I have a view that is drawing "marching ants", a dashed line that moves along an NSBezierPath
Looks like this:
CAAnimation* currentLayerAnimation = [self.marchingBlackLayer animationForKey:NEVER_TRANSLATE(#"linePhase")];
if (currentLayerAnimation == nil)
{
float lineWidth = 0.8 / self.previousZoomLevel;
float lineLengthFloat = 5.0 * lineWidth;
NSNumber* lineLength = [[NSNumber alloc] initWithFloat: lineLengthFloat];
self.marchingBlackLayer.lineWidth = lineWidth;
self.marchingBlackLayer.strokeColor = [[NSColor blackColor] CGColor];
self.marchingBlackLayer.fillColor = [[NSColor clearColor] CGColor];
self.marchingBlackLayer.lineDashPattern = #[lineLength, lineLength];
self.marchingWhiteLayer.lineWidth = lineWidth;
self.marchingWhiteLayer.strokeColor = [[NSColor whiteColor] CGColor];
self.marchingWhiteLayer.fillColor = [[NSColor clearColor] CGColor];
self.marchingWhiteLayer.lineDashPattern = #[lineLength, lineLength];
CABasicAnimation* blackMarchingAntsAnimation;
NSNumber* doubleLineLength = [[NSNumber alloc] initWithFloat: (lineLengthFloat * 2)];
blackMarchingAntsAnimation = [CABasicAnimation animationWithKeyPath:NEVER_TRANSLATE(#"lineDashPhase")];
[blackMarchingAntsAnimation setFromValue:#0.0f];
[blackMarchingAntsAnimation setToValue:doubleLineLength];
[blackMarchingAntsAnimation setDuration:0.5f];
[blackMarchingAntsAnimation setRepeatCount:HUGE_VALF];
CABasicAnimation* whiteMarchingAntsAnimation;
NSNumber* tripleLineLength = [[NSNumber alloc] initWithFloat: (lineLengthFloat * 3) ];
whiteMarchingAntsAnimation = [CABasicAnimation animationWithKeyPath:NEVER_TRANSLATE(#"lineDashPhase")];
[whiteMarchingAntsAnimation setFromValue:lineLength];
[whiteMarchingAntsAnimation setToValue:tripleLineLength];
[whiteMarchingAntsAnimation setDuration:0.5f];
[whiteMarchingAntsAnimation setRepeatCount:HUGE_VALF];
[self.marchingBlackLayer addAnimation:blackMarchingAntsAnimation forKey:NEVER_TRANSLATE(#"linePhase")];
[self.marchingWhiteLayer addAnimation:whiteMarchingAntsAnimation forKey:NEVER_TRANSLATE(#"linePhase")];
}
[self.layer addSublayer:self.marchingBlackLayer];
[self.layer addSublayer:self.marchingWhiteLayer];
Everything is dandy. However, the view that is drawing this path has two parent views.
This View's parent is an NSClipView, who's parent is an NSScrollView subclass.
And just by overriding scrollWheel: in the NSScrollView subclass like so:
- (void)scrollWheel:(NSEvent *)theEvent
{
[super scrollWheel:theEvent];
}
The ants animation disappears.
The scrollWheel: method never gets hit, and if I delete that method and run, the ants appear again.
I am completely baffled how this is possible, and am convinced it must have something to do with threading? Unfortunately drawing is my least knowledgable area of Cocoa, so it's difficult to figure out where to start debugging
EDIT:
Throwing in pictures so ya'll can maybe get a better idea of what I'm talking about
Here is before: (take my word that the dashed line is moving around)
Here is after defining the scrollWheel: override (and that's literally the only difference):
EDIT2: Setting a breakpoint on all exceptions doesn't get hit, and the console doesn't output any warnings or anything
EDIT3: Dispatching the animation creation and adding onto the main thread didn't fix it
Related
I am developing an app that contains lots of custom NSView objects being moved around. I have implemented a gaussian blur background filter for one of the custom NSView subclasses like so:
- (id)init {
self = [super init];
if (self) {
...
