iOS：使用自定义分辨率保存图像 [英] iOS : Save image with custom resolution

问题描述

您好我尝试捕获视图然后将其另存为照片库，但我需要为捕获的图像创建自定义分辨率，这是我的代码，但是当应用程序保存图像时分辨率很低！

Hi I am try to capture a view then save as an image into Photo Library , but I need create a custom resolution for captured image , here is my code but when app saves the images the resolution is low !

UIGraphicsBeginImageContextWithOptions(self.captureView.bounds.size, self.captureView.opaque, 0.0);

[self.captureView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * screenshot = UIGraphicsGetImageFromCurrentImageContext();

CGRect cropRect = CGRectMake(0 ,0 ,1435 ,1435);
CGImageRef imageRef = CGImageCreateWithImageInRect([screenshot CGImage], cropRect);
CGImageRelease(imageRef);

UIImageWriteToSavedPhotosAlbum(screenshot , nil, nil, nil);

UIGraphicsEndImageContext();

但iPhone的分辨率为：320 x 320，视网膜为：640 x 640

but the resolution in iPhone is : 320 x 320 and retina is : 640 x 640

如果您帮助我解决此问题，我将不胜感激。

I would be grateful if you help me to fix this issue .

推荐答案

您的代码非常接近。您需要做的是以自定义分辨率重新渲染屏幕截图。我修改了你的代码：

Your code is pretty close. What you need to do is re-render the screenshot at the custom resolution. I modified your code to do this:

UIView* captureView = self.view;

/* Capture the screen shoot at native resolution */
UIGraphicsBeginImageContextWithOptions(captureView.bounds.size, captureView.opaque, 0.0);
[captureView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * screenshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

/* Render the screen shot at custom resolution */
CGRect cropRect = CGRectMake(0 ,0 ,1435 ,1435);
UIGraphicsBeginImageContextWithOptions(cropRect.size, captureView.opaque, 1.0f);
[screenshot drawInRect:cropRect];
UIImage * customScreenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

/* Save to the photo album */
UIImageWriteToSavedPhotosAlbum(customScreenShot , nil, nil, nil);

请注意，如果捕获视图不是方形，则图像将会失真。保存的图像将始终为方形和1435x1435像素。

Note that if capture view is not square then the image will be distorted. The saved image will always be square and 1435x1435 pixels.

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