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import merge from "../help/merge.js"; |
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import {calculateEncodingAttributes, getTotalWidthOfEncodings, getMaximumHeightOfEncodings} from "./shared.js"; |
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View Code Duplication |
class CanvasRenderer{ |
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constructor(canvas, encodings, options){ |
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this.canvas = canvas; |
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this.encodings = encodings; |
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this.options = options; |
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} |
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render(){ |
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// Abort if the browser does not support HTML5 canvas |
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if (!this.canvas.getContext) { |
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throw new Error('The browser does not support canvas.'); |
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} |
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this.prepareCanvas(); |
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for(let i = 0; i < this.encodings.length; i++){ |
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var encodingOptions = merge(this.options, this.encodings[i].options); |
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this.drawCanvasBarcode(encodingOptions, this.encodings[i]); |
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this.drawCanvasText(encodingOptions, this.encodings[i]); |
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this.moveCanvasDrawing(this.encodings[i]); |
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} |
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this.restoreCanvas(); |
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} |
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prepareCanvas(){ |
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// Get the canvas context |
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var ctx = this.canvas.getContext("2d"); |
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ctx.save(); |
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calculateEncodingAttributes(this.encodings, this.options, ctx); |
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var totalWidth = getTotalWidthOfEncodings(this.encodings); |
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var maxHeight = getMaximumHeightOfEncodings(this.encodings); |
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this.canvas.width = totalWidth + this.options.marginLeft + this.options.marginRight; |
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this.canvas.height = maxHeight; |
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// Paint the canvas |
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ctx.clearRect(0, 0, this.canvas.width, this.canvas.height); |
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if(this.options.background){ |
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ctx.fillStyle = this.options.background; |
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ctx.fillRect(0, 0, this.canvas.width, this.canvas.height); |
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} |
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ctx.translate(this.options.marginLeft, 0); |
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} |
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drawCanvasBarcode(options, encoding){ |
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// Get the canvas context |
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var ctx = this.canvas.getContext("2d"); |
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var binary = encoding.data; |
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// Creates the barcode out of the encoded binary |
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var yFrom; |
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if(options.textPosition == "top"){ |
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yFrom = options.marginTop + options.fontSize + options.textMargin; |
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} |
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else{ |
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yFrom = options.marginTop; |
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} |
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ctx.fillStyle = options.lineColor; |
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for(var b = 0; b < binary.length; b++){ |
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var x = b * options.width + encoding.barcodePadding; |
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if(binary[b] === "1"){ |
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ctx.fillRect(x, yFrom, options.width, options.height); |
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} |
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else if(binary[b]){ |
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ctx.fillRect(x, yFrom, options.width, options.height * binary[b]); |
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} |
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} |
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} |
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drawCanvasText(options, encoding){ |
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// Get the canvas context |
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var ctx = this.canvas.getContext("2d"); |
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var font = options.fontOptions + " " + options.fontSize + "px " + options.font; |
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// Draw the text if displayValue is set |
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if(options.displayValue){ |
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var x, y; |
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if(options.textPosition == "top"){ |
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y = options.marginTop + options.fontSize - options.textMargin; |
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} |
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else{ |
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y = options.height + options.textMargin + options.marginTop + options.fontSize; |
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} |
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ctx.font = font; |
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// Draw the text in the correct X depending on the textAlign option |
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if(options.textAlign == "left" || encoding.barcodePadding > 0){ |
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x = 0; |
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ctx.textAlign = 'left'; |
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} |
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else if(options.textAlign == "right"){ |
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x = encoding.width - 1; |
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ctx.textAlign = 'right'; |
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} |
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// In all other cases, center the text |
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else{ |
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x = encoding.width / 2; |
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ctx.textAlign = 'center'; |
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} |
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ctx.fillText(encoding.text, x, y); |
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} |
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} |
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moveCanvasDrawing(encoding){ |
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var ctx = this.canvas.getContext("2d"); |
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ctx.translate(encoding.width, 0); |
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} |
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restoreCanvas(){ |
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// Get the canvas context |
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var ctx = this.canvas.getContext("2d"); |
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ctx.restore(); |
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} |
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} |
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export default CanvasRenderer; |
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lindell /
JsBarcode
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