CIFilter *saturationFilter = [CIFilter filterWithName:#"CIColorControls"];
[saturationFilter setDefaults];
[saturationFilter setValue:#.5 forKey:#"inputSaturation"];
CIFilter *blurFilter = [CIFilter filterWithName:#"CIGaussianBlur"];
[blurFilter setDefaults];
[blurFilter setValue:#2.0 forKey:#"inputRadius"];
self.wantsLayer = YES;
self.layer.backgroundColor = [NSColor clearColor].CGColor;
self.layer.masksToBounds = YES;
self.layer.needsDisplayOnBoundsChange = YES;
self.layerUsesCoreImageFilters = YES;
[self updateFrame]; //this is where the frame size is set
self.layer.backgroundFilters = #[saturationFilter, blurFilter];
...
return self;
}
else return nil;
}
This works great and creates a gaussian blur effect within the entire contents of the view. The problem is that I do not want the gaussian blur to cover the entire view. There is about an (intentional) 12px padding between the actual size of the NSView and the drawing of its content box:
- (void)drawRect:(NSRect)dirtyRect {
[super drawRect:dirtyRect];
NSColor* strokeColor = [NSColor colorWithRed:.5 green:.8 blue:1 alpha:1];
NSColor* fillColor = [NSColor colorWithRed:.5 green:.8 blue:1 alpha:.2];
...
[strokeColor setStroke];
[fillColor setFill];
NSBezierPath *box = [NSBezierPath bezierPathWithRoundedRect:NSMakeRect(self.bounds.origin.x + 12, self.bounds.origin.y + 12, self.bounds.size.width - 24, self.bounds.size.height - 24) xRadius:6 yRadius:6];
box.lineWidth = 6;
[box stroke];
[box fill];
...
}
The reason for this padding is that there are some pieces of the GUI that inhabit this region and are drawn seamlessly into the containing box. I would like to mask the Blur effect to only have effect on the interior of the drawn box rather than the entire view. Here is what I have tried.
ATTEMPT 1: Create a sublayer
I created a sublayer in the NSView with the appropriately sized frame, and added the blur effect to this sublayer. PROBLEM: The blur effect seems to only apply to the immediate parent layer, so rather than blur the contents behind the NSView, it blurs the contents of the NSView's self.layer (which is basically empty).
ATTEMPT 2: Create a masking layer
I tried to create a masking layer and set it to self.layer.mask. However, since the positions of the GUI content do change (via the DrawRect function), I would need to get a copy of the current layer to use as the masking layer. I tried the following code, but it had no effect.
self.layer.mask = nil;
NSArray *bgFilters = self.layer.backgroundFilters;
self.layer.backgroundFilters = nil;
CALayer *maskingLayer = self.layer.presentationLayer;
self.layer.mask = maskingLayer;
self.layer.backgroundFilters = bgFilters;
ATTEMPT 3: Draw a masking layer directly
I could not find any examples of how to draw directly on a layer. I can not use a static UIImage to mast with, because, as I said above, the mask has to change with user interaction. I was looking for something equivalent to the DrawRect function. Any help would be appreciated.
SO...
It seems to me that the sublayer way would be the best and simplest way to go, if I could just figure out how to change the priority of the blur effect to be the background behind the NSView not the NSView's background layer behind the sublayer.
