blocks|key|241048|text|我可以建议你试试GPU+Image。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|241049|https://github.com/BradLarson/GPUImage|offset|length|241050|它使用openGL，所以速度相当快。它可以处理来自相机的图片，并为它们添加过滤器(有很多)，包括边缘检测，运动检测等等|241051|它类似于OpenCV，但根据我自己的经验，GPU+image更容易与你的项目连接，而且语言是objective-c。|241052|如果您决定将box2d用于物理-+is也使用openGl，则可能会出现问题，您将需要花费一些时间，直到这两个框架停止战斗))|241053|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|12|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@$D|U|E|V|1|W]]|A|$]]|$1|F|3|G|5|6|7|X|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|Z|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|C]]]]

I can advise you to try GPU Image.

<a href="https://github.com/BradLarson/GPUImage" rel="noreferrer">https://github.com/BradLarson/GPUImage</a>

It uses openGL, so it's rather fast. It can process pictures from camera and add filters to them (there are lot of them) including edge detection, motion detection and a far more

It's like OpenCV but based on my own experience GPU image is easier to connect with your project and the language is objective-c. 

Problem could appear if you decided to use box2d for physics - is uses openGl too and you will need to spent some time till this 2 frameworks will stop fighting))

blocks|key|242107|text|我喜欢@Roma关于使用GPU+Image的建议--好主意。。。。但是，如果您想要一种纯CocoaTouch方法，下面是要做的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|242108|实现AVCaptureVideoDataOutputSampleBufferDelegate的|242109|-+(void)captureOutput:(AVCaptureOutput+*)captureOutput+didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
fromConnection:(AVCaptureConnection+*)connection
{
++++//+Create+a+UIImage%2BOrientation+from+the+sample+buffer+data
++++if+(_captureFrame)
++++{
++++++++[captureSession+stopRunning];

++++++++_captureFrame+=+NO;
++++++++UIImage+*image+=+[ImageTools+imageFromSampleBuffer:sampleBuffer];
++++++++image+=+[image+rotate:UIImageOrientationRight];

++++++++_frameCaptured+=+YES;

++++++++if+(delegate+!=+nil)
++++++++{
++++++++++++[delegate+cameraPictureTaken:image];
++++++++}
++++}
}|code-block|syntax|javascript|242110|如下所示的捕获：|offset|length|style|BOLD|242111|%2B+(UIImage+*)+imageFromSampleBuffer:(CMSampleBufferRef)+sampleBuffer+
{
++++//+Get+a+CMSampleBuffer's+Core+Video+image+buffer+for+the+media+data
++++CVImageBufferRef+imageBuffer+=+CMSampleBufferGetImageBuffer(sampleBuffer);+
++++//+Lock+the+base+address+of+the+pixel+buffer
++++CVPixelBufferLockBaseAddress(imageBuffer,+0);+

++++//+Get+the+number+of+bytes+per+row+for+the+pixel+buffer
++++void+*baseAddress+=+CVPixelBufferGetBaseAddress(imageBuffer);+

++++//+Get+the+number+of+bytes+per+row+for+the+pixel+buffer
++++size_t+bytesPerRow+=+CVPixelBufferGetBytesPerRow(imageBuffer);+
++++//+Get+the+pixel+buffer+width+and+height
++++size_t+width+=+CVPixelBufferGetWidth(imageBuffer);+
++++size_t+height+=+CVPixelBufferGetHeight(imageBuffer);+

++++//+Create+a+device-dependent+RGB+color+space
++++CGColorSpaceRef+colorSpace+=+CGColorSpaceCreateDeviceRGB();+

++++//+Create+a+bitmap+graphics+context+with+the+sample+buffer+data
++++CGContextRef+context+=+CGBitmapContextCreate(baseAddress,+width,+height,+8,+
+++++++++++++++++++++++++++++++++++++++++++++bytesPerRow,+colorSpace,+kCGBitmapByteOrder32Little+%7C+kCGImageAlphaPremultipliedFirst);+
++++//+Create+a+Quartz+image+from+the+pixel+data+in+the+bitmap+graphics+context
++++CGImageRef+quartzImage+=+CGBitmapContextCreateImage(context);+
++++//+Unlock+the+pixel+buffer
++++CVPixelBufferUnlockBaseAddress(imageBuffer,0);

++++//+Free+up+the+context+and+color+space
++++CGContextRelease(context);+
++++CGColorSpaceRelease(colorSpace);

++++//+Create+an+image+object+from+the+Quartz+image
++++UIImage+*image+=+[UIImage+imageWithCGImage:quartzImage];

++++//+Release+the+Quartz+image
++++CGImageRelease(quartzImage);

++++return+(image);
}|242112|将UIImage与overlay混合|242113|242114|现在您有了UIImage，请将其添加到新的UIView中。|unordered-list-item|242115|将覆盖添加到顶部作为子视图。|242116|242117|捕获新的UIView|242118|%2B+(UIImage*)imageWithView:(UIView*)view
{
++++UIGraphicsBeginImageContextWithOptions(view.bounds.size,+view.opaque,+[UIScreen++++mainScreen].scale);
++++[view.layer+renderInContext:UIGraphicsGetCurrentContext()];
++++UIImage*+img+=+UIGraphicsGetImageFromCurrentImageContext();
++++UIGraphicsEndImageContext();
++++return+img;
}|242119|entityMap^0|0|0|0|0|8|0|0|0|I|0|0|0|T|0|0|E|0|0|0|A|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|16|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|17|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|18|8|@$K|19|L|1A|M|N]]|9|@]|A|$]]|$1|O|3|P|5|F|7|1B|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|1C|8|@$K|1D|L|1E|M|N]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]|$1|T|3|U|5|V|7|1G|8|@$K|1H|L|1I|M|N]]|9|@]|A|$]]|$1|W|3|X|5|V|7|1J|8|@$K|1K|L|1L|M|N]]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1M|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|1N|8|@$K|1O|L|1P|M|N]]|9|@]|A|$]]|$1|11|3|12|5|F|7|1Q|8|@]|9|@]|A|$G|H]]|$1|13|3|-4|5|6|7|1R|8|@]|9|@]|A|$]]]|14|$]]

