frontend/node_modules/fast-png/lib/PngDecoder.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const iobuffer_1 = require("iobuffer");
const pako_1 = require("pako");
const crc_1 = require("./helpers/crc");
const decodeInterlaceAdam7_1 = require("./helpers/decodeInterlaceAdam7");
const decodeInterlaceNull_1 = require("./helpers/decodeInterlaceNull");
const signature_1 = require("./helpers/signature");
const text_1 = require("./helpers/text");
const internalTypes_1 = require("./internalTypes");
class PngDecoder extends iobuffer_1.IOBuffer {
    _checkCrc;
    _inflator;
    _png;
    _apng;
    _end;
    _hasPalette;
    _palette;
    _hasTransparency;
    _transparency;
    _compressionMethod;
    _filterMethod;
    _interlaceMethod;
    _colorType;
    _isAnimated;
    _numberOfFrames;
    _numberOfPlays;
    _frames;
    _writingDataChunks;
    constructor(data, options = {}) {
        super(data);
        const { checkCrc = false } = options;
        this._checkCrc = checkCrc;
        this._inflator = new pako_1.Inflate();
        this._png = {
            width: -1,
            height: -1,
            channels: -1,
            data: new Uint8Array(0),
            depth: 1,
            text: {},
        };
        this._apng = {
            width: -1,
            height: -1,
            channels: -1,
            depth: 1,
            numberOfFrames: 1,
            numberOfPlays: 0,
            text: {},
            frames: [],
        };
        this._end = false;
        this._hasPalette = false;
        this._palette = [];
        this._hasTransparency = false;
        this._transparency = new Uint16Array(0);
        this._compressionMethod = internalTypes_1.CompressionMethod.UNKNOWN;
        this._filterMethod = internalTypes_1.FilterMethod.UNKNOWN;
        this._interlaceMethod = internalTypes_1.InterlaceMethod.UNKNOWN;
        this._colorType = internalTypes_1.ColorType.UNKNOWN;
        this._isAnimated = false;
        this._numberOfFrames = 1;
        this._numberOfPlays = 0;
        this._frames = [];
        this._writingDataChunks = false;
        // PNG is always big endian
        // https://www.w3.org/TR/PNG/#7Integers-and-byte-order
        this.setBigEndian();
    }
    decode() {
        (0, signature_1.checkSignature)(this);
        while (!this._end) {
            const length = this.readUint32();
            const type = this.readChars(4);
            this.decodeChunk(length, type);
        }
        this.decodeImage();
        return this._png;
    }
    decodeApng() {
        (0, signature_1.checkSignature)(this);
        while (!this._end) {
            const length = this.readUint32();
            const type = this.readChars(4);
            this.decodeApngChunk(length, type);
        }
        this.decodeApngImage();
        return this._apng;
    }
    // https://www.w3.org/TR/PNG/#5Chunk-layout
    decodeChunk(length, type) {
        const offset = this.offset;
        switch (type) {
            // 11.2 Critical chunks
            case 'IHDR': // 11.2.2 IHDR Image header
                this.decodeIHDR();
                break;
            case 'PLTE': // 11.2.3 PLTE Palette
                this.decodePLTE(length);
                break;
            case 'IDAT': // 11.2.4 IDAT Image data
                this.decodeIDAT(length);
                break;
            case 'IEND': // 11.2.5 IEND Image trailer
                this._end = true;
                break;
            // 11.3 Ancillary chunks
            case 'tRNS': // 11.3.2.1 tRNS Transparency
                this.decodetRNS(length);
                break;
            case 'iCCP': // 11.3.3.3 iCCP Embedded ICC profile
                this.decodeiCCP(length);
                break;
            case text_1.textChunkName: // 11.3.4.3 tEXt Textual data
                (0, text_1.decodetEXt)(this._png.text, this, length);
                break;
            case 'pHYs': // 11.3.5.3 pHYs Physical pixel dimensions
                this.decodepHYs();
                break;
            default:
                this.skip(length);
                break;
        }
        if (this.offset - offset !== length) {
            throw new Error(`Length mismatch while decoding chunk ${type}`);
        }
        if (this._checkCrc) {
            (0, crc_1.checkCrc)(this, length + 4, type);
        }
        else {
            this.skip(4);
        }
    }
    decodeApngChunk(length, type) {
        const offset = this.offset;
        if (type !== 'fdAT' && type !== 'IDAT' && this._writingDataChunks) {
            this.pushDataToFrame();
        }
        switch (type) {
            case 'acTL':
                this.decodeACTL();
                break;
            case 'fcTL':
                this.decodeFCTL();
                break;
            case 'fdAT':
                this.decodeFDAT(length);
                break;
            default:
                this.decodeChunk(length, type);
                this.offset = offset + length;
                break;
        }
        if (this.offset - offset !== length) {
            throw new Error(`Length mismatch while decoding chunk ${type}`);
        }
        if (this._checkCrc) {
            (0, crc_1.checkCrc)(this, length + 4, type);