Well, I would still like to know if there is a more elegant way, but I have found a solution that works. Basically, I have created a masking layer from an NSImage drawn from a modified version of the drawRect function:
- (id)init {
self = [super init];
if (self) {
// SETUP VIEW SAME AS ABOVE
CALayer *maskLayer = [CALayer layer];
maskLayer.contents = [NSImage imageWithSize:self.frame.size flipped:YES drawingHandler:^BOOL(NSRect dstRect) {
[self drawMask:self.bounds];
return YES;
}];
maskLayer.frame = self.bounds;
self.layer.mask = maskLayer;
return self;
}
else return nil;
}
- (void)drawMask:(NSRect)dirtyRect {
[[NSColor clearColor] set];
NSRectFill(self.bounds);
[[NSColor blackColor] set];
// SAME DRAWING CODE AS drawRect
// EXCEPT EVERYTHING IS SOLID BLACK (NO ALPHA TRANSPARENCY)
// AND ONLY NEED TO DRAW PARTS THAT EFFECT THE EXTERNAL BOUNDARIES
}
I draw a series of images to various CALayer sublayers, then add those sublayers to a superlayer:
- (void)renderImagesFromArray:(NSArray *)array {
CALayer *superLayer = [CALayer layer];
for (id object in array) {
CALayer* subLayer = [CALayer layer];
// Disregard...
NSURL *path = [NSURL fileURLWithPathComponents:#[NSHomeDirectory(), #"Desktop", object]];
NSImage *image = [[NSImage alloc] initWithContentsOfURL:path];
[self positionImage:image layer:subLayer];
subLayer.contents = image;
subLayer.hidden = YES;
[superLayer addSublayer:subLayer];
}
[self.view setLayer:superLayer];
[self.view setWantsLayer:YES];
// Show top layer
CALayer *top = superLayer.sublayers[0];
top.hidden = NO;
}
I then call [self positionImage: layer:] to stretch the CALayer to it's maximum bounds (essentially using the algorithm for the CSS cover property), and position it in the center of the window:
- (void)positionImage:(NSImage *)image layer:(CALayer *)layer{
float imageWidth = image.size.width;
float imageHeight = image.size.height;
float frameWidth = self.view.frame.size.width;
float frameHeight = self.view.frame.size.height;
float aspectRatioFrame = frameWidth/frameHeight;
float aspectRatioImage = imageWidth/imageHeight;
float computedImageWidth;
float computedImageHeight;
float verticalSpace;
float horizontalSpace;
if (aspectRatioImage <= aspectRatioFrame){
computedImageWidth = frameHeight * aspectRatioImage;
computedImageHeight = frameHeight;
verticalSpace = 0;
horizontalSpace = (frameWidth - computedImageWidth)/2;
} else {
computedImageWidth = frameWidth;
computedImageHeight = frameWidth / aspectRatioImage;
horizontalSpace = 0;
verticalSpace = (frameHeight - computedImageHeight)/2;
}
[CATransaction flush];
[CATransaction begin];
CATransaction.disableActions = YES;
layer.frame = CGRectMake(horizontalSpace, verticalSpace, computedImageWidth, computedImageHeight);
[CATransaction commit];
}
This all works fine, except when the window gets resized. I solved this (in a very ugly way) by subclassing NSView, then implementing the only method that was actually called when the window resized, viewWillDraw::
- (void)viewWillDraw{
[super viewWillDraw];
[self redraw];
}
- (void)redraw{
AppDelegate *appDelegate = (AppDelegate *)[[NSApplication sharedApplication] delegate];
CALayer *superLayer = self.layer;
NSArray *sublayers = superLayer.sublayers;
NSImage *image;
CALayer *current;
for (CALayer *view in sublayers){
if (!view.isHidden){
current = view;
image = view.contents;
}
}
[appDelegate positionImage:image layer:current];
}
So... what's the right way to do this? viewWillDraw: get's called too many times which means I have to do unnecessary and redundant calculations, and I can't use viewWillStartLiveResize: because I need to constantly keep the image in its correct position. What am I overlooking?
Peter Hosey was right; my original method was clunky, and I shouldn't have been overriding setNeedsDisplayInRect:. I first made sure that I was using an auto layout in my app, then implemented the following:
subLayer.layoutManager = [CAConstraintLayoutManager layoutManager];
subLayer.autoresizingMask = kCALayerHeightSizable | kCALayerWidthSizable;
subLayer.contentsGravity = kCAGravityResizeAspect;
Basically, I set the sublayer's autoResizingMask to stretch both horizontally and vertically, and then set contentsGravity to preserve the aspect ratio.
