When subclassing an CALayer and implementing the drawInContext method, I would assume that any drawing I do within there is all that will show up, but instead if I set (for example) borderWidth/borderColor then CALayer will draw a border on it's own above all my custom drawing code.
This is a CALayer subclass:
#implementation MyCustomCALayer
- (id)init
{
self = [super init];
if(self)
{
[self setNeedsDisplayOnBoundsChange:YES];
}
return self;
}
- (void)drawInContext:(CGContextRef)context
{
CGRect rect = CGContextGetClipBoundingBox(context);
CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
CGContextFillRect(context, rect);
}
#end
Created in a UIView something like:
- (void)ensureLayer
{
if(myLayer)
return;
myLayer = [[[MyCustomCALayer alloc] init] autorelease];
myLayer.borderColor = [UIColor greenColor].CGColor;
myLayer.borderWidth = 1;
myLayer.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.height);
}
- (void)layoutSublayersOfLayer:(CALayer *)layer
{
[super layoutSublayersOfLayer:layer];
[self ensureLayer];
if(![[layer.sublayers objectAtIndex:0] isEqual:myLayer])
[layer insertSublayer:myLayer atIndex:0];
}
What happens, is the MyCustomCALayer fills a rectangle with red, this is what I would expect to see and nothing else, since i've implemented the drawInContext method, but instead I see a red rectangle with a green border on top, always on top, i've tried just about every combination I can think of to get rid of the green border being drawn and cannot figure it out.
My reasoning is I would like to use the borderWidth and borderColor and other properties of the CALayer instead of creating my own properties, because the code that I need to draw contains a border, a fill, etc... but the rendering I need to do is not a simple shape. So the only way i've found around this is to set the borderWidth to 0 and add my own property to my subclass, like myBorderWidth, which is ridiculous.
This is done with the latest iOS SDK, but i'd imagine it's the same for Mac.
Hope this makes sense, any thoughts?
Thanks!
You’re out of luck; CoreAnimation doesn’t support overriding its implementation of rendering for the basic layer properties. Please do file a bug.
Related
I'm trying to draw a green circle using drawRect but I'm getting a black background in the rectangle area around the green circle.
I need bounding rectangle's fill to be transparent.
Here my DrawCircle class:
- (void)drawRect:(CGRect)rect {
UIBezierPath *ballBezierPath = [UIBezierPath rect];
[[UIColor greenColor] setFill];
[ballBezierPath stroke];
self.opaque = NO;
self.backgroundColor = [UIColor clearColor];
}
My research indicated that adding the last two lines for setting opaque and backgroundColor would fix the issue, but it still doesn't work.
Here's where I'm adding the sub view in my ViewController's viewDidLoad method:
CGRect positionFrame = CGRectMake(160,160,200,200);
DrawCircle *drawBallView = [[DrawCircle alloc] initWithFrame:positionFrame];
[view1 addSubview:drawBallView];
Have I missed something or is there a different approach I can take?
There are a few problems with your current approach:
the properties are set too late, after you are actually drawing
you are setting those properties on each draw now, they only need to be set once
changing properties could trigger a redraw, and you'll end up redrawing over and over
you are overwriting drawRect: without a call to super. To make the backgroundColor work to either fill the rectangle yourself with that color, or have the superclass do it.
Move your view configuration to the initializers, drawRect is not a good to do any of that. Implement initWithFrame and initWithCoder (to support Interface Builder.
- (id) initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
[self setupView];
}
return self;
}
- (id) initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
[self setupView];
}
return self;
}
- (void) setupView {
self.opaque = NO;
self.backgroundColor = [UIColor clearColor];
}
OK, here's what I have done:
I have an NSCollectionView
I wanted to be able to enable "selecting" items, and drawing a custom border when an items is selected
I subclassed NSCollectionViewItem (to enable selection)
I subclassed NSView for the NSCollectionViewItem view, in order to draw the border
The code
The view item
#implementation MSLibraryCollectionViewItem
- (void)setSelected:(BOOL)flag
{
[super setSelected:flag];
[(MSLibraryCollectionViewView*)[self view] setSelected:flag];
[(MSLibraryCollectionViewView*)[self view] setNeedsDisplay:YES];
}
The custom view
#implementation MSLibraryCollectionViewView
/***************************************
Initialisation
***************************************/
- (MSLibraryCollectionViewView*)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code here.
