【发布时间】:2014-04-24 17:08:07
【问题描述】:
我有一个横跨整个屏幕的画布元素 (canvas-mouse) - 它的目的是在一定大小的鼠标周围绘制一个 50% 不透明度的圆圈 (grabsize)。页面上还有一些 div 中的图像。我希望这些图像可以点击/悬停,但我也希望canvas-mouse 中的 50% 不透明度圆圈出现在它们的顶部。
有没有办法做到这一点?
HTML:
<canvas id="canvas-mouse" class="fullscreen"></canvas>
<div class="object die"><img src="images/Die_d6.svg"></div>
CSS:
html, body {
width: 100%;
height: 100%;
margin: 2px;
overflow: hidden;
color: #FFFFFF;
background-color: #2C744C;
}
canvas.fullscreen {
position: absolute;
left: 0px;
top: 0px;
z-index: -1;
}
.object {
position: absolute;
}
#canvas-mouse {
z-index: 10;
}
JavaScript:
CanvasRenderingContext2D.prototype.drawCircle = function(xpos, ypos, radius, linewidth, linecolor, fill) {
if(typeof(linewidth)==="undefined") {
linewidth = 1;
}
if(typeof(linecolor)==="undefined") {
linecolor = "#000000";
}
this.beginPath();
this.arc(xpos, ypos, radius, 0, 2*Math.PI, false);
this.lineWidth = linewidth;
if(typeof(fill)!=="undefined") {
this.fillStyle = fill
this.fill();
}
this.strokeStyle = linecolor;
this.stroke();
}
CanvasRenderingContext2D.prototype.maximize = function() {
this.canvas.width = window.innerWidth;
this.canvas.height = window.innerHeight;
}
mousectx = $("#canvas-mouse")[0].getContext("2d");
mousectx.maximize();
//Dice handlers
$(".object.die").hover(function() {
//Hover event goes here
})
$(".object.die").mousedown(function() {
//Click event goes here
})
//Mouse movement handler
$(document).mousemove(function(e){
//Get the mouse positions and put them in {mouse}
mouse.x = e.pageX;z
mouse.y = e.pageY;
//Redraw the grab circle
mousectx.clearCanvas();
mousectx.drawCircle(mouse.x,mouse.y,grabsize,1,"#000000","rgba(0,0,255,0.5)");
});
提前致谢。
【问题讨论】:
-
这个stackoverflow.com/questions/3680429/… 可能会解决问题..
-
画布鼠标不应该有一个相对位置来让 z-index 起作用吗?
标签: javascript jquery html css canvas