在画布中制作可点击区域以更改图像-前端问题

make clickable region in canvas to change image(在画布中制作可点击区域以更改图像)

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问题描述

请帮帮我:

在下面的画布中创建可点击区域，我可以将 onmousedown= 事件分配给这些区域.我知道如何用不可见的 DIV 做到这一点，但我认为有一种更优雅的方式可以在我不知道的画布中做到这一点.

create clickable regions in the canvas below that I can assign onmousedown= events to. I know how to do this with invisible DIVs, but I think there is a more elegant way to do it in canvas that I don't know.

当我单击其中一个区域时，想要将图像名称传递给函数，以便它将正在显示的图像更改为另一个图像，然后将其更改回 onmouseup.

when I click one of the regions, want to pass an image name to a function so that it changes the image being displayed to another image, and then changes it back onmouseup.

如果您只给我展示一个区域和一个 mousedown/mouseup 示例，我可以完成剩下的...谢谢.

if you show me just one region and one mousedown/mouseup example I can do the rest...thanks.

<!DOCTYPE HTML>
<html>
<head>
</head>
<body>

        <canvas id="myCanvas" width="506" height="319" style="border:1px solid #c3c3c3;">
        Your browser does not support the canvas element.
        </canvas>

        <script type="text/javascript">
        var c=document.getElementById("myCanvas");
        var ctx=c.getContext("2d");
        var img=new Image();
        img.onload = function(){
        ctx.drawImage(img,0,0);
        };
        img.src="firstImage.gif";
        </script>

        /////////HERE NEED/////////
                    CREATE CLICKABLE REGION <region>
                    <region>
                    onmousedown=changeCanvasImage(secondImage.gif) //change image on click
                    onmouseup=changeCanvasImage(firstImage.gif)  /change it back when done
        </region>
</body>
</html>

在画布中制作可点击区域以更改图像

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