}
return self;
}
/***************************************
Drawing
***************************************/
- (void)drawRect:(NSRect)rect
{
if ([self selected]) {
//[[NSColor redColor] setFill];
//NSRectFill(rect);
//[super drawRect:rect];
NSColor* gS = [NSColor colorWithCalibratedRed:0.06 green:0.45 blue:0.86 alpha:1.0];
NSColor* gE = [NSColor colorWithCalibratedRed:0.12 green:0.64 blue:0.94 alpha:1.0];
NSGradient* g = [[NSGradient alloc] initWithStartingColor:gE endingColor:gS];
NSColor *borderColor = [NSColor colorFromGradient:g];
NSRect frameRect = [self bounds];
if(rect.size.height < frameRect.size.height)
return;
NSRect newRect = NSMakeRect(rect.origin.x+5, rect.origin.y+5, rect.size.width-10, rect.size.height-10);
NSBezierPath *textViewSurround = [NSBezierPath bezierPathWithRoundedRect:newRect xRadius:7 yRadius:7];
[textViewSurround setLineWidth:2.0];
[borderColor set];
[textViewSurround stroke];
}
}
However, the seems to be something wrong with drawing. For example:
When resizing the Collection View's container, a weird line appears at the outer box
When an Collection View item is not 100% visible (e.g. because it's been scrolled down), the selection border doesn't appear at all (while I would expect it to draw just the visible portion).
Some Examples
What's going on?
P.S. I'm not a guru with drawing and custom views in Cocoa - so any ideas/help is more than welcome!
You switched from asking about a collection view to talking about an outline view, but I assume that was just a mental hiccup.
When an Outline View item is not 100% visible (e.g. because it's been scrolled down), the selection border doesn't appear at all
(while I would expect it to draw just the visible portion).
That's because of this code in your -drawRect:.
if(rect.size.height < frameRect.size.height)
return;
It's specifically avoiding drawing a partial selection outline.
Regarding the weird line, I doubt that has to do with your collection item view's custom drawing. Does it stop happening if you disable the custom drawing? You could experiment with using an ordinary color rather than using the third-party +colorFromGradient: code you're using.
By the way, this line:
NSRect newRect = NSMakeRect(rect.origin.x+5, rect.origin.y+5, rect.size.width-10, rect.size.height-10);
could be written more simply as:
NSRect newRect = NSInsetRect(rect, 5, 5);
I have a UIButton and i want it to display a triangle. Is there a function to make it a triangle? Since im not using a UIView class im not sure how to make my frame a triangle.
ViewController(m):
- (IBAction)makeTriangle:(id)sender {
UIView *triangle=[[UIView alloc] init];
triangle.frame= CGRectMake(100, 100, 100, 100);
triangle.backgroundColor = [UIColor yellowColor];
[self.view addSubview: triangle];
Do i have to change my layer or add points and connect them to make a triangle with CGRect?
If im being unclear or not specific add a comment. Thank you!
A button is a subclass of UIView, so you can make it any shape you want using a CAShape layer. For the code below, I added a 100 x 100 point button in the storyboard, and changed its class to RDButton.
#interface RDButton ()
#property (strong,nonatomic) UIBezierPath *shape;
#end
#implementation RDButton
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
self.titleEdgeInsets = UIEdgeInsetsMake(30, 0, 0, 0); // move the title down to make it look more centered
self.shape = [UIBezierPath new];
[self.shape moveToPoint:CGPointMake(0,100)];
[self.shape addLineToPoint:CGPointMake(100,100)];
[self.shape addLineToPoint:CGPointMake(50,0)];
[self.shape closePath];
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = self.shape.CGPath;
shapeLayer.fillColor = [UIColor yellowColor].CGColor;
shapeLayer.strokeColor = [UIColor blueColor].CGColor;
shapeLayer.lineWidth = 2;
[self.layer addSublayer:shapeLayer];
}
return self;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if ([self.shape containsPoint:[touches.anyObject locationInView:self]])
[super touchesBegan:touches withEvent:event];
}
The touchesBegan:withEvent: override restricts the action of the button to touches within the triangle.
A view's frame is always a rect, which is a rectangle. Even if you apply a transform to it so it no longer looks like a rectangle, the view.frame property will still be a rectangle -- just the smallest possible rectangle that contains the new shape you have produced.
So if you want your UIButton to look like a triangle, the simplest solution is probably to set its type to UIButtonTypeCustom and then to set its image to be a png which shows a triangle and is transparent outside of the triangle.
Then the UIButton itself will actually be rectangle, but will look like a triangle.
If you want to get fancy, you can also customize touch delivery so that touches on the transparent part of the PNG are not recognized (as I believe they would be by default), but that might be a bit trickier.
