javascript - 通过一次加载绘制图像数组？

Question

我想用一个 onload 函数绘制一行图像。我已经尝试过这段代码

for(i = 0; i < 8; i++){
var canvas = document.getElementById('ctx');
var context = canvas.getContext("2d");
var imageObj = new Image();
imageObj.src = "thumb.png";
imageObj.setAtX = i * 10;
imageObj.setAtY = i * 10;
imageObj.onload = function() {
context.drawImage(this, this.setAtX, this.setAtY);
};
}

(在java脚本中)

Answer 1

// put the paths to your images in imageURLs[]
var imageURLs=[];  
imageURLs.push("image1.png");
imageURLs.push("image2.png");

// the loaded images will be placed in imgs[]
var imgs=[];

var imagesOK=0;
loadAllImages(start);

function loadAllImages(callback){
    for (var i=0; i<imageURLs.length; i++) {
        var img = new Image();
        imgs.push(img);
        img.onload = function(){ 
            imagesOK++; 
            if (imagesOK>=imageURLs.length ) {
                callback();
            }
        };
        img.onerror=function(){alert("image load failed");} 
        img.crossOrigin="anonymous";
        img.src = imageURLs[i];
    }      
}

function start(){

    // the imgs[] array now holds fully loaded images
    // the imgs[] are in the same order as imageURLs[]

}