Changeset 86973 in webkit

Timestamp:

May 20, 2011 12:04:52 PM (13 years ago)

Author:

krit@webkit.org

Message:

2011-05-20 Dirk Schulze <​krit@webkit.org>

Reviewed by Darin Adler.

SVGPathSegList needs better getTotalLength, getSegmentAtLength path traversal code
​https://bugs.webkit.org/show_bug.cgi?id=12047

Right now SVGPathElement::getTotalLength and SVGPathElement::getPointAtLength use toPathData()
to transform a SVGPathByteStream to a Path. This Path gets traversed to find the searched value.
With this patch both functions use the SVGPathByteStream directly together with the existing
traversing code in SVG. This avoids the intermediate transforming to a platform path and gives
platform independent results.
The traversal code in SVG needed to be extended to support all PathTraversalActions.

No new tests added. The existing tests cover the changes.

• svg/SVGPathElement.cpp: (WebCore::SVGPathElement::getTotalLength): (WebCore::SVGPathElement::getPointAtLength):
• svg/SVGPathParserFactory.cpp: (WebCore::SVGPathParserFactory::getTotalLengthOfSVGPathByteStream): (WebCore::SVGPathParserFactory::getPointAtLengthOfSVGPathByteStream):
• svg/SVGPathParserFactory.h:
• svg/SVGPathTraversalStateBuilder.cpp: (WebCore::SVGPathTraversalStateBuilder::continueConsuming): (WebCore::SVGPathTraversalStateBuilder::totalLength): (WebCore::SVGPathTraversalStateBuilder::currentPoint):
• svg/SVGPathTraversalStateBuilder.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• svg/SVGPathElement.cpp (modified) (1 diff)
• svg/SVGPathParserFactory.cpp (modified) (1 diff)
• svg/SVGPathParserFactory.h (modified) (1 diff)
• svg/SVGPathTraversalStateBuilder.cpp (modified) (2 diffs)
• svg/SVGPathTraversalStateBuilder.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2011-05-20  Dirk Schulze  <krit@webkit.org>
+
+        Reviewed by Darin Adler.
+
+        SVGPathSegList needs better getTotalLength, getSegmentAtLength path traversal code
+        https://bugs.webkit.org/show_bug.cgi?id=12047
+
+        Right now SVGPathElement::getTotalLength and SVGPathElement::getPointAtLength use toPathData()
+        to transform a SVGPathByteStream to a Path. This Path gets traversed to find the searched value.
+        With this patch both functions use the SVGPathByteStream directly together with the existing
+        traversing code in SVG. This avoids the intermediate transforming to a platform path and gives
+        platform independent results.
+        The traversal code in SVG needed to be extended to support all PathTraversalActions.
+
+        No new tests added. The existing tests cover the changes.
+
+        * svg/SVGPathElement.cpp:
+        (WebCore::SVGPathElement::getTotalLength):
+        (WebCore::SVGPathElement::getPointAtLength):
+        * svg/SVGPathParserFactory.cpp:
+        (WebCore::SVGPathParserFactory::getTotalLengthOfSVGPathByteStream):
+        (WebCore::SVGPathParserFactory::getPointAtLengthOfSVGPathByteStream):
+        * svg/SVGPathParserFactory.h:
+        * svg/SVGPathTraversalStateBuilder.cpp:
+        (WebCore::SVGPathTraversalStateBuilder::continueConsuming):
+        (WebCore::SVGPathTraversalStateBuilder::totalLength):
+        (WebCore::SVGPathTraversalStateBuilder::currentPoint):
+        * svg/SVGPathTraversalStateBuilder.h:
+
 2011-05-20  Mark Pilgrim  <pilgrim@chromium.org>
 

trunk/Source/WebCore/svg/SVGPathElement.cpp

@@ -65 +65 @@
 float SVGPathElement::getTotalLength()
 {
-    // FIXME: this may wish to use the pathSegList instead of the pathdata if that's cheaper to build (or cached)
-    Path path;
-    toPathData(path);
-    return path.length();
+    float totalLength = 0;
+    SVGPathParserFactory::self()->getTotalLengthOfSVGPathByteStream(m_pathByteStream.get(), totalLength);
+    return totalLength;
 }
 
 FloatPoint SVGPathElement::getPointAtLength(float length)
 {
-    // FIXME: this may wish to use the pathSegList instead of the pathdata if that's cheaper to build (or cached)
-    bool ok = false;
-    Path path;
-    toPathData(path);
-    return path.pointAtLength(length, ok);
+    FloatPoint point;
+    SVGPathParserFactory::self()->getPointAtLengthOfSVGPathByteStream(m_pathByteStream.get(), length, point);
+    return point;
 }
 
 unsigned long SVGPathElement::getPathSegAtLength(float length)
 {
-    SVGPathParserFactory* factory = SVGPathParserFactory::self();
     unsigned long pathSeg = 0;
-    factory->getSVGPathSegAtLengthFromSVGPathByteStream(m_pathByteStream.get(), length, pathSeg);
+    SVGPathParserFactory::self()->getSVGPathSegAtLengthFromSVGPathByteStream(m_pathByteStream.get(), length, pathSeg);
     return pathSeg;
 }

