import extend from 'extend'
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import {
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QRCode,
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QRErrorCorrectLevel
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} from './qrcode'
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// support Chinese
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function utf16to8 (str) {
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var out, i, len, c
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out = ''
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len = str.length
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for (i = 0; i < len; i++) {
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c = str.charCodeAt(i)
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if ((c >= 0x0001) && (c <= 0x007F)) {
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out += str.charAt(i)
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} else if (c > 0x07FF) {
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out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F))
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out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F))
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out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F))
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} else {
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out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F))
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out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F))
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}
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}
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return out
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}
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function drawQrcode (options) {
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options = options || {}
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options = extend(true, {
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width: 256,
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height: 256,
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x: 0,
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y: 0,
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typeNumber: -1,
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correctLevel: QRErrorCorrectLevel.H,
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background: '#ffffff',
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foreground: '#000000',
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image: {
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imageResource: '',
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dx: 0,
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dy: 0,
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dWidth: 100,
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dHeight: 100
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}
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}, options)
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if (!options.canvasId && !options.ctx) {
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console.warn('please set canvasId or ctx!')
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return
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}
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createCanvas()
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function createCanvas () {
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// create the qrcode itself
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var qrcode = new QRCode(options.typeNumber, options.correctLevel)
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qrcode.addData(utf16to8(options.text))
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qrcode.make()
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// get canvas context
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var ctx
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if (options.ctx) {
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ctx = options.ctx
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} else {
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ctx = options._this ? wx.createCanvasContext && wx.createCanvasContext(options.canvasId, options._this) : wx.createCanvasContext && wx.createCanvasContext(options.canvasId)
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}
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// compute tileW/tileH based on options.width/options.height
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var tileW = options.width / qrcode.getModuleCount()
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var tileH = options.height / qrcode.getModuleCount()
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// draw in the canvas
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for (var row = 0; row < qrcode.getModuleCount(); row++) {
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for (var col = 0; col < qrcode.getModuleCount(); col++) {
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var style = qrcode.isDark(row, col) ? options.foreground : options.background
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ctx.setFillStyle(style)
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var w = (Math.ceil((col + 1) * tileW) - Math.floor(col * tileW))
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var h = (Math.ceil((row + 1) * tileW) - Math.floor(row * tileW))
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ctx.fillRect(Math.round(col * tileW) + options.x, Math.round(row * tileH) + options.y, w, h)
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}
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}
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if (options.image.imageResource) {
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ctx.drawImage(options.image.imageResource, options.image.dx, options.image.dy, options.image.dWidth, options.image.dHeight)
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}
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ctx.draw(false, function (e) {
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options.callback && options.callback(e)
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})
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}
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}
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export default drawQrcode
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