graphics 在线编辑器 | graphics代码测试

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>canvas {
    border:1px solid #d3d3d3;
    background-color: #f1f1f1;
}
</style>
</head>
<body onload="startGame()">
<script>

var myGamePiece;
var myBackground;

function startGame() {
    myGamePiece = new component(30, 30, "smiley.gif", 10, 120, "image");
    myBackground = new component(656, 270, "citymarket.jpg", 0, 0, "image");
    myGameArea.start();
}

function updateGameArea() {
    myGameArea.clear();
    myBackground.newPos();    
    myBackground.update();
    myGamePiece.newPos();    
    myGamePiece.update();
}

function clearmove() {
    myGamePiece.image.src = "smiley.gif";
    myGamePiece.speedX = 0; 
    myGamePiece.speedY = 0; 
}
</script>
<div style="text-align:center;width:480px;">
  <button onmousedown="move('up')" onmouseup="clearmove()" ontouchstart="move('up')">UP</button><br><br>
  <button onmousedown="move('left')" onmouseup="clearmove()" ontouchstart="move('left')">LEFT</button>
  <button onmousedown="move('right')" onmouseup="clearmove()" ontouchstart="move('right')">RIGHT</button><br><br>
  <button onmousedown="move('down')" onmouseup="clearmove()" ontouchstart="move('down')">DOWN</button>
</div>

<p>在更新其他组件之前先更新背景，以确保其他组件显示在背景之上。</p>
</body>
</html>

报个问题: