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Juan Pablo Restrepo
2026-06-09 08:25:57 -05:00
parent 0a9c672c75
commit b19deda02c
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backend/node_modules/png-js/LICENSE
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MIT License
Copyright (c) 2017 Devon Govett
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.
backend/node_modules/png-js/README.md
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png.js
======
A PNG decoder in JS for the canvas element or Node.js.
## Browser Usage
Simply include png.js and zlib.js on your HTML page, create a canvas element, and call PNG.load to load an image.
<canvas></canvas>
<script src="zlib.js"></script>
<script src="png.js"></script>
<script>
var canvas = document.getElementsByTagName('canvas')[0];
PNG.load('some.png', canvas);
</script>
The source code for the browser version resides in `png.js` and also supports loading and displaying animated PNGs.
## Node.js Usage
Install the module using npm
sudo npm install png-js
Require the module and decode a PNG
var PNG = require('png-js');
PNG.decode('some.png', function(pixels) {
// pixels is a 1d array (in rgba order) of decoded pixel data
});
You can also call `PNG.load` if you want to load the PNG (but not decode the pixels) synchronously. If you already
have the PNG data in a buffer, simply use `new PNG(buffer)`. In both of these cases, you need to call `png.decode`
yourself which passes your callback the decoded pixels as a buffer. If you already have a buffer you want the pixels
copied to, call `copyToImageData` with your buffer and the decoded pixels as returned from `decodePixels`.
backend/node_modules/png-js/lib/png-js.browser.cjs
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'use strict';
var zlib = require('browserify-zlib');
function _interopDefaultCompat (e) { return e && typeof e === 'object' && 'default' in e ? e : { default: e }; }
var zlib__default = /*#__PURE__*/_interopDefaultCompat(zlib);
class PNG {
static decode(path, fn) {
{
throw new Error('PNG.decode not available in browser build');
}
}
static load(path) {
{
throw new Error('PNG.load not available in browser build');
}
}
constructor(data) {
let i;
this.data = data;
this.pos = 8; // Skip the default header
this.palette = [];
this.imgData = [];
this.transparency = {};
this.text = {};
while (true) {
const chunkSize = this.readUInt32();
let section = '';
for (i = 0; i < 4; i++) {
section += String.fromCharCode(this.data[this.pos++]);
}
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; i < chunkSize; 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;
if (short > 0) {
for (i = 0; i < short; 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.apply(String, text.slice(0, index));
this.text[key] = String.fromCharCode.apply(
String,
text.slice(index + 1)
);
break;
case 'IEND':
// we've got everything we need!
switch (this.colorType) {
case 0:
case 3:
case 4:
this.colors = 1;
break;
case 2:
case 6:
this.colors = 3;
break;
}
this.hasAlphaChannel = [4, 6].includes(this.colorType);
var colors = this.colors + (this.hasAlphaChannel ? 1 : 0);
this.pixelBitlength = this.bits * colors;
switch (this.colors) {
case 1:
this.colorSpace = 'DeviceGray';
break;
case 3:
this.colorSpace = 'DeviceRGB';
break;
}
this.imgData = Buffer.from(this.imgData);
return;
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 PNG file');
}
}
}
read(bytes) {
const result = new Array(bytes);
for (let i = 0; i < bytes; i++) {
result[i] = this.data[this.pos++];
}
return result;
}
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;
}
decodePixels(fn) {
return zlib__default.default.inflate(this.imgData, (err, data) => {
if (err) {
throw err;
}
const { width, height } = this;
const pixelBytes = this.pixelBitlength / 8;
const pixels = Buffer.alloc(width * height * pixelBytes);
const { length } = data;
let pos = 0;
function pass(x0, y0, dx, dy, singlePass = false) {
const w = Math.ceil((width - x0) / dx);
