drawrect

问题 I have a UITableViewCell subclass that does its drawing in a drawRect: method. The whole rectangle is custom drawn, including the background. I was able to get very complex cells while keeping the scrolling very smooth. My problem: I call [table deselectRowAtIndexPath:path animated:YES]; whenever the view appears, in order to comply with Apple's HIG. However, no animation occurs. It worked when I had a custom view (created with subviews) that was transparent (so Apple's background would

问题 I am working on a circular progress bar for custom game center achievements view and I have kind of "hit the wall". I am struggling with this for over two hours and still cannot get it to work. The thing is, that I need a circular progress bar, where I would be able to set (at least) the track(fill) image. Because my progress fill is a rainbow like gradient and I am not able to achieve the same results using only code. I was messing with CALayers, and drawRect method, however I wasn't

问题 I am trying to create the circles below in my iOS app. I know how to make the circles but am not entirely sure on how to get the points along the arc. It has to be in code not an image. Below is also the code I currently have. - (void)drawRect:(CGRect)rect { CGPoint point; point.x = self.bounds.origin.x + self.bounds.size.width/2; point.y = self.bounds.origin.y + self.bounds.size.height/2; CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetLineWidth(context, 2.0);

问题 I am trying to draw colored text in my UIView subclass. Right now I am using the Single View app template (for testing). There are no modifications except the drawRect: method. The text is drawn but it is always black no matter what I set the color to. - (void)drawRect:(CGRect)rect { UIFont* font = [UIFont fontWithName:@"Arial" size:72]; UIColor* textColor = [UIColor redColor]; NSDictionary* stringAttrs = @{ UITextAttributeFont : font, UITextAttributeTextColor : textColor };

问题 I am trying to draw colored text in my UIView subclass. Right now I am using the Single View app template (for testing). There are no modifications except the drawRect: method. The text is drawn but it is always black no matter what I set the color to. - (void)drawRect:(CGRect)rect { UIFont* font = [UIFont fontWithName:@"Arial" size:72]; UIColor* textColor = [UIColor redColor]; NSDictionary* stringAttrs = @{ UITextAttributeFont : font, UITextAttributeTextColor : textColor };

问题 I have been doing some experimenting with iOS drawing. To do a practical exercise I wrote a BarChart component. The following is the class diagram (well, I wasnt allowed to upload images) so let me write it in words. I have a NGBarChartView which inherits from UIView has 2 protocols NGBarChartViewDataSource and NGBarChartViewDelegate. And the code is at https://github.com/mraghuram/NELGPieChart/blob/master/NELGPieChart/NGBarChartView.m To draw the barChart, I have created each barChart as a

问题 I have an animation using two views where I would call lockFocus and get at the graphics context of the second NSView with [[NSGraphicsContext currentContext] graphicsPort], and draw. That worked fine until macOS 10.14 (Mojave). Found a reference here: https://developer.apple.com/videos/play/wwdc2018/209/ At 22:40 they talk about the "legacy" backing store that has changed. The above lockFocus and context pattern was big on the screen, saying that that won't work any more. And that is true.

问题 Seem to be having a bit of an issue trying to draw my view into a context. My basic setup is, I have a view controller that owns a UIPageViewController in which I load controllers with views that can be drawn on by the users finger. Basically I have a book that can be drawn in. When the page is turned in the book I save the image by calling - (UIImage *)wholeImage { // Render the layer into an image and return UIGraphicsBeginImageContext(self.bounds.size); [self.layer renderInContext

问题 I have a view which implements freehand drawing, but I have a small problem. I noticed on the iPad 3 that everything went to hell, so I tried to update my drawing code (probably as I should have done in the first place) to only update the portion that was stroked. However, the first stroke after open, and the first stroke after about 10 seconds of idle are extremely slow. After everything is "warmed up" it is smooth as butter and only takes about 0.15ms per drawRect. I don't know why, but the

问题 In my application, a user taps 3 times and an angle will be created by the 3 points that were tapped. It draws the angle perfectly. I am trying to calculate the angle at the second tap, but I think I am doing it wrong (probably a math error). I haven't covered this in my calculus class yet, so I am going off of a formula on wikipedia. http://en.wikipedia.org/wiki/Law_of_cosines Here is what I am trying: Note: First, Second, and Third are CGPoints created at the user's tap. CGFloat xDistA =