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SVGPathData.cpp
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "SVGPathData.h"
#include "gfx2DGlue.h"
#include "gfxPlatform.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/Types.h"
#include "mozilla/gfx/Point.h"
#include "mozilla/RefPtr.h"
#include "nsError.h"
#include "nsString.h"
#include "SVGPathDataParser.h"
#include <stdarg.h>
#include "nsStyleConsts.h"
#include "SVGContentUtils.h"
#include "SVGGeometryElement.h"
#include "SVGPathSegUtils.h"
#include <algorithm>
using namespace mozilla::dom::SVGPathSeg_Binding;
using namespace mozilla::gfx;
namespace mozilla {
static inline bool IsMoveto(uint16_t aSegType) {
return aSegType == PATHSEG_MOVETO_ABS || aSegType == PATHSEG_MOVETO_REL;
}
static inline bool IsMoveto(StylePathCommand::Tag aSegType) {
return aSegType == StylePathCommand::Tag::MoveTo;
}
static inline bool IsValidType(uint16_t aSegType) {
return SVGPathSegUtils::IsValidType(aSegType);
}
static inline bool IsValidType(StylePathCommand::Tag aSegType) {
return aSegType != StylePathCommand::Tag::Unknown;
}
static inline bool IsClosePath(uint16_t aSegType) {
return aSegType == PATHSEG_CLOSEPATH;
}
static inline bool IsClosePath(StylePathCommand::Tag aSegType) {
return aSegType == StylePathCommand::Tag::ClosePath;
}
static inline Point ToGfxPoint(const StyleCoordPair& aPair) {
return {aPair._0, aPair._1};
}
static inline bool IsCubicType(StylePathCommand::Tag aType) {
return aType == StylePathCommand::Tag::CurveTo ||
aType == StylePathCommand::Tag::SmoothCurveTo;
}
static inline bool IsQuadraticType(StylePathCommand::Tag aType) {
return aType == StylePathCommand::Tag::QuadBezierCurveTo ||
aType == StylePathCommand::Tag::SmoothQuadBezierCurveTo;
}
nsresult SVGPathData::CopyFrom(const SVGPathData& rhs) {
if (!mData.Assign(rhs.mData, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
return NS_OK;
}
void SVGPathData::GetValueAsString(nsAString& aValue) const {
// we need this function in DidChangePathSegList
aValue.Truncate();
if (!Length()) {
return;
}
uint32_t i = 0;
for (;;) {
nsAutoString segAsString;
SVGPathSegUtils::GetValueAsString(&mData[i], segAsString);
// We ignore OOM, since it's not useful for us to return an error.
aValue.Append(segAsString);
i += 1 + SVGPathSegUtils::ArgCountForType(mData[i]);
if (i >= mData.Length()) {
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
return;
}
aValue.Append(' ');
}
}
nsresult SVGPathData::SetValueFromString(const nsAString& aValue) {
// We don't use a temp variable since the spec says to parse everything up to
// the first error. We still return any error though so that callers know if
// there's a problem.
SVGPathDataParser pathParser(aValue, this);
return pathParser.Parse() ? NS_OK : NS_ERROR_DOM_SYNTAX_ERR;
}
nsresult SVGPathData::AppendSeg(uint32_t aType, ...) {
uint32_t oldLength = mData.Length();
uint32_t newLength = oldLength + 1 + SVGPathSegUtils::ArgCountForType(aType);
if (!mData.SetLength(newLength, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
mData[oldLength] = SVGPathSegUtils::EncodeType(aType);
va_list args;
va_start(args, aType);
for (uint32_t i = oldLength + 1; i < newLength; ++i) {
// NOTE! 'float' is promoted to 'double' when passed through '...'!
mData[i] = float(va_arg(args, double));
}
va_end(args);
return NS_OK;
}
float SVGPathData::GetPathLength() const {
SVGPathTraversalState state;
uint32_t i = 0;
while (i < mData.Length()) {
SVGPathSegUtils::TraversePathSegment(&mData[i], state);
i += 1 + SVGPathSegUtils::ArgCountForType(mData[i]);
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
return state.length;
}
#ifdef DEBUG
uint32_t SVGPathData::CountItems() const {
uint32_t i = 0, count = 0;
while (i < mData.Length()) {
i += 1 + SVGPathSegUtils::ArgCountForType(mData[i]);
count++;
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
return count;
}
#endif
bool SVGPathData::GetDistancesFromOriginToEndsOfVisibleSegments(
FallibleTArray<double>* aOutput) const {
SVGPathTraversalState state;
aOutput->Clear();
uint32_t i = 0;
while (i < mData.Length()) {
uint32_t segType = SVGPathSegUtils::DecodeType(mData[i]);
SVGPathSegUtils::TraversePathSegment(&mData[i], state);
// With degenerately large point coordinates, TraversePathSegment can fail
// and end up producing NaNs.
