svg-pathdata

Manipulate SVG path data (path[d] attribute content) simply and efficiently.

Usage

Install the module:

npm install --save svg-pathdata

Then in your JavaScript files:

import {
  SVGPathData,
  SVGPathDataTransformer,
  SVGPathDataEncoder,
  SVGPathDataParser,
} from 'svg-pathdata';

Reading PathData

const pathData = new SVGPathData(`
  M 10 10
  H 60
  V 60
  L 10 60
  Z`);

console.log(pathData.commands);

// [  {type: SVGPathData.MOVE_TO,       relative: false,  x: 10,  y: 10},
//    {type: SVGPathData.HORIZ_LINE_TO, relative: false,  x: 60},
//    {type: SVGPathData.VERT_LINE_TO,  relative: false,          y: 60},
//    {type: SVGPathData.LINE_TO,       relative: false,  x: 10,  y: 60},
//    {type: SVGPathData.CLOSE_PATH}]

Reading PathData in chunks

const parser = new SVGPathDataParser();

parser.parse('   '); // returns []
parser.parse('M 10'); // returns []
parser.parse(' 10'); // returns [{type: SVGPathData.MOVE_TO, relative: false, x: 10, y: 10 }]

parser.write('H 60'); // returns [{type: SVGPathData.HORIZ_LINE_TO, relative: false, x: 60 }]

parser.write('V'); // returns []
parser.write('60'); // returns [{type: SVGPathData.VERT_LINE_TO, relative: false, y: 60 }]

parser.write('L 10 60 \n  Z');
// returns [
//   {type: SVGPathData.LINE_TO, relative: false, x: 10, y: 60 },
//   {type: SVGPathData.CLOSE_PATH }]

parser.finish(); // tell parser there is no more data: will throw if there are unfinished commands.

Outputting PathData

const pathData = new SVGPathData(`
  M 10 10
  H 60
  V 60
  L 10 60
  Z`);
// returns "M10 10H60V60L10 60Z"

encodeSVGPath({ type: SVGPathData.MOVE_TO, relative: false, x: 10, y: 10 });
// returns "M10 10"

encodeSVGPath({ type: SVGPathData.HORIZ_LINE_TO, relative: false, x: 60 });
// returns "H60"

encodeSVGPath([
  { type: SVGPathData.VERT_LINE_TO, relative: false, y: 60 },
  { type: SVGPathData.LINE_TO, relative: false, x: 10, y: 60 },
  { type: SVGPathData.CLOSE_PATH },
]);
// returns "V60L10 60Z"

Transforming PathData

This library can perform transformations on SVG paths. Here is an example of that kind of use.

Transforming entire paths

new SVGPathData(`
   m 10,10
   h 60
   v 60
   l 10,60
   z`)
  .toAbs()
  .encode();
// return s"M10,10 H70 V70 L80,130 Z"

Transforming partial data

Here, we take SVGPathData from stdin and output it transformed to stdout.

const transformingParser = new SVGPathDataParser().toAbs().scale(2, 2);
transformingParser.parse('m 0 0'); // returns [{ type: SVGPathData.MOVE_TO,       relative: false, x: 0, y: 0 }]
transformingParser.parse('l 2 3'); // returns [{ type: SVGPathData.LINE_TO,       relative: false, x: 4, y: 6 }]

Supported transformations

You can find all supported transformations in src/SVGPathDataTransformer.ts. Additionally, you can create your own by writing a function with the following signature:

type TransformFunction = (command: SVGCommand) => SVGCommand | SVGCommand[];

function SET_X_TO(xValue = 10) {
  return function(command) {
    command.x = xValue; // transform command objects and return them
    return command;
  };
};

// Synchronous usage
new SVGPathData('...')
  .transform(SET_X_TO(25))
  .encode();

// Chunk usage
new SVGPathDataParser().transform(SET_X_TO(25));