Question

When I draw a shape in xcode for ios, how can i change the color of the final drawn shape?

- (void) drawArrowWithContext:(CGContextRef)context atPoint:(CGPoint)startPoint withSize:   (CGSize)size lineWidth:(float)width arrowHeight:(float)aheight
{
float width_wing = (size.width-width)/2;
float main = size.height-aheight;
CGPoint rectangle_points[] =
{
    CGPointMake(startPoint.x + width_wing, startPoint.y + 0.0),
    CGPointMake(startPoint.x + width_wing, startPoint.y + main),
    CGPointMake(startPoint.x + 0.0, startPoint.y + main), // left point
    CGPointMake(startPoint.x + size.width/2, startPoint.y + size.height),

    CGPointMake(startPoint.x + size.width, startPoint.y + main), // right point

    CGPointMake(startPoint.x + size.width-width_wing, startPoint.y + main),

    CGPointMake(startPoint.x + size.width-width_wing, startPoint.y + 0.0),
    CGPointMake(startPoint.x + width_wing, startPoint.y + 0.0),
};

CGContextAddLines(context, rectangle_points, 8);

CGContextFillPath(context);
}

By default the color of this arrow is black, but I would like the user to be able to change it to black, white, or red. How can I do this?

Answer 1

I think what you’re looking for is CGContextSetRGBFillColor or CGContextSetRGBStrokeColor

- (void) drawArrowWithContext:(CGContextRef)context atPoint:(CGPoint)startPoint withSize: (CGSize)size lineWidth:(float)width arrowHeight:(float)aheight andColor:(UIColor *)color
{
float width_wing = (size.width-width)/2;
float main = size.height-aheight;

CGContextSetRGBFillColor(context,color.CGColor);
CGContextSetRGBStrokeColor(context,color.CGColor);

CGPoint rectangle_points[] =
{
    CGPointMake(startPoint.x + width_wing, startPoint.y + 0.0),
    CGPointMake(startPoint.x + width_wing, startPoint.y + main),
    CGPointMake(startPoint.x + 0.0, startPoint.y + main), // left point
    CGPointMake(startPoint.x + size.width/2, startPoint.y + size.height),

    CGPointMake(startPoint.x + size.width, startPoint.y + main), // right point

    CGPointMake(startPoint.x + size.width-width_wing, startPoint.y + main),

    CGPointMake(startPoint.x + size.width-width_wing, startPoint.y + 0.0),
    CGPointMake(startPoint.x + width_wing, startPoint.y + 0.0),
};

CGContextAddLines(context, rectangle_points, 8);

CGContextFillPath(context);
}