if (!std::isfinite(state.length)) {
return false;
}
// We skip all moveto commands except an initial moveto. See the text 'A
// "move to" command does not count as an additional point when dividing up
// the duration...':
//
// http://www.w3.org/TR/SVG11/animate.html#AnimateMotionElement
//
// This is important in the non-default case of calcMode="linear". In
// this case an equal amount of time is spent on each path segment,
// except on moveto segments which are jumped over immediately.
if (i == 0 || !IsMoveto(segType)) {
if (!aOutput->AppendElement(state.length, fallible)) {
return false;
}
}
i += 1 + SVGPathSegUtils::ArgCountForType(segType);
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt?");
return true;
}
/* static */
bool SVGPathData::GetDistancesFromOriginToEndsOfVisibleSegments(
Span<const StylePathCommand> aPath, FallibleTArray<double>* aOutput) {
SVGPathTraversalState state;
aOutput->Clear();
bool firstMoveToIsChecked = false;
for (const auto& cmd : aPath) {
SVGPathSegUtils::TraversePathSegment(cmd, state);
if (!std::isfinite(state.length)) {
return false;
}
// We skip all moveto commands except for the initial moveto.
if (!cmd.IsMoveTo() || !firstMoveToIsChecked) {
if (!aOutput->AppendElement(state.length, fallible)) {
return false;
}
}
if (cmd.IsMoveTo() && !firstMoveToIsChecked) {
firstMoveToIsChecked = true;
}
}
return true;
}
uint32_t SVGPathData::GetPathSegAtLength(float aDistance) const {
// TODO [SVGWG issue] get specified what happen if 'aDistance' < 0, or
// 'aDistance' > the length of the path, or the seg list is empty.
// Return -1? Throwing would better help authors avoid tricky bugs (DOM
// could do that if we return -1).
uint32_t i = 0, segIndex = 0;
SVGPathTraversalState state;
while (i < mData.Length()) {
SVGPathSegUtils::TraversePathSegment(&mData[i], state);
if (state.length >= aDistance) {
return segIndex;
}
i += 1 + SVGPathSegUtils::ArgCountForType(mData[i]);
segIndex++;
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
return std::max(1U, segIndex) -
1; // -1 because while loop takes us 1 too far
}
/* static */
uint32_t SVGPathData::GetPathSegAtLength(Span<const StylePathCommand> aPath,
float aDistance) {
uint32_t segIndex = 0;
SVGPathTraversalState state;
for (const auto& cmd : aPath) {
SVGPathSegUtils::TraversePathSegment(cmd, state);
if (state.length >= aDistance) {
return segIndex;
}
segIndex++;
}
return std::max(1U, segIndex) - 1;
}
/**
* The SVG spec says we have to paint stroke caps for zero length subpaths:
*
* http://www.w3.org/TR/SVG11/implnote.html#PathElementImplementationNotes
*
* Cairo only does this for |stroke-linecap: round| and not for
* |stroke-linecap: square| (since that's what Adobe Acrobat has always done).
* Most likely the other backends that DrawTarget uses have the same behavior.
*
* To help us conform to the SVG spec we have this helper function to draw an
* approximation of square caps for zero length subpaths. It does this by
* inserting a subpath containing a single user space axis aligned straight
* line that is as small as it can be while minimizing the risk of it being
* thrown away by the DrawTarget's backend for being too small to affect
* rendering. The idea is that we'll then get stroke caps drawn for this axis
* aligned line, creating an axis aligned rectangle that approximates the
* square that would ideally be drawn.
*
* Since we don't have any information about transforms from user space to
* device space, we choose the length of the small line that we insert by
* making it a small percentage of the stroke width of the path. This should
* hopefully allow us to make the line as long as possible (to avoid rounding
* issues in the backend resulting in the backend seeing it as having zero
* length) while still avoiding the small rectangle being noticeably different
* from a square.
*
* Note that this function inserts a subpath into the current gfx path that
* will be present during both fill and stroke operations.
*/
static void ApproximateZeroLengthSubpathSquareCaps(PathBuilder* aPB,
const Point& aPoint,
Float aStrokeWidth) {
// Note that caps are proportional to stroke width, so if stroke width is
// zero it's actually fine for |tinyLength| below to end up being zero.
