blob: c059f36625b93d18de07f251b5e9aea6b61555f8 [file] [log] [blame]
/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/core/SkPath.h"
#include "include/core/SkPoint.h"
#include "include/core/SkScalar.h"
#include "include/core/SkStream.h"
#include "include/core/SkString.h"
#include "include/core/SkTypes.h"
#include "include/utils/SkParse.h"
#include "include/utils/SkParsePath.h"
#include "src/core/SkGeometry.h"
#include <cstdio>
enum class SkPathDirection;
static inline bool is_between(int c, int min, int max) {
return (unsigned)(c - min) <= (unsigned)(max - min);
}
static inline bool is_ws(int c) {
return is_between(c, 1, 32);
}
static inline bool is_digit(int c) {
return is_between(c, '0', '9');
}
static inline bool is_sep(int c) {
return is_ws(c) || c == ',';
}
static inline bool is_lower(int c) {
return is_between(c, 'a', 'z');
}
static inline int to_upper(int c) {
return c - 'a' + 'A';
}
static const char* skip_ws(const char str[]) {
SkASSERT(str);
while (is_ws(*str))
str++;
return str;
}
static const char* skip_sep(const char str[]) {
if (!str) {
return nullptr;
}
while (is_sep(*str))
str++;
return str;
}
static const char* find_points(const char str[], SkPoint value[], int count,
bool isRelative, SkPoint* relative) {
str = SkParse::FindScalars(str, &value[0].fX, count * 2);
if (isRelative) {
for (int index = 0; index < count; index++) {
value[index].fX += relative->fX;
value[index].fY += relative->fY;
}
}
return str;
}
static const char* find_scalar(const char str[], SkScalar* value,
bool isRelative, SkScalar relative) {
str = SkParse::FindScalar(str, value);
if (!str) {
return nullptr;
}
if (isRelative) {
*value += relative;
}
str = skip_sep(str);
return str;
}
// https://www.w3.org/TR/SVG11/paths.html#PathDataBNF
//
// flag:
// "0" | "1"
static const char* find_flag(const char str[], bool* value) {
if (!str) {
return nullptr;
}
if (str[0] != '1' && str[0] != '0') {
return nullptr;
}
*value = str[0] != '0';
str = skip_sep(str + 1);
return str;
}
bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
SkPath path;
SkPoint first = {0, 0};
SkPoint c = {0, 0};
SkPoint lastc = {0, 0};
SkPoint points[3];
char op = '\0';
char previousOp = '\0';
bool relative = false;
for (;;) {
if (!data) {
// Truncated data
return false;
}
data = skip_ws(data);
if (data[0] == '\0') {
break;
}
char ch = data[0];
if (is_digit(ch) || ch == '-' || ch == '+' || ch == '.') {
if (op == '\0' || op == 'Z') {
return false;
}
} else if (is_sep(ch)) {
data = skip_sep(data);
} else {
op = ch;
relative = false;
if (is_lower(op)) {
op = (char) to_upper(op);
relative = true;
}
data++;
data = skip_sep(data);
}
switch (op) {
case 'M':
data = find_points(data, points, 1, relative, &c);
path.moveTo(points[0]);
previousOp = '\0';
op = 'L';
c = points[0];
break;
case 'L':
data = find_points(data, points, 1, relative, &c);
path.lineTo(points[0]);
c = points[0];
break;
case 'H': {
SkScalar x;
data = find_scalar(data, &x, relative, c.fX);
path.lineTo(x, c.fY);
c.fX = x;
} break;
case 'V': {
SkScalar y;
data = find_scalar(data, &y, relative, c.fY);
path.lineTo(c.fX, y);
c.fY = y;
} break;
case 'C':
data = find_points(data, points, 3, relative, &c);
goto cubicCommon;
case 'S':
data = find_points(data, &points[1], 2, relative, &c);
points[0] = c;
if (previousOp == 'C' || previousOp == 'S') {