const h = Math.ceil((height - y0) / dy);
const scanlineLength = pixelBytes * w;
const buffer = singlePass ? pixels : Buffer.alloc(scanlineLength * h);
let row = 0;
let c = 0;
while (row < h && pos < length) {
var byte, col, i, left, upper;
switch (data[pos++]) {
case 0: // None
for (i = 0; i < scanlineLength; i++) {
buffer[c++] = data[pos++];
}
break;
case 1: // Sub
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
buffer[c++] = (byte + left) % 256;
}
break;
case 2: // Up
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (upper + byte) % 256;
}
break;
case 3: // Average
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (byte + Math.floor((left + upper) / 2)) % 256;
}
break;
case 4: // Paeth
for (i = 0; i < scanlineLength; i++) {
var paeth, upperLeft;
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
if (row === 0) {
upper = upperLeft = 0;
} else {
upper =
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
upperLeft =
col &&
buffer[
(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;
}
buffer[c++] = (byte + paeth) % 256;
}
break;
default:
throw new Error(`Invalid filter algorithm: ${data[pos - 1]}`);
}
if (!singlePass) {
let pixelsPos = ((y0 + row * dy) * width + x0) * pixelBytes;
let bufferPos = row * scanlineLength;
for (i = 0; i < w; i++) {
for (let j = 0; j < pixelBytes; j++)
pixels[pixelsPos++] = buffer[bufferPos++];
pixelsPos += (dx - 1) * pixelBytes;
}
}
row++;
}
}
if (this.interlaceMethod === 1) {
/*
1 6 4 6 2 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
3 6 4 6 3 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
*/
pass(0, 0, 8, 8); // 1
pass(4, 0, 8, 8); // 2
pass(0, 4, 4, 8); // 3
pass(2, 0, 4, 4); // 4
pass(0, 2, 2, 4); // 5
pass(1, 0, 2, 2); // 6
pass(0, 1, 1, 2); // 7
} else {
pass(0, 0, 1, 1, true);
}
return fn(pixels);
});
}
decodePalette() {
const { palette } = this;
const { length } = palette;
const transparency = this.transparency.indexed || [];
const ret = Buffer.alloc(transparency.length + length);
let pos = 0;
let c = 0;
for (let i = 0; i < length; 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;
}
copyToImageData(imageData, pixels) {
let j, k;
let { colors } = this;
let palette = null;
let alpha = this.hasAlphaChannel;
if (this.palette.length) {
palette =
this._decodedPalette || (this._decodedPalette = this.decodePalette());
colors = 4;
alpha = true;
}
const data = imageData.data || imageData;
const { length } = data;
const input = palette || pixels;
let i = (j = 0);
if (colors === 1) {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
const v = input[k++];
data[i++] = v;
data[i++] = v;
data[i++] = v;
data[i++] = alpha ? input[k++] : 255;
j = k;
}
} else {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = alpha ? input[k++] : 255;
j = k;
}
}
}
decode(fn) {
const ret = Buffer.alloc(this.width * this.height * 4);
return this.decodePixels(pixels => {
this.copyToImageData(ret, pixels);
return fn(ret);
});
}
}
module.exports = PNG;
backend/node_modules/png-js/lib/png-js.browser.js
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import zlib from 'browserify-zlib';
class PNG {
static decode(path, fn) {
{
throw new Error('PNG.decode not available in browser build');
}
}
static load(path) {
{
throw new Error('PNG.load not available in browser build');
}
}
constructor(data) {
let i;
this.data = data;
this.pos = 8; // Skip the default header
this.palette = [];
this.imgData = [];
this.transparency = {};
this.text = {};
while (true) {
const chunkSize = this.readUInt32();
let section = '';
for (i = 0; i < 4; i++) {
section += String.fromCharCode(this.data[this.pos++]);
}
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; i < chunkSize; 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;
if (short > 0) {
for (i = 0; i < short; 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.apply(String, text.slice(0, index));
this.text[key] = String.fromCharCode.apply(
String,
text.slice(index + 1)
);
break;
case 'IEND':
// we've got everything we need!