// However, it would be a waste to inserting a LineTo in that case, so better
// not to.
MOZ_ASSERT(aStrokeWidth > 0.0f,
"Make the caller check for this, or check it here");
// The fraction of the stroke width that we choose for the length of the
// line is rather arbitrary, other than being chosen to meet the requirements
// described in the comment above.
Float tinyLength = aStrokeWidth / SVG_ZERO_LENGTH_PATH_FIX_FACTOR;
aPB->LineTo(aPoint + Point(tinyLength, 0));
aPB->MoveTo(aPoint);
}
#define MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT \
do { \
if (!subpathHasLength && hasLineCaps && aStrokeWidth > 0 && \
subpathContainsNonMoveTo && IsValidType(prevSegType) && \
(!IsMoveto(prevSegType) || IsClosePath(segType))) { \
ApproximateZeroLengthSubpathSquareCaps(aBuilder, segStart, \
aStrokeWidth); \
} \
} while (0)
already_AddRefed<Path> SVGPathData::BuildPath(PathBuilder* aBuilder,
StyleStrokeLinecap aStrokeLineCap,
Float aStrokeWidth) const {
if (mData.IsEmpty() || !IsMoveto(SVGPathSegUtils::DecodeType(mData[0]))) {
return nullptr; // paths without an initial moveto are invalid
}
bool hasLineCaps = aStrokeLineCap != StyleStrokeLinecap::Butt;
bool subpathHasLength = false; // visual length
bool subpathContainsNonMoveTo = false;
uint32_t segType = PATHSEG_UNKNOWN;
uint32_t prevSegType = PATHSEG_UNKNOWN;
Point pathStart(0.0, 0.0); // start point of [sub]path
Point segStart(0.0, 0.0);
Point segEnd;
Point cp1, cp2; // previous bezier's control points
Point tcp1, tcp2; // temporaries
// Regarding cp1 and cp2: If the previous segment was a cubic bezier curve,
// then cp2 is its second control point. If the previous segment was a
// quadratic curve, then cp1 is its (only) control point.
uint32_t i = 0;
while (i < mData.Length()) {
segType = SVGPathSegUtils::DecodeType(mData[i++]);
uint32_t argCount = SVGPathSegUtils::ArgCountForType(segType);
switch (segType) {
case PATHSEG_CLOSEPATH:
// set this early to allow drawing of square caps for "M{x},{y} Z":
subpathContainsNonMoveTo = true;
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
segEnd = pathStart;
aBuilder->Close();
break;
case PATHSEG_MOVETO_ABS:
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
pathStart = segEnd = Point(mData[i], mData[i + 1]);
aBuilder->MoveTo(segEnd);
subpathHasLength = false;
break;
case PATHSEG_MOVETO_REL:
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
pathStart = segEnd = segStart + Point(mData[i], mData[i + 1]);
aBuilder->MoveTo(segEnd);
subpathHasLength = false;
break;
case PATHSEG_LINETO_ABS:
segEnd = Point(mData[i], mData[i + 1]);
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_REL:
segEnd = segStart + Point(mData[i], mData[i + 1]);
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(segEnd);
}
break;
case PATHSEG_CURVETO_CUBIC_ABS:
cp1 = Point(mData[i], mData[i + 1]);
cp2 = Point(mData[i + 2], mData[i + 3]);
segEnd = Point(mData[i + 4], mData[i + 5]);
if (segEnd != segStart || segEnd != cp1 || segEnd != cp2) {
subpathHasLength = true;
aBuilder->BezierTo(cp1, cp2, segEnd);
}
break;
case PATHSEG_CURVETO_CUBIC_REL:
cp1 = segStart + Point(mData[i], mData[i + 1]);
cp2 = segStart + Point(mData[i + 2], mData[i + 3]);
segEnd = segStart + Point(mData[i + 4], mData[i + 5]);
if (segEnd != segStart || segEnd != cp1 || segEnd != cp2) {
subpathHasLength = true;
aBuilder->BezierTo(cp1, cp2, segEnd);
}
break;
case PATHSEG_CURVETO_QUADRATIC_ABS:
cp1 = Point(mData[i], mData[i + 1]);
// Convert quadratic curve to cubic curve:
tcp1 = segStart + (cp1 - segStart) * 2 / 3;
segEnd = Point(mData[i + 2], mData[i + 3]); // set before setting tcp2!
