来自UIImage的数据URL / PNG [英] Data URL / PNG from UIImage

问题描述

我有一个iPhone程序，有一个UIImage。这个UIImage需要传递到UIWebView中的一个javascript Image对象。我认为这可以通过使用数据url我发送到UIWebView这样做：

I have a iPhone program that has a UIImage. This UIImage needs to be transferred to a javascript Image object in a UIWebView. I was thinking this could be done by using a data url I send to the UIWebView like this:

[wview stringByEvaluatingJavaScriptFromString:@"loadimage('%d')",dataurlfromuiimage];

因此，我需要将UIImage转换为数据：URL。我可以自己做，如果我只能得到PNG数据，但我不能找到如何做到这一点。如果有更好的方式发送到WebView，这也是很好的。

So, I need to transfer my UIImage into a Data: URL. I could do this myself if I can just get the PNG data, but I cannot find how do do that either. If there is a better way to send this to the WebView, that would be good also.

推荐答案

您的图片格式为PNG，请使用

To get an NSData representation of your image in the PNG format, use

NSData *dataForPNGFile = UIImagePNGRepresentation(yourImage);

同样，使用

NSData *dataForJPEGFile = UIImageJPEGRepresentation(yourImage, 0.9f);

一旦你有了NSData，你可以使用writeToFile：atomically：然后我相信你可以传递它作为本地URL（虽然我没有尝试过）。一个替代方法是使用Base64 NSData类别，FrançoisP.引用并以某种方式将其作为Base64发送到JavaScript。

Once you have the NSData, you could write it to your Documents directory using writeToFile:atomically:, and then I believe you can pass it in as a local URL (although I've not tried this). An alternative is to use the Base64 NSData category that François P. references and somehow send it to JavaScript as Base64.

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