skia2/experimental/svg/model/SkSVGAttributeParser.cpp

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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "experimental/svg/model/SkSVGAttributeParser.h"
#include "experimental/svg/model/SkSVGTypes.h"
#include "include/utils/SkParse.h"
namespace {
// TODO: these should be shared with SkParse.cpp
inline bool is_between(char c, char min, char max) {
SkASSERT(min <= max);
return (unsigned)(c - min) <= (unsigned)(max - min);
}
inline bool is_eos(char c) {
return !c;
}
inline bool is_ws(char c) {
return is_between(c, 1, 32);
}
inline bool is_sep(char c) {
return is_ws(c) || c == ',' || c == ';';
}
} // anonymous ns
SkSVGAttributeParser::SkSVGAttributeParser(const char attributeString[])
: fCurPos(attributeString) {}
template <typename F>
inline bool SkSVGAttributeParser::advanceWhile(F f) {
auto initial = fCurPos;
while (f(*fCurPos)) {
fCurPos++;
}
return fCurPos != initial;
}
inline bool SkSVGAttributeParser::parseEOSToken() {
return is_eos(*fCurPos);
}
inline bool SkSVGAttributeParser::parseSepToken() {
return this->advanceWhile(is_sep);
}
inline bool SkSVGAttributeParser::parseWSToken() {
return this->advanceWhile(is_ws);
}
inline bool SkSVGAttributeParser::parseCommaWspToken() {
// comma-wsp:
// (wsp+ comma? wsp*) | (comma wsp*)
return this->parseWSToken() || this->parseExpectedStringToken(",");
}
inline bool SkSVGAttributeParser::parseExpectedStringToken(const char* expected) {
const char* c = fCurPos;
while (*c && *expected && *c == *expected) {
c++;
expected++;
}
if (*expected) {
return false;
}
fCurPos = c;
return true;
}
bool SkSVGAttributeParser::parseScalarToken(SkScalar* res) {
if (const char* next = SkParse::FindScalar(fCurPos, res)) {
fCurPos = next;
return true;
}
return false;
}
bool SkSVGAttributeParser::parseHexToken(uint32_t* res) {
if (const char* next = SkParse::FindHex(fCurPos, res)) {
fCurPos = next;
return true;
}
return false;
}
bool SkSVGAttributeParser::parseLengthUnitToken(SkSVGLength::Unit* unit) {
static const struct {
const char* fUnitName;
SkSVGLength::Unit fUnit;
} gUnitInfo[] = {
{ "%" , SkSVGLength::Unit::kPercentage },
{ "em", SkSVGLength::Unit::kEMS },
{ "ex", SkSVGLength::Unit::kEXS },
{ "px", SkSVGLength::Unit::kPX },
{ "cm", SkSVGLength::Unit::kCM },
{ "mm", SkSVGLength::Unit::kMM },
{ "in", SkSVGLength::Unit::kIN },
{ "pt", SkSVGLength::Unit::kPT },
{ "pc", SkSVGLength::Unit::kPC },
};
for (size_t i = 0; i < SK_ARRAY_COUNT(gUnitInfo); ++i) {
if (this->parseExpectedStringToken(gUnitInfo[i].fUnitName)) {
*unit = gUnitInfo[i].fUnit;
return true;
}
}
return false;
}
// https://www.w3.org/TR/SVG11/types.html#DataTypeColor
bool SkSVGAttributeParser::parseNamedColorToken(SkColor* c) {
if (const char* next = SkParse::FindNamedColor(fCurPos, strlen(fCurPos), c)) {
fCurPos = next;
return true;
}
return false;
}
bool SkSVGAttributeParser::parseHexColorToken(SkColor* c) {
uint32_t v;
const char* initial = fCurPos;
if (!this->parseExpectedStringToken("#") || !this->parseHexToken(&v)) {
return false;
}
switch (fCurPos - initial) {
case 7:
// matched #xxxxxxx
break;
case 4:
// matched '#xxx;
v = ((v << 12) & 0x00f00000) |
((v << 8) & 0x000ff000) |
((v << 4) & 0x00000ff0) |
((v << 0) & 0x0000000f);
break;
default:
return false;
}
*c = v | 0xff000000;
return true;
}
bool SkSVGAttributeParser::parseColorComponentToken(int32_t* c) {
const auto parseIntegral = [this](int32_t* c) -> bool {
const char* p = SkParse::FindS32(fCurPos, c);
if (!p || *p == '.') {
// No value parsed, or fractional value.
