core-graphics

I have a CGImage (core graphics, C/C++). It's grayscale. Well, originally it was B/W, but the CGImage may be RGB. That shouldn't matter. I want to create a CCITT-Group 4 TIFF. I can create an LZW TIFF (grayscale or color) via creating a destination with the correct dictionary and adding the image in. No problem. However, there doesn't seem to be an equivalent kCGImagePropertyTIFFCompression value to represent CCITT-4. It should be 4, but that produces uncompressed. I have a manual CCITT compression routine, so if I can get the binary (1 bit per pixel) data, I'm set. But I can't seem to get 1

I've tried to build reading RGB pixel data in Swift. Getting the basic Image Information is no problem, but I think I've got something wrong with the pointer and the byte-offset: let provider:CGDataProviderRef = CGImageGetDataProvider(inImage) let data:NSData = CGDataProviderCopyData(provider) let bytes: COpaquePointer = data.bytes // Needs to be changed to ConstUnsafePointer<()> in xCode beta3 let bytePointer = UnsafePointer<UInt8>(bytes) println("Pixel Data:\n") var printString:String = "" for var row:Int = 0; row < Int(height); row++ { for var col:Int = 0; col < Int(width); col++ { var

I'm creating an image offscreen using a context from CGBitmapContextCreate() . While drawing text, I tried to use the: CGContextSetTextMatrix(contextRef, CGAffineTransformMake(1.0, 0.0, 0.0, -1.0, 0.0, 0.0)); but my text was still upside down. If I used the standard transforms it was correct: CGContextTranslateCTM(contextRef, 0.0, contextRect.size.height); CGContextScaleCTM(contextRef, 1.0, -1.0); My question is should the CGContextSetTextMatrix work for an offscreen bitmap? Maybe I was doing something wrong. No. The text matrix, as its name says, only affects text. All drawing goes through

I have a UIBezierPath inside custom UIView , draw() . I want to fill that path, lets say a rectangle from bottom to top. How can I implement this. From Here I have seen using CAShapeLayer its possible. That is working fine with animation but filling is not happening from bottom to top on the rectangle. Please guide. Is this what you are asking for? func zoom() { let startPath = UIBezierPath(rect: CGRect(x: 0, y: self.frame.size.height-30, width: self.frame.size.width, height: 30)) let endPath = UIBezierPath(rect: CGRect(x: 0, y: 0, width: self.frame.size.width, height: self.frame.size.height))

For generating PDF files we can use Core Graphics. Similarly is there any framework / class that can be used for generating .ppt (power point presentation) files via code ? Or is there any third party framework for this purpose. There's no in-built Apple API, and I've never heard of a third-party framework for this. Seems there are still no open source solutions for this for iOS platform. Aspose seems to have something and another commercial that pretty recently emerged - libpptx.com , at least it provides some generic functionality to craft pptx 来源： https://stackoverflow.com/questions

Our product contains a kind of software image decoder that essentially produces full-frame pixel data that needs to be rapidly copied the screen (we're running on iOS). Currently we're using CGBitmapContextCreate and we access the memory buffer directly, then for each frame we call CGBitmapContextCreateImage, and then draw that bitmap to the screen. This is WAY too slow for full-screen refreshes on the iPad's retina display at a decent framerate (but it was okay for non-Retina-devices). We've tried all kinds of OpenGL ES-based approaches, including the use of glTexImage2D and glTexSubImage2D