        }
        else {
            this.skip(4);
        }
    }
    // https://www.w3.org/TR/PNG/#11IHDR
    decodeIHDR() {
        const image = this._png;
        image.width = this.readUint32();
        image.height = this.readUint32();
        image.depth = checkBitDepth(this.readUint8());
        const colorType = this.readUint8();
        this._colorType = colorType;
        let channels;
        switch (colorType) {
            case internalTypes_1.ColorType.GREYSCALE:
                channels = 1;
                break;
            case internalTypes_1.ColorType.TRUECOLOUR:
                channels = 3;
                break;
            case internalTypes_1.ColorType.INDEXED_COLOUR:
                channels = 1;
                break;
            case internalTypes_1.ColorType.GREYSCALE_ALPHA:
                channels = 2;
                break;
            case internalTypes_1.ColorType.TRUECOLOUR_ALPHA:
                channels = 4;
                break;
            // Kept for exhaustiveness.
            // eslint-disable-next-line unicorn/no-useless-switch-case
            case internalTypes_1.ColorType.UNKNOWN:
            default:
                throw new Error(`Unknown color type: ${colorType}`);
        }
        this._png.channels = channels;
        this._compressionMethod = this.readUint8();
        if (this._compressionMethod !== internalTypes_1.CompressionMethod.DEFLATE) {
            throw new Error(`Unsupported compression method: ${this._compressionMethod}`);
        }
        this._filterMethod = this.readUint8();
        this._interlaceMethod = this.readUint8();
    }
    decodeACTL() {
        this._numberOfFrames = this.readUint32();
        this._numberOfPlays = this.readUint32();
        this._isAnimated = true;
    }
    decodeFCTL() {
        const image = {
            sequenceNumber: this.readUint32(),
            width: this.readUint32(),
            height: this.readUint32(),
            xOffset: this.readUint32(),
            yOffset: this.readUint32(),
            delayNumber: this.readUint16(),
            delayDenominator: this.readUint16(),
            disposeOp: this.readUint8(),
            blendOp: this.readUint8(),
            data: new Uint8Array(0),
        };
        this._frames.push(image);
    }
    // https://www.w3.org/TR/PNG/#11PLTE
    decodePLTE(length) {
        if (length % 3 !== 0) {
            throw new RangeError(`PLTE field length must be a multiple of 3. Got ${length}`);
        }
        const l = length / 3;
        this._hasPalette = true;
        const palette = [];
        this._palette = palette;
        for (let i = 0; i < l; i++) {
            palette.push([this.readUint8(), this.readUint8(), this.readUint8()]);
        }
    }
    // https://www.w3.org/TR/PNG/#11IDAT
    decodeIDAT(length) {
        this._writingDataChunks = true;
        const dataLength = length;
        const dataOffset = this.offset + this.byteOffset;
        this._inflator.push(new Uint8Array(this.buffer, dataOffset, dataLength));
        if (this._inflator.err) {
            throw new Error(`Error while decompressing the data: ${this._inflator.err}`);
        }
        this.skip(length);
    }
    decodeFDAT(length) {
        this._writingDataChunks = true;
        let dataLength = length;
        let dataOffset = this.offset + this.byteOffset;
        dataOffset += 4;
        dataLength -= 4;
        this._inflator.push(new Uint8Array(this.buffer, dataOffset, dataLength));
        if (this._inflator.err) {
            throw new Error(`Error while decompressing the data: ${this._inflator.err}`);
        }
        this.skip(length);
    }
    // https://www.w3.org/TR/PNG/#11tRNS
    decodetRNS(length) {
        switch (this._colorType) {
            case internalTypes_1.ColorType.GREYSCALE:
            case internalTypes_1.ColorType.TRUECOLOUR: {
                if (length % 2 !== 0) {
                    throw new RangeError(`tRNS chunk length must be a multiple of 2. Got ${length}`);
                }
                if (length / 2 > this._png.width * this._png.height) {
                    throw new Error(`tRNS chunk contains more alpha values than there are pixels (${length / 2} vs ${this._png.width * this._png.height})`);
                }
                this._hasTransparency = true;
                this._transparency = new Uint16Array(length / 2);
                for (let i = 0; i < length / 2; i++) {
                    this._transparency[i] = this.readUint16();
                }
                break;
            }
            case internalTypes_1.ColorType.INDEXED_COLOUR: {
                if (length > this._palette.length) {
                    throw new Error(`tRNS chunk contains more alpha values than there are palette colors (${length} vs ${this._palette.length})`);
                }
                let i = 0;
                for (; i < length; i++) {
                    const alpha = this.readByte();
                    this._palette[i].push(alpha);
                }
                for (; i < this._palette.length; i++) {
                    this._palette[i].push(255);
                }
                break;
            }
            // Kept for exhaustiveness.