tcp2 = cp1 + (segEnd - cp1) / 3;
if (segEnd != segStart || segEnd != cp1) {
subpathHasLength = true;
aBuilder->BezierTo(tcp1, tcp2, segEnd);
}
break;
case PATHSEG_CURVETO_QUADRATIC_REL:
cp1 = segStart + Point(mData[i], mData[i + 1]);
// Convert quadratic curve to cubic curve:
tcp1 = segStart + (cp1 - segStart) * 2 / 3;
segEnd = segStart +
Point(mData[i + 2], mData[i + 3]); // set before setting tcp2!
tcp2 = cp1 + (segEnd - cp1) / 3;
if (segEnd != segStart || segEnd != cp1) {
subpathHasLength = true;
aBuilder->BezierTo(tcp1, tcp2, segEnd);
}
break;
case PATHSEG_ARC_ABS:
case PATHSEG_ARC_REL: {
Point radii(mData[i], mData[i + 1]);
segEnd = Point(mData[i + 5], mData[i + 6]);
if (segType == PATHSEG_ARC_REL) {
segEnd += segStart;
}
if (segEnd != segStart) {
subpathHasLength = true;
if (radii.x == 0.0f || radii.y == 0.0f) {
aBuilder->LineTo(segEnd);
} else {
SVGArcConverter converter(segStart, segEnd, radii, mData[i + 2],
mData[i + 3] != 0, mData[i + 4] != 0);
while (converter.GetNextSegment(&cp1, &cp2, &segEnd)) {
aBuilder->BezierTo(cp1, cp2, segEnd);
}
}
}
break;
}
case PATHSEG_LINETO_HORIZONTAL_ABS:
segEnd = Point(mData[i], segStart.y);
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_HORIZONTAL_REL:
segEnd = segStart + Point(mData[i], 0.0f);
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_VERTICAL_ABS:
segEnd = Point(segStart.x, mData[i]);
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_VERTICAL_REL:
segEnd = segStart + Point(0.0f, mData[i]);
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(segEnd);
}
break;
case PATHSEG_CURVETO_CUBIC_SMOOTH_ABS:
cp1 = SVGPathSegUtils::IsCubicType(prevSegType) ? segStart * 2 - cp2
: segStart;
cp2 = Point(mData[i], mData[i + 1]);
segEnd = Point(mData[i + 2], mData[i + 3]);
if (segEnd != segStart || segEnd != cp1 || segEnd != cp2) {
subpathHasLength = true;
aBuilder->BezierTo(cp1, cp2, segEnd);
}
break;
case PATHSEG_CURVETO_CUBIC_SMOOTH_REL:
cp1 = SVGPathSegUtils::IsCubicType(prevSegType) ? segStart * 2 - cp2
: segStart;
cp2 = segStart + Point(mData[i], mData[i + 1]);
segEnd = segStart + Point(mData[i + 2], mData[i + 3]);
if (segEnd != segStart || segEnd != cp1 || segEnd != cp2) {
subpathHasLength = true;
aBuilder->BezierTo(cp1, cp2, segEnd);
}
break;
case PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS:
cp1 = SVGPathSegUtils::IsQuadraticType(prevSegType) ? segStart * 2 - cp1
: segStart;
// Convert quadratic curve to cubic curve:
tcp1 = segStart + (cp1 - segStart) * 2 / 3;
segEnd = Point(mData[i], mData[i + 1]); // set before setting tcp2!
tcp2 = cp1 + (segEnd - cp1) / 3;
if (segEnd != segStart || segEnd != cp1) {
subpathHasLength = true;
aBuilder->BezierTo(tcp1, tcp2, segEnd);
}
break;
case PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL:
cp1 = SVGPathSegUtils::IsQuadraticType(prevSegType) ? segStart * 2 - cp1
: segStart;
// Convert quadratic curve to cubic curve:
tcp1 = segStart + (cp1 - segStart) * 2 / 3;
segEnd = segStart +
Point(mData[i], mData[i + 1]); // changed before setting tcp2!
tcp2 = cp1 + (segEnd - cp1) / 3;
if (segEnd != segStart || segEnd != cp1) {
subpathHasLength = true;
aBuilder->BezierTo(tcp1, tcp2, segEnd);
}
break;
default:
MOZ_ASSERT_UNREACHABLE("Bad path segment type");
return nullptr; // according to spec we'd use everything up to the bad
// seg anyway
}
subpathContainsNonMoveTo = !IsMoveto(segType);
i += argCount;
prevSegType = segType;
segStart = segEnd;
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
MOZ_ASSERT(prevSegType == segType,
"prevSegType should be left at the final segType");
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
return aBuilder->Finish();
}
already_AddRefed<Path> SVGPathData::BuildPathForMeasuring() const {
// Since the path that we return will not be used for painting it doesn't
// matter what we pass to CreatePathBuilder as aFillRule. Hawever, we do want
// to pass something other than NS_STYLE_STROKE_LINECAP_SQUARE as
// aStrokeLineCap to avoid the insertion of extra little lines (by
// ApproximateZeroLengthSubpathSquareCaps), in which case the value that we
// pass as aStrokeWidth doesn't matter (since it's only used to determine the
// length of those extra little lines).