That last variable I found by chance, but it's worth noting that you can only use a few contentsGravity constants if, like in my case, you're setting an NSImage as the layer's contents:
That method creates an image that is suited for use as the contents of a layer and that is supports all of the layer’s gravity modes. By contrast, the NSImage class supports only the kCAGravityResize, kCAGravityResizeAspect, and kCAGravityResizeAspectFill modes.
Always fun when a complicated solution can be simplified to 3 lines of code.
How can I draw this style of text in Cocoa (OS X)? It seems to be used in several Apple apps including Mail (as pictured above) and several places in Xcode sidebars. I've looked around but haven't been able to find any resources suggesting how to reproduce this specific style of text. It looks like an inset shadow and my first guess was to try using an NSShadow with the blur radius set to a negative value but apparently only positive values are allowed. Any ideas?
I have some code that draws an embossed cell (originally written Jonathon Mah, I believe). It might not do exactly what you want but it'll give you a place to start:
#implementation DMEmbossedTextFieldCell
#pragma mark NSCell
- (void)drawInteriorWithFrame:(NSRect)cellFrame inView:(NSView *)controlView;
{
/* This method copies the three-layer method used by Safari's error page. That's accessible by forcing an
* error (e.g. visiting <foo://>) and opening the web inspector. */
// I tried to use NSBaselineOffsetAttributeName instead of shifting the frame, but that didn't seem to work
const NSRect onePixelUpFrame = NSOffsetRect(cellFrame, 0.0, [NSGraphicsContext currentContext].isFlipped ? -1.0 : 1.0);
const NSRange fullRange = NSMakeRange(0, self.attributedStringValue.length);
NSMutableAttributedString *scratchString = [self.attributedStringValue mutableCopy];
BOOL overDark = (self.backgroundStyle == NSBackgroundStyleDark);
CGFloat (^whenLight)(CGFloat) = ^(CGFloat b) { return overDark ? 1.0 - b : b; };
// Layer 1
[scratchString addAttribute:NSForegroundColorAttributeName value:[NSColor colorWithCalibratedWhite:whenLight(1.0) alpha:1.0] range:fullRange];
[scratchString drawInRect:cellFrame];
// Layer 2
BOOL useGradient = NO; // Safari 5.2 preview has switched to a lighter, solid color look for the detail text. Since we use the same class, use bold-ness to decide
if (self.attributedStringValue.length > 0) {
NSFont *font = [self.attributedStringValue attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL];
if ([[NSFontManager sharedFontManager] traitsOfFont:font] & NSBoldFontMask)
useGradient = YES;
}
NSColor *solidShade = [NSColor colorWithCalibratedHue:200/360.0 saturation:0.03 brightness:whenLight(0.41) alpha:1.0];
[scratchString addAttribute:NSForegroundColorAttributeName value:solidShade range:fullRange];
[scratchString drawInRect:onePixelUpFrame];
// Layer 3 (Safari uses alpha of 0.25)
[scratchString addAttribute:NSForegroundColorAttributeName value:[NSColor colorWithCalibratedWhite:whenLight(1.0) alpha:0.25] range:fullRange];
[scratchString drawInRect:cellFrame];
}
#end
Please don't pick this as the answer I just implemented the above suggestions for fun and put it here because it will probably be useful to someone in the future!
https://github.com/danieljfarrell/InnerShadowTextFieldCell
Following from the advice of indragie and wil-shipley here is a subclass of NSTextFieldCell that draws the text with an inner shadow.