            /* eslint-disable unicorn/no-useless-switch-case */
            case internalTypes_1.ColorType.UNKNOWN:
            case internalTypes_1.ColorType.GREYSCALE_ALPHA:
            case internalTypes_1.ColorType.TRUECOLOUR_ALPHA:
            default: {
                throw new Error(`tRNS chunk is not supported for color type ${this._colorType}`);
            }
            /* eslint-enable unicorn/no-useless-switch-case */
        }
    }
    // https://www.w3.org/TR/PNG/#11iCCP
    decodeiCCP(length) {
        const name = (0, text_1.readKeyword)(this);
        const compressionMethod = this.readUint8();
        if (compressionMethod !== internalTypes_1.CompressionMethod.DEFLATE) {
            throw new Error(`Unsupported iCCP compression method: ${compressionMethod}`);
        }
        const compressedProfile = this.readBytes(length - name.length - 2);
        this._png.iccEmbeddedProfile = {
            name,
            profile: (0, pako_1.inflate)(compressedProfile),
        };
    }
    // https://www.w3.org/TR/PNG/#11pHYs
    decodepHYs() {
        const ppuX = this.readUint32();
        const ppuY = this.readUint32();
        const unitSpecifier = this.readByte();
        this._png.resolution = { x: ppuX, y: ppuY, unit: unitSpecifier };
    }
    decodeApngImage() {
        this._apng.width = this._png.width;
        this._apng.height = this._png.height;
        this._apng.channels = this._png.channels;
        this._apng.depth = this._png.depth;
        this._apng.numberOfFrames = this._numberOfFrames;
        this._apng.numberOfPlays = this._numberOfPlays;
        this._apng.text = this._png.text;
        this._apng.resolution = this._png.resolution;
        for (let i = 0; i < this._numberOfFrames; i++) {
            const newFrame = {
                sequenceNumber: this._frames[i].sequenceNumber,
                delayNumber: this._frames[i].delayNumber,
                delayDenominator: this._frames[i].delayDenominator,
                data: this._apng.depth === 8
                    ? new Uint8Array(this._apng.width * this._apng.height * this._apng.channels)
                    : new Uint16Array(this._apng.width * this._apng.height * this._apng.channels),
            };
            const frame = this._frames.at(i);
            if (frame) {
                frame.data = (0, decodeInterlaceNull_1.decodeInterlaceNull)({
                    data: frame.data,
                    width: frame.width,
                    height: frame.height,
                    channels: this._apng.channels,
                    depth: this._apng.depth,
                });
                if (this._hasPalette) {
                    this._apng.palette = this._palette;
                }
                if (this._hasTransparency) {
                    this._apng.transparency = this._transparency;
                }
                if (i === 0 ||
                    (frame.xOffset === 0 &&
                        frame.yOffset === 0 &&
                        frame.width === this._png.width &&
                        frame.height === this._png.height)) {
                    newFrame.data = frame.data;
                }
                else {
                    const prevFrame = this._apng.frames.at(i - 1);
                    this.disposeFrame(frame, prevFrame, newFrame);
                    this.addFrameDataToCanvas(newFrame, frame);
                }
                this._apng.frames.push(newFrame);
            }
        }
        return this._apng;
    }
    disposeFrame(frame, prevFrame, imageFrame) {
        switch (frame.disposeOp) {
            case internalTypes_1.DisposeOpType.NONE:
                break;
            case internalTypes_1.DisposeOpType.BACKGROUND:
                for (let row = 0; row < this._png.height; row++) {
                    for (let col = 0; col < this._png.width; col++) {
                        const index = (row * frame.width + col) * this._png.channels;
                        for (let channel = 0; channel < this._png.channels; channel++) {
                            imageFrame.data[index + channel] = 0;
                        }
                    }
                }
                break;
            case internalTypes_1.DisposeOpType.PREVIOUS:
                imageFrame.data.set(prevFrame.data);
                break;
            default:
                throw new Error('Unknown disposeOp');
        }
    }
    addFrameDataToCanvas(imageFrame, frame) {
        const maxValue = 1 << this._png.depth;
        const calculatePixelIndices = (row, col) => {
