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Questions tagged [cgimage]

CGImage represents a drawable image object in Core Graphics (the low-level procedural drawing API for iOS and Mac OS X).

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Why is cgImage?.cropping rotating the image?

I have written a UICropperViewController and it is working perfectly for images in landscape mode. Images in portrait mode have a huge problem. The following picture shows a simple picture with a yellow crop frame: The cropping result is: Now when…
Mulgard
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How to crop a UIImage without losing it's scale property?

Goal: Crop a UIImage (that starts with a scale property of 2.0) I perform the following code: let croppedCGImage = originalUIImage.cgImage!.cropping(to: cropRect) let croppedUIImage = UIImage(cgImage: croppedCGImage!) This code works, however the…
bearMountain
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Swift 3.0: How to call CGImageCreateWithImageInRect()?

I need to implement this Objective-C code in Swift 3.0 (I'm using Xcode 8 Beta 3): // Note: this code comes from an Obj-C category on UIImage CGImageRef imageRef = CGImageCreateWithImageInRect(self.CGImage, cropRect); UIImage *image = [UIImage…
RobertJoseph
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Turning an NSImage* into a CGImageRef?

Is there an easy way to do this that works in 10.5? In 10.6 I can use nsImage CGImageForProposedRect: NULL context: NULL hints: NULL If I'm not using 1b black and white images (Like Group 4 TIFF), I can use bitmaps, but cgbitmaps seem to not like…
Brian Postow
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Why is my image's Bytes per Row more than its Bytes per Pixel times its Width?

I'm converting images to a MOV file, and had an interesting thing happen to me. I logged my bits per color component, bits per pixel, and bytes per row. Here's my code: NSLog(@"Image width: %d, Height: %d", CGImageGetWidth(image),…
Herm
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Core Graphics CGImage mask not affecting

What I'm essentially trying to do is have a text label 'cut' a text-shaped hole through the view. I've tried using self.mask = uiLabel but those refused to position the text correctly so I'm approaching this through Core Graphics. Here's the code…
Downgoat
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Square thumbnail from UIImagePickerViewController image

In my app the user selects an image or take a picture using UIImagePickerViewController. Once the image was selected I want to display its thumbnail on a square UIImageView (90x90). I'm using Apple's code to create a thumbnail. The problem is the…
douglasd3
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Rotating a CGImage

I have a UIImage that I'm getting from a UIImagePickerController. When I receive the image from the - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info method I put it straight into a…
null0pointer
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What does a correct call to CGImageCreate look like if the data provider for it uses an array created by the app?

I'm trying to create a bitmap in memory as part of a pattern function that a drawLayer:inContext: method (this method is part of the CALayer delegate protocol) will call. The pattern function looks similar to this: static const size_t…
Jim
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UIImage created from CGImageRef fails with UIImagePNGRepresentation

I'm using the following code to crop and create a new UIImage out of a bigger one. I've isolated the issue to be with the function CGImageCreateWithImageInRect() which seem to not set some CGImage property the way I want. :-) The problem is that a…
Ari J.R.
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Generating custom thumbnail from ALAssetRepresentation

My main problem is i need to obtain a thumbnail for an ALAsset object. I tried a lot of solutions and searched stack overflow for days, all the solutions i found are not working for me due to these constraint: I can't use the default thumbnail…
Scakko
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How to create empty/blank UIImage or CGImage and manipulate pixels on it (Xcode)?

I have following problem and only could solve it partially yet. I am working with XCode 3.2.5, developing for iOS 4+. I simply try to create an Image of pre-defined size, manipulate pixels on it and then show the Image in an UIImageView. My view…
EliteTUM
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Drawing image in Swift takes forever

In my app I'm creating an image mapping floats to a pixel value and use it as an overlay on Google Maps, but it takes forever to do, the same thing in Android is almost instant. My code looks like this: private func imageFromPixels(pixels:…
Recusiwe
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Should I use UIImage or CGImage in a Swift iOS App?

All the code I can find revolves around loading images directly into visual controls. However, I have my own cache system (converting a project from another language) and so I as efficient as possible want the following: Load jpg/png images -…
Tom
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Image decompression in iOS 7

The problem of image decompression has been much discussed in Stack Overflow but up to this question there were 0 mentions of kCGImageSourceShouldCacheImmediately, an option introduced in iOS 7 that, in theory, takes care of this problem. From the…
hpique
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