I like @Roma's suggestion of using GPU Image - great idea. . . . however if you want a pure CocoaTouch approach, here's what to do: 

Implement AVCaptureVideoDataOutputSampleBufferDelegate

<pre><code>- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
fromConnection:(AVCaptureConnection *)connection
{
 // Create a UIImage+Orientation from the sample buffer data
 if (_captureFrame)
 {
 [captureSession stopRunning];

 _captureFrame = NO;
 UIImage *image = [ImageTools imageFromSampleBuffer:sampleBuffer];
 image = [image rotate:UIImageOrientationRight];

 _frameCaptured = YES;

 if (delegate != nil)
 {
 [delegate cameraPictureTaken:image];
 }
 }
}
</code></pre>

Capture as Follows:

<pre><code>+ (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer 
{
 // Get a CMSampleBuffer's Core Video image buffer for the media data
 CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
 // Lock the base address of the pixel buffer
 CVPixelBufferLockBaseAddress(imageBuffer, 0); 

 // Get the number of bytes per row for the pixel buffer
 void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); 

 // Get the number of bytes per row for the pixel buffer
 size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
 // Get the pixel buffer width and height
 size_t width = CVPixelBufferGetWidth(imageBuffer); 
 size_t height = CVPixelBufferGetHeight(imageBuffer); 

 // Create a device-dependent RGB color space
 CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

 // Create a bitmap graphics context with the sample buffer data
 CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, 
 bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); 
 // Create a Quartz image from the pixel data in the bitmap graphics context
 CGImageRef quartzImage = CGBitmapContextCreateImage(context); 
 // Unlock the pixel buffer
 CVPixelBufferUnlockBaseAddress(imageBuffer,0);

 // Free up the context and color space
 CGContextRelease(context); 
 CGColorSpaceRelease(colorSpace);

 // Create an image object from the Quartz image
 UIImage *image = [UIImage imageWithCGImage:quartzImage];

 // Release the Quartz image
 CGImageRelease(quartzImage);

 return (image);
}
</code></pre>

Blend the UIImage with the overlay

<ul>
<li>Now that you have the UIImage, add it to a new UIView. </li>
<li>Add the overlay on top as a sub-view. </li>
</ul>

Capture the new UIView

<pre><code>+ (UIImage*)imageWithView:(UIView*)view
{
 UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, [UIScreen mainScreen].scale);
 [view.layer renderInContext:UIGraphicsGetCurrentContext()];
 UIImage* img = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();
 return img;
}
</code></pre>

This seems like a simple task, yet it is driving me nuts. Is it possible to convert a UIView containing AVCaptureVideoPreviewLayer as a sublayer into an image to be saved? I want to create an augmented reality overlay and have a button save the picture to the camera roll. Holding the power button + home key captures the screenshot to the camera roll, meaning that all of my capture logic is working, AND the task is possible. But I cannot seem to be able to make it work programmatically. 

I'm capturing a live preview of the camera's image using AVCaptureVideoPreviewLayer . All of my attempts to render the image fail:

<pre><code> previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:captureSession];
//start the session, etc...


//this saves a white screen
- (IBAction)saveOverlay:(id)sender {
 NSLog(@"saveOverlay");

 UIGraphicsBeginImageContext(appDelegate.window.bounds.size);
 UIGraphicsBeginImageContext(scrollView.frame.size);

 [previewLayer.presentationLayer renderInContext:UIGraphicsGetCurrentContext()];


// [appDelegate.window.layer renderInContext:UIGraphicsGetCurrentContext()];

 UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();

 UIImageWriteToSavedPhotosAlbum(screenshot, self, 
 @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
</code></pre>

//this renders everything, EXCEPT for the preview layer, which is blank. 

<pre><code>[appDelegate.window.layer renderInContext:UIGraphicsGetCurrentContext()];
</code></pre>

I've read somewhere that this may be due to security issues of the iPhone. Is this true?

Just to be clear: I don't want to save the image for the camera. I want to save the transparent preview layer superimposed over another image, thus creating transparency. Yet for some reason I cannot make it work.

Is it possible to render AVCaptureVideoPreviewLayer in a graphics context?

增强现实

这似乎是一项简单的任务，但它快把我逼疯了。是否可以将包含AVCaptureVideoPreviewLayer作为子层的UIView转换为要保存的图像？我想创建增强现实覆盖图，并使用按钮将图片保存到相机胶卷中。按住电源按钮+Home键可以将屏幕截图捕捉到相机胶卷上，这意味着我的所有捕捉逻辑都在工作，并且任务是可能的。但我...

问可以在图形环境中呈现AVCaptureVideoPreviewLayer吗？
EN

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问可以在图形环境中呈现AVCaptureVideoPreviewLayer吗？EN

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问可以在图形环境中呈现AVCaptureVideoPreviewLayer吗？
EN