Top "Core-graphics" questions

Core Graphics is Apple's framework for low-level drawing operations on Mac OS X and iOS.

How do I create a smoothly resizable circular UIView?

I'm trying to create a UIView which shows a semitransparent circle with an opaque border inside its bounds. I want …

uiview core-graphics uiviewanimation
Why does my CGContext-drawn circle suck?

I have a custom table view cell that is intended to draw a circle like the iPhone’s Mail.app …

iphone objective-c core-graphics cgcontext
Access C Array within blocks (variable array count) Objective-C

Blocks are fine but what about writing C arrays? Given this simplified situation: CGPoint points[10]; [myArray forEachElementWithBlock:^(int idx) { points[…

objective-c struct core-graphics objective-c-blocks arrays
Performance when frequently drawing CGPaths

I am working on an iOS App that visualizes data as a line-graph. The graph is drawn as a CGPath …

objective-c ios core-graphics cgpath
Is there a way to calculate the CGAffineTransform needed to transform a view from frame A to frame B?

Say, I have two CGRects, CGRect A and CGRect B. My UIView's frame is the same as CGRect B, but …

ios core-graphics linear-algebra
Detecting tap inside a bezier path

I have a UIView which is added as a subview to my view controller. I have drawn a bezier path …

ios objective-c core-graphics uibezierpath
Turn two CGPoints into a CGRect

How can I, given two different CGPoints, turn them into an CGRect? Example: CGPoint p1 = CGPointMake(0,10); CGPoint p2 = CGPointMake(10,0); How …

ios iphone core-graphics cgrect cgpoint
CGAffineTransformIdentity not resetting a UIImageView after multiple transforms?

I have created a simple app with a segmented control at the top. When I click on one of two …

ios objective-c core-graphics cgaffinetransform
CGContext: how do I erase pixels (e.g. kCGBlendModeClear) outside of a bitmap context?

I'm trying to build an eraser tool using Core Graphics, and I'm finding it incredibly difficult to make a performant …

ios objective-c core-graphics cgcontext
Rotate CGImage taken from video frame

This is Apple's code (from Technical Q&A QA1702) for getting a UIImage from a video buffer. Unfortunately, the …

iphone core-graphics quartz-2d avfoundation