switch (this.colorType) {
case 0:
case 3:
case 4:
this.colors = 1;
break;
case 2:
case 6:
this.colors = 3;
break;
}
this.hasAlphaChannel = [4, 6].includes(this.colorType);
var colors = this.colors + (this.hasAlphaChannel ? 1 : 0);
this.pixelBitlength = this.bits * colors;
switch (this.colors) {
case 1:
this.colorSpace = 'DeviceGray';
break;
case 3:
this.colorSpace = 'DeviceRGB';
break;
}
this.imgData = Buffer.from(this.imgData);
return;
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 PNG file');
}
}
}
read(bytes) {
const result = new Array(bytes);
for (let i = 0; i < bytes; i++) {
result[i] = this.data[this.pos++];
}
return result;
}
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;
}
decodePixels(fn) {
return zlib.inflate(this.imgData, (err, data) => {
if (err) {
throw err;
}
const { width, height } = this;
const pixelBytes = this.pixelBitlength / 8;
const pixels = Buffer.alloc(width * height * pixelBytes);
const { length } = data;
let pos = 0;
function pass(x0, y0, dx, dy, singlePass = false) {
const w = Math.ceil((width - x0) / dx);
const h = Math.ceil((height - y0) / dy);
const scanlineLength = pixelBytes * w;
const buffer = singlePass ? pixels : Buffer.alloc(scanlineLength * h);
let row = 0;
let c = 0;
while (row < h && pos < length) {
var byte, col, i, left, upper;
switch (data[pos++]) {
case 0: // None
for (i = 0; i < scanlineLength; i++) {
buffer[c++] = data[pos++];
}
break;
case 1: // Sub
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
buffer[c++] = (byte + left) % 256;
}
break;
case 2: // Up
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (upper + byte) % 256;
}
break;
case 3: // Average
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (byte + Math.floor((left + upper) / 2)) % 256;
}
break;
case 4: // Paeth
for (i = 0; i < scanlineLength; i++) {
var paeth, upperLeft;
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
if (row === 0) {
upper = upperLeft = 0;
} else {
upper =
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
upperLeft =
col &&
buffer[
(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;
}
buffer[c++] = (byte + paeth) % 256;
}
break;
default:
throw new Error(`Invalid filter algorithm: ${data[pos - 1]}`);
}
if (!singlePass) {
let pixelsPos = ((y0 + row * dy) * width + x0) * pixelBytes;
let bufferPos = row * scanlineLength;
for (i = 0; i < w; i++) {
for (let j = 0; j < pixelBytes; j++)
pixels[pixelsPos++] = buffer[bufferPos++];
pixelsPos += (dx - 1) * pixelBytes;
}
}
row++;
}
}
if (this.interlaceMethod === 1) {
/*
1 6 4 6 2 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
3 6 4 6 3 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
*/
pass(0, 0, 8, 8); // 1
pass(4, 0, 8, 8); // 2
pass(0, 4, 4, 8); // 3
pass(2, 0, 4, 4); // 4
pass(0, 2, 2, 4); // 5
pass(1, 0, 2, 2); // 6
pass(0, 1, 1, 2); // 7
} else {
pass(0, 0, 1, 1, true);
}
return fn(pixels);
});
}
decodePalette() {
const { palette } = this;
const { length } = palette;
const transparency = this.transparency.indexed || [];
const ret = Buffer.alloc(transparency.length + length);
let pos = 0;
let c = 0;
for (let i = 0; i < length; 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;
}
copyToImageData(imageData, pixels) {
let j, k;
let { colors } = this;
let palette = null;
let alpha = this.hasAlphaChannel;
if (this.palette.length) {
palette =
this._decodedPalette || (this._decodedPalette = this.decodePalette());
colors = 4;
alpha = true;
}
const data = imageData.data || imageData;
const { length } = data;
const input = palette || pixels;
let i = (j = 0);
if (colors === 1) {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
const v = input[k++];
data[i++] = v;
data[i++] = v;
data[i++] = v;
data[i++] = alpha ? input[k++] : 255;
j = k;
}
} else {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = alpha ? input[k++] : 255;
j = k;
}
}
}
decode(fn) {
const ret = Buffer.alloc(this.width * this.height * 4);
return this.decodePixels(pixels => {
this.copyToImageData(ret, pixels);
return fn(ret);
});
}
}
export { PNG as default };
backend/node_modules/png-js/lib/png-js.cjs
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'use strict';
var fs = require('fs');
var zlib = require('zlib');
function _interopDefaultCompat (e) { return e && typeof e === 'object' && 'default' in e ? e : { default: e }; }
var fs__default = /*#__PURE__*/_interopDefaultCompat(fs);
var zlib__default = /*#__PURE__*/_interopDefaultCompat(zlib);
class PNG {
static decode(path, fn) {
{
return fs__default.default.readFile(path, function(err, file) {
const png = new PNG(file);
return png.decode(pixels => fn(pixels));
});
}
}
static load(path) {
{
const file = fs__default.default.readFileSync(path);
return new PNG(file);
}
}
constructor(data) {
let i;
this.data = data;
this.pos = 8; // Skip the default header
this.palette = [];
this.imgData = [];
this.transparency = {};
this.text = {};
while (true) {
const chunkSize = this.readUInt32();
let section = '';
for (i = 0; i < 4; i++) {
section += String.fromCharCode(this.data[this.pos++]);
}
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; i < chunkSize; 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;
if (short > 0) {
for (i = 0; i < short; 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.apply(String, text.slice(0, index));
this.text[key] = String.fromCharCode.apply(
String,
text.slice(index + 1)
);
break;
case 'IEND':
// we've got everything we need!