            const index = ((row + frame.yOffset) * this._png.width + frame.xOffset + col) *
                this._png.channels;
            const frameIndex = (row * frame.width + col) * this._png.channels;
            return { index, frameIndex };
        };
        switch (frame.blendOp) {
            case internalTypes_1.BlendOpType.SOURCE:
                for (let row = 0; row < frame.height; row++) {
                    for (let col = 0; col < frame.width; col++) {
                        const { index, frameIndex } = calculatePixelIndices(row, col);
                        for (let channel = 0; channel < this._png.channels; channel++) {
                            imageFrame.data[index + channel] =
                                frame.data[frameIndex + channel];
                        }
                    }
                }
                break;
            // https://www.w3.org/TR/png-3/#13Alpha-channel-processing
            case internalTypes_1.BlendOpType.OVER:
                for (let row = 0; row < frame.height; row++) {
                    for (let col = 0; col < frame.width; col++) {
                        const { index, frameIndex } = calculatePixelIndices(row, col);
                        for (let channel = 0; channel < this._png.channels; channel++) {
                            const sourceAlpha = frame.data[frameIndex + this._png.channels - 1] / maxValue;
                            const foregroundValue = channel % (this._png.channels - 1) === 0
                                ? 1
                                : frame.data[frameIndex + channel];
                            const value = Math.floor(sourceAlpha * foregroundValue +
                                (1 - sourceAlpha) * imageFrame.data[index + channel]);
                            imageFrame.data[index + channel] += value;
                        }
                    }
                }
                break;
            default:
                throw new Error('Unknown blendOp');
        }
    }
    decodeImage() {
        if (this._inflator.err) {
            throw new Error(`Error while decompressing the data: ${this._inflator.err}`);
        }
        const data = this._isAnimated
            ? (this._frames?.at(0)).data
            : this._inflator.result;
        if (this._filterMethod !== internalTypes_1.FilterMethod.ADAPTIVE) {
            throw new Error(`Filter method ${this._filterMethod} not supported`);
        }
        if (this._interlaceMethod === internalTypes_1.InterlaceMethod.NO_INTERLACE) {
            this._png.data = (0, decodeInterlaceNull_1.decodeInterlaceNull)({
                data: data,
                width: this._png.width,
                height: this._png.height,
                channels: this._png.channels,
                depth: this._png.depth,
            });
        }
        else if (this._interlaceMethod === internalTypes_1.InterlaceMethod.ADAM7) {
            this._png.data = (0, decodeInterlaceAdam7_1.decodeInterlaceAdam7)({
                data: data,
                width: this._png.width,
                height: this._png.height,
                channels: this._png.channels,
                depth: this._png.depth,
            });
        }
        else {
            throw new Error(`Interlace method ${this._interlaceMethod} not supported`);
        }
        if (this._hasPalette) {
            this._png.palette = this._palette;
        }
        if (this._hasTransparency) {
            this._png.transparency = this._transparency;
        }
    }
    pushDataToFrame() {
        const result = this._inflator.result;
        const lastFrame = this._frames.at(-1);
        if (lastFrame) {
            lastFrame.data = result;
        }
        else {
            this._frames.push({
                sequenceNumber: 0,
                width: this._png.width,
                height: this._png.height,
                xOffset: 0,
                yOffset: 0,
                delayNumber: 0,
                delayDenominator: 0,
                disposeOp: internalTypes_1.DisposeOpType.NONE,
                blendOp: internalTypes_1.BlendOpType.SOURCE,
                data: result,
            });
        }
        this._inflator = new pako_1.Inflate();
        this._writingDataChunks = false;
    }
}
exports.default = PngDecoder;
function checkBitDepth(value) {
    if (value !== 1 &&
        value !== 2 &&
        value !== 4 &&
        value !== 8 &&
        value !== 16) {
        throw new Error(`invalid bit depth: ${value}`);
    }
    return value;
}
//# sourceMappingURL=PngDecoder.js.map