使用 HTML Canvas 的问题Greasemonkey 无法在 2D 上下文中绘制Image()

发布于 2024-08-18 03:35:36 字数 946 浏览 4 评论 0原文

在我的 Greasemonkey 脚本中，当我获取要与 HTML Canvas 一起使用的 HTMLImageElement 的句柄时，我在 Firefox 的错误控制台 ~~中收到以下错误（我认为这是因为它包含在 XPCNativeWrapper 中）~~：

Error: Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) 
       [nsIDOMCanvasRenderingContext2D.drawImage]

~~在我的代码中放置 GM_log() 语句，我已经跟踪了我尝试使用的图像对象，从它的初始分配一直到我尝试将它与 HTML Canvas 一起使用。~~

它总是包装在 XPCNativeWrapper 中：
[object XPCNativeWrapper [object HTMLImageElement]]

我通过使用 image.wrappedJSObject 获取对 HTMLImageElement 的引用来解开 HTMLImageElement 的包装。

我的画布代码：

var canvas = document.createElement("canvas");
canvas.width = image.width;
canvas.height = image.height;

var ctx = canvas.getContext("2d");
ctx.drawImage(image, 0, 0);

您知道为什么 Firefox 会抛出上述组件故障代码吗？

原文

In my Greasemonkey script, when I obtain a handle on an HTMLImageElement I want to use with an HTML Canvas, I get the following error in Firefox's Error Console ~~(I assume it's because it's enclosed in an XPCNativeWrapper)~~:

Error: Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) 
       [nsIDOMCanvasRenderingContext2D.drawImage]

~~Putting GM_log() statements throughout my code, I have traced the image object I'm trying to use from it's initial assignment through until I try to use it with an HTML Canvas.~~

It's always wrapped in an XPCNativeWrapper:

[object XPCNativeWrapper [object HTMLImageElement]]

I've unwrapped the HTMLImageElement by obtaining reference to it with image.wrappedJSObject.

My canvas code:

var canvas = document.createElement("canvas");
canvas.width = image.width;
canvas.height = image.height;

var ctx = canvas.getContext("2d");
ctx.drawImage(image, 0, 0);

Any ideas why Firefox is throwing the above component failure code?

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叫思念不要吵 2024-08-25 03:35:36

我应该更彻底地在谷歌上查看。

image.wrappedJSObject;

作品。

I should have looked more thoroughly on Google.

image.wrappedJSObject;

Works.

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爱她像谁 2024-08-25 03:35:36

var canvas = document.createElement("canvas").wrappedJSObject,
ctx = canvas.getContext("2d");

canvas.width = image.width;
canvas.height = image.height;

ctx.drawImage(image, 0, 0);

这就是我所做的。希望有帮助

var canvas = document.createElement("canvas").wrappedJSObject,
ctx = canvas.getContext("2d");

canvas.width = image.width;
canvas.height = image.height;

ctx.drawImage(image, 0, 0);

this is what i did. hope it helps

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