switch (this.colorType) {
case 0:
case 3:
case 4:
this.colors = 1;
break;
case 2:
case 6:
this.colors = 3;
break;
}
this.hasAlphaChannel = [4, 6].includes(this.colorType);
var colors = this.colors + (this.hasAlphaChannel ? 1 : 0);
this.pixelBitlength = this.bits * colors;
switch (this.colors) {
case 1:
this.colorSpace = 'DeviceGray';
break;
case 3:
this.colorSpace = 'DeviceRGB';
break;
}
this.imgData = Buffer.from(this.imgData);
return;
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 PNG file');
}
}
}
read(bytes) {
const result = new Array(bytes);
for (let i = 0; i < bytes; i++) {
result[i] = this.data[this.pos++];
}
return result;
}
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;
}
decodePixels(fn) {
return zlib__default.default.inflate(this.imgData, (err, data) => {
if (err) {
throw err;
}
const { width, height } = this;
const pixelBytes = this.pixelBitlength / 8;
const pixels = Buffer.alloc(width * height * pixelBytes);
const { length } = data;
let pos = 0;
function pass(x0, y0, dx, dy, singlePass = false) {
const w = Math.ceil((width - x0) / dx);
const h = Math.ceil((height - y0) / dy);
const scanlineLength = pixelBytes * w;
const buffer = singlePass ? pixels : Buffer.alloc(scanlineLength * h);
let row = 0;
let c = 0;
while (row < h && pos < length) {
var byte, col, i, left, upper;
switch (data[pos++]) {
case 0: // None
for (i = 0; i < scanlineLength; i++) {
buffer[c++] = data[pos++];
}
break;
case 1: // Sub
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
buffer[c++] = (byte + left) % 256;
}
break;
case 2: // Up
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (upper + byte) % 256;
}
break;
case 3: // Average
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (byte + Math.floor((left + upper) / 2)) % 256;
}
break;
case 4: // Paeth
for (i = 0; i < scanlineLength; i++) {
var paeth, upperLeft;
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
if (row === 0) {
upper = upperLeft = 0;
} else {
upper =
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
upperLeft =
col &&
buffer[
(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;
}
buffer[c++] = (byte + paeth) % 256;
}
break;
default:
throw new Error(`Invalid filter algorithm: ${data[pos - 1]}`);
}
if (!singlePass) {
let pixelsPos = ((y0 + row * dy) * width + x0) * pixelBytes;
let bufferPos = row * scanlineLength;
for (i = 0; i < w; i++) {
for (let j = 0; j < pixelBytes; j++)
pixels[pixelsPos++] = buffer[bufferPos++];
pixelsPos += (dx - 1) * pixelBytes;
}
}
row++;
}
}
if (this.interlaceMethod === 1) {
/*
1 6 4 6 2 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
3 6 4 6 3 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
*/
pass(0, 0, 8, 8); // 1
pass(4, 0, 8, 8); // 2
pass(0, 4, 4, 8); // 3
pass(2, 0, 4, 4); // 4
pass(0, 2, 2, 4); // 5
pass(1, 0, 2, 2); // 6
pass(0, 1, 1, 2); // 7
} else {
pass(0, 0, 1, 1, true);
}
return fn(pixels);
});
}
decodePalette() {
const { palette } = this;
const { length } = palette;
const transparency = this.transparency.indexed || [];
const ret = Buffer.alloc(transparency.length + length);
let pos = 0;
let c = 0;
for (let i = 0; i < length; 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;
}
copyToImageData(imageData, pixels) {
let j, k;
let { colors } = this;
let palette = null;
let alpha = this.hasAlphaChannel;
if (this.palette.length) {
palette =
this._decodedPalette || (this._decodedPalette = this.decodePalette());
colors = 4;
alpha = true;
}
const data = imageData.data || imageData;
const { length } = data;
const input = palette || pixels;
let i = (j = 0);
if (colors === 1) {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
const v = input[k++];
data[i++] = v;
data[i++] = v;
data[i++] = v;
data[i++] = alpha ? input[k++] : 255;
j = k;
}
} else {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = alpha ? input[k++] : 255;
j = k;
}
}
}
decode(fn) {
const ret = Buffer.alloc(this.width * this.height * 4);
return this.decodePixels(pixels => {
this.copyToImageData(ret, pixels);
return fn(ret);
});
}
}
module.exports = PNG;
backend/node_modules/png-js/lib/png-js.js
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import fs from 'fs';
import zlib from 'zlib';
class PNG {
static decode(path, fn) {
{
return fs.readFile(path, function(err, file) {
const png = new PNG(file);
return png.decode(pixels => fn(pixels));
});
}
}
static load(path) {
{
const file = fs.readFileSync(path);
return new PNG(file);
}
}
constructor(data) {
let i;
this.data = data;
this.pos = 8; // Skip the default header
this.palette = [];
this.imgData = [];
this.transparency = {};
this.text = {};
while (true) {
const chunkSize = this.readUInt32();
let section = '';
for (i = 0; i < 4; i++) {
section += String.fromCharCode(this.data[this.pos++]);
}
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; i < chunkSize; 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;
if (short > 0) {
for (i = 0; i < short; 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.apply(String, text.slice(0, index));
this.text[key] = String.fromCharCode.apply(
String,
text.slice(index + 1)
);
break;
case 'IEND':
// we've got everything we need!