trunk/Source/WebCore/svg/SVGPathParserFactory.cpp

@@ -268 +268 @@
 }
 
+bool SVGPathParserFactory::getTotalLengthOfSVGPathByteStream(SVGPathByteStream* stream, float& totalLength)
+{
+    ASSERT(stream);
+    if (stream->isEmpty())
+        return false;
+    
+    PathTraversalState traversalState(PathTraversalState::TraversalTotalLength);
+    SVGPathTraversalStateBuilder* builder = globalSVGPathTraversalStateBuilder(traversalState, 0);
+    
+    OwnPtr<SVGPathByteStreamSource> source = SVGPathByteStreamSource::create(stream);
+    SVGPathParser* parser = globalSVGPathParser(source.get(), builder);
+    bool ok = parser->parsePathDataFromSource(NormalizedParsing);
+    totalLength = builder->totalLength();
+    parser->cleanup();
+    return ok;
+}
+
+bool SVGPathParserFactory::getPointAtLengthOfSVGPathByteStream(SVGPathByteStream* stream, float length, FloatPoint& point)
+{
+    ASSERT(stream);
+    if (stream->isEmpty())
+        return false;
+    
+    PathTraversalState traversalState(PathTraversalState::TraversalPointAtLength);
+    SVGPathTraversalStateBuilder* builder = globalSVGPathTraversalStateBuilder(traversalState, length);
+    
+    OwnPtr<SVGPathByteStreamSource> source = SVGPathByteStreamSource::create(stream);
+    SVGPathParser* parser = globalSVGPathParser(source.get(), builder);
+    bool ok = parser->parsePathDataFromSource(NormalizedParsing);
+    point = builder->currentPoint();
+    parser->cleanup();
+    return ok;
+}
+
 }
 

trunk/Source/WebCore/svg/SVGPathParserFactory.h

@@ -55 +55 @@
     bool buildAnimatedSVGPathByteStream(SVGPathByteStream*, SVGPathByteStream*, OwnPtr<SVGPathByteStream>&, float);
     bool getSVGPathSegAtLengthFromSVGPathByteStream(SVGPathByteStream*, float length, unsigned long& pathSeg);
+    bool getTotalLengthOfSVGPathByteStream(SVGPathByteStream*, float& totalLength);
+    bool getPointAtLengthOfSVGPathByteStream(SVGPathByteStream*, float length, FloatPoint&);
 
 private:

trunk/Source/WebCore/svg/SVGPathTraversalStateBuilder.cpp

@@ -66 +66 @@
 bool SVGPathTraversalStateBuilder::continueConsuming()
 {
-    ASSERT(m_traversalState);
-    ASSERT(m_traversalState->m_action == PathTraversalState::TraversalSegmentAtLength);
-    return m_traversalState->m_totalLength < m_traversalState->m_desiredLength;
+    ASSERT(m_traversalState);    
+    if (m_traversalState->m_action == PathTraversalState::TraversalSegmentAtLength
+        && m_traversalState->m_totalLength >= m_traversalState->m_desiredLength)
+        m_traversalState->m_success = true;
+    
+    if ((m_traversalState->m_action == PathTraversalState::TraversalPointAtLength
+         || m_traversalState->m_action == PathTraversalState::TraversalNormalAngleAtLength)
+        && m_traversalState->m_totalLength >= m_traversalState->m_desiredLength) {
+        FloatSize change = m_traversalState->m_current - m_traversalState->m_previous;
+        float slope = atan2f(change.height(), change.width());
+        if (m_traversalState->m_action == PathTraversalState::TraversalPointAtLength) {
+            float offset = m_traversalState->m_desiredLength - m_traversalState->m_totalLength;
+            m_traversalState->m_current.move(offset * cosf(slope), offset * sinf(slope));
+        } else
+            m_traversalState->m_normalAngle = rad2deg(slope);
+        m_traversalState->m_success = true;
+    }
+    m_traversalState->m_previous = m_traversalState->m_current;
+
+    return !m_traversalState->m_success;
 }
 
@@ -83 +100 @@
 }
 
+float SVGPathTraversalStateBuilder::totalLength()
+{
+    ASSERT(m_traversalState);
+    return m_traversalState->m_totalLength;
+}
+
+FloatPoint SVGPathTraversalStateBuilder::currentPoint()
+{
+    ASSERT(m_traversalState);
+    return m_traversalState->m_current;
+}
+
 }
 

trunk/Source/WebCore/svg/SVGPathTraversalStateBuilder.h

@@ -34 +34 @@
 
     unsigned long pathSegmentIndex();
+    float totalLength();
+    FloatPoint currentPoint();
+
     void setCurrentTraversalState(PathTraversalState* traversalState) { m_traversalState = traversalState; }
     void setDesiredLength(float);