The header file,
// InnerShadowTextFieldCell.h
#import <Cocoa/Cocoa.h>
#interface InnerShadowTextFieldCell : NSTextFieldCell
#property (strong) NSShadow *innerShadow;
#end
Now the implementation file,
// InnerShadowTextFieldCell.m
#import "InnerShadowTextFieldCell.h"
// This class needs the NSString category -bezierWithFont: from,
// https://developer.apple.com/library/mac/samplecode/SpeedometerView/Listings/SpeedyCategories_m.html
#implementation InnerShadowTextFieldCell
- (void)drawInteriorWithFrame:(NSRect)cellFrame inView:(NSView *)controlView {
//// Shadow Declarations
if (_innerShadow == nil) {
/* Inner shadow has not been set, override here with default shadow.
You may or may not want this behaviour. */
_innerShadow = [[NSShadow alloc] init];
[_innerShadow setShadowColor: [NSColor darkGrayColor]];
[_innerShadow setShadowOffset: NSMakeSize(0.1, 0.1)];
/* Trying to find a default shadow radius which will look good for
a label of any size, let's get a rough estimate based on the
hypotenuse of the cell frame. */
[_innerShadow setShadowBlurRadius: 0.0075 * hypot(NSWidth(cellFrame), NSHeight(cellFrame)) ];
}
/* Because we are using the -bezierWithFont: we get a slightly
different path than had we used the superclass to drawn the
text path. This means that the background colour and text
colour looks odd if we use call the superclass's,
-drawInteriorWithFrame:inView: method let's do that
drawing here. Not making the call to super might cause
problems for general use (?) but for a simple label is seems
to work OK */
[self.backgroundColor setFill];
NSRectFill(cellFrame);
NSBezierPath *bezierPath = [self.title bezierWithFont:self.font];
[self.textColor setFill];
[bezierPath fill];
/* The following is inner shadow drawing method is taken from Paint Code */
////// Bezier Inner Shadow
NSShadow *shadow = _innerShadow;
NSRect bezierBorderRect = NSInsetRect([bezierPath bounds], -shadow.shadowBlurRadius, -shadow.shadowBlurRadius);
bezierBorderRect = NSOffsetRect(bezierBorderRect, -shadow.shadowOffset.width, shadow.shadowOffset.height);
bezierBorderRect = NSInsetRect(NSUnionRect(bezierBorderRect, [bezierPath bounds]), -1, -1);
NSBezierPath* bezierNegativePath = [NSBezierPath bezierPathWithRect: bezierBorderRect];
[bezierNegativePath appendBezierPath: bezierPath];
[bezierNegativePath setWindingRule: NSEvenOddWindingRule];
[NSGraphicsContext saveGraphicsState];
{
NSShadow* shadowWithOffset = [shadow copy];
CGFloat xOffset = shadowWithOffset.shadowOffset.width + round(bezierBorderRect.size.width);
CGFloat yOffset = shadowWithOffset.shadowOffset.height;
shadowWithOffset.shadowOffset = NSMakeSize(xOffset + copysign(0.0, xOffset), yOffset + copysign(0.1, yOffset));
[shadowWithOffset set];
[[NSColor grayColor] setFill];
[bezierPath addClip];
NSAffineTransform* transform = [NSAffineTransform transform];
[transform translateXBy: -round(bezierBorderRect.size.width) yBy: 0];
[[transform transformBezierPath: bezierNegativePath] fill];
}
[NSGraphicsContext restoreGraphicsState];
}
#end
This could probably be made more robust but it seems fine for just drawing static labels.
Make sure your change the text color and text background color properties in Interface Builder otherwise you will not be able to see the shadow.
From your screenshot, that looks like text drawn with an inner shadow. Hence, the standard NSShadow method of using a blur radius of 0 won't work because that only draws the shadow under/above the text.
There are two steps to drawing text with an inner shadow.
1. Get the drawing path of the text
To be able to draw a shadow inside the text glyphs, you need to create a bezier path from the string. The Apple sample code SpeedometerView has a category that adds the method -bezierWithFont: to NSString. Run the project to see how this method is used.