return false;
}
if (*p == '%') {
*c = SkScalarRoundToInt(*c * 255.0f / 100);
p++;
}
fCurPos = p;
return true;
};
const auto parseFractional = [this](int32_t* c) -> bool {
SkScalar s;
const char* p = SkParse::FindScalar(fCurPos, &s);
if (!p || *p != '%') {
// Floating point must be a percentage (CSS2 rgb-percent syntax).
return false;
}
p++; // Skip '%'
*c = SkScalarRoundToInt(s * 255.0f / 100);
fCurPos = p;
return true;
};
if (!parseIntegral(c) && !parseFractional(c)) {
return false;
}
*c = SkTPin<int32_t>(*c, 0, 255);
return true;
}
bool SkSVGAttributeParser::parseRGBColorToken(SkColor* c) {
return this->parseParenthesized("rgb", [this](SkColor* c) -> bool {
int32_t r, g, b;
if (this->parseColorComponentToken(&r) &&
this->parseSepToken() &&
this->parseColorComponentToken(&g) &&
this->parseSepToken() &&
this->parseColorComponentToken(&b)) {
*c = SkColorSetRGB(static_cast<uint8_t>(r),
static_cast<uint8_t>(g),
static_cast<uint8_t>(b));
return true;
}
return false;
}, c);
}
// https://www.w3.org/TR/SVG11/types.html#DataTypeColor
// And https://www.w3.org/TR/CSS2/syndata.html#color-units for the alternative
// forms supported by SVG (e.g. RGB percentages).
bool SkSVGAttributeParser::parseColor(SkSVGColorType* color) {
SkColor c;
// consume preceding whitespace
this->parseWSToken();
bool parsedValue = false;
if (this->parseHexColorToken(&c)
|| this->parseNamedColorToken(&c)
|| this->parseRGBColorToken(&c)) {
*color = SkSVGColorType(c);
parsedValue = true;
// consume trailing whitespace
this->parseWSToken();
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/linking.html#IRIReference
bool SkSVGAttributeParser::parseIRI(SkSVGStringType* iri) {
// consume preceding whitespace
this->parseWSToken();
// we only support local fragments
if (!this->parseExpectedStringToken("#")) {
return false;
}
const auto* start = fCurPos;
this->advanceWhile([](char c) -> bool { return !is_eos(c) && c != ')'; });
if (start == fCurPos) {
return false;
}
*iri = SkString(start, fCurPos - start);
return true;
}
// https://www.w3.org/TR/SVG11/types.html#DataTypeFuncIRI
bool SkSVGAttributeParser::parseFuncIRI(SkSVGStringType* iri) {
return this->parseParenthesized("url", [this](SkSVGStringType* iri) -> bool {
return this->parseIRI(iri);
}, iri);
}
// https://www.w3.org/TR/SVG11/types.html#DataTypeNumber
bool SkSVGAttributeParser::parseNumber(SkSVGNumberType* number) {
// consume WS
this->parseWSToken();
SkScalar s;
if (this->parseScalarToken(&s)) {
*number = SkSVGNumberType(s);
// consume trailing separators
this->parseSepToken();
return true;
}
return false;
}
// https://www.w3.org/TR/SVG11/types.html#DataTypeLength
bool SkSVGAttributeParser::parseLength(SkSVGLength* length) {
SkScalar s;
SkSVGLength::Unit u = SkSVGLength::Unit::kNumber;
if (this->parseScalarToken(&s) &&
(this->parseLengthUnitToken(&u) || this->parseSepToken() || this->parseEOSToken())) {
*length = SkSVGLength(s, u);
// consume trailing separators
this->parseSepToken();
return true;
}
return false;
}
// https://www.w3.org/TR/SVG11/coords.html#ViewBoxAttribute
bool SkSVGAttributeParser::parseViewBox(SkSVGViewBoxType* vb) {
SkScalar x, y, w, h;
this->parseWSToken();
bool parsedValue = false;
if (this->parseScalarToken(&x) && this->parseSepToken() &&
this->parseScalarToken(&y) && this->parseSepToken() &&
this->parseScalarToken(&w) && this->parseSepToken() &&
this->parseScalarToken(&h)) {
*vb = SkSVGViewBoxType(SkRect::MakeXYWH(x, y, w, h));
parsedValue = true;
// consume trailing whitespace
this->parseWSToken();
}
