drawrect

filling a path with a solid color is easy enough: CGPoint aPoint; for (id pointValue in points) { aPoint = [pointValue CGPointValue]; CGContextAddLineToPoint(context, aPoint.x, aPoint.y); } [[UIColor redColor] setFill]; [[UIColor blackColor] setStroke]; CGContextDrawPath(context, kCGPathFillStroke); I'd like to draw a gradient instead of solid red, but I am having trouble. I've tried the code listed in the Question/Answer: Gradients on UIView and UILabels On iPhone which is: CAGradientLayer *gradient = [CAGradientLayer layer]; [gradient setFrame:rect]; [gradient setColors:[NSArray

I would like to have a UIView subclass that implements a method similar to setNeedsDisplay , except that redrawing (i.e., that would usually be called via drawRect: ) will occur in a background thread sometime soonish, rather than at the end of the current update cycle. It might be called setNeedsAsynchronousDisplay . Or the existing setNeedsDisplay could get hijacked and not cause redraw at the end of the cycle, or whatever, as long as it lets the redraw not happen on the main thread blocking screen updating an interaction until its completed. Until the redraw occurs, the view can continue to

I am subclassing a UIView and overwrite the drawRect method. I'm noticing that the view's drawrect is only being called when the view first loads. After that it is never called again. How to I make sure it gets called after an orientation change? I've tried calling setNeedsDisplay on the view before and after the rotation and that doesn't do it. [myView setContentMode:UIViewContentModeRedraw]; You can set this in IB as well (i.e., set mode to "redraw") This was a bug related to something completely different. setNeedsDisplay does indeed cause drawRect to be called. to answer this and the other

I am looking to draw a UILabel (preferable through subclassing) as a transparent label, but with solid background. I draw up an quick example (sorry, it's ugly, but it gets the points across :)). Basically I have a UILabel and I would like the background to be a set colour, and the text should be transparent. I do not want to colour the text with the views background, but instead have it be 100% transparent, since I have a texture in the background that I want to make sure lines up inside and outside of the label. I've been spending the night browsing SO and searching on Google, but I have

I have an UIImage which I want to draw on a UIView . But instead of creating an UIImageView and adding this as a subview, I want to overwrite -drawRect: and draw my UIView directly. For example, my code looks like: - (void)drawRect:(CGRect)rect { CGContextRef myContext = UIGraphicsGetCurrentContext(); UIImage *img = [UIImage imageNamed:@"foo.png"]; // how to draw the directly into the view now? } Call [img drawInRect:rect]; . BTW, you shouldn't load the image file in the drawRect method. Because the method is called whenever the view is required to update. Therefore, it (of course, loading

I searched everywhere but didn't find the solution. I have image 1. How can I programatically tint them with gradient to get images 2 and 3? Here are those images: Tints that I applied to them via Photoshop are simple 2-color linear gradients. And my question is: how can I achieve this effect programatically? Solution: jrtc27 gave me almost working example. I fixed it (for ARC) and made it reusable (using UIImage's category). Here is it: - (UIImage *)tintedWithLinearGradientColors:(NSArray *)colorsArr { CGFloat scale = self.scale; UIGraphicsBeginImageContext(CGSizeMake(self.size.width * scale,

I have to create a custom UIView that will have round corners, a border, a shadow and its drawRect() method is overridden to provide custom drawing code with which several straight lines are drawn into the view (I need to use a fast, lightweight approach here since many of these views may be rendered). The problem I'm currently facing is that the shadow doesn't apply anymore to the round corners as soon as I override drawRect() in the view class (even without any custom code yet in it). See the attached image for the difference: In the view controller I'm using the following code: view.layer

Given an UIImage and a CGRect , what is the most efficient way (in memory and time) to draw the part of the image corresponding to the CGRect (without scaling)? For reference, this is how I currently do it: - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGRect frameRect = CGRectMake(frameOrigin.x + rect.origin.x, frameOrigin.y + rect.origin.y, rect.size.width, rect.size.height); CGImageRef imageRef = CGImageCreateWithImageInRect(image_.CGImage, frameRect); CGContextTranslateCTM(context, 0, rect.size.height); CGContextScaleCTM(context, 1.0, -1.0);