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/*
* Copyright (C) Research In Motion Limited 2010. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_SVG_SVG_MARKER_DATA_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_SVG_SVG_MARKER_DATA_H_
#include "third_party/blink/renderer/platform/graphics/path.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
namespace blink {
enum SVGMarkerType { kStartMarker, kMidMarker, kEndMarker };
struct MarkerPosition {
DISALLOW_NEW();
MarkerPosition(SVGMarkerType use_type,
const FloatPoint& use_origin,
float use_angle)
: type(use_type), origin(use_origin), angle(use_angle) {}
SVGMarkerType type;
FloatPoint origin;
float angle;
};
class LayoutSVGResourceMarker;
class SVGMarkerData {
STACK_ALLOCATED();
public:
SVGMarkerData(Vector<MarkerPosition>& positions, bool auto_start_reverse)
: positions_(positions),
element_index_(0),
auto_start_reverse_(auto_start_reverse) {}
static void UpdateFromPathElement(void* info, const PathElement* element) {
static_cast<SVGMarkerData*>(info)->UpdateFromPathElement(*element);
}
void PathIsDone() {
float angle = clampTo<float>(CurrentAngle(kEndMarker));
positions_.push_back(MarkerPosition(kEndMarker, origin_, angle));
}
static inline LayoutSVGResourceMarker* MarkerForType(
const SVGMarkerType& type,
LayoutSVGResourceMarker* marker_start,
LayoutSVGResourceMarker* marker_mid,
LayoutSVGResourceMarker* marker_end) {
switch (type) {
case kStartMarker:
return marker_start;
case kMidMarker:
return marker_mid;
case kEndMarker:
return marker_end;
}
NOTREACHED();
return nullptr;
}
private:
static double BisectingAngle(double in_angle, double out_angle) {
// WK193015: Prevent bugs due to angles being non-continuous.
if (fabs(in_angle - out_angle) > 180)
in_angle += 360;
return (in_angle + out_angle) / 2;
}
double CurrentAngle(SVGMarkerType type) const {
// For details of this calculation, see:
// http://www.w3.org/TR/SVG/single-page.html#painting-MarkerElement
double in_angle = rad2deg(FloatPoint(in_slope_).SlopeAngleRadians());
double out_angle = rad2deg(FloatPoint(out_slope_).SlopeAngleRadians());
switch (type) {
case kStartMarker:
if (auto_start_reverse_)
out_angle += 180;
return out_angle;
case kMidMarker:
return BisectingAngle(in_angle, out_angle);
case kEndMarker:
return in_angle;
}
NOTREACHED();
return 0;
}
struct SegmentData {
FloatSize start_tangent; // Tangent in the start point of the segment.
FloatSize end_tangent; // Tangent in the end point of the segment.
FloatPoint position; // The end point of the segment.
};
static void ComputeQuadTangents(SegmentData& data,
const FloatPoint& start,
const FloatPoint& control,
const FloatPoint& end) {
data.start_tangent = control - start;
data.end_tangent = end - control;
if (data.start_tangent.IsZero())
data.start_tangent = data.end_tangent;
else if (data.end_tangent.IsZero())
data.end_tangent = data.start_tangent;
}
SegmentData ExtractPathElementFeatures(const PathElement& element) const {
SegmentData data;
const FloatPoint* points = element.points;
switch (element.type) {
case kPathElementAddCurveToPoint:
data.position = points[2];
data.start_tangent = points[0] - origin_;
data.end_tangent = points[2] - points[1];
if (data.start_tangent.IsZero())
ComputeQuadTangents(data, points[0], points[1], points[2]);
else if (data.end_tangent.IsZero())
ComputeQuadTangents(data, origin_, points[0], points[1]);
break;
case kPathElementAddQuadCurveToPoint:
data.position = points[1];
ComputeQuadTangents(data, origin_, points[0], points[1]);
break;
case kPathElementMoveToPoint:
case kPathElementAddLineToPoint:
data.position = points[0];
data.start_tangent = data.position - origin_;
data.end_tangent = data.position - origin_;
break;
case kPathElementCloseSubpath:
data.position = subpath_start_;
data.start_tangent = data.position - origin_;
data.end_tangent = data.position - origin_;
break;
}
return data;
}
void UpdateFromPathElement(const PathElement& element) {
SegmentData segment_data = ExtractPathElementFeatures(element);
// First update the outgoing slope for the previous element.
out_slope_ = segment_data.start_tangent;
// Record the marker for the previous element.
if (element_index_ > 0) {
SVGMarkerType marker_type =
element_index_ == 1 ? kStartMarker : kMidMarker;
float angle = clampTo<float>(CurrentAngle(marker_type));
positions_.push_back(MarkerPosition(marker_type, origin_, angle));
}
// Update the incoming slope for this marker position.
in_slope_ = segment_data.end_tangent;
// Update marker position.
origin_ = segment_data.position;
// If this is a 'move to' segment, save the point for use with 'close'.
if (element.type == kPathElementMoveToPoint)
subpath_start_ = element.points[0];
else if (element.type == kPathElementCloseSubpath)
subpath_start_ = FloatPoint();
++element_index_;
}
Vector<MarkerPosition>& positions_;
unsigned element_index_;
FloatPoint origin_;
FloatPoint subpath_start_;
FloatSize in_slope_;
FloatSize out_slope_;
bool auto_start_reverse_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_SVG_SVG_MARKER_DATA_H_
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