2. Fill the path with an inner shadow
Drawing shadows under bezier paths is easy, but drawing a shadow inside one is not trivial. Fortunately, the NSBezierPath+MCAdditions category adds the -[NSBezierPath fillWithInnerShadow:] method to make this easy.
i am new to programming, objective-c (and stackoverflow). I'm learning and moving forward very slowly ;) but then I ran into a problem, which google couldn't solve. I have a single window and a NSview and then added a mouse event that should draw the coordinates into my view, but it doesn't. The funny thing is: it is drawn when the mouse moves over the window buttons of my apps window...
- (void)drawRect:(NSRect)dirtyRect {
NSPoint imagePos = NSMakePoint(0, 0);
NSImage *aImage = [NSImage imageNamed:#"mw_bg01.png"];
[aImage dissolveToPoint:imagePos fraction:1.0];
}
- (void)mouseDown:(NSEvent*)theEvent;{
mouseLoc = [NSEvent mouseLocation];
mousePosX = mouseLoc.x;mousePosY = mouseLoc.y;
NSString* mouseString = [NSString stringWithFormat:#"%d", mousePosX];
NSPoint textPoint = NSMakePoint(5, 5);
NSMutableDictionary *textAttrib = [[NSMutableDictionary alloc] init];
[textAttrib setObject:[NSFont fontWithName:#"Helvetica Light" size:10]
forKey:NSFontAttributeName];
[textAttrib setObject:[NSColor grayColor] forKey:NSForegroundColorAttributeName];
[mouseString drawAtPoint:textPoint withAttributes:textAttrib];
}
I don't know how to go on, any suggestions? Thanks!
You shouldn't do drawing in the -mouseDown: method. Rather, you must do all your drawing in -drawRect: (or methods that you call from -drawRect:). Try something like this:
#interface MyView ()
#property NSPoint lastMousePoint;
#end
#implementation MyView
- (void)drawLastMousePoint
{
NSString *mouseString = NSStringFromPoint(self.lastMousePoint);
NSPoint textPoint = NSMakePoint(5, 5);
NSMutableDictionary *textAttrib = [[NSMutableDictionary alloc] init];
[textAttrib setObject:[NSFont fontWithName:#"Helvetica Light" size:10]
forKey:NSFontAttributeName];
[textAttrib setObject:[NSColor grayColor] forKey:NSForegroundColorAttributeName];
[mouseString drawAtPoint:textPoint withAttributes:textAttrib];
}
- (void)drawRect:(NSRect)dirtyRect
{
NSPoint imagePos = NSMakePoint(0, 0);
NSImage *aImage = [NSImage imageNamed:#"mw_bg01.png"];
[aImage dissolveToPoint:imagePos fraction:1.0];
[self drawLastMousePoint];
}
- (void)mouseDown:(NSEvent*)theEvent;
{
self.lastMousePoint = [theEvent locationInWindow];
[self setNeedsDisplay:YES];
}
#end
When you get a mouse down event, you simply store the location of the mouse down. The drawing is done in -drawLastMousePoint which you call in your -drawRect: method. Since you know you need to redraw anytime the mouse is clicked, you call -setNeedsDisplay: to inform the view that it needs to be redrawn. Note that the redraw doesn't happen immediately, rather, it will happen the next time through the run loop. In other words, you're saying "hey, something changed, and I need to draw my view's contents again. Please call -drawRect: again as soon as possible!"
One other note: +[NSEvent mouseLocation] is really designed for getting the current mouse location outside the event stream. Typically, in a -mouseDown: method, you call -locationInWindow on the NSEvent passed as the argument to the method. If you need to convert to local/view coordinates, you should call [self convertPoint:[theEvent locationInWindow] fromView:nil];.
I'd like to change the fill of a button that I've drawn (I subclassed NSButton)
Here's the code I've got already:
- (void)drawRect:(NSRect)dirtyRect {
// Drawing code here.