RefPtr<DrawTarget> drawTarget =
gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget();
RefPtr<PathBuilder> builder =
drawTarget->CreatePathBuilder(FillRule::FILL_WINDING);
return BuildPath(builder, StyleStrokeLinecap::Butt, 0);
}
/* static */
already_AddRefed<Path> SVGPathData::BuildPathForMeasuring(
Span<const StylePathCommand> aPath) {
RefPtr<DrawTarget> drawTarget =
gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget();
RefPtr<PathBuilder> builder =
drawTarget->CreatePathBuilder(FillRule::FILL_WINDING);
return BuildPath(aPath, builder, StyleStrokeLinecap::Butt, 0);
}
// We could simplify this function because this is only used by CSS motion path
// and clip-path, which don't render the SVG Path. i.e. The returned path is
// used as a reference.
/* static */
already_AddRefed<Path> SVGPathData::BuildPath(
Span<const StylePathCommand> aPath, PathBuilder* aBuilder,
StyleStrokeLinecap aStrokeLineCap, Float aStrokeWidth, float aZoomFactor) {
if (aPath.IsEmpty() || !aPath[0].IsMoveTo()) {
return nullptr; // paths without an initial moveto are invalid
}
bool hasLineCaps = aStrokeLineCap != StyleStrokeLinecap::Butt;
bool subpathHasLength = false; // visual length
bool subpathContainsNonMoveTo = false;
StylePathCommand::Tag segType = StylePathCommand::Tag::Unknown;
StylePathCommand::Tag prevSegType = StylePathCommand::Tag::Unknown;
Point pathStart(0.0, 0.0); // start point of [sub]path
Point segStart(0.0, 0.0);
Point segEnd;
Point cp1, cp2; // previous bezier's control points
Point tcp1, tcp2; // temporaries
auto scale = [aZoomFactor](const Point& p) {
return Point(p.x * aZoomFactor, p.y * aZoomFactor);
};
// Regarding cp1 and cp2: If the previous segment was a cubic bezier curve,
// then cp2 is its second control point. If the previous segment was a
// quadratic curve, then cp1 is its (only) control point.
for (const StylePathCommand& cmd : aPath) {
segType = cmd.tag;
switch (segType) {
case StylePathCommand::Tag::ClosePath:
// set this early to allow drawing of square caps for "M{x},{y} Z":
subpathContainsNonMoveTo = true;
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
segEnd = pathStart;
aBuilder->Close();
break;
case StylePathCommand::Tag::MoveTo: {
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
const Point& p = ToGfxPoint(cmd.move_to.point);
pathStart = segEnd =
cmd.move_to.absolute == StyleIsAbsolute::Yes ? p : segStart + p;
aBuilder->MoveTo(scale(segEnd));
subpathHasLength = false;
break;
}
case StylePathCommand::Tag::LineTo: {
const Point& p = ToGfxPoint(cmd.line_to.point);
segEnd =
cmd.line_to.absolute == StyleIsAbsolute::Yes ? p : segStart + p;
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(scale(segEnd));
}
break;
}
case StylePathCommand::Tag::CurveTo:
cp1 = ToGfxPoint(cmd.curve_to.control1);
cp2 = ToGfxPoint(cmd.curve_to.control2);
segEnd = ToGfxPoint(cmd.curve_to.point);
if (cmd.curve_to.absolute == StyleIsAbsolute::No) {
cp1 += segStart;
cp2 += segStart;
segEnd += segStart;
}
if (segEnd != segStart || segEnd != cp1 || segEnd != cp2) {
subpathHasLength = true;
aBuilder->BezierTo(scale(cp1), scale(cp2), scale(segEnd));
}
break;
case StylePathCommand::Tag::QuadBezierCurveTo:
cp1 = ToGfxPoint(cmd.quad_bezier_curve_to.control1);
segEnd = ToGfxPoint(cmd.quad_bezier_curve_to.point);
if (cmd.quad_bezier_curve_to.absolute == StyleIsAbsolute::No) {
cp1 += segStart;
segEnd += segStart; // set before setting tcp2!
