HTML Canvas globalAlpha set transparent

Description

HTML Canvas globalAlpha set transparent

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<html>
    <head>
        <script>
            window.onload = function(){
                var canvas = document.getElementById("myCanvas");
                var context = canvas.getContext("2d");
                /*from   www  .j  a  v  a  2 s .co  m*/
                // draw rectangle
                context.beginPath();
                context.rect(230, 30, 130, 130);
                context.fillStyle = "blue";
                context.fill();
                
                // draw circle
                context.globalAlpha = 0.5; // set global alpha
                context.beginPath();
                context.arc(359, 150, 70, 0, 2 * Math.PI, false);
                context.fillStyle = "red";
                context.fill();
            };
        </script>
    </head>
    <body>
        <canvas id="myCanvas" 
                width="600" 
                height="250" 
                style="border:1px solid black;">
        </canvas>
    </body>
</html>



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