Javascript getImageData for canvas html5

发布于 2024-10-01 06:05:18 字数 618 浏览 3 评论 0原文

我已经把头发扯下来了！我得到了这个工作，认为“我可以承担不保存这个版本的费用”，然后我..打破了“构建”。

myImageData = context.getImageData(0, 0, canvas.width, canvas.height); 行似乎打破了这一点，因为警报会在之前起作用，但在之后不起作用。

图像本身正在加载。

欢迎提出任何建议 ^_^ 我已无计可施，很快就会摆脱 RSI 的困扰。

var myImageData;

var image_var = new Image();
image_var.onload  = function () {
    canvas.width  = image_var.width;
    canvas.height = image_var.height;
    context.drawImage(image_var, 0, 0, image_var.width, image_var.height);
    myImageData   = context.getImageData(0, 0, canvas.width, canvas.height);
    alert('');
}
image_var.src = "example1.jpeg";

原文

I've tearing my hair out! I got this working, thought 'i can afford not to save a version of this', then i .. broke the 'build'.

The line myImageData = context.getImageData(0, 0, canvas.width, canvas.height); seems to breaking this, as an alert will work before, but not after it.

The image itself is loading.

Any and all suggestions welcomed ^_^ I'm at tether's end, and going to get RSI from kicking myself soon.

var myImageData;

var image_var = new Image();
image_var.onload  = function () {
    canvas.width  = image_var.width;
    canvas.height = image_var.height;
    context.drawImage(image_var, 0, 0, image_var.width, image_var.height);
    myImageData   = context.getImageData(0, 0, canvas.width, canvas.height);
    alert('');
}
image_var.src = "example1.jpeg";

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め可乐爱微笑 2024-10-08 06:05:18

将下面的代码添加到您的实际代码中，firefox 允许您在本地工作，

netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");

它实际上做了什么？

当脚本调用此函数时，如果签名有效或启用了代码库主体，则可以授予扩展权限。如果用户以前没有访问过此主体，则会出现一个对话框，询问用户是否要接受签名的代码。与 Communicator 4.x 不同，Mozilla 不显示详细的 Java 授权对话框，而是显示一个简单的对话框，询问主体是否可信。用户可以接受或拒绝，并允许浏览器记住他们的选择。如第二个示例所示，可能会同时请求两项权限，因此只出现一个对话框。

仅在请求功能的范围内授予权限。此范围包括请求函数调用的任何函数。当脚本离开请求函数时，特权不再适用。

您可以在此处阅读更多相关信息

这是一个演示 alt text

Add below piece of code to your actual code, firefox allows you to work locally

netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");

what actually it does ?

When the script calls this function, if the signature is valid or codebase principal are enabled, expanded privileges can be granted. If a user has not accessed this principal before, a dialog asks the user if he wants to accept the signed code. Unlike Communicator 4.x, Mozilla does not display a detailed Java grant dialog, rather a simple dialog asking if the principal can be trusted. The user can accept or deny and allow their choice to be remembered by the browser. As shown in the second example, two privileges may be asked for at once, so only one dialog appears.

Privileges are granted only in the scope of the requesting function. This scope includes any functions called by the requesting function. When the script leaves the requesting function, privileges no longer apply.

You can read more about it here

Here's a demo alt text

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