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mirror of https://github.com/kettek/png-js synced 2025-03-14 14:34:30 -07:00

Commit of png-js fork

This commit is contained in:
kts of kettek (Gliese) 2019-01-15 00:58:38 -08:00
commit 39e8ee8f25
6 changed files with 2417 additions and 0 deletions

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LICENSE Normal file
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MIT License
Copyright (c) 2017 Devon Govett
Copyright (c) 2019 MindFire Games, LLC
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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{
"name": "@mindfire/png-js",
"description": "A PNG decoder in ES6 JavaScript.",
"version": "1.2.0",
"main": "dist/png-js.cjs.js",
"module": "dist/png-js.es.js",
"browser": {
"./dist/png-js.es.js": "./dist/png-js.browser.es.js",
"./dist/png-js.cjs.js": "./dist/png-js.browser.cjs.js"
},
"author": {
"name": "Mindfire Games, LLC",
"email": "founders@mindfire.games",
"url": "https://mindfire.games/"
},
"scripts": {
"build": "rollup -c",
"prepublish": "npm run build",
"test:size": "bundlesize"
},
"devDependencies": {
"babel-plugin-external-helpers": "^6.22.0",
"babel-preset-es2015": "^6.24.1",
"bundlesize": "^0.17.0",
"rollup": "^0.52.2",
"rollup-plugin-babel": "^2.7.1",
"rollup-plugin-ignore": "^1.0.3",
"rollup-plugin-replace": "^1.1.1",
"rollup-plugin-uglify": "^3.0.0"
},
"files": [
"dist"
],
"bundlesize": [
{
"path": "./dist/png-js.cjs.min.js",
"maxSize": "2kB"
},
{
"path": "./dist/png-js.browser.cjs.min.js",
"maxSize": "2kB"
}
]
}

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import babel from 'rollup-plugin-babel';
import uglify from 'rollup-plugin-uglify';
import replace from 'rollup-plugin-replace'
import ignore from 'rollup-plugin-ignore'
const cjs = {
exports: 'named',
format: 'cjs'
}
const esm = {
format: 'es'
}
const getCJS = override => Object.assign({}, cjs, override)
const getESM = override => Object.assign({}, esm, override)
const configBase = {
input: 'src/index.js',
plugins: [
babel({
babelrc: false,
presets: [['es2015', { modules: false }]],
plugins: ['external-helpers'],
runtimeHelpers: true
})
],
}
const serverConfig = Object.assign({}, configBase, {
output: [
getESM({ file: 'dist/png-js.es.js' }),
getCJS({ file: 'dist/png-js.cjs.js' }),
],
plugins: configBase.plugins.concat(
replace({
BROWSER: JSON.stringify(false),
})
),
external: ['fs']
})
const serverProdConfig = Object.assign({}, serverConfig, {
output: [
getESM({ file: 'dist/png-js.es.min.js' }),
getCJS({ file: 'dist/png-js.cjs.min.js' }),
],
plugins: serverConfig.plugins.concat(
uglify()
),
})
const browserConfig = Object.assign({}, configBase, {
output: [
getESM({ file: 'dist/png-js.browser.es.js' }),
getCJS({ file: 'dist/png-js.browser.cjs.js' }),
],
plugins: configBase.plugins.concat(
replace({
BROWSER: JSON.stringify(true),
"png-js": "png-js/png.js"
}),
ignore(['fs'])
)
})
const browserProdConfig = Object.assign({}, browserConfig, {
output: [
getESM({ file: 'dist/png-js.browser.es.min.js' }),
getCJS({ file: 'dist/png-js.browser.cjs.min.js' }),
],
plugins: browserConfig.plugins.concat(
uglify()
),
})
export default [
serverConfig,
serverProdConfig,
browserConfig,
browserProdConfig
]

