iOS CG help: how to get something to draw (very simple)

[foges]

Hello people, Im an absolute newb here but anyways. I created a new view based application and pasted the following code into the ViewController.m file, what else do i need to do to get it to display:

Code:

- (void)drawRect:(CGRect)rect
{
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGContextClearRect(ctx, rect);
}

Im sorry for the simple question, but i cant seem to find any good CG tutorials

 

[robbieduncan]

What are you expecting that to display? All you are doing is clearing a rectangle back to the background.

 

[lloyddean]

<http://www.cocoadevcentral.com/d/intro_to_quartz_two/>

 

[foges]

oops sorry, incomplete code, here is what i meant to post:

-(void)drawRect:(CGRect)rect
{
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGContextClearRect(ctx, rect);
	CGContextSetRGBFillColor(ctx, 255, 0, 0, 1);
    CGContextFillRect(ctx, CGRectMake(10, 10, 50, 50));
}

Thanks ill check out that link

 

[robbieduncan]

I posted some of my code some time ago that shows how I draw a couple of the iPhone system images in core graphics to get them in different colours. I render into images but the basics are the same.

https://forums.macrumors.com/threads/884715/

 

[PhoneyDeveloper]

Look at the quartz demo example code and then look at the quartz docs. A view controller doesn't get drawn. Only views get drawn.