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| // pages/promisesign/promisesign.js
| Page({
|
| /**
| * 页面的初始数据
| */
| data: {
| isDrawed: false,
|
| width: '1px',
| height: '1px'
| },
|
| //决定是否绘制的最小像素距离
| TOUCH_TOLERANCE: 4,
|
| /**
| * 生命周期函数--监听页面加载
| */
| onLoad: function (options) {
|
| },
|
| /**
| * 生命周期函数--监听页面初次渲染完成
| */
| onReady: function () {
| this.init()
| },
|
| init: function () {
| wx.createSelectorQuery().in(this)
| .select('.sign-canvas')
| .fields({
| node: true,
| size: true
| })
| .exec((res) => {
| //Canvas 对象
| const canvas = res[0].node
| //渲染上下文
| const ctx = canvas.getContext('2d')
|
| //Canvas画布的实际绘制高度
| this.width = res[0].width
| this.height = res[0].height
|
| //初始化画布大小
| const dpr = wx.getWindowInfo().pixelRatio
| canvas.width = this.width * dpr
| canvas.height = this.height * dpr
| ctx.scale(dpr, dpr)
|
| this.canvas = canvas
| this.ctx = ctx
| })
| },
| touchStart(e) {
| if (this.canvas && e.touches.length > 0) {
| var t = e.touches[0];
| this.ctx.moveTo(t.x, t.y)
| this.tempX = t.x
| this.tempY = t.y
| }
| },
| touchMove(e) {
| if (this.canvas && e.touches.length > 0) {
| var t = e.touches[0];
| var dx = Math.abs(t.x - this.tempX)
| var dy = Math.abs(t.y - this.tempY)
| if (dx >= this.TOUCH_TOLERANCE || dy >= this.TOUCH_TOLERANCE) {
| this.ctx.lineTo(t.x, t.y)
| this.ctx.stroke()
| this.tempX = t.x
| this.tempY = t.y
| }
| }
| },
| touchEnd(e) {
| if (this.canvas && e.touches.length > 0) {
| var t = e.touches[0];
| this.ctx.lineTo(t.x, t.y)
| this.ctx.stroke()
| }
| this.setData({
| isDrawed: true
| })
| },
|
| onCancel() {
| wx.navigateBack({
| success: (res) => {},
| fail: (res) => {},
| complete: (res) => {},
| })
| },
| onSubmit() {
| if (!this.data.isDrawed) {
| wx.showToast({
| title: '请先在签名区域签名',
| duration: 2000,
| icon: 'none',
| mask: true,
| })
| return
| }
| wx.showLoading({
| title: '签名图片处理中',
| mask: true,
| success: (res) => {},
| fail: (res) => {},
| complete: (res) => {},
| })
| setTimeout(() => {
| wx.hideLoading()
| }, 10000);
| var that = this
| this.rotate(function (rotateCanvas){
| wx.canvasToTempFilePath({
| canvas: rotateCanvas,
| success(res) {
| let imgPath = res.tempFilePath
| wx.setStorage({
| data: imgPath,
| key: 'signPath',
| success(){
| console.log('sign-success:' + imgPath);
| wx.hideLoading({
| success: (res) => {
| wx.showToast({
| title: '签名生成成功',
| duration: 1500,
| icon: 'success',
| })
| that.getOpenerEventChannel().emit('onSignSuccess', imgPath)
| wx.navigateBack()
| },
| })
| }
| })
| },
| fail(err) {
| console.log(err)
| wx.hideLoading({
| success: (res) => {
| wx.showToast({
| title: '签名图片导出异常，请重试',
| duration: 1500,
| icon: 'error',
| })
| },
| })
| },
| })
| })
| },
| //旋转图片，生成新canvas实例
| rotate(cb) {
| const that = this;
| wx.createSelectorQuery().select('#handWriting2')
| .fields({
| node: true,
| size: true
| })
| .exec((res) => {
| const rotateCanvas = res[0].node;
| const rotateCtx = rotateCanvas.getContext('2d');
| //this.ctxW-->所绘制canvas的width
| //this.ctxH -->所绘制canvas的height
| rotateCanvas.width = that.canvas.height;
| rotateCanvas.height = that.canvas.width;
| that.setData({
| width: rotateCanvas.width,
| height: rotateCanvas.height,
| })
| wx.canvasToTempFilePath({
| canvas: that.canvas,
| success(res) {
| that.tempFilePath = res.tempFilePath;
| const img = rotateCanvas.createImage();
| img.src = res.tempFilePath;
| img.onload = function () {
| rotateCtx.translate(rotateCanvas.width / 2, rotateCanvas.height / 2);
| rotateCtx.rotate(270 * Math.PI / 180);
| rotateCtx.drawImage(img, -rotateCanvas.height / 2, -rotateCanvas.width / 2);
| // rotateCtx.scale(that.pixelRatio, that.pixelRatio);
| cb(rotateCanvas);
| };
| },
| fail(err) {
| console.log(err)
| wx.hideLoading({
| success: (res) => {
| wx.showToast({
| title: '签名图片处理异常，请重试',
| duration: 1500,
| icon: 'error',
| })
| },
| })
| }
| })
| })
| }
| })
|
|