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import fs from 'fs';
import zlib from 'zlib';
import range from './range';
import { promisify } from 'util';
const inflateAsync = promisify(zlib.inflate);
const readFileAsync = promisify(fs.readFile)
class IndexedPNG {
constructor(data) {
this.data = data;
this.pos = 8; // Skip the default header
this.palette = [];
this.imgData = [];
this.transparency = {};
this.text = {};
this.process()
}
process() {
let i;
while (true) {
var end;
const chunkSize = this.readUInt32();
const section = ((() => {
const result = [];
for (i = 0; i < 4; i++) {
result.push(String.fromCharCode(this.data[this.pos++]));
}
return result;
})()).join('');
switch (section) {
case 'IHDR':
// we can grab interesting values from here (like width, height, etc)
this.width = this.readUInt32();
this.height = this.readUInt32();
this.bits = this.data[this.pos++];
this.colorType = this.data[this.pos++];
this.compressionMethod = this.data[this.pos++];
this.filterMethod = this.data[this.pos++];
this.interlaceMethod = this.data[this.pos++];
break;
case 'PLTE':
this.palette = this.read(chunkSize);
break;
case 'IDAT':
for (i = 0, end = chunkSize; i < end; i++) {
this.imgData.push(this.data[this.pos++]);
}
break;
case 'tRNS':
// This chunk can only occur once and it must occur after the
// PLTE chunk and before the IDAT chunk.
this.transparency = {};
switch (this.colorType) {
case 3:
// Indexed color, RGB. Each byte in this chunk is an alpha for
// the palette index in the PLTE ("palette") chunk up until the
// last non-opaque entry. Set up an array, stretching over all
// palette entries which will be 0 (opaque) or 1 (transparent).
this.transparency.indexed = this.read(chunkSize);
//var short = 255 - this.transparency.indexed.length;
var short = this.transparency.indexed.length-1;
if (short > 0) {
var asc,
end1;
for (
i = 0, end1 = short, asc = 0 <= end1; asc
? i < end1
: i > end1; asc
? i++
: i--) {
this.transparency.indexed.push(255);
}
}
break;
case 0:
// Greyscale. Corresponding to entries in the PLTE chunk.
// Grey is two bytes, range 0 .. (2 ^ bit-depth) - 1
this.transparency.grayscale = this.read(chunkSize)[0];
break;
case 2:
// True color with proper alpha channel.
this.transparency.rgb = this.read(chunkSize);
break;
}
break;
case 'tEXt':
var text = this.read(chunkSize);
var index = text.indexOf(0);
var key = String.fromCharCode(...Array.from(text.slice(0, index) || []));
this.text[key] = String.fromCharCode(...Array.from(text.slice(index + 1) || []));
break;
case 'IEND':
// we've got everything we need!
this.colors = (() => {
switch (this.colorType) {
case 0:
case 3:
case 4:
return 1;
case 2:
case 6:
return 3;
}
})();
this.hasAlphaChannel = [4, 6].includes(this.colorType);
var colors = this.colors + (
this.hasAlphaChannel
? 1
: 0);
this.pixelBitlength = this.bits * colors;
this.colorSpace = (() => {
switch (this.colors) {
case 1:
return 'DeviceGray';
case 3:
return 'DeviceRGB';
}
})();
this.imgData = Buffer.from(this.imgData);
return;
break;
default:
// unknown (or unimportant) section, skip it
this.pos += chunkSize;
}
this.pos += 4; // Skip the CRC
if (this.pos > this.data.length) {
throw new Error("Incomplete or corrupt IndexedPNG file");
}
}
}
read(bytes) {
return (range(0, bytes, false).map((i) => this.data[this.pos++]));
}
readUInt32() {
const b1 = this.data[this.pos++] << 24;
const b2 = this.data[this.pos++] << 16;
const b3 = this.data[this.pos++] << 8;
const b4 = this.data[this.pos++];
return b1 | b2 | b3 | b4;
}
readUInt16() {
const b1 = this.data[this.pos++] << 8;
const b2 = this.data[this.pos++];
