image-in-browser/lib/formats/pnm-decoder.js

Package for encoding / decoding images, transforming images, applying filters, drawing primitives on images on the client side (no need for server Node.js)

import { Format } from '../color/format.js';
import { InputBuffer } from '../common/input-buffer.js';
import { MemoryImage } from '../image/image.js';
import { ImageFormat } from './image-format.js';
import { PnmFormat } from './pnm/pnm-format.js';
import { PnmInfo } from './pnm/pnm-info.js';
export class PnmDecoder {
    constructor() {
        this._tokens = [];
    }
    get input() {
        return this._input;
    }
    get info() {
        return this._info;
    }
    get format() {
        return ImageFormat.pnm;
    }
    get numFrames() {
        return this._info !== undefined ? 1 : 0;
    }
    getNextToken() {
        var _a;
        if (this._input === undefined) {
            return '';
        }
        if (this._tokens.length > 0) {
            return this._tokens.shift();
        }
        let line = this._input.readStringLine().trim();
        if (line.length === 0) {
            return '';
        }
        while (line.startsWith('#')) {
            line = this._input.readStringLine(70).trim();
        }
        const tk = line.split(' ').filter((l) => l.length > 0);
        for (let i = 0; i < tk.length; ++i) {
            if (tk[i].startsWith('#')) {
                tk.length = i;
                break;
            }
        }
        this._tokens.push(...tk);
        return (_a = this._tokens.shift()) !== null && _a !== void 0 ? _a : '';
    }
    parseNextInt() {
        const tk = this.getNextToken();
        if (tk.length === 0) {
            return 0;
        }
        const res = parseInt(tk);
        return isNaN(res) ? 0 : res;
    }
    formatFromMaxValue(maxValue) {
        if (maxValue > 255) {
            return Format.uint16;
        }
        if (maxValue > 15) {
            return Format.uint8;
        }
        if (maxValue > 3) {
            return Format.uint4;
        }
        if (maxValue > 1) {
            return Format.uint2;
        }
        return Format.uint1;
    }
    readValue(format, _maxValue) {
        if (format === PnmFormat.pgm5 || format === PnmFormat.ppm6) {
            return this.input.read();
        }
        return this.parseNextInt();
    }
    isValidFile(bytes) {
        this._input = new InputBuffer({
            buffer: bytes,
        });
        const tk = this.getNextToken();
        return (tk === 'P1' || tk === 'P2' || tk === 'P5' || tk === 'P3' || tk === 'P6');
    }
    startDecode(bytes) {
        this._input = new InputBuffer({
            buffer: bytes,
        });
        const tk = this.getNextToken();
        if (tk === 'P1') {
            this._info = new PnmInfo(PnmFormat.pbm);
        }
        else if (tk === 'P2') {
            this._info = new PnmInfo(PnmFormat.pgm2);
        }
        else if (tk === 'P5') {
            this._info = new PnmInfo(PnmFormat.pgm5);
        }
        else if (tk === 'P3') {
            this._info = new PnmInfo(PnmFormat.ppm3);
        }
        else if (tk === 'P6') {
            this._info = new PnmInfo(PnmFormat.ppm6);
        }
        else {
            this._input = undefined;
            return undefined;
        }
        this._info.width = this.parseNextInt();
        this._info.height = this.parseNextInt();
        if (this._info.width === 0 || this._info.height === 0) {
            this._input = undefined;
            this._info = undefined;
            return undefined;
        }
        return this._info;
    }
    decode(opt) {
        var _a;
        if (this.startDecode(opt.bytes) === undefined) {
            return undefined;
        }
        return this.decodeFrame((_a = opt.frameIndex) !== null && _a !== void 0 ? _a : 0);
    }
    decodeFrame(_frameIndex) {
        if (this._info === undefined) {
            return undefined;
        }
        if (this._info.format === PnmFormat.pbm) {
            const image = new MemoryImage({
                width: this._info.width,
                height: this._info.height,
                numChannels: 1,
                format: Format.uint1,
            });
            for (const p of image) {
                const tk = this.getNextToken();
                if (tk === '1') {
                    p.setRgb(1, 1, 1);
                }
                else {
                    p.setRgb(0, 0, 0);
                }
            }
            return image;
        }
        else if (this._info.format === PnmFormat.pgm2 ||
            this._info.format === PnmFormat.pgm5) {
            const maxValue = this.parseNextInt();
            if (maxValue === 0) {
                return undefined;
            }
            const image = new MemoryImage({
                width: this._info.width,
                height: this._info.height,
                numChannels: 1,
                format: this.formatFromMaxValue(maxValue),
            });
            for (const p of image) {
                const g = this.readValue(this._info.format, maxValue);
                p.setRgb(g, g, g);
            }
            return image;
        }
        else if (this._info.format === PnmFormat.ppm3 ||
            this._info.format === PnmFormat.ppm6) {
            const maxValue = this.parseNextInt();
            if (maxValue === 0) {
                return undefined;
            }
            const image = new MemoryImage({
                width: this._info.width,
                height: this._info.height,
                format: this.formatFromMaxValue(maxValue),
            });
            for (const p of image) {
                const r = this.readValue(this._info.format, maxValue);
                const g = this.readValue(this._info.format, maxValue);
                const b = this.readValue(this._info.format, maxValue);
                p.setRgb(r, g, b);
            }
            return image;
        }
        return undefined;
    }
}
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