你的函数正在返回undefined
因为load
是异步的。getImage
正在尝试返回之前的某些内容load
加载完成。
您需要传递一个回调来在图像加载时执行,以getImage
:
function getImage(imgsrc, callback){
var img = $( "<img>", {
src: imgsrc
});
var imageMap = new Object();
img.load(function() {
var canvas = $('<canvas/>')[0].getContext('2d');
canvas.width = this.width;
canvas.height = this.height;
canvas.drawImage(this, 0, 0, this.width, this.height);
for(var i = 0;i < this.width;i++){
imageMap[i] = new Object();
for(var j = 0;j < this.width;j++){
var pixelData = canvas.getImageData(i, j, 1, 1).data;
imageMap[i][j] = rgbToHex(pixelData[0],pixelData[1],pixelData[2]);
}
}
console.log(imageMap[40][40]);
callback(imageMap)
});
}
然后你只需这样调用该函数:
getImage("http://some.src.jpg", function(imageMap){
// Do stuff with imageMap here;
});
当然,你也可以在其他地方定义回调:
var myCallback = function(imageMap){
// Do stuff with imageMap here;
};
getImage("http://some.src.jpg", myCallback);