return b1 | b2;
}
async decodePixels() {
let data
try {
data = await inflateAsync(this.imgData)
} catch (err) {
throw err
}
const pixelBytes = this.pixelBitlength / 8;
const scanlineLength = pixelBytes * this.width;
const pixels = Buffer.allocUnsafe(scanlineLength * this.height);
const {length} = data;
let row = 0;
let pos = 0;
let c = 0;
while (pos < length) {
var byte,
col,
i,
left,
upper;
var end;
var end1;
var end2;
var end3;
var end4;
switch (data[pos++]) {
case 0: // None
for (i = 0, end = scanlineLength; i < end; i++) {
pixels[c++] = data[pos++];
}
break;
case 1: // Sub
for (i = 0, end1 = scanlineLength; i < end1; i++) {
byte = data[pos++];
left = i < pixelBytes
? 0
: pixels[c - pixelBytes];
pixels[c++] = (byte + left) % 256;
}
break;
case 2: // Up
for (i = 0, end2 = scanlineLength; i < end2; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
upper = row && pixels[((row - 1) * scanlineLength) + (col * pixelBytes) + (i % pixelBytes)];
pixels[c++] = (upper + byte) % 256;
}
break;
case 3: // Average
for (i = 0, end3 = scanlineLength; i < end3; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes
? 0
: pixels[c - pixelBytes];
upper = row && pixels[((row - 1) * scanlineLength) + (col * pixelBytes) + (i % pixelBytes)];
pixels[c++] = (byte + Math.floor((left + upper) / 2)) % 256;
}
break;
case 4: // Paeth
for (i = 0, end4 = scanlineLength; i < end4; i++) {
var paeth,
upperLeft;
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes
? 0
: pixels[c - pixelBytes];
if (row === 0) {
upper = (upperLeft = 0);
} else {
upper = pixels[((row - 1) * scanlineLength) + (col * pixelBytes) + (i % pixelBytes)];
upperLeft = col && pixels[((row - 1) * scanlineLength) + ((col - 1) * pixelBytes) + (i % pixelBytes)];
}
const p = (left + upper) - upperLeft;
const pa = Math.abs(p - left);
const pb = Math.abs(p - upper);
const pc = Math.abs(p - upperLeft);
if ((pa <= pb) && (pa <= pc)) {
paeth = left;
} else if (pb <= pc) {
paeth = upper;
} else {
paeth = upperLeft;
}
pixels[c++] = (byte + paeth) % 256;
}
break;
default:
throw new Error(`Invalid filter algorithm: ${data[pos - 1]}`);
}
row++;
}
return pixels
}
decodePalette() {
const {palette} = this;
const transparency = this.transparency.indexed || [];
const ret = Buffer.allocUnsafe((palette.length/3) * 4);
let pos = 0;
const {length} = palette;
let c = 0;
for (let i = 0, end = palette.length; i < end; i += 3) {
var left;
ret[pos++] = palette[i];
ret[pos++] = palette[i + 1];
ret[pos++] = palette[i + 2];
ret[pos++] = (left = transparency[c++]) != null
? left
: 255;
}
return ret;
}
async toImageData(palette = this.decodePalette()) {
if (!this.decodedPixels) {
await this.decode()
}
// Allocate RGBA buffer
const pixels = new Uint8ClampedArray(this.decodedPixels.length * 4)
let j = 0
for (let i = 0; i < this.decodedPixels.length; i++) {
let index = this.decodedPixels[i] * 4
pixels[j++] = palette[index] // R
pixels[j++] = palette[index+1] // G
pixels[j++] = palette[index+2] // B
pixels[j++] = palette[index+3] // A
}
return new ImageData(pixels, this.width)
}
async decode() {
this.decodedPalette = this.decodePalette()
this.decodedPixels = await this.decodePixels()
}
};
export default IndexedPNG;

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const range = (left, right, inclusive) => {
let range = [];
let ascending = left < right;
let end = !inclusive ? right : ascending ? right + 1 : right - 1;
for (let i = left; ascending ? i < end : i > end; ascending ? i++ : i--) {
range.push(i);
}
return range;
}
export default range;

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