动画在画布中移动图像

Im new to using canvas but wonder if i could get some help or advice on where to start with this. i currently have a circle drawn on canvas and have tried multiple ways i thought might work but cant get my head round it. When searching online i can only really find help where the shapes are drawn in canvas itself.

我是使用画布的新手,但想知道我是否可以获得一些帮助或建议从哪里开始。我目前在画布上绘制了一个圆圈,并尝试了多种我认为可行的方法,但我无法绕过它。在线搜索时,我只能在画布本身绘制形状时找到帮助。

Here is what i have so far: JSFiddle

这是我到目前为止:JSFiddle

JavaScript:

var one = document.getElementById("canvOne");
var canvOne = one.getContext("2d");
var img = new Image();
img.onload = function(){
    canvOne.drawImage(img, 10, 10);
};

img.src = "img/circle.jpg";

function oneStart(){
    for(var i = 0; i < 300; i++){
        img.style.left = i + 'px';
        setTimeout(oneStart, 1000);
    }
};

can anyone give me a hand with this please?

请有人帮我一把吗?

1 个解决方案

#1

jsFiddle : http://jsfiddle.net/8eLL7L5L/3/

jsFiddle:http://jsfiddle.net/8eLL7L5L/3/

javascript

//canvas one
var one = document.getElementById("canvOne");
var canvOne = one.getContext("2d");
var img = new Image();

var animate = false;
var circlePosX = 10;
var circlePosY = 10;

img.onload = function () {
    canvOne.drawImage(img, circlePosX, circlePosY);
};

img.src = "http://www.alexvolley.co.uk/other/circle.jpg";

var start = function()
{
    animate = true;
}

var stop = function()
{
    animate = false;   
}

setInterval(function () {
    // Only update circle position if animate is true
    if (animate) {
        circlePosX += 1;
        canvOne.fillStyle = "#FFF";
        canvOne.fillRect(0, 0, one.width, one.height);
        canvOne.drawImage(img, circlePosX, circlePosY);
    }
}, 3);

All I have done is created 3 variables and added a few little functions, the circle's XPos and YPos are now stored so we can access them, I have also created a bool variable animate which is used to check if we should animate the circle.

我所做的就是创建了3个变量并添加了一些小函数,现在存储圆圈的XPos和YPos以便我们可以访问它们,我还创建了一个bool变量animate,用于检查是否应该为圆圈设置动画。

The start function simply sets animate to true

start函数只是将animate设置为true

The stop function simple sets animate to false

stop函数simple将animate设置为false

the setInterval just keeps running the same code over and over every 3 miliseconds, all this does is clears the canvas and then redraws the circle. If we don't clear the canvas you would see multiple circles appear when animate is true.

setInterval每隔3毫秒就会一直运行相同的代码,所有这一切都会清除画布,然后重绘圆圈。如果我们不清除画布,您会看到当animate为true时会出现多个圆圈。

I hope this helped

我希望这有帮助

1 个解决方案

#1

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