CODEWITHSUNDEEP
ioscore-graphics
RK-
RK-

Reputation: 12221

Why does a dot occurs in joints of lines drawn using core graphics in iOS?

I am using the below code to draw a polygon. The image I get is below:

enter image description here

The code I am using for drawing the square is below:

CGContextRef currentContext = UIGraphicsGetCurrentContext();
[topLeftBoxBorderColor set];
CGContextSetLineWidth(currentContext, 1.0f);
CGContextSetLineJoin(currentContext,kCGLineJoinMiter);
CGContextMoveToPoint(currentContext, originXOfSubviews, originYOfSubviews);
CGContextAddLineToPoint(currentContext, originXOfSubviews+widthOfBox, originYOfSubviews);
CGContextAddLineToPoint(currentContext, originXOfSubviews+widthOfBox, originYOfSubviews+heightOfBox);
CGContextAddLineToPoint(currentContext, originXOfSubviews, originYOfSubviews+heightOfBox);
CGContextAddLineToPoint(currentContext, originXOfSubviews, originYOfSubviews);
CGContextStrokePath(currentContext);

There is a white dot at the junction of two lines in all corners. Is there any way to avoid having this dot?

UPDATE 1:

I know the below solution: Based on the line width the , starting point of the line can be changed and achieved what I expect. But is there any other solution?

UPDATE 2:

I am using the below code to draw the polygon

When ever I set the lineWidth to 1 or less than that, the same problem happens. If I set it to 2 or above the problem does not arise.

CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetLineWidth(context, 2.0);

    CGContextSetStrokeColorWithColor(context, topLeftBoxBorderColor.CGColor);

    CGRect rectangle = CGRectMake(originXOfSubviews,originYOfSubviews,widthOfBox,heightOfBox);

    CGContextAddRect(context, rectangle);

    CGContextStrokePath(context);

Upvotes: 0

Views: 194

Answers (1)

Anoop Vaidya
Anoop Vaidya

Reputation: 46543

It is the intersection of both the lines (Horizontal and Vertical).

What you can do is make this line few pixels/points lesser than the total lenght that you are using now. It wont intersect and no dot will come.

EDIT:

Or you can draw square,instead of drawling lines

- (void)drawSquare:(CGRect)rect{
    //Get the CGContext from this view
    CGContextRef context = UIGraphicsGetCurrentContext();
    //Draw a rectangle
    CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
    //Define a rectangle
    CGContextAddRect(context, rect);
    //Draw it
    CGContextFillPath(context); 
}

Upvotes: 2

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