canvas实现图片的镜像翻转
1. 通过canvas自带的画布办法进行翻转
var img = new Image(); //这个就是 img标签的dom对象 img.src = './sy.png'; img.onload = function () { //图片加载实现后，执行此办法 ctx.drawImage(img, posx, posy, 210, 80); };play.addEventListener('click', function () { ctx.clearRect(0, 0, canvas.width, canvas.height);//革除画布 //位移来做镜像翻转 ctx.translate(210+ posx * 2, 0); ctx.scale(-1, 1); //左右镜像翻转 //ctx.translate(0, 160 + posy * 2); //ctx.scale(1, -1); //高低镜像翻转 ctx.drawImage(img, 0, 0, 210, 80); });2.像素点的镜像翻转办法
//竖向像素反转 function imageDataVRevert(sourceData, newData) { for (var i = 0, h = sourceData.height; i < h; i++) { for (var j = 0, w = sourceData.width; j < w; j++) { newData.data[i * w * 4 + j * 4 + 0] = sourceData.data[(h - i) * w * 4 + j * 4 + 0]; newData.data[i * w * 4 + j * 4 + 1] = sourceData.data[(h - i) * w * 4 + j * 4 + 1]; newData.data[i * w * 4 + j * 4 + 2] = sourceData.data[(h - i) * w * 4 + j * 4 + 2]; newData.data[i * w * 4 + j * 4 + 3] = sourceData.data[(h - i) * w * 4 + j * 4 + 3]; } } return newData; } //横向像素反转 function imageDataHRevert(sourceData, newData) { for (var i = 0, h = sourceData.height; i < h; i++) { for (j = 0, w = sourceData.width; j < w; j++) { newData.data[i * w * 4 + j * 4 + 0] = sourceData.data[i * w * 4 + (w - j) * 4 + 0]; newData.data[i * w * 4 + j * 4 + 1] = sourceData.data[i * w * 4 + (w - j) * 4 + 1]; newData.data[i * w * 4 + j * 4 + 2] = sourceData.data[i * w * 4 + (w - j) * 4 + 2]; newData.data[i * w * 4 + j * 4 + 3] = sourceData.data[i * w * 4 + (w - j) * 4 + 3]; } } return newData; }``
var img = new Image(); //这个就是 img标签的dom对象 img.src = './sy.png'; img.onload = function () { //图片加载实现后，执行此办法 ctx.drawImage(img, 0, 0, 210, 80); }; //像素点操作 var imgData = ctx.getImageData(0, 0, 210, 80); var newImgData = ctx.getImageData(0, 0, 210, 80); // var newImgData = ctx.getImageData(0, 0, w, h); ctx.putImageData(imageDataVRevert(newImgData, imgData), 0, 0); //高低翻转 // ctx.putImageData(imageDataHRevert(newImgData, imgData), 0, 0);//左右翻转~~~~