I am working on a small application on Mac that I need to create customed cursor and move it. I used NSImageView to implement it. However when I call setFrameOrigin (the same to setFrame) it will leaves images on the previous place.
Here is my code:
#property (nonatomic, strong) NSImageView *eraserView;
this is the define
_eraserView = [[NSImageView alloc] initWithFrame:CGRectMake(100, 100, 32, 32)];
_eraserView.image = [NSImage imageNamed:#"EraserCursor"];
[self.view addSubview:_eraserView];
[_eraserView setHidden:YES];
here is the initialization. Everything goes well until now but:
- (void)setImageatPoint:(NSPoint)point
{
[_eraserView setFrameOrigin:point];
}
- (void)hidePenImage
{
[_eraserView setHidden:YES];
}
- (void)unhidePenImage: (BOOL)isEraser
{
[_eraserView setHidden:NO];
}
These are methods I use to change the state of the NSImageView. They will be called by another class using delegate when corresponding events of trackpad occurs.
However every time I change the state of the NSImageView, it seems like it is drawn on the superview.
I debugged it and found there was no extra subviews. And when I use setHidden it has no effect on those tracks. I think it somehow did something to the CALayer, but I have no idea how to fix it.
Screenshots would help but in general if you move a view or change the area of the view that is drawn, you need to redraw.
To do this it kind of depends on how your drawing happens. Calling setNeedsDisplay may not be enough if your implementation of drawRect only draws a sub rect of the view bounds. Cocoa only draws what it is told to draw.
You can erase sections of the view that should be empty by drawing (filling) where it should be empty. That means drawing a color ( NSColor clearColor if nothing else) in the area that was previously drawn.
Related
I have a Mac OS X (10.9) application with a custom NSView for my main NSWindow's contentView property. The only thing the custom view does is override drawRect: so that it's transparent. Transparency is required so that my NSOpenGLView is visible (see below):
/* Transparent NSView Subclass */
- (void)drawRect:(NSRect)dirtyRect
{
NSLog(#"Drawing Rect");
[[NSColor clearColor] set];
NSRectFillUsingOperation(dirtyRect, NSCompositeClear);
}
The contentView has an NSOpenGLView as a subview, with its surface order set to -1 (it's 'below' the main NSWindow, which is also transparent):
/* NSOpenGLView subclass: */
GLint order = -1;
[self.openGLContext setValues:&order forParameter:NSOpenGLCPSurfaceOrder];
I then instantiate a WebView and place it as a subview of this custom view:
_webview = [[WebView alloc] initWithFrame:frame];
[_webview setMaintainsBackForwardList:NO];
[_webview setTranslatesAutoresizingMaskIntoConstraints:NO];
[_webview setDrawsBackground:NO];
[_window.contentView addSubview:_webview];
The WebView is a small box in the window (on top of the NSOpenGLView) which is used to login to a service. Once login happens it should disappear, showing only the NSOpenGLView.
Here's the problem: when I call [_webview removeFromSuperview]; the contentView does not redraw; therefore, the WebView is still drawn on the screen (although not responsive to mouse or keyboard). If I use my mouse to resize the window that everything is in, the contentView redraws (I see the message in the logs) and the WebView's content disappears.
Also, if I don't add the NSOpenGLView as a subview, the WebView goes away as it should.
Shouldn't the contentView fire a drawRect after a subview is removed? Even when I used setNeedsDisplay: or setNeedsLayout: after removing the WebView the contentView still didn't redraw.
Apple's advice these days is to use Core Animation layers to put normal views on top of OpenGL views.
I suspect that the content view has redrawn itself. It draws clear. What you're seeing is the OpenGL surface behind it. The nearly-raw-VRAM nature of OpenGL surfaces may mean that the web view that was drawn on top of it actually modified the contents of the surface. So, I recommend that you force the OpenGL view to redraw itself. If it draws in its -drawRect:, then it should be enough to send it -setNeedsDisplay:. If you do rendering outside of -drawRect: by manually making the context current, issuing rendering commands, and then calling -flushBuffer, then you'll need to do that.
