draw a stroke around the shape, core graphic

Question

I am drawing a shape like following :

- (void)drawRect:(CGRect)rect
{
    // Draw a cross rectagle
    CGContextRef    context     =   UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);
    CGContextMoveToPoint(context, 190, 0);
    CGContextAddLineToPoint(context, 220, 0);
    CGContextAddLineToPoint(context, 310, 90);
    CGContextAddLineToPoint(context, 310, 120);
    CGContextSetFillColorWithColor(context, [UIColor lightGrayColor].CGColor);
    CGContextFillPath(context);
    CGContextRestoreGState(context);
}

I am getting a light-dark cross flag below

enter image description here

Now I would like to draw a stroke around the cross flag I have just drawn

What should I do to achieve this. Please advice me on this issue. Thanks.

WDUK · Accepted Answer · 2012-11-06T20:23:00.660

Surely CGContextDrawPath(context, kCGPathFillStroke); is what you're after

You can adjust the pattern and color using:

CGContextSetStrokePattern
CGContextSetStrokeColor

https://developer.apple.com/library/ios/#documentation/graphicsimaging/reference/CGContext/Reference/reference.html

So, in your case, assuming you want a plain black stroke, you'd have:

- (void)drawRect:(CGRect)rect
{
    CGContextRef    context     =   UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);

    CGContextSetLineWidth(context, 2.0);
    CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);
    CGContextSetFillColorWithColor(context, [UIColor lightGrayColor].CGColor);

    CGContextMoveToPoint(context, 190, 0);
    CGContextAddLineToPoint(context, 220, 0);
    CGContextAddLineToPoint(context, 310, 90);
    CGContextAddLineToPoint(context, 310, 120);
    CGContextClosePath(context);

    CGContextDrawPath(context, kCGPathFillStroke);
    CGContextFillPath(context);

    CGContextRestoreGState(context);
}

Produces:

Reminds me of Kraftwork! Result of drawRect:

I have just added these lines `CGContextSetLineWidth(context, 2.0); CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor); CGContextStrokePath(context);`.However, it does not work. I am sure I am missing something in the middle. Do you have any idea about it ? — tranvutuan, Nov 06 '12 at 18:12

score 0 · Answer 2 · answered Nov 06 '12 at 19:43

- (void)drawRect:(CGRect)rect
{
    // Draw a cross rectagle
    CGContextRef    context     =   UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);

    //New
    CGContextSetLineWidth(context, 2.0);

    CGContextMoveToPoint(context, 190, 0);
    CGContextAddLineToPoint(context, 220, 0);
    CGContextAddLineToPoint(context, 310, 90);
    CGContextAddLineToPoint(context, 310, 120);

    //New
    CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);

    CGContextSetFillColorWithColor(context, [UIColor lightGrayColor].CGColor);
    CGContextFillPath(context);

    //New
    CGContextStrokePath(context);

    CGContextRestoreGState(context);
}

@WDUK :after spending hours to figure it out, I know why your above answer is not working. The reason is when you do CGContextFillPath first, the path is eventually cleared and then you can no long do CGContextStrokePath on it again. Therefore in order to do CGContextFillPath and CGContextStrokePath, we have to do

CGContextDrawPath(context,  kCGPathFillStroke);

After trying it , I am getting the following

enter image description here

Cool, glad you got it working! Do you want me to update my answer for this? — WDUK, Nov 06 '12 at 19:48
Edit done, with screenshot of what I get when I run it. Thanks again :) — WDUK, Nov 06 '12 at 20:24

draw a stroke around the shape, core graphic

2 Answers2