1. 通过canvas自带的画布方法进行翻转
var img = new Image(); //这个就是 img标签的dom对象
img.src = \’./sy.png\’;
img.onload = function () {
//图片加载完成后，执行此方法
ctx.drawImage(img, posx, posy, 210, 80);
};
play.addEventListener(\’click\’, function () {
ctx.clearRect(0, 0, canvas.width, canvas.height);//清除画布
//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); //上下镜像翻转
ctx.drawImage(img, 0, 0, 210, 80);
});
2.像素点的镜像翻转方法
//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 () {
//图片加载完成后，执行此方法
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); //上下翻转
// ctx.putImageData(imageDataHRevert(newImgData, imgData), 0, 0);//左右翻转~~~~
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