switch (this.colorType) {
case 0:
case 3:
case 4:
this.colors = 1;
break;
case 2:
case 6:
this.colors = 3;
break;
}
this.hasAlphaChannel = [4, 6].includes(this.colorType);
var colors = this.colors + (this.hasAlphaChannel ? 1 : 0);
this.pixelBitlength = this.bits * colors;
switch (this.colors) {
case 1:
this.colorSpace = 'DeviceGray';
break;
case 3:
this.colorSpace = 'DeviceRGB';
break;
}
this.imgData = Buffer.from(this.imgData);
return;
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 PNG file');
}
}
}
read(bytes) {
const result = new Array(bytes);
for (let i = 0; i < bytes; i++) {
result[i] = this.data[this.pos++];
}
return result;
}
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;
}
decodePixels(fn) {
return zlib.inflate(this.imgData, (err, data) => {
if (err) {
throw err;
}
const { width, height } = this;
const pixelBytes = this.pixelBitlength / 8;
const pixels = Buffer.alloc(width * height * pixelBytes);
const { length } = data;
let pos = 0;
function pass(x0, y0, dx, dy, singlePass = false) {
const w = Math.ceil((width - x0) / dx);
const h = Math.ceil((height - y0) / dy);
const scanlineLength = pixelBytes * w;
const buffer = singlePass ? pixels : Buffer.alloc(scanlineLength * h);
let row = 0;
let c = 0;
while (row < h && pos < length) {
var byte, col, i, left, upper;
switch (data[pos++]) {
case 0: // None
for (i = 0; i < scanlineLength; i++) {
buffer[c++] = data[pos++];
}
break;
case 1: // Sub
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
buffer[c++] = (byte + left) % 256;
}
break;
case 2: // Up
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (upper + byte) % 256;
}
break;
case 3: // Average
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (byte + Math.floor((left + upper) / 2)) % 256;
}
break;
case 4: // Paeth
for (i = 0; i < scanlineLength; i++) {
var paeth, upperLeft;
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
if (row === 0) {
upper = upperLeft = 0;
} else {
upper =
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
upperLeft =
col &&
buffer[
(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;
}
buffer[c++] = (byte + paeth) % 256;
}
break;
default:
throw new Error(`Invalid filter algorithm: ${data[pos - 1]}`);
}
if (!singlePass) {
let pixelsPos = ((y0 + row * dy) * width + x0) * pixelBytes;
let bufferPos = row * scanlineLength;
for (i = 0; i < w; i++) {
for (let j = 0; j < pixelBytes; j++)
pixels[pixelsPos++] = buffer[bufferPos++];
pixelsPos += (dx - 1) * pixelBytes;
}
}
row++;
}
}
if (this.interlaceMethod === 1) {
/*
1 6 4 6 2 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
3 6 4 6 3 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
*/
pass(0, 0, 8, 8); // 1
pass(4, 0, 8, 8); // 2
pass(0, 4, 4, 8); // 3
pass(2, 0, 4, 4); // 4
pass(0, 2, 2, 4); // 5
pass(1, 0, 2, 2); // 6
pass(0, 1, 1, 2); // 7
} else {
pass(0, 0, 1, 1, true);
}
return fn(pixels);
});
}
decodePalette() {
const { palette } = this;
const { length } = palette;
const transparency = this.transparency.indexed || [];
const ret = Buffer.alloc(transparency.length + length);
let pos = 0;
let c = 0;
for (let i = 0; i < length; 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;
}
copyToImageData(imageData, pixels) {
let j, k;
let { colors } = this;
let palette = null;
let alpha = this.hasAlphaChannel;
if (this.palette.length) {
palette =
this._decodedPalette || (this._decodedPalette = this.decodePalette());
colors = 4;
alpha = true;
}
const data = imageData.data || imageData;
const { length } = data;
const input = palette || pixels;
let i = (j = 0);
if (colors === 1) {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
const v = input[k++];
data[i++] = v;
data[i++] = v;
data[i++] = v;
data[i++] = alpha ? input[k++] : 255;