}
// Convert quadratic curve to cubic curve:
tcp1 = segStart + (cp1 - segStart) * 2 / 3;
tcp2 = cp1 + (segEnd - cp1) / 3;
if (segEnd != segStart || segEnd != cp1) {
subpathHasLength = true;
aBuilder->BezierTo(scale(tcp1), scale(tcp2), scale(segEnd));
}
break;
case StylePathCommand::Tag::EllipticalArc: {
const auto& arc = cmd.elliptical_arc;
Point radii(arc.rx, arc.ry);
segEnd = ToGfxPoint(arc.point);
if (arc.absolute == StyleIsAbsolute::No) {
segEnd += segStart;
}
if (segEnd != segStart) {
subpathHasLength = true;
if (radii.x == 0.0f || radii.y == 0.0f) {
aBuilder->LineTo(scale(segEnd));
} else {
SVGArcConverter converter(segStart, segEnd, radii, arc.angle,
arc.large_arc_flag._0, arc.sweep_flag._0);
while (converter.GetNextSegment(&cp1, &cp2, &segEnd)) {
aBuilder->BezierTo(scale(cp1), scale(cp2), scale(segEnd));
}
}
}
break;
}
case StylePathCommand::Tag::HorizontalLineTo:
if (cmd.horizontal_line_to.absolute == StyleIsAbsolute::Yes) {
segEnd = Point(cmd.horizontal_line_to.x, segStart.y);
} else {
segEnd = segStart + Point(cmd.horizontal_line_to.x, 0.0f);
}
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(scale(segEnd));
}
break;
case StylePathCommand::Tag::VerticalLineTo:
if (cmd.vertical_line_to.absolute == StyleIsAbsolute::Yes) {
segEnd = Point(segStart.x, cmd.vertical_line_to.y);
} else {
segEnd = segStart + Point(0.0f, cmd.vertical_line_to.y);
}
if (segEnd != segStart) {
subpathHasLength = true;
aBuilder->LineTo(scale(segEnd));
}
break;
case StylePathCommand::Tag::SmoothCurveTo:
cp1 = IsCubicType(prevSegType) ? segStart * 2 - cp2 : segStart;
cp2 = ToGfxPoint(cmd.smooth_curve_to.control2);
segEnd = ToGfxPoint(cmd.smooth_curve_to.point);
if (cmd.smooth_curve_to.absolute == StyleIsAbsolute::No) {
cp2 += segStart;
segEnd += segStart;
}
if (segEnd != segStart || segEnd != cp1 || segEnd != cp2) {
subpathHasLength = true;
aBuilder->BezierTo(scale(cp1), scale(cp2), scale(segEnd));
}
break;
case StylePathCommand::Tag::SmoothQuadBezierCurveTo: {
cp1 = IsQuadraticType(prevSegType) ? segStart * 2 - cp1 : segStart;
// Convert quadratic curve to cubic curve:
tcp1 = segStart + (cp1 - segStart) * 2 / 3;
const Point& p = ToGfxPoint(cmd.smooth_quad_bezier_curve_to.point);
// set before setting tcp2!
segEnd =
cmd.smooth_quad_bezier_curve_to.absolute == StyleIsAbsolute::Yes
? p
: segStart + p;
tcp2 = cp1 + (segEnd - cp1) / 3;
if (segEnd != segStart || segEnd != cp1) {
subpathHasLength = true;
aBuilder->BezierTo(scale(tcp1), scale(tcp2), scale(segEnd));
}
break;
}
case StylePathCommand::Tag::Unknown:
MOZ_ASSERT_UNREACHABLE("Unacceptable path segment type");
return nullptr;
}
subpathContainsNonMoveTo = !IsMoveto(segType);
prevSegType = segType;
segStart = segEnd;
}
MOZ_ASSERT(prevSegType == segType,
"prevSegType should be left at the final segType");
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
return aBuilder->Finish();
}
static double AngleOfVector(const Point& aVector) {
// C99 says about atan2 "A domain error may occur if both arguments are
// zero" and "On a domain error, the function returns an implementation-
// defined value". In the case of atan2 the implementation-defined value
// seems to commonly be zero, but it could just as easily be a NaN value.
