@zxing/browser
Version:
ZXing for JS's browser layer.
122 lines • 5.49 kB
JavaScript
import { EncodeHintType, IllegalArgumentException, IllegalStateException, QRCodeDecoderErrorCorrectionLevel, QRCodeEncoder, } from '@zxing/library';
const svgNs = 'http://www.w3.org/2000/svg';
/**/
class BrowserQRCodeSvgWriter {
/**
* Writes and renders a QRCode SVG element.
*
* @param contents
* @param width
* @param height
* @param hints
*/
write(contents, width, height, hints) {
if (contents.length === 0) {
throw new IllegalArgumentException('Found empty contents');
}
// if (format != BarcodeFormat.QR_CODE) {
// throw new IllegalArgumentException("Can only encode QR_CODE, but got " + format)
// }
if (width < 0 || height < 0) {
throw new IllegalArgumentException('Requested dimensions are too small: ' + width + 'x' + height);
}
let errorCorrectionLevel = QRCodeDecoderErrorCorrectionLevel.L;
let quietZone = BrowserQRCodeSvgWriter.QUIET_ZONE_SIZE;
if (hints) {
if (undefined !== hints.get(EncodeHintType.ERROR_CORRECTION)) {
const correctionStr = hints.get(EncodeHintType.ERROR_CORRECTION).toString();
errorCorrectionLevel = QRCodeDecoderErrorCorrectionLevel.fromString(correctionStr);
}
if (undefined !== hints.get(EncodeHintType.MARGIN)) {
quietZone = Number.parseInt(hints.get(EncodeHintType.MARGIN).toString(), 10);
}
}
const code = QRCodeEncoder.encode(contents, errorCorrectionLevel, hints);
return this.renderResult(code, width, height, quietZone);
}
/**
* Renders the result and then appends it to the DOM.
*/
writeToDom(containerElement, contents, width, height, hints) {
if (typeof containerElement === 'string') {
const targetEl = document.querySelector(containerElement);
if (!targetEl) {
throw new Error('Could no find the target HTML element.');
}
containerElement = targetEl;
}
const svgElement = this.write(contents, width, height, hints);
if (containerElement instanceof HTMLElement) {
containerElement.appendChild(svgElement);
}
}
/**
* Note that the input matrix uses 0 == white, 1 == black.
* The output matrix uses 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
*/
renderResult(code, width /*int*/, height /*int*/, quietZone /*int*/) {
const input = code.getMatrix();
if (input === null) {
throw new 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);
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;
}
/**
* Creates a SVG element.
*
* @param w SVG's width attribute
* @param h SVG's height attribute
*/
createSVGElement(w, h) {
const svgElement = document.createElementNS(svgNs, 'svg');
const width = w.toString();
const height = h.toString();
svgElement.setAttribute('height', height);
svgElement.setAttribute('width', width);
svgElement.setAttribute('viewBox', "0 0 " + width + " " + height);
return svgElement;
}
/**
* Creates a SVG rect element.
*
* @param x Element's x coordinate
* @param y Element's y coordinate
* @param w Element's width attribute
* @param h Element's height attribute
*/
createSvgRectElement(x, y, w, h) {
const rect = document.createElementNS(svgNs, 'rect');
rect.setAttribute('x', x.toString());
rect.setAttribute('y', y.toString());
rect.setAttribute('height', w.toString());
rect.setAttribute('width', h.toString());
rect.setAttribute('fill', '#000000');
return rect;
}
}
BrowserQRCodeSvgWriter.QUIET_ZONE_SIZE = 4;
export { BrowserQRCodeSvgWriter };
//# sourceMappingURL=BrowserQRCodeSvgWriter.js.map