Question

我在页面中显示一个画布，画布中显示的内容的分辨率很高，但并不是所有页面都适合，但是滚动条没有出现，无法向上/向下滚动（没有问题）现在的宽度）。我尝试将显示更改为“阻止”，但这没有帮助。

Answer 1

您始终可以添加jqueryUI滚动条并滚动浏览高大的画布。

这是代码和小提琴：http://jsfiddle.net/m1erickson/a9KDB/

<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script src="http://code.jquery.com/ui/1.10.1/jquery-ui.js"></script>

<style>
body{ background-color: ivory; }
div, canvas {
    position:absolute;
}
.wrapper {
    top:10px;
    left:10px;
    width: 300px;
    height: 300px;
    border: 2px solid black;
    margin:30px 0 2;
    overflow: hidden;
    background-color:green;
}
.vertical-scroll {
    left:320px;
    top:10px;
    border: 1px solid green;
    width: 20px;
    height: 300px;
}
.vertical-scroll div.bar {
    left:0px;
    top:0px;
    width: 20px;
    background-color: blue;
    height: 20px;
}
#mycanvas {
    left:0px;
    top:0px;
}

</style>

<script>
    $(function(){

        var canvas=document.getElementById("mycanvas");
        var ctx=canvas.getContext("2d");

        var wrapper;
        var canvasHeight;
        var vScrollHeight;
        var canvasWrapperHeight=300;

        $(".bar").draggable({
            containment: "parent"
        });

        $(".bar").on("drag", function (event, ui) {
            var ctop=(-ui.position.top * canvasHeight / canvasWrapperHeight);
            canvas.style.top = ctop + "px"
        });

        var img=new Image();
        img.onload=function(){
          canvas.width=this.width;
          canvas.height=this.height;
          canvasHeight=this.height;
          vbarHeight=canvasWrapperHeight*canvasWrapperHeight/canvasHeight;
          document.getElementById("vbar").style.height=vbarHeight+"px";
          ctx.drawImage(this,260,0,300,this.height,0,0,300,this.height);
        }
        img.src="http://sciencedude.blog.ocregister.com/files/2008/02/zot1-copy.jpg";

    }); // end $(function(){});
</script>

</head>

<body>
    <div class="wrapper" id="wrap1">
        <canvas id="mycanvas" width="300px" height="300px" />
    </div>
    <div class="vertical-scroll" id="vscroll">
        <div class="bar" id="vbar"></div>
    </div>
 </body>
</html>

虽然内容不适合页面，但画布未显示滚动条

1 个答案: