gecko/dom/svg/SVGPathSegUtils.cpp
2015-05-03 15:32:37 -04:00

453 lines
14 KiB
C++

/* -*- 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 "mozilla/ArrayUtils.h" // MOZ_ARRAY_LENGTH
#include "SVGPathSegUtils.h"
#include "gfx2DGlue.h"
#include "nsSVGPathDataParser.h"
#include "nsTextFormatter.h"
using namespace mozilla;
using namespace mozilla::gfx;
static const float PATH_SEG_LENGTH_TOLERANCE = 0.0000001f;
static const uint32_t MAX_RECURSION = 10;
/* static */ void
SVGPathSegUtils::GetValueAsString(const float* aSeg, nsAString& aValue)
{
// Adding new seg type? Is the formatting below acceptable for the new types?
static_assert(NS_SVG_PATH_SEG_LAST_VALID_TYPE ==
PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL,
"Update GetValueAsString for the new value.");
static_assert(NS_SVG_PATH_SEG_MAX_ARGS == 7,
"Add another case to the switch below.");
uint32_t type = DecodeType(aSeg[0]);
char16_t typeAsChar = GetPathSegTypeAsLetter(type);
// Special case arcs:
if (IsArcType(type)) {
bool largeArcFlag = aSeg[4] != 0.0f;
bool sweepFlag = aSeg[5] != 0.0f;
nsTextFormatter::ssprintf(aValue,
MOZ_UTF16("%c%g,%g %g %d,%d %g,%g"),
typeAsChar, aSeg[1], aSeg[2], aSeg[3],
largeArcFlag, sweepFlag, aSeg[6], aSeg[7]);
} else {
switch (ArgCountForType(type)) {
case 0:
aValue = typeAsChar;
break;
case 1:
nsTextFormatter::ssprintf(aValue, MOZ_UTF16("%c%g"),
typeAsChar, aSeg[1]);
break;
case 2:
nsTextFormatter::ssprintf(aValue, MOZ_UTF16("%c%g,%g"),
typeAsChar, aSeg[1], aSeg[2]);
break;
case 4:
nsTextFormatter::ssprintf(aValue, MOZ_UTF16("%c%g,%g %g,%g"),
typeAsChar, aSeg[1], aSeg[2], aSeg[3], aSeg[4]);
break;
case 6:
nsTextFormatter::ssprintf(aValue,
MOZ_UTF16("%c%g,%g %g,%g %g,%g"),
typeAsChar, aSeg[1], aSeg[2], aSeg[3], aSeg[4],
aSeg[5], aSeg[6]);
break;
default:
MOZ_ASSERT(false, "Unknown segment type");
aValue = MOZ_UTF16("<unknown-segment-type>");
return;
}
}
// nsTextFormatter::ssprintf is one of the nsTextFormatter methods that
// randomly appends '\0' to its output string, which means that the length
// of the output string is one too long. We need to manually remove that '\0'
// until nsTextFormatter is fixed.
//
if (aValue[aValue.Length() - 1] == char16_t('\0')) {
aValue.SetLength(aValue.Length() - 1);
}
}
static float
CalcDistanceBetweenPoints(const Point& aP1, const Point& aP2)
{
return NS_hypot(aP2.x - aP1.x, aP2.y - aP1.y);
}
static void
SplitQuadraticBezier(const Point* aCurve, Point* aLeft, Point* aRight)
{
aLeft[0].x = aCurve[0].x;
aLeft[0].y = aCurve[0].y;
aRight[2].x = aCurve[2].x;
aRight[2].y = aCurve[2].y;
aLeft[1].x = (aCurve[0].x + aCurve[1].x) / 2;
aLeft[1].y = (aCurve[0].y + aCurve[1].y) / 2;
aRight[1].x = (aCurve[1].x + aCurve[2].x) / 2;
aRight[1].y = (aCurve[1].y + aCurve[2].y) / 2;
aLeft[2].x = aRight[0].x = (aLeft[1].x + aRight[1].x) / 2;
aLeft[2].y = aRight[0].y = (aLeft[1].y + aRight[1].y) / 2;
}
static void
SplitCubicBezier(const Point* aCurve, Point* aLeft, Point* aRight)
{
Point tmp;
tmp.x = (aCurve[1].x + aCurve[2].x) / 4;
tmp.y = (aCurve[1].y + aCurve[2].y) / 4;
aLeft[0].x = aCurve[0].x;
aLeft[0].y = aCurve[0].y;
aRight[3].x = aCurve[3].x;
aRight[3].y = aCurve[3].y;
aLeft[1].x = (aCurve[0].x + aCurve[1].x) / 2;
aLeft[1].y = (aCurve[0].y + aCurve[1].y) / 2;
aRight[2].x = (aCurve[2].x + aCurve[3].x) / 2;
aRight[2].y = (aCurve[2].y + aCurve[3].y) / 2;
aLeft[2].x = aLeft[1].x / 2 + tmp.x;
aLeft[2].y = aLeft[1].y / 2 + tmp.y;
aRight[1].x = aRight[2].x / 2 + tmp.x;
aRight[1].y = aRight[2].y / 2 + tmp.y;
aLeft[3].x = aRight[0].x = (aLeft[2].x + aRight[1].x) / 2;
aLeft[3].y = aRight[0].y = (aLeft[2].y + aRight[1].y) / 2;
}
static float
CalcBezLengthHelper(const Point* aCurve, uint32_t aNumPts,
uint32_t aRecursionCount,
void (*aSplit)(const Point*, Point*, Point*))
{
Point left[4];
Point right[4];
float length = 0, dist;
for (uint32_t i = 0; i < aNumPts - 1; i++) {
length += CalcDistanceBetweenPoints(aCurve[i], aCurve[i+1]);
}
dist = CalcDistanceBetweenPoints(aCurve[0], aCurve[aNumPts - 1]);
if (length - dist > PATH_SEG_LENGTH_TOLERANCE &&
aRecursionCount < MAX_RECURSION) {
