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'use strict';
/**
* @typedef {import('./types').PathDataItem} PathDataItem
* @typedef {import('./types').PathDataCommand} PathDataCommand
*/
// Based on https://www.w3.org/TR/SVG11/paths.html#PathDataBNF
const argsCountPerCommand = {
M: 2,
m: 2,
Z: 0,
z: 0,
L: 2,
l: 2,
H: 1,
h: 1,
V: 1,
v: 1,
C: 6,
c: 6,
S: 4,
s: 4,
Q: 4,
q: 4,
T: 2,
t: 2,
A: 7,
a: 7,
};
/**
* @type {(c: string) => c is PathDataCommand}
*/
const isCommand = (c) => {
return c in argsCountPerCommand;
};
/**
* @type {(c: string) => boolean}
*/
const isWsp = (c) => {
const codePoint = c.codePointAt(0);
return (
codePoint === 0x20 ||
codePoint === 0x9 ||
codePoint === 0xd ||
codePoint === 0xa
);
};
/**
* @type {(c: string) => boolean}
*/
const isDigit = (c) => {
const codePoint = c.codePointAt(0);
if (codePoint == null) {
return false;
}
return 48 <= codePoint && codePoint <= 57;
};
/**
* @typedef {'none' | 'sign' | 'whole' | 'decimal_point' | 'decimal' | 'e' | 'exponent_sign' | 'exponent'} ReadNumberState
*/
/**
* @type {(string: string, cursor: number) => [number, number | null]}
*/
const readNumber = (string, cursor) => {
let i = cursor;
let value = '';
let state = /** @type {ReadNumberState} */ ('none');
for (; i < string.length; i += 1) {
const c = string[i];
if (c === '+' || c === '-') {
if (state === 'none') {
state = 'sign';
value += c;
continue;
}
if (state === 'e') {
state = 'exponent_sign';
value += c;
continue;
}
}
if (isDigit(c)) {
if (state === 'none' || state === 'sign' || state === 'whole') {
state = 'whole';
value += c;
continue;
}
if (state === 'decimal_point' || state === 'decimal') {
state = 'decimal';
value += c;
continue;
}
if (state === 'e' || state === 'exponent_sign' || state === 'exponent') {
state = 'exponent';
value += c;
continue;
}
}
if (c === '.') {
if (state === 'none' || state === 'sign' || state === 'whole') {
state = 'decimal_point';
value += c;
continue;
}
}
if (c === 'E' || c == 'e') {
if (
state === 'whole' ||
state === 'decimal_point' ||
state === 'decimal'
) {
state = 'e';
value += c;
continue;
}
}
break;
}
const number = Number.parseFloat(value);
if (Number.isNaN(number)) {
return [cursor, null];
} else {
// step back to delegate iteration to parent loop
return [i - 1, number];
}
};
/**
* @type {(string: string) => Array<PathDataItem>}
*/
const parsePathData = (string) => {
/**
* @type {Array<PathDataItem>}
*/
const pathData = [];
/**
* @type {null | PathDataCommand}
*/
let command = null;
let args = /** @type {number[]} */ ([]);
let argsCount = 0;
let canHaveComma = false;
let hadComma = false;
for (let i = 0; i < string.length; i += 1) {
const c = string.charAt(i);
if (isWsp(c)) {
continue;
}
// allow comma only between arguments
if (canHaveComma && c === ',') {
if (hadComma) {
break;
}
hadComma = true;
continue;
}
if (isCommand(c)) {
if (hadComma) {
return pathData;
}
if (command == null) {
// moveto should be leading command
if (c !== 'M' && c !== 'm') {
return pathData;
}
} else {
// stop if previous command arguments are not flushed
if (args.length !== 0) {
return pathData;
}
}
command = c;
args = [];
argsCount = argsCountPerCommand[command];
canHaveComma = false;
// flush command without arguments
if (argsCount === 0) {
pathData.push({ command, args });
}
continue;
}
// avoid parsing arguments if no command detected
if (command == null) {
return pathData;
}
// read next argument
let newCursor = i;
let number = null;
if (command === 'A' || command === 'a') {
const position = args.length;