// Create the Gradient
NSGradient *fillGradient = [[NSGradient alloc] initWithStartingColor:[NSColor lightGrayColor] endingColor:[NSColor darkGrayColor]];
// Create the path
aPath = [NSBezierPath bezierPath];
[aPath moveToPoint:NSMakePoint(10.0, 0.0)];
[aPath lineToPoint:NSMakePoint(85.0, 0.0)];
[aPath lineToPoint:NSMakePoint(85.0, 20.0)];
[aPath lineToPoint:NSMakePoint(10.0, 20.0)];
[aPath lineToPoint:NSMakePoint(0.0, 10.0)];
[aPath lineToPoint:NSMakePoint(10.0, 0.0)];
[fillGradient drawInBezierPath:aPath angle:90.0];
[fillGradient release];
}
- (void)mouseDown:(NSEvent *)theEvent {
NSGradient *fillGradient = [[NSGradient alloc] initWithStartingColor:[NSColor lightGrayColor] endingColor:[NSColor darkGrayColor]];
[fillGradient drawInBezierPath:aPath angle:-90.0];
}
and I get a EXC_BAD_ACCESS signal. How would I do this ?
The reason for the EXC_BAD_ACCESS is that the following line:
aPath = [NSBezierPath bezierPath];
creates an autoreleased bezierPath which will be released at the end of the current iteration of the run loop. To avoid the error, you'd need to change it to:
aPath = [[NSBezierPath bezierPath] retain];
However, you're approaching the problem from the wrong direction. Drawing should only be done in the -drawRect: method (or methods which are only called from -drawRect:). Instead of trying to draw in your mouseDown: method, you should create a new BOOL instance variable for your class (called, for instance, mouseIsDown) and set that in mouseDown:. Then use that boolean to determine how to fill the button:
- (void)drawRect:(NSRect)aRect {
NSGradient *fillGradient = nil;
if (mouseIsDown)
fillGradient = [[NSGradient alloc] initWithStartingColor:[NSColor lightGrayColor] endingColor:[NSColor darkGrayColor]];
else
fillGradient = [[NSGradient alloc] initWithStartingColor:[NSColor lightGrayColor] endingColor:[NSColor darkGrayColor]];
// Do the rest of your drawRect method
}
- (void)mouseDown:(NSEvent *)theEvent {
mouseIsDown = YES;
[self setNeedsDisplay:YES];
}
- (void)mouseUp:(NSEvent *)theEvent {
mouseIsDown = NO;
[self setNeedsDisplay:YES];
}
This isn't directly related to your question, but your question's title belies a false assumption that I want to address.
Changing the fill to a already drawn NSBezierPath
That's not possible.
In Cocoa, “fill” is a verb, not a property of an object like it is in Illustrator or Lineform. You do not set the fill of a path, nor change it later; you fill the path, and what you change by this is pixels in some unseen backing store. The real-world analogy would be setting up splines on a flat pane of glass, then filling the area bounded by the splines with paint and letting it dry. The “fill” is not a property of the splines; it's the act of pouring paint into the shape they define.
As with the analogy, you cannot remove or alter a fill you have previously done—the paint is stuck to the glass; there's no getting it off*. The only way to accomplish that effect is to re-do the fill with some other color. You can move the splines (create a new path) or add splines (add an intersecting subpath to the existing path) before filling, if you want to only change part of the existing drawing.
All of that applies to all drawing operations, including stroking paths and drawing raster images. Text drawing, too, as that's just another case of filling and/or stroking a path.
*OK, you probably could remove real paint from real glass, either chemically or by scraping. No analogy is perfect. ☺
Retain aPath after you create it, since it will have been autoreleased by the time the mouseDown: message is sent. Just make sure to release it in your class's dealloc or wherever else that it would be appropriate.
Edit:
Refer to Matt Ball's answer instead.