@tjieco/library/src/browser/BrowserQRCodeSvgWriter.ts

TypeScript port of ZXing multi-format 1D/2D barcode image processing library, with Code128 and ITF support.

import Exception from '../core/Exception';
import EncodeHintType from '../core/EncodeHintType';
import Encoder from '../core/qrcode/encoder/Encoder';
import QRCode from '../core/qrcode/encoder/QRCode';
import ErrorCorrectionLevel from '../core/qrcode/decoder/ErrorCorrectionLevel';

class BrowserQRCodeSvgWriter {
    private static readonly QUIET_ZONE_SIZE = 4;
    private static readonly SVG_NS = 'http://www.w3.org/2000/svg';

    private containerElement: HTMLElement;

    public constructor(containerElement: string | HTMLElement) {
        if (typeof containerElement === 'string') {
            this.containerElement = document.getElementById(containerElement);
        } else {
            this.containerElement = containerElement;
        }
    }

    public write(contents: string,
        width: number,
        height: number,
        hints: Map<EncodeHintType, any> = null): SVGSVGElement {

        if (contents.length === 0) {
            throw new Exception(Exception.IllegalArgumentException, 'Found empty contents');
        }

        // if (format != BarcodeFormat.QR_CODE) {
        //   throw new Exception(Exception.IllegalArgumentException, "Can only encode QR_CODE, but got " + format)
        // }

        if (width < 0 || height < 0) {
            throw new Exception('IllegalArgumentException', 'Requested dimensions are too small: ' + width + 'x' +
                height);
        }

        let errorCorrectionLevel = ErrorCorrectionLevel.L;
        let quietZone = BrowserQRCodeSvgWriter.QUIET_ZONE_SIZE;
        if (hints !== null) {
            if (undefined !== hints.get(EncodeHintType.ERROR_CORRECTION)) {
                errorCorrectionLevel = ErrorCorrectionLevel.fromString(hints.get(EncodeHintType.ERROR_CORRECTION).toString());
            }
            if (undefined !== hints.get(EncodeHintType.MARGIN)) {
                quietZone = Number.parseInt(hints.get(EncodeHintType.MARGIN).toString(), 10);
            }
        }

        const code = Encoder.encode(contents, errorCorrectionLevel, hints);
        return this.renderResult(code, width, height, quietZone);
    }

    // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
    // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
    private renderResult(code: QRCode, width: number /*int*/, height: number /*int*/, quietZone: number /*int*/): SVGSVGElement {
        const input = code.getMatrix();
        if (input === null) {
            throw new Exception(Exception.IllegalStateException);
        }
        const inputWidth = input.getWidth();
        const inputHeight = input.getHeight();
        const qrWidth = inputWidth + (quietZone * 2);
        const qrHeight = inputHeight + (quietZone * 2);
        const outputWidth = Math.max(width, qrWidth);
        const outputHeight = Math.max(height, qrHeight);

        const multiple = Math.min(Math.floor(outputWidth / qrWidth), Math.floor(outputHeight / qrHeight));
        // Padding includes both the quiet zone and the extra white pixels to accommodate the requested
        // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
        // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
        // handle all the padding from 100x100 (the actual QR) up to 200x160.
        const leftPadding = Math.floor((outputWidth - (inputWidth * multiple)) / 2);
        const topPadding = Math.floor((outputHeight - (inputHeight * multiple)) / 2);

        const svgElement = this.createSVGElement(outputWidth, outputHeight);
        this.containerElement.appendChild(svgElement);
        for (let inputY = 0, outputY = topPadding; inputY < inputHeight; inputY++ , outputY += multiple) {
            // Write the contents of this row of the barcode
            for (let inputX = 0, outputX = leftPadding; inputX < inputWidth; inputX++ , outputX += multiple) {
                if (input.get(inputX, inputY) === 1) {
                    const svgRectElement = this.createSvgRectElement(outputX, outputY, multiple, multiple);
                    svgElement.appendChild(svgRectElement);
                }
            }
        }

        return svgElement;
    }

    private createSVGElement(w: number, h: number): SVGSVGElement {
        const svgElement = document.createElementNS(BrowserQRCodeSvgWriter.SVG_NS, 'svg');
        svgElement.setAttributeNS(null, 'height', w.toString());
        svgElement.setAttributeNS(null, 'width', h.toString());
        return svgElement;
    }

    private createSvgRectElement(x: number, y: number, w: number, h: number): SVGRectElement {
        const rect = document.createElementNS(BrowserQRCodeSvgWriter.SVG_NS, 'rect');
        rect.setAttributeNS(null, 'x', x.toString());
        rect.setAttributeNS(null, 'y', y.toString());
        rect.setAttributeNS(null, 'height', w.toString());
        rect.setAttributeNS(null, 'width', h.toString());
        rect.setAttributeNS(null, 'fill', '#000000');
        return rect;
    }
}

export { BrowserQRCodeSvgWriter };