I have an NSView with a drawRect
- (void)drawRect:(CGRect)rect {
// Drawing code
NSPoint origin = [self visibleRect].origin;
[[NSGraphicsContext currentContext]
setPatternPhase:NSMakePoint(origin.x, origin.y)];
[[NSColor colorWithPatternImage: self.image] set];
[NSBezierPath fillRect: [self bounds]];
}
It draws my pattern perfectly, but i can see the pattern scroll when i change the the size of my window.
i have tried to set the view isFlipped to YES but that doesn't change anything.
You need to do some off-screen drawing first and then draw that result onto the view. For example you can use a blank NSImage of the exact same size as the view, draw the pattern on that image and then draw that image on the view.
Your code may look something like that:
- (void)drawRect:(NSRect)dirtyRect
{
// call super
[super drawRect:dirtyRect];
// create blank image and lock drawing on it
NSImage* bigImage = [[[NSImage alloc] initWithSize:self.bounds.size] autorelease];
[bigImage lockFocus];
// draw your image patter on the new blank image
NSColor* backgroundColor = [NSColor colorWithPatternImage:bgImage];
[backgroundColor set];
NSRectFill(self.bounds);
[bigImage unlockFocus];
// draw your new image
[bigImage drawInRect:self.bounds
fromRect:NSZeroRect
operation:NSCompositeSourceOver
fraction:1.0f];
}
// I think you may also need to flip your view
- (BOOL)isFlipped
{
return YES;
}
Swift
A lot has changed, now things are easier, unfortunately part of objective-C's patrimony is lost and when it comes to Cocoa, Swift is like an orphan child. Anyways, based on Neovibrant's we can deduct the solution.
Subclass NSView
Override draw method
Call parent method (this is important)
Set a fill on buffer within the bounds of the view
Draw fill on buffer
code
override func draw(_ dirtyRect: NSRect) {
super.draw(dirtyRect)
let bgimage : NSImage = /* Set the image you want */
let background = NSColor.init(patternImage: bgimage)
background.setFill()
bgimage.draw(in: self.bounds, from: NSZeroRect, operation: .sourceOver, fraction: 1.0)
}
EVERYTHING WRITTEN HERE ACTUALLY WORKS RIGHT
EXEPT FOR [UIImage imageNamed:] METHOD USAGE
Implementation
I am using model in witch you have a custom UITableViewCell with one custom UIView set up as Cell's backgroundView.
Custom UIView contains two Cell-sized images (320x80 px), one of which is 100% transparent to half of the view. All elements are set to be Opaque and have 1.0 Alpha property.
I don't reuse Cells because I failed to make them loading different images. Cell's reused one-by-one up to 9 cells overall. So I have 9 reusable Cells in memory.
Cell initWithStyle:reuseIdentifier method part:
CGRect viewFrame = CGRectMake(0.0f, 0.0f, 320.0f, 80.0f);
customCellView = [[CustomCellView alloc] initWithFrame:viewFrame];
customCellView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self setBackgroundView:customCellView];
CustomCellView's initialization method:
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
self.opaque = YES;
self.backgroundColor = [UIColor UICustomColor];
}
return self;
}
Images are being pre-loaded to NSMutableArray as UIImage objects from PNG files with UIImage's imageNamed: method.
They are being set in UITableViewDelegate's method tableView:cellForRowAtIndexPath: and passed through UITableViewCell with custom method to UIView.
And then drawn in UIView's drawRect: overridden method:
- (void)drawRect:(CGRect)rect {
CGRect contentRect = self.bounds;
if (!self.editing) {
CGFloat boundsX = contentRect.origin.x;
CGFloat boundsY = contentRect.origin.y;
CGPoint point;
point = CGPointMake(boundsX, boundsY);
if (firstImage) { [firstImage drawInRect:contentRect blendMode:kCGBlendModeNormal alpha:1.0f]; }
if (secondImage) { [secondImage drawInRect:contentRect blendMode:kCGBlendModeNormal alpha:1.0f]; }
}
}
As you see images are being drawn with drawInRect:blendMode:alpha: method.
Problem
Well, UITableView can't be scrolled at all, it's being struck on every cell, it's chunky and creepy.
Thoughts
Well digging sample code, stackoverflow and forums gave me thought to use OpenGL ES to pre-render images, but, really, is it that hard to make a smooth scrolling?
What's wrong with just using UIImageViews? Are they not fast enough? (They should be if you're preloading the UIImages).
One thing to note is that [UIImage imageNamed:] won't explicitly load the image data into memory. It'll give you a reference which is backed by the data on disk. You can get around this by making a call to [yourImage CGImage].