if (position === 0 || position === 1) {
// allow only positive number without sign as first two arguments
if (c !== '+' && c !== '-') {
[newCursor, number] = readNumber(string, i);
}
}
if (position === 2 || position === 5 || position === 6) {
[newCursor, number] = readNumber(string, i);
}
if (position === 3 || position === 4) {
// read flags
if (c === '0') {
number = 0;
}
if (c === '1') {
number = 1;
}
}
} else {
[newCursor, number] = readNumber(string, i);
}
if (number == null) {
return pathData;
}
args.push(number);
canHaveComma = true;
hadComma = false;
i = newCursor;
// flush arguments when necessary count is reached
if (args.length === argsCount) {
pathData.push({ command, args });
// subsequent moveto coordinates are threated as implicit lineto commands
if (command === 'M') {
command = 'L';
}
if (command === 'm') {
command = 'l';
}
args = [];
}
}
return pathData;
};
exports.parsePathData = parsePathData;
/**
* @type {(number: number, precision?: number) => string}
*/
const stringifyNumber = (number, precision) => {
if (precision != null) {
const ratio = 10 ** precision;
number = Math.round(number * ratio) / ratio;
}
// remove zero whole from decimal number
return number.toString().replace(/^0\./, '.').replace(/^-0\./, '-.');
};
/**
* Elliptical arc large-arc and sweep flags are rendered with spaces
* because many non-browser environments are not able to parse such paths
*
* @type {(
* command: string,
* args: number[],
* precision?: number,
* disableSpaceAfterFlags?: boolean
* ) => string}
*/
const stringifyArgs = (command, args, precision, disableSpaceAfterFlags) => {
let result = '';
let prev = '';
for (let i = 0; i < args.length; i += 1) {
const number = args[i];
const numberString = stringifyNumber(number, precision);
if (
disableSpaceAfterFlags &&
(command === 'A' || command === 'a') &&
// consider combined arcs
(i % 7 === 4 || i % 7 === 5)
) {
result += numberString;
} else if (i === 0 || numberString.startsWith('-')) {
// avoid space before first and negative numbers
result += numberString;
} else if (prev.includes('.') && numberString.startsWith('.')) {
// remove space before decimal with zero whole
// only when previous number is also decimal
result += numberString;
} else {
result += ` ${numberString}`;
}
prev = numberString;
}
return result;
};
/**
* @typedef {{
* pathData: Array<PathDataItem>;
* precision?: number;
* disableSpaceAfterFlags?: boolean;
* }} StringifyPathDataOptions
*/
/**
* @type {(options: StringifyPathDataOptions) => string}
*/
const stringifyPathData = ({ pathData, precision, disableSpaceAfterFlags }) => {
// combine sequence of the same commands
let combined = [];
for (let i = 0; i < pathData.length; i += 1) {
const { command, args } = pathData[i];
if (i === 0) {
combined.push({ command, args });
} else {
/**
* @type {PathDataItem}
*/
const last = combined[combined.length - 1];
// match leading moveto with following lineto
if (i === 1) {
if (command === 'L') {
last.command = 'M';
}
if (command === 'l') {
last.command = 'm';
}
}
if (
(last.command === command &&
last.command !== 'M' &&
last.command !== 'm') ||
// combine matching moveto and lineto sequences
(last.command === 'M' && command === 'L') ||
(last.command === 'm' && command === 'l')
) {
last.args = [...last.args, ...args];
} else {
combined.push({ command, args });
}
}
}
let result = '';
for (const { command, args } of combined) {
result +=
command + stringifyArgs(command, args, precision, disableSpaceAfterFlags);
}
return result;
};
exports.stringifyPathData = stringifyPathData;