标签：context bsp path wim fun func this 简单 create
doDraw: function (path, height, width) {
let that = this;
var ctx = wx.createCanvasContext(‘firstCanvas‘)
let scale = width / height;
let drawWidth = 0; // 绘制图片的宽度
let drawHeight = 0; // 绘制图片的高度
// 假设高度确定
if (scale >= (360/ 640)) {
// 宽度过大：高度设置为1280
drawHeight = 640;
drawWidth = scale * 640;
let left = (drawWidth - 360) / 2; // 左边偏移量
ctx.drawImage(path, -left, 0, drawWidth, drawHeight);
} else {
// 宽度过小：宽度设置为720
drawWidth = 360;
drawHeight = 360 / scale;
let top = (drawHeight - 640) / 2; // 顶部偏移量
ctx.drawImage(path, 0, -top, drawWidth, drawHeight);
}
//模板
// 绘制前景图
ctx.drawImage(that.data.path, 72 / 2, 128 / 2, 576 / 2, 1024 / 2);
ctx.draw();
setTimeout(function () {
that.doCanvas();
}, 300)
},
手机适应屏幕简单图片处理算法
标签：context bsp path wim fun func this 简单 create
原文地址：http://www.cnblogs.com/xinhang/p/7780242.html
