我有一个canvas元素(canvas-mouse
),它覆盖整个屏幕 - 它的目的是在鼠标周围绘制一个50%不透明度的圆形,大小为(grabsize
)。页面上还有一些包含图片的div。我希望这些图片可以被点击/悬停,但同时也要让位于canvas-mouse
中的50%不透明度圆形显示在它们上面。
有没有办法实现这个效果?
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)");
});
预先致谢。