points[0].fX -= lastc.fX - c.fX;
points[0].fY -= lastc.fY - c.fY;
}
cubicCommon:
path.cubicTo(points[0], points[1], points[2]);
lastc = points[1];
c = points[2];
break;
case 'Q': // Quadratic Bezier Curve
data = find_points(data, points, 2, relative, &c);
goto quadraticCommon;
case 'T':
data = find_points(data, &points[1], 1, relative, &c);
points[0] = c;
if (previousOp == 'Q' || previousOp == 'T') {
points[0].fX -= lastc.fX - c.fX;
points[0].fY -= lastc.fY - c.fY;
}
quadraticCommon:
path.quadTo(points[0], points[1]);
lastc = points[0];
c = points[1];
break;
case 'A': {
SkPoint radii;
SkScalar angle;
bool largeArc, sweep;
if ((data = find_points(data, &radii, 1, false, nullptr))
&& (data = skip_sep(data))
&& (data = find_scalar(data, &angle, false, 0))
&& (data = skip_sep(data))
&& (data = find_flag(data, &largeArc))
&& (data = skip_sep(data))
&& (data = find_flag(data, &sweep))
&& (data = skip_sep(data))
&& (data = find_points(data, &points[0], 1, relative, &c))) {
path.arcTo(radii, angle, (SkPath::ArcSize) largeArc,
(SkPathDirection) !sweep, points[0]);
path.getLastPt(&c);
}
} break;
case 'Z':
path.close();
c = first;
break;
case '~': {
SkPoint args[2];
data = find_points(data, args, 2, false, nullptr);
path.moveTo(args[0].fX, args[0].fY);
path.lineTo(args[1].fX, args[1].fY);
} break;
default:
return false;
}
if (previousOp == 0) {
first = c;
}
previousOp = op;
}
// we're good, go ahead and swap in the result
result->swap(path);
return true;
}
///////////////////////////////////////////////////////////////////////////////
static void write_scalar(SkWStream* stream, SkScalar value) {
char buffer[64];
int len = snprintf(buffer, sizeof(buffer), "%g", value);
char* stop = buffer + len;
stream->write(buffer, stop - buffer);
}
SkString SkParsePath::ToSVGString(const SkPath& path, PathEncoding encoding) {
SkDynamicMemoryWStream stream;
SkPoint current_point{0,0};
const auto rel_selector = encoding == PathEncoding::Relative;
const auto append_command = [&](char cmd, const SkPoint pts[], size_t count) {
// Use lower case cmds for relative encoding.
cmd += 32 * rel_selector;
stream.write(&cmd, 1);
for (size_t i = 0; i < count; ++i) {
const auto pt = pts[i] - current_point;
if (i > 0) {
stream.write(" ", 1);
}
write_scalar(&stream, pt.fX);
stream.write(" ", 1);
write_scalar(&stream, pt.fY);
}
SkASSERT(count > 0);
// For relative encoding, track the current point (otherwise == origin).
current_point = pts[count - 1] * rel_selector;
};
SkPath::Iter iter(path, false);
SkPoint pts[4];
for (;;) {
switch (iter.next(pts)) {
case SkPath::kConic_Verb: {
const SkScalar tol = SK_Scalar1 / 1024; // how close to a quad
SkAutoConicToQuads quadder;
const SkPoint* quadPts = quadder.computeQuads(pts, iter.conicWeight(), tol);
for (int i = 0; i < quadder.countQuads(); ++i) {
append_command('Q', &quadPts[i*2 + 1], 2);
}
} break;
case SkPath::kMove_Verb:
append_command('M', &pts[0], 1);
break;
case SkPath::kLine_Verb:
append_command('L', &pts[1], 1);
break;
case SkPath::kQuad_Verb:
append_command('Q', &pts[1], 2);
break;
case SkPath::kCubic_Verb:
append_command('C', &pts[1], 3);
break;
case SkPath::kClose_Verb:
stream.write("Z", 1);
break;
case SkPath::kDone_Verb: {
SkString str;
str.resize(stream.bytesWritten());
stream.copyTo(str.data());
return str;
}
}
}
}