aSplit(aCurve, left, right);
++aRecursionCount;
return CalcBezLengthHelper(left, aNumPts, aRecursionCount, aSplit) +
CalcBezLengthHelper(right, aNumPts, aRecursionCount, aSplit);
}
return length;
}
static inline float
CalcLengthOfCubicBezier(const Point& aPos, const Point &aCP1,
const Point& aCP2, const Point &aTo)
{
Point curve[4] = { aPos, aCP1, aCP2, aTo };
return CalcBezLengthHelper(curve, 4, 0, SplitCubicBezier);
}
static inline float
CalcLengthOfQuadraticBezier(const Point& aPos, const Point& aCP,
const Point& aTo)
{
Point curve[3] = { aPos, aCP, aTo };
return CalcBezLengthHelper(curve, 3, 0, SplitQuadraticBezier);
}
static void
TraverseClosePath(const float* aArgs, SVGPathTraversalState& aState)
{
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += CalcDistanceBetweenPoints(aState.pos, aState.start);
aState.cp1 = aState.cp2 = aState.start;
}
aState.pos = aState.start;
}
static void
TraverseMovetoAbs(const float* aArgs, SVGPathTraversalState& aState)
{
aState.start = aState.pos = Point(aArgs[0], aArgs[1]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
// aState.length is unchanged, since move commands don't affect path length.
aState.cp1 = aState.cp2 = aState.start;
}
}
static void
TraverseMovetoRel(const float* aArgs, SVGPathTraversalState& aState)
{
aState.start = aState.pos += Point(aArgs[0], aArgs[1]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
// aState.length is unchanged, since move commands don't affect path length.
aState.cp1 = aState.cp2 = aState.start;
}
}
static void
TraverseLinetoAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aArgs[0], aArgs[1]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += CalcDistanceBetweenPoints(aState.pos, to);
aState.cp1 = aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseLinetoRel(const float* aArgs, SVGPathTraversalState& aState)
{
Point to = aState.pos + Point(aArgs[0], aArgs[1]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += CalcDistanceBetweenPoints(aState.pos, to);
aState.cp1 = aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseLinetoHorizontalAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aArgs[0], aState.pos.y);
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += fabs(to.x - aState.pos.x);
aState.cp1 = aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseLinetoHorizontalRel(const float* aArgs, SVGPathTraversalState& aState)
{
aState.pos.x += aArgs[0];
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += fabs(aArgs[0]);
aState.cp1 = aState.cp2 = aState.pos;
}
}
static void
TraverseLinetoVerticalAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aState.pos.x, aArgs[0]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += fabs(to.y - aState.pos.y);
aState.cp1 = aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseLinetoVerticalRel(const float* aArgs, SVGPathTraversalState& aState)
{
aState.pos.y += aArgs[0];
if (aState.ShouldUpdateLengthAndControlPoints()) {
aState.length += fabs(aArgs[0]);
aState.cp1 = aState.cp2 = aState.pos;
}
}
static void
TraverseCurvetoCubicAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aArgs[4], aArgs[5]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp1(aArgs[0], aArgs[1]);
Point cp2(aArgs[2], aArgs[3]);
aState.length += (float)CalcLengthOfCubicBezier(aState.pos, cp1, cp2, to);
aState.cp2 = cp2;
aState.cp1 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoCubicSmoothAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aArgs[2], aArgs[3]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp1 = aState.pos - (aState.cp2 - aState.pos);
Point cp2(aArgs[0], aArgs[1]);
aState.length += (float)CalcLengthOfCubicBezier(aState.pos, cp1, cp2, to);
aState.cp2 = cp2;
aState.cp1 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoCubicRel(const float* aArgs, SVGPathTraversalState& aState)
{
Point to = aState.pos + Point(aArgs[4], aArgs[5]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp1 = aState.pos + Point(aArgs[0], aArgs[1]);
Point cp2 = aState.pos + Point(aArgs[2], aArgs[3]);
aState.length += (float)CalcLengthOfCubicBezier(aState.pos, cp1, cp2, to);
