本文实例为大家分享了微信小程序实现电子签名的具体代码,供大家参考,具体内容如下
// XXXX.wxml


bindtouchmove="canvasMove" bindtouchend="canvasEnd" touchcancel="canvasEnd"

binderror="canvasIdErrorCallback">





上传签名



清除签名

// XXXX.wxml


bindtouchmove="canvasMove" bindtouchend="canvasEnd" touchcancel="canvasEnd"

binderror="canvasIdErrorCallback">





上传签名



清除签名
js:
var context = null;// 使用 wx.createContext 获取绘图上下文 context
var isButtonDown = false;//是否在绘制中
var arrx = [];//动作横坐标
var arry = [];//动作纵坐标
var arrz = [];//总做状态,标识按下到抬起的一个组合
var canvasw = 0;//画布宽度
var canvash = 0;//画布高度
Page({

data: {
},

onLoad: function () {

this.startCanvas();
},
/**
* 以下 - 手写签名 / 上传签名
*/
startCanvas: function () {//画布初始化执行
var that = this;
//获取系统信息
wx.getSystemInfo({

success: function (res) {

canvasw = res.windowWidth;

canvash = res.windowHeight;

that.setData({ canvasw: canvasw });

that.setData({ canvash: canvash });

}
});
this.initCanvas();
this.cleardraw();
},
//初始化函数
initCanvas: function () {
context = wx.createCanvasContext('canvas');
context.beginPath()
context.fillStyle = 'rgba(255, 255, 255, 0)';
context.setStrokeStyle('#000000');
context.setLineWidth(4);
context.setLineCap('round');
context.setLineJoin('round');
},
canvasStart: function (event) {
isButtonDown = true;
arrz.push(0);
arrx.push(event.changedTouches[0].x);
arry.push(event.changedTouches[0].y);
},
canvasMove: function (event) {
if (isButtonDown) {

arrz.push(1);

arrx.push(event.changedTouches[0].x);

arry.push(event.changedTouches[0].y);
}
for (var i = 0; i < arrx.length; i++) {

if (arrz[i] == 0) {

context.moveTo(arrx[i], arry[i])

} else {

context.lineTo(arrx[i], arry[i])

}
}
context.clearRect(0, 0, canvasw, canvash);
context.setStrokeStyle('#000000');
context.setLineWidth(4);
context.setLineCap('round');
context.setLineJoin('round');
context.stroke();
context.draw(false);
},
canvasEnd: function (event) {
isButtonDown = false;
},
//清除画布
cleardraw: function () {
arrx = [];
arry = [];
arrz = [];
context.clearRect(0, 0, canvasw, canvash);
context.draw(true);
},
uploadImg(){
var that = this
//生成图片
wx.canvasToTempFilePath({

canvasId: 'canvas',

//设置输出图片的宽高

// destWidth:150,

// destHeight:150,

// fileType:'jpg',

quality:1.0,

success: function (res) {

console.log(res)

// canvas图片地址 res.tempFilePath

},

fail: function () {

wx.showModal({

title: '提示',

content: 'canvas生成图片失败。微信当前版本不支持,请更新到最新版本!',

showCancel: false

});

},

complete: function () {}
})
},
})
var context = null;// 使用 wx.createContext 获取绘图上下文 context
var isButtonDown = false;//是否在绘制中
var arrx = [];//动作横坐标
var arry = [];//动作纵坐标
var arrz = [];//总做状态,标识按下到抬起的一个组合
var canvasw = 0;//画布宽度
var canvash = 0;//画布高度
Page({

data: {
},

onLoad: function () {

this.startCanvas();
},
/**
* 以下 - 手写签名 / 上传签名
*/
startCanvas: function () {//画布初始化执行
var that = this;
//获取系统信息
wx.getSystemInfo({

success: function (res) {

canvasw = res.windowWidth;

canvash = res.windowHeight;

that.setData({ canvasw: canvasw });

that.setData({ canvash: canvash });

}
});
this.initCanvas();
this.cleardraw();
},
//初始化函数
initCanvas: function () {
context = wx.createCanvasContext('canvas');
context.beginPath()
context.fillStyle = 'rgba(255, 255, 255, 0)';
context.setStrokeStyle('#000000');
context.setLineWidth(4);
context.setLineCap('round');
context.setLineJoin('round');
},
canvasStart: function (event) {
isButtonDown = true;
arrz.push(0);
arrx.push(event.changedTouches[0].x);
arry.push(event.changedTouches[0].y);
},
canvasMove: function (event) {
if (isButtonDown) {

arrz.push(1);

arrx.push(event.changedTouches[0].x);

arry.push(event.changedTouches[0].y);
}
for (var i = 0; i < arrx.length; i++) {

if (arrz[i] == 0) {

context.moveTo(arrx[i], arry[i])

} else {

context.lineTo(arrx[i], arry[i])

}
}
context.clearRect(0, 0, canvasw, canvash);
context.setStrokeStyle('#000000');
context.setLineWidth(4);
context.setLineCap('round');
context.setLineJoin('round');
context.stroke();
context.draw(false);
},
canvasEnd: function (event) {
isButtonDown = false;
},
//清除画布
cleardraw: function () {
arrx = [];
arry = [];
arrz = [];
context.clearRect(0, 0, canvasw, canvash);
context.draw(true);
},
uploadImg(){
var that = this
//生成图片
wx.canvasToTempFilePath({

canvasId: 'canvas',

//设置输出图片的宽高

// destWidth:150,

// destHeight:150,

// fileType:'jpg',

quality:1.0,

success: function (res) {

console.log(res)

// canvas图片地址 res.tempFilePath

},

fail: function () {

wx.showModal({

title: '提示',

content: 'canvas生成图片失败。微信当前版本不支持,请更新到最新版本!',

showCancel: false

});

},

complete: function () {}
})
},
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