine with submitting this, but please create a new bug to track the fact
that there is a discrepancy between this implementation and the specification.
The specification still does not say that the Path2D flavor of
scrollPathIntoView is supposed to transform the path by the CTM, but it probably
should.

+    FloatRect boundingRect = transformedPath.boundingRect();
+
+    // Offset by the canvas rect (We should take border and padding into account).
+    RenderBoxModelObject* rbmo = canvas()->renderBoxModelObject();
+    IntRect canvasRect = canvas()->renderer()->absoluteBoundingBoxRect();
+    canvasRect.move(rbmo->borderLeft() + rbmo->paddingLeft(),
+        rbmo->borderTop() + rbmo->paddingTop());
+    LayoutRect pathRect = enclosingLayoutRect(boundingRect);
+    pathRect.moveBy(canvasRect.location());
+
+    if (canvas()->renderer()) {
+        canvas()->renderer()->scrollRectToVisible(
+            pathRect, ScrollAlignment::alignCenterAlways, ScrollAlignment::alignTopAlways);
+    }
+
+    // TODO: should implement "inform the user" that the caret and/or

[Justin Novosad, 2014/03/27 21:26:21]

If there isn't already a bug for this, please create one, and specify the URL
(crbug.com/xxx) in this comment

+    // selection the specified rectangle of the canvas.
+}
+
 void CanvasRenderingContext2D::clearRect(float x, float y, float width, float height)
 {
     if (!validateRectForCanvas(x, y, width, height))
         return;
     GraphicsContext* context = drawingContext();
     if (!context)
         return;
     if (!state().m_invertibleCTM)
         return;
     FloatRect rect(x, y, width, height);
@@ skipping 1175 matching lines @@
     const int focusRingWidth = 5;
     const int focusRingOutline = 0;
     c->drawFocusRing(path, focusRingWidth, focusRingOutline, focusRingColor);
 
     c->restore();
 
     didDraw(dirtyRect);
 }
 
 } // namespace WebCore