HTML Canvas save() wrap drawing code with save-restore combination

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HTML Canvas save() wrap drawing code with save-restore combination

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<html>
    <head>
        <script>
            window.onload = function(){
                var canvas = document.getElementById("myCanvas");
                var context = canvas.getContext("2d");
                /*from w  w w  .ja v a  2  s  .  com*/
                // draw rectangle
                context.beginPath();
                context.rect(150, 30, 130, 130);
                context.fillStyle = "blue";
                context.fill();
                
                // wrap circle drawing code with save-restore combination
                context.save();
                context.globalAlpha = 0.5; // set global alpha
                context.beginPath();
                context.arc(canvas.width / 2, canvas.height / 2, 70, 0, 2 * Math.PI, false);
                context.fillStyle = "red";
                context.fill();
                context.restore();
                
                // draw another rectangle
                context.beginPath();
                context.rect(canvas.width - (150 + 130), canvas.height - (30 + 130), 130, 130);
                context.fillStyle = "green";
                context.fill();
            };
        </script>
    </head>
    <body>
        <canvas id="myCanvas" width="600" height="250" style="border:1px solid black;">
        </canvas>
    </body>
</html>



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