j = k;
}
} else {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = alpha ? input[k++] : 255;
j = k;
}
}
}
decode(fn) {
const ret = Buffer.alloc(this.width * this.height * 4);
return this.decodePixels(pixels => {
this.copyToImageData(ret, pixels);
return fn(ret);
});
}
}
export { PNG as default };
backend/node_modules/png-js/package.json
Generated Vendored
+66
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{
"name": "png-js",
"description": "A PNG decoder in JavaScript",
"version": "1.1.0",
"type": "module",
"main": "./lib/png-js.cjs",
"module": "./lib/png-js.js",
"browser": {
"./lib/png-js.js": "./lib/png-js.browser.js",
"./lib/png-js.cjs": "./lib/png-js.browser.cjs"
},
"exports": {
".": {
"node": {
"import": "./lib/png-js.js",
"require": "./lib/png-js.cjs"
},
"import": "./lib/png-js.browser.js",
"require": "./lib/png-js.browser.cjs"
}
},
"author": {
"name": "Devon Govett",
"email": "devongovett@gmail.com",
"url": "http://badassjs.com/"
},
"files": [
"lib",
"png.js",
"LICENSE",
"README.md"
],
"repository": {
"type": "git",
"url": "https://github.com/devongovett/png.js.git"
},
"bugs": "http://github.com/devongovett/png.js/issues",
"dependencies": {
"browserify-zlib": "^0.2.0"
},
"devDependencies": {
"@rollup/plugin-alias": "5.1.0",
"@rollup/plugin-node-resolve": "15.2.0",
"@rollup/plugin-replace": "5.0.0",
"jest": "24.1.0",
"prettier": "1.16.4",
"rimraf": "2.6.3",
"rollup": "4.9.0",
"rollup-plugin-ignore": "1.0.10"
},
"scripts": {
"test": "yarn build && jest",
"build": "rimraf ./lib && rollup -c",
"prettier": "prettier test/**/*.js png-node.js png.js --write"
},
"engine": [
"node >= v0.6.0"
],
"jest": {
"setupFiles": [
"<rootDir>/test/patch-canvas.js",
"<rootDir>/zlib.js",
"<rootDir>/png.js"
]
}
}
backend/node_modules/png-js/png.js
Generated Vendored
+560
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/*
* MIT LICENSE
* Copyright (c) 2011 Devon Govett
*
* 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.
*/
window.PNG = (function() {
let APNG_DISPOSE_OP_NONE = 0;
let APNG_DISPOSE_OP_BACKGROUND = 1;
let APNG_DISPOSE_OP_PREVIOUS = 2;
let APNG_BLEND_OP_SOURCE = 0;
let APNG_BLEND_OP_OVER = 1;
let scratchCanvas = document.createElement('canvas');
let scratchCtx = scratchCanvas.getContext('2d');
let makeImage = function(imageData) {
scratchCtx.width = imageData.width;
scratchCtx.height = imageData.height;
scratchCtx.clearRect(0, 0, imageData.width, imageData.height);
scratchCtx.putImageData(imageData, 0, 0);
const img = new Image();
img.src = scratchCanvas.toDataURL();
return img;
};
class PNG {
static load(url, canvas, callback) {
if (typeof canvas === 'function') {
callback = canvas;
}
const xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = 'arraybuffer';
xhr.onload = () => {
const data = new Uint8Array(xhr.response || xhr.mozResponseArrayBuffer);
const png = new PNG(data);
if (typeof (canvas && canvas.getContext) === 'function') {
png.render(canvas);
}
return typeof callback === 'function' ? callback(png) : undefined;
};
return xhr.send(null);
}
constructor(data1) {
let i;
this.data = data1;
this.pos = 8; // Skip the default header
this.palette = [];
this.imgData = [];
this.transparency = {};
this.animation = null;
this.text = {};
let frame = null;
while (true) {
var data;
let chunkSize = this.readUInt32();
let section = '';
for (i = 0; i < 4; i++) {
section += String.fromCharCode(this.data[this.pos++]);
}
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 'acTL':
// we have an animated PNG
this.animation = {
numFrames: this.readUInt32(),
numPlays: this.readUInt32() || Infinity,
frames: []
};
break;
case 'PLTE':
this.palette = this.read(chunkSize);
break;
case 'fcTL':
if (frame) {
this.animation.frames.push(frame);
