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Questions tagged [cgbitmapcontext]

35 questions
34
votes
8 answers

I am getting unsupported parameter combination CGBitmap error with swift

I am trying to create a CGContext in swift. It compiles but throws an error at runtime. let colorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB() let context:CGContext = CGBitmapContextCreate(nil, 20, 20, 8, 0, colorSpace,…
loopmasta
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3 answers

Handle large images in iOS

I want to allow the user to select a photo, without limiting the size, and then edit it. My idea is to create a thumbnail of the large photo with the same size as the screen for editing, and then, when the editing is finished, use the large photo to…
lingtianlan
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How to use renderInContext: with CGBitmapContextCreate and Retina?

I have manually created a CGBitmapContext: bitmapContext = CGBitmapContextCreate( myImageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big ); And drawing a layer to it: [self.myView.layer…
anna
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2 answers

iPhone: Retina Display Writing Font to a UIImage

Objective-C Answers are fine, I am using MonoTouch for reference. I am writing text on top of a UIImage. Retina displays the font in a choppy way. Looks pixel doubled, which I guess is what's happening. How can I get a crisp Font written to a…
Ian Vink
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1 answer

iOS inverted coordinates chaos

So I am using CGBitmapContext to adapt a software blitter to iOS. I write my data to the bitmap, then I use CoreGraphics functions to write text over the CGBitmapContext. The software blitter uses Upper Left Hand Origin, while the CoreGraphics…
user563948
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invalid data bytes/row:CGBitmapContextCreate: CGContextDrawImage: invalid context 0x0

I'm trying to convert array of images into a video file. In the process I have to fill pixel buffer from selected images. Here is the code snippet: CVPixelBufferLockBaseAddress(pixelBuffer, 0) let pixelData =…
Linkon Sid
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0 answers

Pixel Manipulation in CGBitmapContext depend on the view's superview?

I came across something really strange with while manipulating pixels using CGBitmapContext. Basically I'm changing the Alpha values of PNGs. I have an example where I can successfully Zero the Alpha value of a PNGs pixel EXCEPT when my ImageView's…
LampShade
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1 answer

Replace specific color in CGBitmapContext

How can I replace specific color(RGB value) in CGBitmapContext that has already drawn? Is there any easy way? Thanks in advance.
Jun
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iPhone - Image created with CGBitmapContextCreate as Opengl texture

I want to call CGBitmapContextCreate with texture->data to create a CGContextRef, and create a CGImageRef by CGBitmapContextCreateImage(context). However, the image created is not as expected :( The one created from CGBitmapContextCreateImage: The…
LKS
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error in CGBitmapContextCreate

i'm trying to create UIImage from the sampleBufferData and here what i have in the console : CGBitmapContextCreate: invalid data bytes/row: should be at least 1920 for 8 integer bits/component, 3 components, kCGImageAlphaPremultipliedFirst. :…
OXXY
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1 answer

Invalid parameters in CGBitmapContext constructor

I'm trying to create a blank bitmap in a Xamarin.iOS project using the CGBitmapContext constructor(s). However, no matter what I try I just get the error "System.Exception: Invalid parameters to context creation" Example code: const int width =…
Stuart Whitehouse
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What's the meaning of kCGBitmapByteOrder32Little

What are the meaning all of CGBitmapInfo constants？ typedef CF_OPTIONS(uint32_t, CGBitmapInfo) { kCGBitmapAlphaInfoMask = 0x1F, kCGBitmapFloatInfoMask = 0xF00, kCGBitmapFloatComponents = (1 << 8), kCGBitmapByteOrderDefault = (0 << 12), …
Tryndamere
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iOS custom image crop using paths

I need to implement a custom image crop on iOS and I can't seem to be able to find a technology that will allow me to do that easily. The goal is to have an interface as follows: The idea is to have some sort of path or something around the face…
mcottingham
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Getting an image from a sample buffer

I am trying to capture a screen shot on the ipad while the camera is on. My code looks exactly like the AVCaptureFrames from the Xamarin MonoTouch sample: For some reason, though, I keep getting an Invalid Handler Exception. I have looked at other…
j will
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2 answers

"Invalid Handle" Create CGBitmapContext

I've got a problem with the CGBitmapcontext. I get en error while creating the CGBitmapContext with the message "invalid Handle". Here is my code: var previewContext = new CGBitmapContext(null, (int)ExportedImage.Size.Width,…
Alex
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