aState.cp2 = cp2;
aState.cp1 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoCubicSmoothRel(const float* aArgs, SVGPathTraversalState& aState)
{
Point to = aState.pos + Point(aArgs[2], aArgs[3]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp1 = aState.pos - (aState.cp2 - aState.pos);
Point cp2 = aState.pos + Point(aArgs[0], aArgs[1]);
aState.length += (float)CalcLengthOfCubicBezier(aState.pos, cp1, cp2, to);
aState.cp2 = cp2;
aState.cp1 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoQuadraticAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aArgs[2], aArgs[3]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp(aArgs[0], aArgs[1]);
aState.length += (float)CalcLengthOfQuadraticBezier(aState.pos, cp, to);
aState.cp1 = cp;
aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoQuadraticSmoothAbs(const float* aArgs,
SVGPathTraversalState& aState)
{
Point to(aArgs[0], aArgs[1]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp = aState.pos - (aState.cp1 - aState.pos);
aState.length += (float)CalcLengthOfQuadraticBezier(aState.pos, cp, to);
aState.cp1 = cp;
aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoQuadraticRel(const float* aArgs, SVGPathTraversalState& aState)
{
Point to = aState.pos + Point(aArgs[2], aArgs[3]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp = aState.pos + Point(aArgs[0], aArgs[1]);
aState.length += (float)CalcLengthOfQuadraticBezier(aState.pos, cp, to);
aState.cp1 = cp;
aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseCurvetoQuadraticSmoothRel(const float* aArgs,
SVGPathTraversalState& aState)
{
Point to = aState.pos + Point(aArgs[0], aArgs[1]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
Point cp = aState.pos - (aState.cp1 - aState.pos);
aState.length += (float)CalcLengthOfQuadraticBezier(aState.pos, cp, to);
aState.cp1 = cp;
aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseArcAbs(const float* aArgs, SVGPathTraversalState& aState)
{
Point to(aArgs[5], aArgs[6]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
float dist = 0;
Point radii(aArgs[0], aArgs[1]);
Point bez[4] = { aState.pos, Point(0, 0), Point(0, 0), Point(0, 0) };
nsSVGArcConverter converter(aState.pos, to, radii, aArgs[2],
aArgs[3] != 0, aArgs[4] != 0);
while (converter.GetNextSegment(&bez[1], &bez[2], &bez[3])) {
dist += CalcBezLengthHelper(bez, 4, 0, SplitCubicBezier);
bez[0] = bez[3];
}
aState.length += dist;
aState.cp1 = aState.cp2 = to;
}
aState.pos = to;
}
static void
TraverseArcRel(const float* aArgs, SVGPathTraversalState& aState)
{
Point to = aState.pos + Point(aArgs[5], aArgs[6]);
if (aState.ShouldUpdateLengthAndControlPoints()) {
float dist = 0;
Point radii(aArgs[0], aArgs[1]);
Point bez[4] = { aState.pos, Point(0, 0), Point(0, 0), Point(0, 0) };
nsSVGArcConverter converter(aState.pos, to, radii, aArgs[2],
aArgs[3] != 0, aArgs[4] != 0);
while (converter.GetNextSegment(&bez[1], &bez[2], &bez[3])) {
dist += CalcBezLengthHelper(bez, 4, 0, SplitCubicBezier);
bez[0] = bez[3];
}
aState.length += dist;
aState.cp1 = aState.cp2 = to;
}
aState.pos = to;
}
typedef void (*TraverseFunc)(const float*, SVGPathTraversalState&);
static TraverseFunc gTraverseFuncTable[NS_SVG_PATH_SEG_TYPE_COUNT] = {
nullptr, // 0 == PATHSEG_UNKNOWN
TraverseClosePath,
TraverseMovetoAbs,
TraverseMovetoRel,
TraverseLinetoAbs,
TraverseLinetoRel,
TraverseCurvetoCubicAbs,
TraverseCurvetoCubicRel,
TraverseCurvetoQuadraticAbs,
TraverseCurvetoQuadraticRel,
TraverseArcAbs,
TraverseArcRel,
TraverseLinetoHorizontalAbs,
TraverseLinetoHorizontalRel,
TraverseLinetoVerticalAbs,
TraverseLinetoVerticalRel,
TraverseCurvetoCubicSmoothAbs,
TraverseCurvetoCubicSmoothRel,
TraverseCurvetoQuadraticSmoothAbs,
TraverseCurvetoQuadraticSmoothRel
};
/* static */ void
SVGPathSegUtils::TraversePathSegment(const float* aData,
SVGPathTraversalState& aState)
{
static_assert(MOZ_ARRAY_LENGTH(gTraverseFuncTable) ==
NS_SVG_PATH_SEG_TYPE_COUNT,
"gTraverseFuncTable is out of date");
uint32_t type = DecodeType(aData[0]);
gTraverseFuncTable[type](aData + 1, aState);
}