}
this.pos += 4; // skip sequence number
frame = {
width: this.readUInt32(),
height: this.readUInt32(),
xOffset: this.readUInt32(),
yOffset: this.readUInt32()
};
var delayNum = this.readUInt16();
var delayDen = this.readUInt16() || 100;
frame.delay = (1000 * delayNum) / delayDen;
frame.disposeOp = this.data[this.pos++];
frame.blendOp = this.data[this.pos++];
frame.data = [];
break;
case 'IDAT':
case 'fdAT':
if (section === 'fdAT') {
this.pos += 4; // skip sequence number
chunkSize -= 4;
}
data = (frame && frame.data) || this.imgData;
for (i = 0; i < chunkSize; i++) {
data.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;
if (short > 0) {
for (i = 0; i < short; 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.apply(String, text.slice(0, index));
this.text[key] = String.fromCharCode.apply(
String,
text.slice(index + 1)
);
break;
case 'IEND':
if (frame) {
this.animation.frames.push(frame);
}
// we've got everything we need!
switch (this.colorType) {
case 0:
case 3:
case 4:
this.colors = 1;
break;
case 2:
case 6:
this.colors = 3;
break;
}
this.hasAlphaChannel = [4, 6].includes(this.colorType);
var colors = this.colors + (this.hasAlphaChannel ? 1 : 0);
this.pixelBitlength = this.bits * colors;
switch (this.colors) {
case 1:
this.colorSpace = 'DeviceGray';
break;
case 3:
this.colorSpace = 'DeviceRGB';
break;
}
this.imgData = new Uint8Array(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 PNG file');
}
}
}
read(bytes) {
const result = new Array(bytes);
for (let i = 0; i < bytes; i++) {
result[i] = this.data[this.pos++];
}
return result;
}
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;
}
decodePixels(data) {
if (data == null) {
data = this.imgData;
}
if (data.length === 0) {
return new Uint8Array(0);
}
data = new FlateStream(data);
data = data.getBytes();
const { width, height } = this;
const pixelBytes = this.pixelBitlength / 8;
const pixels = new Uint8Array(width * height * pixelBytes);
const { length } = data;
let pos = 0;
function pass(x0, y0, dx, dy, singlePass = false) {
const w = Math.ceil((width - x0) / dx);
const h = Math.ceil((height - y0) / dy);
const scanlineLength = pixelBytes * w;
const buffer = singlePass ? pixels : new Uint8Array(scanlineLength * h);
let row = 0;
let c = 0;
while (row < h && pos < length) {
var byte, col, i, left, upper;
switch (data[pos++]) {
case 0: // None
for (i = 0; i < scanlineLength; i++) {
buffer[c++] = data[pos++];
}
break;
case 1: // Sub
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
buffer[c++] = (byte + left) % 256;
}
break;
case 2: // Up
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (upper + byte) % 256;
}
break;
case 3: // Average
for (i = 0; i < scanlineLength; i++) {
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
upper =
row &&
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
buffer[c++] = (byte + Math.floor((left + upper) / 2)) % 256;
}
break;
case 4: // Paeth
for (i = 0; i < scanlineLength; i++) {
var paeth, upperLeft;
byte = data[pos++];
col = (i - (i % pixelBytes)) / pixelBytes;
left = i < pixelBytes ? 0 : buffer[c - pixelBytes];
if (row === 0) {
upper = upperLeft = 0;
} else {
upper =
buffer[
(row - 1) * scanlineLength +
col * pixelBytes +
(i % pixelBytes)
];
upperLeft =
col &&
buffer[
(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;
}
buffer[c++] = (byte + paeth) % 256;
}
break;
default:
throw new Error(`Invalid filter algorithm: ${data[pos - 1]}`);
}
if (!singlePass) {
let pixelsPos = ((y0 + row * dy) * width + x0) * pixelBytes;
let bufferPos = row * scanlineLength;
for (i = 0; i < w; i++) {
for (let j = 0; j < pixelBytes; j++)
pixels[pixelsPos++] = buffer[bufferPos++];
pixelsPos += (dx - 1) * pixelBytes;
}
}
row++;
}
}
