七巧板的問題
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>七巧板的實現</title>
</head>
<body>
<script type="text/javascript">
var tangram = [
{p:[{x:0,y:0},{x:800,y:0},{x:400,y:400}],color:"#caff67"},
{p:[{x:0,y:0},{x:400,y:400},{x:0,y:800}],color:"#67becf"},
{p:[{x:800,y:0},{x:800,y:400},{x:600,y:600},{x:600,y:200}],color:"#ef3d61"},
{p:[{x:600,y:200},{x:600,y:600},{x:400,y:400}],color:"#f9f51a"},
{p:[{x:400,y:400},{x:600,y:600},{x:400,y:800},{x:200,y:600}],color:"#a594c0"},
{p:[{x:200,y:600},{x:400,y:800},{x:0,y:800}],color:"#fa8ecc"},
{p:[{x:800,y:400},{x:800,y:800},{x:400,y:800}],color:"#f6ca29"}
];
window.onload = function(){
var canvas = document.getElementById('canvas');
canvas.width = 800;
canvas.height = 800;
var context = canvas.getContext('2d');
for (var i=0;i<tangram.length;i++) {
draw(tangram[i],context);
}
}
function draw(piece,cxt) {
cxt.beginPath();
cxt.moveTo(piece.p[0].x,piece.p[0].y);
for (var i=1;i<piece.length;i++) {
cxt.lineTo(piece.p[i].x,piece.p[i].y);
}
cxt.closePath();
cxt.fillStyle = piece.color;
cxt.fill();
}
</script>
<canvas id="canvas"></canvas>
</body>
</html>
自己到底哪里錯了?
2016-03-31
for (var i=1;i<piece.p.length;i++) {
cxt.lineTo(piece.p[i].x,piece.p[i].y);
}?
應該是piece對象的p屬性的長度
2016-03-31
function draw(piece,cxt){
? ?cxt.beginPath();
? ?cxt.moveTo(piece.p[0].x,piece.p[0].y);
? ?for(var i = 0;i<piece.p.length;i++){
? ? ? ?cxt.lineTo(piece.p[i].x,piece.p[i].y);
? ?}
? ?cxt.closePath();
? ?cxt.fillStyle = piece.color;
? ?cxt.fill();
? ?cxt.strokeStyle = "black";
? ?cxt.stroke();
}
第2個for循環里，索引應該是var i = 0；