ios html 图片旋转了,在ios上图片旋转 · Issue #11 · AlloyTeam/AlloyCrop · GitHub

重置图片方法 做一个转换

function resetOrientation(srcBase64, srcOrientation, callback) {

var img = new Image();

img.onload = function() {

var width = img.width,

height = img.height,

canvas = document.createElement('canvas'),

ctx = canvas.getContext("2d");

// set proper canvas dimensions before transform & export

if (4 < srcOrientation && srcOrientation < 9) {

canvas.width = height;

canvas.height = width;

} else {

canvas.width = width;

canvas.height = height;

}

// transform context before drawing image

switch (srcOrientation) {

case 2:

ctx.transform(-1, 0, 0, 1, width, 0);

break;

case 3:

ctx.transform(-1, 0, 0, -1, width, height);

break;

case 4:

ctx.transform(1, 0, 0, -1, 0, height);

break;

case 5:

ctx.transform(0, 1, 1, 0, 0, 0);

break;

case 6:

ctx.transform(0, 1, -1, 0, height, 0);

break;

case 7:

ctx.transform(0, -1, -1, 0, height, width);

break;

case 8:

ctx.transform(0, -1, 1, 0, 0, width);

break;

default:

break;

}

// draw image

ctx.drawImage(img, 0, 0);

// export base64

callback(canvas);

};

img.src = srcBase64;

}