我需要通过这个对象的属性名称叫做source
如何将对象的属性名称传递给drawImage?
Object {
one: "img/20160602_112823_001.jpg",
two: "img/UHEGP 17.1.jpg",
three: "img/UHEGP 17.3.jpg",
badge: "img/badge-gold-big-no-shadow-tilted.png",
top_layer: "img/watermark_bronze_GOLD_Final-70-opacity.png"
}
到drawImage
功能。
function loadImages(source, callback) {
var images = {};
var loadedImages = 0;
var numImages = 0;
// get num of sources
for (var src in source) {
numImages++;
}
for (var src in source) {
images[src] = new Image();
images[src].onload = function() {
if (++loadedImages >= numImages) {
callback(images);
}
};
images[src].src = source[src];
}
}
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
loadImages(source, function (images) {
for (var key in source) {
context.drawImage(images.key, 0, 0, 921, 680);
context.drawImage(images.top_layer, 0, 0, 921, 57);
context.drawImage(images.badge, 700, -20, 175, 175);
}
});
它的工作原理,如果我只是把有属性名称不涉及循环:
context.drawImage(images.top_layer, 0, 0, 921, 57);
但是,如果我试图通过循环来做到这一点,并把所有的属性名称何尝不是呢里面的key
变量。当我将它传递给context.drawImage(images.key, 0, 0, 921, 680);
时,它不起作用。
您的要求不明确,能否请您详细一点 – brk
@ user2181397我编辑它。希望现在很清楚 – hasan
@AmiramKorach但它工作,如果我只是把那里属性名称不涉及循环: 'context.drawImage(images.top_layer,0,0,921,57);' – hasan