// We specifically want zero in this case, hence the check:
return (aVector != Point(0.0, 0.0)) ? atan2(aVector.y, aVector.x) : 0.0;
}
static float AngleOfVector(const Point& cp1, const Point& cp2) {
return static_cast<float>(AngleOfVector(cp1 - cp2));
}
// This implements F.6.5 and F.6.6 of
// http://www.w3.org/TR/SVG11/implnote.html#ArcImplementationNotes
static std::tuple<float, float, float, float>
/* rx, ry, segStartAngle, segEndAngle */
ComputeSegAnglesAndCorrectRadii(const Point& aSegStart, const Point& aSegEnd,
const float aAngle, const bool aLargeArcFlag,
const bool aSweepFlag, const float aRx,
const float aRy) {
float rx = fabs(aRx); // F.6.6.1
float ry = fabs(aRy);
// F.6.5.1:
const float angle = static_cast<float>(aAngle * M_PI / 180.0);
double x1p = cos(angle) * (aSegStart.x - aSegEnd.x) / 2.0 +
sin(angle) * (aSegStart.y - aSegEnd.y) / 2.0;
double y1p = -sin(angle) * (aSegStart.x - aSegEnd.x) / 2.0 +
cos(angle) * (aSegStart.y - aSegEnd.y) / 2.0;
// This is the root in F.6.5.2 and the numerator under that root:
double root;
double numerator =
rx * rx * ry * ry - rx * rx * y1p * y1p - ry * ry * x1p * x1p;
if (numerator >= 0.0) {
root = sqrt(numerator / (rx * rx * y1p * y1p + ry * ry * x1p * x1p));
if (aLargeArcFlag == aSweepFlag) root = -root;
} else {
// F.6.6 step 3 - |numerator < 0.0|. This is equivalent to the result
// of F.6.6.2 (lamedh) being greater than one. What we have here is
// ellipse radii that are too small for the ellipse to reach between
// segStart and segEnd. We scale the radii up uniformly so that the
// ellipse is just big enough to fit (i.e. to the point where there is
// exactly one solution).
double lamedh =
1.0 - numerator / (rx * rx * ry * ry); // equiv to eqn F.6.6.2
double s = sqrt(lamedh);
rx = static_cast<float>((double)rx * s); // F.6.6.3
ry = static_cast<float>((double)ry * s);
root = 0.0;
}
double cxp = root * rx * y1p / ry; // F.6.5.2
double cyp = -root * ry * x1p / rx;
double theta =
AngleOfVector(Point(static_cast<float>((x1p - cxp) / rx),
static_cast<float>((y1p - cyp) / ry))); // F.6.5.5
double delta =
AngleOfVector(Point(static_cast<float>((-x1p - cxp) / rx),
static_cast<float>((-y1p - cyp) / ry))) - // F.6.5.6
theta;
if (!aSweepFlag && delta > 0) {
delta -= 2.0 * M_PI;
} else if (aSweepFlag && delta < 0) {
delta += 2.0 * M_PI;
}
double tx1, ty1, tx2, ty2;
tx1 = -cos(angle) * rx * sin(theta) - sin(angle) * ry * cos(theta);
ty1 = -sin(angle) * rx * sin(theta) + cos(angle) * ry * cos(theta);
tx2 = -cos(angle) * rx * sin(theta + delta) -
sin(angle) * ry * cos(theta + delta);
ty2 = -sin(angle) * rx * sin(theta + delta) +
cos(angle) * ry * cos(theta + delta);
if (delta < 0.0f) {
tx1 = -tx1;
ty1 = -ty1;
tx2 = -tx2;
ty2 = -ty2;
}
return {rx, ry, static_cast<float>(atan2(ty1, tx1)),
static_cast<float>(atan2(ty2, tx2))};
}
void SVGPathData::GetMarkerPositioningData(nsTArray<SVGMark>* aMarks) const {
// This code should assume that ANY type of segment can appear at ANY index.
// It should also assume that segments such as M and Z can appear in weird
// places, and repeat multiple times consecutively.
