使用画布在 HTML5 中逐帧动画 [英] Frame by frame animation in HTML5 with canvas

问题描述

我有一个 Flash 动画，我正在尝试将其转换为 HTML5.现在我已经取出了所有的图像.例如在手部动画中，我拍摄了所有手部图像的图像.我已经用基础绘图制作了画布，但我不知道如何逐帧替换这些图像.

I have a flash animation I am trying to convert to HTML5. Now I have taken out all the images. For example in the hand animation, I have taken images of all hand images. I have made the canvas with the base drawing but I don't know how to replace those images frame by frame.

function draw(){
    var canvas = document.getElementById('canvas');
    if(canvas.getContext){
        // canvas animation code here:
        var ctx = canvas.getContext('2d');

        var lhs = new Image();

        lhs.src = "images/left_hnd_1.png";

        lhs.onload = function(){
            ctx.drawImage(lhs, 293, 137);
        }

    } else {
        // canvas unsupported code here:
        document.getElementById('girl').style.display = "block";
    }
}

现在我有这幅图像的三个框架.left_hnd_2.png, left_hnd_3.png &left_hnd_4.png.我会使用一张图像，但帧的差异太大了，无法用一张图像完成.我怎样才能用我想要的时差来制作这个动画.

Now I have three more frame for this image. left_hnd_2.png, left_hnd_3.png & left_hnd_4.png. I would've used one image but the difference in frames is way too much for it to be done with one image. How can I animate this with the time differences I want.

任何想法将不胜感激.谢谢！

Any ideas would be greatly appreciated. Thanks!

推荐答案

试试这个:

var imgNumber = 1;
var lastImgNumber = 4;

var ctx = canvas.getContext('2d');
var img = new Image;
img.onload = function(){
  ctx.clearRect( 0, 0, ctx.canvas.width, ctx.canvas.height );
  ctx.drawImage( img, 0, 0 );
};
var timer = setInterval( function(){
  if (imgNumber>lastImgNumber){
    clearInterval( timer );
  }else{
    img.src = "images/left_hnd_"+( imgNumber++ )+".png";
  }
}, 1000/15 ); //Draw at 15 frames per second

另一种选择，如果您只有 4 张图像，则可以在纹理图集"中创建一个包含所有四个图像的单个巨大图像，然后使用 setTimeout 或 setInterval 使用不同的参数调用 drawImage() 以将图像的不同子集绘制到画布上.

An alternative, if you only have 4 images, would be to create a single huge image with all four in a 'texture atlas', and then use setTimeout or setInterval to call drawImage() with different parameters to draw different subsets of the image to the canvas.

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