You simply want to be able to draw lines on a graphics context.
Retrieve the handle to your graphics context and then use the
CGContextAddLineToPoint functions to draw
When we talk about drawing shapes in iOS or OS X, we are implicitly talking about paths. What are paths, you may ask? A path is constructed from one or more series of points drawn on a screen. There is a big difference between paths and lines. A path can contain many lines, but a line cannot contain many paths. Think of paths as series of points—it’s as simple as that.
Lines have to be drawn using paths. Specify the start and end points, and then ask Core Graphics to fill that path for you. Core Graphics realizes that you have created a line on that path, and will paint that path for you using the color that you specified (see Recipe 15.3).
We will be talking about paths more in-depth later (see Recipe 15.6), but for now let’s focus on using paths to create straight lines. To do this, follow these steps:
Choose a color on your graphics context (see Recipe 15.3).
Retrieve the handle to the
graphics context, using the
Set the starting point for your line using the
Move your pen on the graphics context using the
CGContextAddLineToPoint procedure to
specify the ending point of your line.
Create the path that you have laid out using the
CGContextStrokePath procedure. This procedure ...