64 lines
1.5 KiB
JavaScript
64 lines
1.5 KiB
JavaScript
const Utils = require('./utils')
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function clearCanvas (ctx, canvas, size) {
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ctx.clearRect(0, 0, canvas.width, canvas.height)
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if (!canvas.style) canvas.style = {}
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canvas.height = size
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canvas.width = size
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canvas.style.height = size + 'px'
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canvas.style.width = size + 'px'
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}
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function getCanvasElement () {
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try {
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return document.createElement('canvas')
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} catch (e) {
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throw new Error('You need to specify a canvas element')
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}
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}
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exports.render = function render (qrData, canvas, options) {
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let opts = options
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let canvasEl = canvas
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if (typeof opts === 'undefined' && (!canvas || !canvas.getContext)) {
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opts = canvas
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canvas = undefined
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}
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if (!canvas) {
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canvasEl = getCanvasElement()
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}
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opts = Utils.getOptions(opts)
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const size = Utils.getImageWidth(qrData.modules.size, opts)
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const ctx = canvasEl.getContext('2d')
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const image = ctx.createImageData(size, size)
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Utils.qrToImageData(image.data, qrData, opts)
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clearCanvas(ctx, canvasEl, size)
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ctx.putImageData(image, 0, 0)
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return canvasEl
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}
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exports.renderToDataURL = function renderToDataURL (qrData, canvas, options) {
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let opts = options
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if (typeof opts === 'undefined' && (!canvas || !canvas.getContext)) {
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opts = canvas
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canvas = undefined
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}
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if (!opts) opts = {}
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const canvasEl = exports.render(qrData, canvas, opts)
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const type = opts.type || 'image/png'
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const rendererOpts = opts.rendererOpts || {}
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return canvasEl.toDataURL(type, rendererOpts.quality)
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}
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