我正在尝试将tileset图像（类型为.png）解析为数组。我有一个测试画布，我用它来绘制它，然后我从中提取图像信息。当我运行此代码时，它会抛出“Uncaught TypeError：Type error”。我能够记录this.mainTiles是空的。有任何想法吗？我还不知道Canvas的所有细微之处，所以我被卡住了。谢谢您的帮助！ （另外，你可以忽略最后一行，我只是用它来测试 - 但我想说明它不起作用。）
function TileSet() {
this.tileSheets = [];
this.mainTiles = [];
this.tileHeight = 32;
this.tileWidth = 32;
this.addSpriteSheet = function (spriteSheetLoc, name) {
var tileSheet = new Image();
try {
tileSheet.src = spriteSheetLoc;
}
catch(err) {
dMode.Log("Invalid TileSheet Src ( TileSet.setSpriteSheet() Failed ); ERR: " + err);
}
tempContext.drawImage(tileSheet, 0, 0);
var tilesX = tempContext.width / this.tileWidth;
var tilesY = tempContext.height / this.tileHeight;
for(var i=0; i<tilesY; i++) {
for(var j=0; j<tilesX; j++) {
// Store the image data of each tile in the array.
this.mainTiles.push(tempContext.getImageData(j*this.tileWidth, i*this.tileHeight, this.tileWidth, this.tileHeight));
}
}
context.putImageData(this.mainTiles[0], 5, 5);
}
编辑：以下是画布等的定义方式：
var tempCanvas = document.getElementById("tempCanvas");
var tempContext = tempCanvas.getContext("2d");
var canvas = document.getElementById("gameCanvas");
var context = canvas.getContext("2d");
var Tiles = new TileSet;
//this is the line it gets stuck at
Tiles.addSpriteSheet("resources/tiles/tilea2.png");
编辑2：在markE的回答之后，这是最新的更新。仍然觉得我错过了关于.onload的基本属性。
function TileSet() {
this.Tiles = [];
this.tileHeight = 32;
this.tileWidth = 32;
this.tileCount = 4;
this.addSpriteSheet = function (spriteSheetLoc, name) {
var tileSheet = new Image();
tileSheet.onload = function() {
tempCanvas.width = tileSheet.width;
tempCanvas.height = tileSheet.height;
tempContext.drawImage(tileSheet, 0, 0);
for (var t=0;t<this.tileCount;t++) {
this.Tiles[t]=tempContext.getImageData(t*this.tileWidth,t*32,this.tileWidth,tileSheet.height);
dMode.Log(this.Tiles);
}
context.putImageData(this.Tiles[this.Tiles.length-1],0,0);
dMode.Log(this.Tiles);
}
tileSheet.src = spriteSheetLoc;
}
答案 0 :(得分：2)
以下是如何将spritesheet解析为单独的canvas imageData数组
我有一些可以做你想做的工作代码。
我没有你的“resources / tiles / tilea2.png”所以我使用了我自己的“monstersArun.png”，这是一张64x64瓷砖的10个spritesheet。
您可以修改此代码以适合您的spritesheet布局（行x列和平铺大小）。
以下是代码：
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var tileCount=10;
var tiles=new Array();
var tileWidth;
var t;
var img=new Image();
img.onload=function(){
canvas.width=img.width;
canvas.height=img.height;
tileWidth=img.width/tileCount;
ctx.drawImage(img,0,0);
for(var t=0;t<tileCount;t++){
tiles[t]=ctx.getImageData(t*tileWidth,0,tileWidth,img.height);
}
// just a test
// draw the last tiles[] into another canvas
var canvasTile=document.getElementById("canvasTile");
var ctxTile=canvasTile.getContext("2d");
canvasTile.width=tileWidth;
canvasTile.height=canvas.height;
ctxTile.putImageData(tiles[tiles.length-1],0,0);
}
img.src="monsterarun.png";
}); // end $(function(){});
</script>
</head>
<body>
<canvas id="canvas" width=300 height=300></canvas><br/>
<canvas id="canvasTile" width=64 height=64></canvas>
</body>
</html>
[编辑 - 包括Juan Mendes好主意在编码问题上提供帮助]
另外，当我查看你的代码时......在这里：
tileSheet.src = spriteSheetLoc;
这会导致您的图片加载。这种加载需要时间，因此javascript开始加载图片，但也会立即转到您的下一行代码。因此，下面的代码尝试在图像可用之前使用它 - 没有用！
因此，在处理其余代码之前，您应该让javascript有机会完全加载您的图像。您可以使用Image的onload方法执行此操作：
var tileSheet = new Image();
tileSheet.onload=function(){
// put ALL you code that depends on the image being fully loaded here
}
tileSheet.src = spriteSheetLoc;
注意如何在 onload函数之后放置tileSheet.src 。实际上，javascript执行tilesheet.src然后返回来执行onload块中的所有代码！
[再次编辑 - 完整代码]
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var tempCanvas = document.getElementById("tempCanvas");
var tempContext = tempCanvas.getContext("2d");
var canvas = document.getElementById("gameCanvas");
var context = canvas.getContext("2d");
// create a new TileSet
var Tiles = new TileSet();
// parse a spritesheet into tiles
//Tiles.addSpriteSheet("resources/tiles/tilea2.png","anyName");
Tiles.addSpriteSheet("houseIcon.png","anyName");
function TileSet() {
this.Tiles = [];
this.tileHeight = 32;
this.tileWidth = 32;
this.tileCount = 4;
this.addSpriteSheet = function (spriteSheetLoc, name) {
var me=this; // me==this==TileSet
var tileSheet = new Image();
tileSheet.onload = function() {
// calculate the rows/cols in the spritesheet
// tilesX=rows, tilesY=cols
var tilesX = tileSheet.width / me.tileWidth;
var tilesY = tileSheet.height / me.tileHeight;
// set the spritesheet canvas to spritesheet.png size
// then draw spritesheet.png into the canvas
tempCanvas.width = tileSheet.width;
tempCanvas.height = tileSheet.height;
tempContext.drawImage(tileSheet, 0, 0);
for(var i=0; i<tilesY; i++) {
for(var j=0; j<tilesX; j++) {
// Store the image data of each tile in the array.
me.Tiles.push(tempContext.getImageData(j*me.tileWidth, i*me.tileHeight, me.tileWidth, me.tileHeight));
}
}
// this is just a test
// display the last tile in a canvas
context.putImageData(me.Tiles[me.Tiles.length-1],0,0);
}
// load the spritesheet .png into tileSheet Image()
tileSheet.src = spriteSheetLoc;
}
}
}); // end $(function(){});
</script>
</head>
<body>
<canvas id="tempCanvas" width=300 height=300></canvas><br/>
<canvas id="gameCanvas" width=300 height=300></canvas>
</body>
</html>
答案 1 :(得分：1)
尝试分别用tempContext.width和tempContext.height替换tempCanvas.width和tempCanvas.height。我不相信上下文有宽度/高度。