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tenfourfox/dom/svg/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 "nsSVGPathDataParser.h"
#include "nsSVGPathGeometryElement.h" // for nsSVGMark
#include <stdarg.h>
#include "nsStyleConsts.h"
#include "SVGContentUtils.h"
#include "SVGPathSegUtils.h"
#include <algorithm>
using namespace mozilla;
using namespace mozilla::gfx;
static bool IsMoveto(uint16_t aSegType)
{
return aSegType == PATHSEG_MOVETO_ABS ||
aSegType == PATHSEG_MOVETO_REL;
}
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.
nsSVGPathDataParser 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::GetSegmentLengths(nsTArray<double> *aLengths) const
{
aLengths->Clear();
SVGPathTraversalState state;
uint32_t i = 0;
while (i < mData.Length()) {
state.length = 0.0;
SVGPathSegUtils::TraversePathSegment(&mData[i], state);
if (!aLengths->AppendElement(state.length)) {
aLengths->Clear();
return false;
}
i += 1 + SVGPathSegUtils::ArgCountForType(mData[i]);
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
return true;
}
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);
// 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 || (segType != PATHSEG_MOVETO_ABS &&
segType != PATHSEG_MOVETO_REL)) {
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;
}
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(0U, segIndex - 1); // -1 because while loop takes us 1 too far
}
/**
* 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 noticably 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 && \
SVGPathSegUtils::IsValidType(prevSegType) && \
(!IsMoveto(prevSegType) || segType == PATHSEG_CLOSEPATH)) { \
ApproximateZeroLengthSubpathSquareCaps(builder, segStart, aStrokeWidth);\
} \
} while(0)
already_AddRefed<Path>
SVGPathData::BuildPath(PathBuilder* builder,
uint8_t aStrokeLineCap,
Float aStrokeWidth) const
{
if (mData.IsEmpty() || !IsMoveto(SVGPathSegUtils::DecodeType(mData[0]))) {
return nullptr; // paths without an initial moveto are invalid
}
bool hasLineCaps = aStrokeLineCap != NS_STYLE_STROKE_LINECAP_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;
builder->Close();
break;
case PATHSEG_MOVETO_ABS:
MAYBE_APPROXIMATE_ZERO_LENGTH_SUBPATH_SQUARE_CAPS_TO_DT;
pathStart = segEnd = Point(mData[i], mData[i+1]);
builder->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]);
builder->MoveTo(segEnd);
subpathHasLength = false;
break;
case PATHSEG_LINETO_ABS:
segEnd = Point(mData[i], mData[i+1]);
if (segEnd != segStart) {
subpathHasLength = true;
builder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_REL:
segEnd = segStart + Point(mData[i], mData[i+1]);
if (segEnd != segStart) {
subpathHasLength = true;
builder->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;
builder->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;
builder->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;
builder->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;
builder->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) {
builder->LineTo(segEnd);
} else {
nsSVGArcConverter converter(segStart, segEnd, radii, mData[i+2],
mData[i+3] != 0, mData[i+4] != 0);
while (converter.GetNextSegment(&cp1, &cp2, &segEnd)) {
builder->BezierTo(cp1, cp2, segEnd);
}
}
}
break;
}
case PATHSEG_LINETO_HORIZONTAL_ABS:
segEnd = Point(mData[i], segStart.y);
if (segEnd != segStart) {
subpathHasLength = true;
builder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_HORIZONTAL_REL:
segEnd = segStart + Point(mData[i], 0.0f);
if (segEnd != segStart) {
subpathHasLength = true;
builder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_VERTICAL_ABS:
segEnd = Point(segStart.x, mData[i]);
if (segEnd != segStart) {
subpathHasLength = true;
builder->LineTo(segEnd);
}
break;
case PATHSEG_LINETO_VERTICAL_REL:
segEnd = segStart + Point(0.0f, mData[i]);
if (segEnd != segStart) {
subpathHasLength = true;
builder->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;
builder->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;
builder->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;
builder->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;
builder->BezierTo(tcp1, tcp2, segEnd);
}
break;
default:
NS_NOTREACHED("Bad path segment type");
return nullptr; // according to spec we'd use everything up to the bad seg anyway
}
subpathContainsNonMoveTo = segType != PATHSEG_MOVETO_ABS &&
segType != PATHSEG_MOVETO_REL;
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 builder->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, NS_STYLE_STROKE_LINECAP_BUTT, 0);
}
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));
}
void
SVGPathData::GetMarkerPositioningData(nsTArray<nsSVGMark> *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;
// 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;
// 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:
{
double rx = mData[i];
double ry = mData[i+1];
double 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
segStartAngle = segEndAngle = AngleOfVector(segEnd, segStart);
i += 7;
break;
}
rx = fabs(rx); // F.6.6.1
ry = fabs(ry);
// F.6.5.1:
angle = angle * M_PI/180.0;
double x1p = cos(angle) * (segStart.x - segEnd.x) / 2.0
+ sin(angle) * (segStart.y - segEnd.y) / 2.0;
double y1p = -sin(angle) * (segStart.x - segEnd.x) / 2.0
+ cos(angle) * (segStart.y - segEnd.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 (largeArcFlag == sweepFlag)
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 *= s; // F.6.6.3
ry *= s;
root = 0.0;
}
double cxp = root * rx * y1p / ry; // F.6.5.2
double cyp = -root * ry * x1p / rx;
double theta, delta;
theta = AngleOfVector(Point((x1p-cxp)/rx, (y1p-cyp)/ry)); // F.6.5.5
delta = AngleOfVector(Point((-x1p-cxp)/rx, (-y1p-cyp)/ry)) - // F.6.5.6
theta;
if (!sweepFlag && delta > 0)
delta -= 2.0 * M_PI;
else if (sweepFlag && 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;
}
segStartAngle = static_cast<float>(atan2(ty1, tx1));
segEndAngle = static_cast<float>(atan2(ty2, tx2));
i += 7;
break;
}
case PATHSEG_LINETO_HORIZONTAL_ABS:
case PATHSEG_LINETO_HORIZONTAL_REL:
if (segType == PATHSEG_LINETO_HORIZONTAL_ABS) {
segEnd = Point(mData[i++], segStart.y);
} else {
segEnd = segStart + Point(mData[i++], 0.0f);
}
segStartAngle = segEndAngle = AngleOfVector(segEnd, segStart);
break;
case PATHSEG_LINETO_VERTICAL_ABS:
case PATHSEG_LINETO_VERTICAL_REL:
if (segType == PATHSEG_LINETO_VERTICAL_ABS) {
segEnd = Point(segStart.x, mData[i++]);
} else {
segEnd = segStart + Point(0.0f, mData[i++]);
}
segStartAngle = segEndAngle = AngleOfVector(segEnd, segStart);
break;
case PATHSEG_CURVETO_CUBIC_SMOOTH_ABS:
case PATHSEG_CURVETO_CUBIC_SMOOTH_REL:
{
Point cp1 = SVGPathSegUtils::IsCubicType(prevSegType) ?
segStart * 2 - prevCP : segStart;
Point cp2;
if (segType == PATHSEG_CURVETO_CUBIC_SMOOTH_ABS) {
cp2 = Point(mData[i], mData[i+1]);
segEnd = Point(mData[i+2], mData[i+3]);
} else {
cp2 = segStart + Point(mData[i], mData[i+1]);
segEnd = segStart + Point(mData[i+2], mData[i+3]);
}
prevCP = cp2;
segStartAngle =
AngleOfVector(cp1 == segStart ? (cp1 == cp2 ? segEnd : cp2) : cp1, segStart);
segEndAngle =
AngleOfVector(segEnd, cp2 == segEnd ? (cp1 == cp2 ? segStart : cp1) : cp2);
i += 4;
break;
}
case PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS:
case PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL:
{
Point cp1 = SVGPathSegUtils::IsQuadraticType(prevSegType) ?
segStart * 2 - prevCP : segStart;
if (segType == PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS) {
segEnd = Point(mData[i], mData[i+1]);
} else {
segEnd = segStart + Point(mData[i], mData[i+1]);
}
prevCP = cp1;
segStartAngle = AngleOfVector(cp1 == segStart ? segEnd : cp1, segStart);
segEndAngle = AngleOfVector(segEnd, cp1 == segEnd ? segStart : cp1);
i += 2;
break;
}
default:
// Leave any existing marks in aMarks so we have a visual indication of
// when things went wrong.
MOZ_ASSERT(false, "Unknown segment type - path corruption?");
return;
}
// Set the angle of the mark at the start of this segment:
if (aMarks->Length()) {
nsSVGMark &mark = aMarks->LastElement();
if (!IsMoveto(segType) && IsMoveto(prevSegType)) {
// start of new subpath
pathStartAngle = mark.angle = segStartAngle;
} else if (IsMoveto(segType) && !IsMoveto(prevSegType)) {
// end of a subpath
if (prevSegType != PATHSEG_CLOSEPATH)
mark.angle = prevSegEndAngle;
} else {
if (!(segType == PATHSEG_CLOSEPATH &&
prevSegType == PATHSEG_CLOSEPATH))
mark.angle = SVGContentUtils::AngleBisect(prevSegEndAngle, segStartAngle);
}
}
// Add the mark at the end of this segment, and set its position:
if (!aMarks->AppendElement(nsSVGMark(static_cast<float>(segEnd.x),
static_cast<float>(segEnd.y),
0.0f,
nsSVGMark::eMid))) {
aMarks->Clear(); // OOM, so try to free some
return;
}
if (segType == PATHSEG_CLOSEPATH &&
prevSegType != PATHSEG_CLOSEPATH) {
aMarks->LastElement().angle =
//aMarks->ElementAt(pathStartIndex).angle =
SVGContentUtils::AngleBisect(segEndAngle, pathStartAngle);
}
prevSegType = segType;
prevSegEnd = segEnd;
prevSegEndAngle = segEndAngle;
}
MOZ_ASSERT(i == mData.Length(), "Very, very bad - mData corrupt");
if (aMarks->Length()) {
if (prevSegType != PATHSEG_CLOSEPATH) {
aMarks->LastElement().angle = prevSegEndAngle;
}
aMarks->LastElement().type = nsSVGMark::eEnd;
aMarks->ElementAt(0).type = nsSVGMark::eStart;
}
}
size_t
SVGPathData::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
{
return mData.ShallowSizeOfExcludingThis(aMallocSizeOf);
}
size_t
SVGPathData::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
{
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
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