Icard/angular-clarity-master(work.../node_modules/pngjs/lib/packer.js

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2024-07-16 14:55:36 +00:00
"use strict";
let constants = require("./constants");
let CrcStream = require("./crc");
let bitPacker = require("./bitpacker");
let filter = require("./filter-pack");
let zlib = require("zlib");
let Packer = (module.exports = function (options) {
this._options = options;
options.deflateChunkSize = options.deflateChunkSize || 32 * 1024;
options.deflateLevel =
options.deflateLevel != null ? options.deflateLevel : 9;
options.deflateStrategy =
options.deflateStrategy != null ? options.deflateStrategy : 3;
options.inputHasAlpha =
options.inputHasAlpha != null ? options.inputHasAlpha : true;
options.deflateFactory = options.deflateFactory || zlib.createDeflate;
options.bitDepth = options.bitDepth || 8;
// This is outputColorType
options.colorType =
typeof options.colorType === "number"
? options.colorType
: constants.COLORTYPE_COLOR_ALPHA;
options.inputColorType =
typeof options.inputColorType === "number"
? options.inputColorType
: constants.COLORTYPE_COLOR_ALPHA;
if (
[
constants.COLORTYPE_GRAYSCALE,
constants.COLORTYPE_COLOR,
constants.COLORTYPE_COLOR_ALPHA,
constants.COLORTYPE_ALPHA,
].indexOf(options.colorType) === -1
) {
throw new Error(
"option color type:" + options.colorType + " is not supported at present"
);
}
if (
[
constants.COLORTYPE_GRAYSCALE,
constants.COLORTYPE_COLOR,
constants.COLORTYPE_COLOR_ALPHA,
constants.COLORTYPE_ALPHA,
].indexOf(options.inputColorType) === -1
) {
throw new Error(
"option input color type:" +
options.inputColorType +
" is not supported at present"
);
}
if (options.bitDepth !== 8 && options.bitDepth !== 16) {
throw new Error(
"option bit depth:" + options.bitDepth + " is not supported at present"
);
}
});
Packer.prototype.getDeflateOptions = function () {
return {
chunkSize: this._options.deflateChunkSize,
level: this._options.deflateLevel,
strategy: this._options.deflateStrategy,
};
};
Packer.prototype.createDeflate = function () {
return this._options.deflateFactory(this.getDeflateOptions());
};
Packer.prototype.filterData = function (data, width, height) {
// convert to correct format for filtering (e.g. right bpp and bit depth)
let packedData = bitPacker(data, width, height, this._options);
// filter pixel data
let bpp = constants.COLORTYPE_TO_BPP_MAP[this._options.colorType];
let filteredData = filter(packedData, width, height, this._options, bpp);
return filteredData;
};
Packer.prototype._packChunk = function (type, data) {
let len = data ? data.length : 0;
let buf = Buffer.alloc(len + 12);
buf.writeUInt32BE(len, 0);
buf.writeUInt32BE(type, 4);
if (data) {
data.copy(buf, 8);
}
buf.writeInt32BE(
CrcStream.crc32(buf.slice(4, buf.length - 4)),
buf.length - 4
);
return buf;
};
Packer.prototype.packGAMA = function (gamma) {
let buf = Buffer.alloc(4);
buf.writeUInt32BE(Math.floor(gamma * constants.GAMMA_DIVISION), 0);
return this._packChunk(constants.TYPE_gAMA, buf);
};
Packer.prototype.packIHDR = function (width, height) {
let buf = Buffer.alloc(13);
buf.writeUInt32BE(width, 0);
buf.writeUInt32BE(height, 4);
buf[8] = this._options.bitDepth; // Bit depth
buf[9] = this._options.colorType; // colorType
buf[10] = 0; // compression
buf[11] = 0; // filter
buf[12] = 0; // interlace
return this._packChunk(constants.TYPE_IHDR, buf);
};
Packer.prototype.packIDAT = function (data) {
return this._packChunk(constants.TYPE_IDAT, data);
};
Packer.prototype.packIEND = function () {
return this._packChunk(constants.TYPE_IEND, null);
};