I want to change background color for many nsview. I override drawRect: on subclass NSview but i don't know how to set background color for myview( is reference IBOUTLET). please help me. Thanks so much
Code for CustomView.h
#import <Cocoa/Cocoa.h>
#interface CustomView : NSView
#end
Code for CustomView.m
#import "CustomView.h"
#implementation CustomView
- (void) drawRect:(NSRect)dirtyRect {
[[NSColor whiteColor] setFill];
NSRectFill(dirtyRect);
[super drawRect:dirtyRect];
}
#end
And in main class, i added #import "CustomView.h" but i don't know how to set background for myview.
Welcome to Cocoa drawing.
Cocoa drawing uses Quartz which is a PDF model.
Drawing in this occurs in a back to front procedural order.
In Quartz drawing there is a drawing environment state object called the Graphics Context.
This is an implicit object in many of the drawing ops in AppKit.
(in Core Graphics or other APIs it could need to be explicitly called)
You tell the Graphics Context what the current color and other parameters are, then draw something, then change parameters and draw more, etc...
In AppKit, you do this by sending a message to the NSColor object, which is weird. but that's how it works.
In your drawRect: method you should call super first usually, because you probably want your drawing on top of that...
- (void) drawRect:(NSRect)dirtyRect {
[super drawRect:dirtyRect];
// This next line sets the the current fill color parameter of the Graphics Context
[[NSColor whiteColor] setFill];
// This next function fills a rect the same as dirtyRect with the current fill color of the Graphics Context.
NSRectFill(dirtyRect);
// You might want to use _bounds or self.bounds if you want to be sure to fill the entire bounds rect of the view.
}
If you want to change the color, you'll need an #property NSColor
You might need more than one for your drawing.
That allows you to set the color.
You might want the view to use KVO and observe its own color property then draw itself if the color property changes.
You could do a lot of different things to set the color. (a button or pallette elsewhere) But all of them would eventually result in sending a message to set the color of a property of your view for drawing.
Finally, if you want to update the drawing, you need to call [myView setNeedsDisplay:YES]; where myView is a reference to an instance of the NSView subclass.
There is also display but that's forceful.
setNeedsDisplay: says to schedule it on the next run of the event loop (runLoop). display kind of makes everything jump to that right away.
The event loop comes back around fast enough you shouldn't force it.
Of note, setNeedsDisplay: is the entire view.
In a fancy ideal world with complex views, you might want to more appropriately optimize things by calling setNeedsDisplayInRect: where you designate a specific CG/NSRect of the view as needing to be redrawn.
This allows the system to focus redrawing to the smallest union rect possible in the window.
I'm super late, but this is how I do it - there's no need to sub class:
NSView *myview = [NSView new];
[view setWantsLayer:YES];
view.layer.backgroundColor = [NSColor greenColor].CGColor;
I'm working on an iPad app that lets you control different things in a prototype of an intelligent house. For example it lets you turn lights on and off. For this, I have made a UIImageView that shows the floor plan of the house and added UIButtons as subviews for each lamp that can be toggled.
As you can see the buttons are placed perfectly on the floor plan using the setFrame method of each UIButton. However, when I rotate the iPad to portrait orientation, the following happens:
The buttons obviously still have the same origin, however it is not relative to the repositioning of the image.
The floor plan image has the following settings for struts and springs:
and has its content mode set to Aspect Fit.
My question is
how do I dynamically reposition each UIButton, such that it has the same relative position. I figure I have to handle this in the {did/should}AutorotateToInterfaceOrientation delegate method.
It should be noted that the UIImageView is zoomable and to handle this I have implemented the scrollViewDidZoom delegate method as follows:
for (UIView *button in _floorPlanImage.subviews) {
CGRect oldFrame = button.frame;
[button.layer setAnchorPoint:CGPointMake(0.5, 1)];
button.frame = oldFrame;
button.transform = CGAffineTransformMakeScale(1.0/scrollView.zoomScale, 1.0/scrollView.zoomScale);
}
Thank you in advance!
