0
當我試圖將圖像繪製到一個Canvas元素我得到這個exeption：畫布繪製錯誤
Uncaught Error: INDEX_SIZE_ERR: DOM Exception 1
textureLoadedstaticsprite.js:14
StaticSpritestaticsprite.js:21
(anonymous function)
所有兩個CanvasRenderingContent和HTMLImageElement存在。 我只是不明白這一點：S
這裏是前述代碼我使用：
/**
* Class for drawing static sprites, like trees and blocks
*/
function StaticSprite(args) {
// Private Fields
var texture = new Image();
// Events
function textureLoaded(context) {
console.log(context);
console.log(texture);
context.drawImage(texture, 0, 0, 32, 32);
}
// Constructor
// Add event listeners
texture.addEventListener("load", textureLoaded(this.graphics), false);
// Load texture
texture.src = "img/assets/wall1.png";
if(args != undefined) {
// Set local fields
this.x = args.x || this.x;
this.y = args.y || this.y;
this.z = args.z || this.z;
this.width = args.width || this.width;
this.height = args.height || this.height;
}
this.width = 32;
this.height = 32;
}
// Inherit from GraphicsEntity
StaticSprite.prototype = new GraphicsEntity();
這裏是GraphicsEntity基類，如果你需要它：P
/**
* Class for presentation of graphical objects.
*/
function GraphicsEntity(args) {
// Private Fields
var x = 0; // The X-position of the GraphicsEntity relative to it's parent container
var y = 0; // The Y-position of the GraphicsEntity relative to it's parent container
var z = 0; // The Z-position of the GraphicsEntity relative to it's parent container
var width = 0; // The width of the GraphicsEntity
var height = 0; // The height of the GraphicsEntity
// Public Fields
this.DOMElement = null; // Reference to the corresponding HTML Element
this.graphics = null; // The 2D context for rendering 2D onto the element.
this.name = ""; // The name of the GraphicsEntity
// Properties
// The Alpha or transparency value of the GraphicsEntity, 1 is completely opaque, 0 is completely transparent.
Object.defineProperty(this, "alpha", {
get: function() { return parseFloat(this.DOMElement.style.opacity); },
set: function(value) { this.DOMElement.style.opacity = value; }
});
// The height of the GraphicsEntity
Object.defineProperty(this, "height", {
get: function() { return height; },
set: function(value) {
height = value; // Set internal width
this.DOMElement.setAttribute("height", height); // Set DOMElement width
}
});
// The width of the GraphicsEntity
Object.defineProperty(this, "width", {
get: function() { return width; },
set: function(value) {
width = value; // Set internal width
this.DOMElement.setAttribute("width", width); // Set DOMElement width
}
});
// The X-position of the GraphicsEntity relative to it's parent container
Object.defineProperty(this, "x", {
get: function() { return x; },
set: function(value) {
x = value; // Set internal X-axis
this.DOMElement.style.left = Math.ceil(x) + "px"; // Set DOMElement X-axis
}
});
// The Y-position of the GraphicsEntity relative to it's parent container
Object.defineProperty(this, "y", {
get: function() { return y; },
set: function(value) {
y = value; // Set internal Y-axis
this.DOMElement.style.top = Math.ceil(y) + "px"; // Set DOMElement Y-axis
}
});
// The Z-position of the GraphicsEntity relative to it's parent container
Object.defineProperty(this, "z", {
get: function() { return z; },
set: function(value) { this.DOMElement.style.zIndex = parseInt(value); }
});
// Constructor
// Get constructor values of use default
if(args) {
x = args.x || x;
y = args.y || y;
z = args.z || z;
width = args.width || width;
height = args.height || height;
}
// Create a new canvas element
this.DOMElement = document.createElement('canvas');
// Set postion
this.DOMElement.style.position = "absolute"; // Positioning style
this.DOMElement.style.left = x + "px"; // X-axis
this.DOMElement.style.top = y + "px"; // Y-axis
this.DOMElement.style.zIndex = z; // Z-Axis
this.DOMElement.width = width;
this.DOMElement.height = height;
// Set opacity/alpha
this.DOMElement.style.opacity = 1;
// Get 2d canvas context
this.graphics = this.DOMElement.getContext('2d');
}
你能告訴我們的HTML行？何時以及如何稱呼「紋理上鍊」？如果您在drawimage中設置參數，那麼所有參數或默認參數都將被使用或調用？你究竟在哪裏調用畫布元素？設置2D上下文等？ – alonisser
雖然看起來像您的'texture.addEventListener'行是錯誤的，我還沒有正確地查看您的代碼。你在那裏調用函數，而不是作爲處理程序發送它。你可以嘗試捲曲或裝訂。在當前版本中，發送的處理程序是「未定義」的，因爲這是函數的返回值。 – davin