Top "Quartz-2d" questions

Quartz 2D is the primary two-dimensional graphics rendering API for Mac OS X, part of the Core Graphics framework.

How to map atan2() to degrees 0-360

atan2(y, x) has that discontinuity at 180° where it switches to -180°..0° going clockwise. How do I map the range …

math quartz-2d atan2
UIView with a Dashed line

What I have: To create this line, I basically have an UIView and I do the following: void setLayerToLineFromAToB(CALayer *…

iphone ios uiview calayer quartz-2d
How to use CGAffineTransformMakeRotation?

I want to draw text use Quartz 2D. The "menu" direction is wrong. I want "Menu" still readable and have 45 …

ios cocoa-touch core-graphics quartz-2d
What's the difference between Quartz Core, Core Graphics and Quartz 2D?

I wonder if someone can distinguish precisely between these? For my understanding, Core Graphics is just a "Framework Package" which …

iphone core-graphics quartz-graphics quartz-2d
Curve text on existing circle

For an application I am building I have drawn 2 circles. One a bit bigger than the other. I want to …

iphone cocoa-touch math quartz-graphics quartz-2d
How can I draw an arrow using Core Graphics?

I need to draw line with arrow on its end in my Draw app. I'm not good in trigonometry, so …

objective-c ios core-graphics quartz-2d
Most efficient way to draw part of an image in iOS

Given an UIImage and a CGRect, what is the most efficient way (in memory and time) to draw the part …

iphone ios uiimage quartz-2d drawrect
CGContext line drawing: CGContextFillPath not working?

Anyone have any idea why CGContextFillPath won't work in the code snippet below? I'm using the following code to draw …

iphone quartz-2d cgcontext
Mac OS X: Drawing into an offscreen NSGraphicsContext using CGContextRef C functions has no effect. Why?

Mac OS X 10.7.4 I am drawing into an offscreen graphics context created via +[NSGraphicsContext graphicsContextWithBitmapImageRep:]. When I draw into this …

objective-c macos cocoa core-graphics quartz-2d
What this error is invalid context 0x0?

I wrote the following code in ViewDidLoad // Implement viewDidLoad to do additional setup after loading the view, typically from a …

ios cocoa-touch cgcontext quartz-2d