if (this.interlaceMethod === 1) {
/*
1 6 4 6 2 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
3 6 4 6 3 6 4 6
7 7 7 7 7 7 7 7
5 6 5 6 5 6 5 6
7 7 7 7 7 7 7 7
*/
pass(0, 0, 8, 8); // 1
pass(4, 0, 8, 8); // 2
pass(0, 4, 4, 8); // 3
pass(2, 0, 4, 4); // 4
pass(0, 2, 2, 4); // 5
pass(1, 0, 2, 2); // 6
pass(0, 1, 1, 2); // 7
} else {
pass(0, 0, 1, 1, true);
}
return pixels;
}
decodePalette() {
const { palette } = this;
const { length } = palette;
const transparency = this.transparency.indexed || [];
const ret = new Uint8Array((transparency.length || 0) + length);
let pos = 0;
let c = 0;
for (let i = 0; i < length; 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;
}
copyToImageData(imageData, pixels) {
let j, k;
let { colors } = this;
let palette = null;
let alpha = this.hasAlphaChannel;
if (this.palette.length) {
palette =
this._decodedPalette || (this._decodedPalette = this.decodePalette());
colors = 4;
alpha = true;
}
const data = imageData.data || imageData;
const { length } = data;
const input = palette || pixels;
let i = (j = 0);
if (colors === 1) {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
const v = input[k++];
data[i++] = v;
data[i++] = v;
data[i++] = v;
data[i++] = alpha ? input[k++] : 255;
j = k;
}
} else {
while (i < length) {
k = palette ? pixels[i / 4] * 4 : j;
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = input[k++];
data[i++] = alpha ? input[k++] : 255;
j = k;
}
}
}
decode() {
const ret = new Uint8Array(this.width * this.height * 4);
this.copyToImageData(ret, this.decodePixels());
return ret;
}
decodeFrames(ctx) {
if (!this.animation) {
return;
}
for (let i = 0; i < this.animation.frames.length; i++) {
const frame = this.animation.frames[i];
const imageData = ctx.createImageData(frame.width, frame.height);
const pixels = this.decodePixels(new Uint8Array(frame.data));
this.copyToImageData(imageData, pixels);
frame.imageData = imageData;
frame.image = makeImage(imageData);
}
}
renderFrame(ctx, number) {
const { frames } = this.animation;
const frame = frames[number];
const prev = frames[number - 1];
// if we're on the first frame, clear the canvas
if (number === 0) {
ctx.clearRect(0, 0, this.width, this.height);
}
// check the previous frame's dispose operation
if ((prev && prev.disposeOp) === APNG_DISPOSE_OP_BACKGROUND) {
ctx.clearRect(prev.xOffset, prev.yOffset, prev.width, prev.height);
} else if ((prev && prev.disposeOp) === APNG_DISPOSE_OP_PREVIOUS) {
ctx.putImageData(prev.imageData, prev.xOffset, prev.yOffset);
}
// APNG_BLEND_OP_SOURCE overwrites the previous data
if (frame.blendOp === APNG_BLEND_OP_SOURCE) {
ctx.clearRect(frame.xOffset, frame.yOffset, frame.width, frame.height);
}
// draw the current frame
return ctx.drawImage(frame.image, frame.xOffset, frame.yOffset);
}
animate(ctx) {
let frameNumber = 0;
const { numFrames, frames, numPlays } = this.animation;
const doFrame = () => {
const f = frameNumber++ % numFrames;
const frame = frames[f];
this.renderFrame(ctx, f);
if (numFrames > 1 && frameNumber / numFrames < numPlays) {
this.animation._timeout = setTimeout(doFrame, frame.delay);
}
};
doFrame();
}
stopAnimation() {
return clearTimeout(this.animation && this.animation._timeout);
}
render(canvas) {
// if this canvas was displaying another image before,
// stop the animation on it
if (canvas._png) {
canvas._png.stopAnimation();
}
canvas._png = this;
canvas.width = this.width;
canvas.height = this.height;
const ctx = canvas.getContext('2d');
if (this.animation) {
this.decodeFrames(ctx);
return this.animate(ctx);
} else {
const data = ctx.createImageData(this.width, this.height);
this.copyToImageData(data, this.decodePixels());
return ctx.putImageData(data, 0, 0);
}
}
}
return PNG;
})();