// info on current [sub]path (reset every M command):
Point pathStart(0.0, 0.0);
float pathStartAngle = 0.0f;
uint32_t pathStartIndex = 0;
// info on previous segment:
uint16_t prevSegType = PATHSEG_UNKNOWN;
Point prevSegEnd(0.0, 0.0);
float prevSegEndAngle = 0.0f;
Point prevCP; // if prev seg was a bezier, this was its last control point
uint32_t i = 0;
while (i < mData.Length()) {
// info on current segment:
uint16_t segType =
SVGPathSegUtils::DecodeType(mData[i++]); // advances i to args
Point& segStart = prevSegEnd;
Point segEnd;
float segStartAngle, segEndAngle;
switch (segType) // to find segStartAngle, segEnd and segEndAngle
{
case PATHSEG_CLOSEPATH:
segEnd = pathStart;
segStartAngle = segEndAngle = AngleOfVector(segEnd, segStart);
break;
case PATHSEG_MOVETO_ABS:
case PATHSEG_MOVETO_REL:
if (segType == PATHSEG_MOVETO_ABS) {
segEnd = Point(mData[i], mData[i + 1]);
} else {
segEnd = segStart + Point(mData[i], mData[i + 1]);
}
pathStart = segEnd;
pathStartIndex = aMarks->Length();
// If authors are going to specify multiple consecutive moveto commands
// with markers, me might as well make the angle do something useful:
segStartAngle = segEndAngle = AngleOfVector(segEnd, segStart);
i += 2;
break;
case PATHSEG_LINETO_ABS:
case PATHSEG_LINETO_REL:
if (segType == PATHSEG_LINETO_ABS) {
segEnd = Point(mData[i], mData[i + 1]);
} else {
segEnd = segStart + Point(mData[i], mData[i + 1]);
}
segStartAngle = segEndAngle = AngleOfVector(segEnd, segStart);
i += 2;
break;
case PATHSEG_CURVETO_CUBIC_ABS:
case PATHSEG_CURVETO_CUBIC_REL: {
Point cp1, cp2; // control points
if (segType == PATHSEG_CURVETO_CUBIC_ABS) {
cp1 = Point(mData[i], mData[i + 1]);
cp2 = Point(mData[i + 2], mData[i + 3]);
segEnd = Point(mData[i + 4], mData[i + 5]);
} else {
cp1 = segStart + Point(mData[i], mData[i + 1]);
cp2 = segStart + Point(mData[i + 2], mData[i + 3]);
segEnd = segStart + Point(mData[i + 4], mData[i + 5]);
}
prevCP = cp2;
segStartAngle = AngleOfVector(
cp1 == segStart ? (cp1 == cp2 ? segEnd : cp2) : cp1, segStart);
segEndAngle = AngleOfVector(
segEnd, cp2 == segEnd ? (cp1 == cp2 ? segStart : cp1) : cp2);
i += 6;
break;
}
case PATHSEG_CURVETO_QUADRATIC_ABS:
case PATHSEG_CURVETO_QUADRATIC_REL: {
Point cp1; // control point
if (segType == PATHSEG_CURVETO_QUADRATIC_ABS) {
cp1 = Point(mData[i], mData[i + 1]);
segEnd = Point(mData[i + 2], mData[i + 3]);
} else {
cp1 = segStart + Point(mData[i], mData[i + 1]);
segEnd = segStart + Point(mData[i + 2], mData[i + 3]);
}
prevCP = cp1;
segStartAngle = AngleOfVector(cp1 == segStart ? segEnd : cp1, segStart);
segEndAngle = AngleOfVector(segEnd, cp1 == segEnd ? segStart : cp1);
i += 4;
break;
}
case PATHSEG_ARC_ABS:
case PATHSEG_ARC_REL: {
float rx = mData[i];
float ry = mData[i + 1];
float angle = mData[i + 2];
bool largeArcFlag = mData[i + 3] != 0.0f;
bool sweepFlag = mData[i + 4] != 0.0f;
if (segType == PATHSEG_ARC_ABS) {
segEnd = Point(mData[i + 5], mData[i + 6]);
} else {
segEnd = segStart + Point(mData[i + 5], mData[i + 6]);
}
// See section F.6 of SVG 1.1 for details on what we're doing here:
// http://www.w3.org/TR/SVG11/implnote.html#ArcImplementationNotes
if (segStart == segEnd) {
// F.6.2 says "If the endpoints (x1, y1) and (x2, y2) are identical,
// then this is equivalent to omitting the elliptical arc segment
// entirely." We take that very literally here, not adding a mark, and
// not even setting any of the 'prev' variables so that it's as if
// this arc had never existed; note the difference this will make e.g.
// if the arc is proceeded by a bezier curve and followed by a
// "smooth" bezier curve of the same degree!
i += 7;
continue;
}
// Below we have funny interleaving of F.6.6 (Correction of out-of-range
// radii) and F.6.5 (Conversion from endpoint to center
// parameterization) which is designed to avoid some unnecessary
// calculations.
if (rx == 0.0 || ry == 0.0) {
// F.6.6 step 1 - straight line or coincidental points