return parsedValue && this->parseEOSToken();
}
template <typename Func, typename T>
bool SkSVGAttributeParser::parseParenthesized(const char* prefix, Func f, T* result) {
this->parseWSToken();
if (prefix && !this->parseExpectedStringToken(prefix)) {
return false;
}
this->parseWSToken();
if (!this->parseExpectedStringToken("(")) {
return false;
}
this->parseWSToken();
if (!f(result)) {
return false;
}
this->parseWSToken();
return this->parseExpectedStringToken(")");
}
bool SkSVGAttributeParser::parseMatrixToken(SkMatrix* matrix) {
return this->parseParenthesized("matrix", [this](SkMatrix* m) -> bool {
SkScalar scalars[6];
for (int i = 0; i < 6; ++i) {
if (!(this->parseScalarToken(scalars + i) &&
(i > 4 || this->parseSepToken()))) {
return false;
}
}
m->setAll(scalars[0], scalars[2], scalars[4], scalars[1], scalars[3], scalars[5], 0, 0, 1);
return true;
}, matrix);
}
bool SkSVGAttributeParser::parseTranslateToken(SkMatrix* matrix) {
return this->parseParenthesized("translate", [this](SkMatrix* m) -> bool {
SkScalar tx = 0.0, ty = 0.0;
this->parseWSToken();
if (!this->parseScalarToken(&tx)) {
return false;
}
if (!this->parseSepToken() || !this->parseScalarToken(&ty)) {
ty = 0.0;
}
m->setTranslate(tx, ty);
return true;
}, matrix);
}
bool SkSVGAttributeParser::parseScaleToken(SkMatrix* matrix) {
return this->parseParenthesized("scale", [this](SkMatrix* m) -> bool {
SkScalar sx = 0.0, sy = 0.0;
if (!this->parseScalarToken(&sx)) {
return false;
}
if (!(this->parseSepToken() && this->parseScalarToken(&sy))) {
sy = sx;
}
m->setScale(sx, sy);
return true;
}, matrix);
}
bool SkSVGAttributeParser::parseRotateToken(SkMatrix* matrix) {
return this->parseParenthesized("rotate", [this](SkMatrix* m) -> bool {
SkScalar angle;
if (!this->parseScalarToken(&angle)) {
return false;
}
SkScalar cx = 0;
SkScalar cy = 0;
// optional [<cx> <cy>]
if (this->parseSepToken() && this->parseScalarToken(&cx)) {
if (!(this->parseSepToken() && this->parseScalarToken(&cy))) {
return false;
}
}
m->setRotate(angle, cx, cy);
return true;
}, matrix);
}
bool SkSVGAttributeParser::parseSkewXToken(SkMatrix* matrix) {
return this->parseParenthesized("skewX", [this](SkMatrix* m) -> bool {
SkScalar angle;
if (!this->parseScalarToken(&angle)) {
return false;
}
m->setSkewX(tanf(SkDegreesToRadians(angle)));
return true;
}, matrix);
}
bool SkSVGAttributeParser::parseSkewYToken(SkMatrix* matrix) {
return this->parseParenthesized("skewY", [this](SkMatrix* m) -> bool {
SkScalar angle;
if (!this->parseScalarToken(&angle)) {
return false;
}
m->setSkewY(tanf(SkDegreesToRadians(angle)));
return true;
}, matrix);
}
// https://www.w3.org/TR/SVG11/coords.html#TransformAttribute
bool SkSVGAttributeParser::parseTransform(SkSVGTransformType* t) {
SkMatrix matrix = SkMatrix::I();
bool parsed = false;
while (true) {
SkMatrix m;
if (!( this->parseMatrixToken(&m)
|| this->parseTranslateToken(&m)
|| this->parseScaleToken(&m)
|| this->parseRotateToken(&m)
|| this->parseSkewXToken(&m)
|| this->parseSkewYToken(&m))) {
break;
}
matrix.preConcat(m);
parsed = true;
this->parseCommaWspToken();
}
this->parseWSToken();
if (!parsed || !this->parseEOSToken()) {
return false;
}
*t = SkSVGTransformType(matrix);
return true;
}
// https://www.w3.org/TR/SVG11/painting.html#SpecifyingPaint
bool SkSVGAttributeParser::parsePaint(SkSVGPaint* paint) {
SkSVGColorType c;
SkSVGStringType iri;
bool parsedValue = false;
if (this->parseColor(&c)) {
*paint = SkSVGPaint(c);
parsedValue = true;
} else if (this->parseExpectedStringToken("none")) {
*paint = SkSVGPaint(SkSVGPaint::Type::kNone);
parsedValue = true;
} else if (this->parseExpectedStringToken("currentColor")) {
*paint = SkSVGPaint(SkSVGPaint::Type::kCurrentColor);
parsedValue = true;
} else if (this->parseExpectedStringToken("inherit")) {
*paint = SkSVGPaint(SkSVGPaint::Type::kInherit);
parsedValue = true;
} else if (this->parseFuncIRI(&iri)) {
*paint = SkSVGPaint(iri);
parsedValue = true;
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/masking.html#ClipPathProperty
bool SkSVGAttributeParser::parseClipPath(SkSVGClip* clip) {
SkSVGStringType iri;
bool parsedValue = false;
if (this->parseExpectedStringToken("none")) {
*clip = SkSVGClip(SkSVGClip::Type::kNone);
parsedValue = true;
} else if (this->parseExpectedStringToken("inherit")) {
*clip = SkSVGClip(SkSVGClip::Type::kInherit);
parsedValue = true;
} else if (this->parseFuncIRI(&iri)) {
*clip = SkSVGClip(iri);
parsedValue = true;
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/painting.html#StrokeLinecapProperty
bool SkSVGAttributeParser::parseLineCap(SkSVGLineCap* cap) {
static const struct {
SkSVGLineCap::Type fType;
const char* fName;
} gCapInfo[] = {
{ SkSVGLineCap::Type::kButt , "butt" },
{ SkSVGLineCap::Type::kRound , "round" },
{ SkSVGLineCap::Type::kSquare , "square" },
{ SkSVGLineCap::Type::kInherit, "inherit" },
};
bool parsedValue = false;
for (size_t i = 0; i < SK_ARRAY_COUNT(gCapInfo); ++i) {
if (this->parseExpectedStringToken(gCapInfo[i].fName)) {
*cap = SkSVGLineCap(gCapInfo[i].fType);
parsedValue = true;
break;
}
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/painting.html#StrokeLinejoinProperty
bool SkSVGAttributeParser::parseLineJoin(SkSVGLineJoin* join) {
static const struct {
SkSVGLineJoin::Type fType;
const char* fName;
} gJoinInfo[] = {
{ SkSVGLineJoin::Type::kMiter , "miter" },
{ SkSVGLineJoin::Type::kRound , "round" },
{ SkSVGLineJoin::Type::kBevel , "bevel" },
{ SkSVGLineJoin::Type::kInherit, "inherit" },
};
bool parsedValue = false;
for (size_t i = 0; i < SK_ARRAY_COUNT(gJoinInfo); ++i) {
if (this->parseExpectedStringToken(gJoinInfo[i].fName)) {
*join = SkSVGLineJoin(gJoinInfo[i].fType);
parsedValue = true;
break;
}
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementSpreadMethodAttribute
bool SkSVGAttributeParser::parseSpreadMethod(SkSVGSpreadMethod* spread) {
static const struct {
SkSVGSpreadMethod::Type fType;
const char* fName;
} gSpreadInfo[] = {
{ SkSVGSpreadMethod::Type::kPad , "pad" },
{ SkSVGSpreadMethod::Type::kReflect, "reflect" },
{ SkSVGSpreadMethod::Type::kRepeat , "repeat" },
};
bool parsedValue = false;
for (size_t i = 0; i < SK_ARRAY_COUNT(gSpreadInfo); ++i) {
if (this->parseExpectedStringToken(gSpreadInfo[i].fName)) {
*spread = SkSVGSpreadMethod(gSpreadInfo[i].fType);
parsedValue = true;
break;
}
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/pservers.html#StopElement
bool SkSVGAttributeParser::parseStopColor(SkSVGStopColor* stopColor) {
SkSVGColorType c;
bool parsedValue = false;
if (this->parseColor(&c)) {
*stopColor = SkSVGStopColor(c);
parsedValue = true;
} else if (this->parseExpectedStringToken("currentColor")) {
*stopColor = SkSVGStopColor(SkSVGStopColor::Type::kCurrentColor);
parsedValue = true;
} else if (this->parseExpectedStringToken("inherit")) {
*stopColor = SkSVGStopColor(SkSVGStopColor::Type::kInherit);
parsedValue = true;
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/shapes.html#PolygonElementPointsAttribute
bool SkSVGAttributeParser::parsePoints(SkSVGPointsType* points) {
SkTDArray<SkPoint> pts;
// Skip initial wsp.
