HTML5 canvas画矩形时出现边框样式不一致的解决方法

<canvas id="myCanvas" width="578" height="200"></canvas>
<script>
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');

context.beginPath();

context.rect(188.0, 50, 200, 100.375);
context.fillStyle = 'white';
context.fill();
context.lineWidth = 1;
context.strokeStyle = 'red';
context.stroke();
</script>