I find the best way to layout subviews is in the - (void) layoutSubviews method. You will have to subclass your UIImageView and override the method.
This method will automatically get called whenever your frame changes and also gets called the first time your view gets presented.
If you put all your layout code in this method, it prevents layout fragmentation and repetition, keeps your view code in your views, and most things just work by default.
I'm working on some drawing code. I have that portion working great.
I want to draw over an image, but I want to still be able to see the detail of the image, the black lines, etc.
What I am working on is making a transparent UIImageView that holds the image.
I'm not sure how to get this set up properly though.
Should this be added above the other UIImageView that I color on or below it?
Here's what I have so far:
- (void)viewDidLoad
{
[super viewDidLoad];
topImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 46, 320, 370)];
[topImageView setImage:[UIImage imageNamed:#"imagesmall.png"]];
topImageView.alpha = 1.0;
topImageView.layer.opacity = 1.0;
topImageView.layer.opaque = NO;
[self.view addSubview:topImageView];
[topImageView release];
}
Thoughts anyone?
Yes, you can draw views over other views. They are drawn in the order that they're added as subviews, unless you reorder them after that.
You may need to set the opaque property for some views (this is distinct from and overrides their layer opacity), and set their backgroundColor to nil. UIImageView seems to be transparent by default, as long as its image is; some other UIView subclasses are not.
So, just what is your overlay going to be? If you just need to display one image over another, what you have here seems to work already. If you need to draw some lines programmatically, you'll need to do this:
Create a subclass of UIView.
Implement its drawRect method to display the content you need.
When you add your custom view on top of the background image, make sure it is not opaque and has no backgroundColor.
A common problem here is to find that your foreground is working, but the background isn't being loaded properly. To make sure the background is there, set the alpha of the foreground view to 0.5. You won't want to do that in production, but it will allow you to verify that both views exist.
I have a UIImageView in a UIScrollView in another UIScrollView (based on Apple's
PhotoScroller sample code). When the UIScrollView calls back to its controller to dismiss itself, it calls this method:
- (void)dismiss {
[scrollView removeFromSuperview];
ImageScrollView *isv = [self currentImageScrollView];
UIImage *image = isv.imageView;
image.frame = [self.view convertRect:image.frame fromView:isv];
[self.view insertSubview:image belowSubview:captionView];
[(NSObject *)delegate performSelector:#selector(scrollViewDidClose:)
withObject:self
afterDelay:2.0];
}
Now here's the weird part: the image view jumps to a different position right after this method executes, but before the scollViewDidClose method gets called on the delegate. If the image is larger than its new super view, it jumps so that its left edge is aligned with the left edge of its super view. If it's smaller than its new super view, it jumps to the very center of the view. There is no animation to this change.
So my question is, how do I prevent it from doing that? I've tweaked both the super view (self.view) class and the image view class to see what methods might be called. Neither the frame nor the center is set on the image view after this method is called, and while the layoutSubviews method is called on the super view, that is not what jumps the image to the center or left side of the superview. I've also tried turning off autoResizesSubviews in the super view, and setting the autoresizingMask of the image view to UIViewAutoresizingNone, with no change in behavior.
So where is this happening, and why? And more importantly, how do I make it stop?
I've been beating my head on this for days. Any pointers or guidance would be greatly appreciated.
ImageScrollView is the one centering your UIImageView. Set a breakpoint in ImageScrollView layoutSubviews and you'll see how your UIImageView is being centered.
You're taking ImageScrollView's internal imageView and placing it into another view. That's not going to work because ImageScrollView still retains ownership of that UIImageView instance and is still managing its layout.
You'll either need to copy the image into another UIImageView instance, or you'll need to change ImageScrollView to allow it to relinquish ownership of its imageView.
You're not setting up the frame of the 'image' view when you insert it as a subview. You probably want to do that explicitly if you want the view to appear at a particular position in the scroll view.