Good evening everyone! Can you please tell me how can I cut an area in UIView so that this area is transparent? Found that you can somehow through the mask, but still did not understand how to do it, it does not work with the implementation.

Layer with the background color is not an option, because gradient background.

    1 answer 1

    Create a UIView UIView like this:

    Header (.h) file:

     #import <UIKit/UIKit.h> @interface TranparentView : UIView - (id)initWithFrame:(CGRect)frame backgroundColor:(UIColor*)color transparentRects:(NSArray*)rects circle:(BOOL)circle;

    Implementation (.m) file:

     #import "TranparentView.h" @implementation TranparentView { NSArray *rectsArray; UIColor *backgroundColor; BOOL isCircle; } - (id)initWithFrame:(CGRect)frame backgroundColor:(UIColor*)color transparentRects:(NSArray*)rects circle:(BOOL)circle { backgroundColor = color; rectsArray = rects; isCircle = circle; self = [super initWithFrame:frame]; if (self) { // Initialization code self.opaque = NO; } return self; } - (void)drawRect:(CGRect)rect { [backgroundColor setFill]; UIRectFill(rect); for (NSValue *holeRectValue in rectsArray) { CGRect holeRect = [holeRectValue CGRectValue]; CGRect holeRectIntersection = CGRectIntersection( holeRect, rect ); if (isCircle) { CGContextRef context = UIGraphicsGetCurrentContext(); if( CGRectIntersectsRect( holeRectIntersection, rect ) ) { CGContextAddEllipseInRect(context, holeRectIntersection); CGContextClip(context); CGContextClearRect(context, holeRectIntersection); CGContextSetFillColorWithColor( context, [UIColor clearColor].CGColor ); CGContextFillRect( context, holeRectIntersection); } } else { [[UIColor clearColor] setFill]; UIRectFill(holeRectIntersection); } } }

    And in your controller, for example, create a TranparentView with settings:

    backgroundColor - the color of the view;

    transparentRects - an array of frames;

    circle (BOOL) - yes - circle / oval, no - square / rectangle.

    So:

     NSArray *transparentRects = @[[NSValue valueWithCGRect:CGRectMake(20, 20, 60, 50)]]; TransparentView *transparentView = [[TransparentView alloc] initWithFrame:CGRectMake(0, 0, 100, 100) backgroundColor:[UIColor greenColor] transparentRects:transparentRects circle:NO]; [self.view addSubview:transparentView];

    You can cut both a circular area and a square one. The code can be improved to suit your needs. Hope this helps you.