// list-of-points:
// wsp* coordinate-pairs? wsp*
this->advanceWhile(is_ws);
bool parsedValue = false;
for (;;) {
// Adjacent coordinate-pairs separated by comma-wsp.
// coordinate-pairs:
// coordinate-pair
// | coordinate-pair comma-wsp coordinate-pairs
if (parsedValue && !this->parseCommaWspToken()) {
break;
}
SkScalar x, y;
if (!this->parseScalarToken(&x)) {
break;
}
// Coordinate values separated by comma-wsp or '-'.
// coordinate-pair:
// coordinate comma-wsp coordinate
// | coordinate negative-coordinate
if (!this->parseCommaWspToken() && !this->parseEOSToken() && *fCurPos != '-') {
break;
}
if (!this->parseScalarToken(&y)) {
break;
}
pts.push_back(SkPoint::Make(x, y));
parsedValue = true;
}
if (parsedValue && this->parseEOSToken()) {
*points = pts;
return true;
}
return false;
}
// https://www.w3.org/TR/SVG11/painting.html#FillRuleProperty
bool SkSVGAttributeParser::parseFillRule(SkSVGFillRule* fillRule) {
static const struct {
SkSVGFillRule::Type fType;
const char* fName;
} gFillRuleInfo[] = {
{ SkSVGFillRule::Type::kNonZero, "nonzero" },
{ SkSVGFillRule::Type::kEvenOdd, "evenodd" },
{ SkSVGFillRule::Type::kInherit, "inherit" },
};
bool parsedValue = false;
for (size_t i = 0; i < SK_ARRAY_COUNT(gFillRuleInfo); ++i) {
if (this->parseExpectedStringToken(gFillRuleInfo[i].fName)) {
*fillRule = SkSVGFillRule(gFillRuleInfo[i].fType);
parsedValue = true;
break;
}
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/painting.html#VisibilityProperty
bool SkSVGAttributeParser::parseVisibility(SkSVGVisibility* visibility) {
static const struct {
SkSVGVisibility::Type fType;
const char* fName;
} gVisibilityInfo[] = {
{ SkSVGVisibility::Type::kVisible , "visible" },
{ SkSVGVisibility::Type::kHidden , "hidden" },
{ SkSVGVisibility::Type::kCollapse, "collapse" },
{ SkSVGVisibility::Type::kInherit , "inherit" },
};
bool parsedValue = false;
for (const auto& parseInfo : gVisibilityInfo) {
if (this->parseExpectedStringToken(parseInfo.fName)) {
*visibility = SkSVGVisibility(parseInfo.fType);
parsedValue = true;
break;
}
}
return parsedValue && this->parseEOSToken();
}
// https://www.w3.org/TR/SVG11/painting.html#StrokeDasharrayProperty
bool SkSVGAttributeParser::parseDashArray(SkSVGDashArray* dashArray) {
bool parsedValue = false;
if (this->parseExpectedStringToken("none")) {
*dashArray = SkSVGDashArray(SkSVGDashArray::Type::kNone);
parsedValue = true;
} else if (this->parseExpectedStringToken("inherit")) {
*dashArray = SkSVGDashArray(SkSVGDashArray::Type::kInherit);
parsedValue = true;
} else {
SkTDArray<SkSVGLength> dashes;
for (;;) {
SkSVGLength dash;
// parseLength() also consumes trailing separators.
if (!this->parseLength(&dash)) {
break;
}
dashes.push_back(dash);
parsedValue = true;
}
if (parsedValue) {
*dashArray = SkSVGDashArray(std::move(dashes));
}
}
return parsedValue && this->parseEOSToken();
}