I'm trying to implement a custom slider in Cocoa with 5 values. See my demo project, which can be downloaded here: http://s000.tinyupload.com/index.php?file_id=07311576247413689572.
I've subclassed the NSSliderCell and implemented methods like drawKnob:(NSRect)knobRect and drawBarInside:(NSRect)cellFrame flipped:(BOOL)flipped etc.
I'm facing some issues:
I'm not able to position the knob correctly regarding to the background image. I know that I'm able to change the knob's frame, and I've tried doing some calculation to position the knob correctly, but I'm not able to make it work for my custom slider. Could someone please help me with this?
The height of my custom slider background is 41px. In the drawBarInside:(NSRect)cellFrame flipped:(BOOL)flipped I change the height of the frame to 41px as well, but the entire background is not visible. Why?
I've noticed that the included images (the background and knob) are flipped vertically. Why? Note that the border top is darker in the background compared to the bottom, but this is reversed when I draw the background.
I found a mistake in your calculation of the x position of the knob rectangle: You used the height of the image where you should have used the width.
The cell drawing is being clipped to the frame of the control. Maybe you could expand the control frame when your cell awakes.
You need to use the NSImage method drawInRect:fromRect:operation:fraction:respectFlipped:hints:, and pass YES for the respectFlipped: parameter. Apple's controls generally do use flipped coordinates.
Added: Expanding the frame in awakeFromNib doesn't seem to work, the frame gets set back. Here's something that does work. Instead of overriding drawBarInside:flipped:, add this override:
- (void)drawWithFrame:(NSRect)cellFrame inView:(NSView *)controlView
{
NSRect controlFrame = [controlView frame];
float bgHeight = self.backgroundImage.size.height;
if (controlFrame.size.height < bgHeight)
{
controlFrame.size.height = bgHeight;
[controlView setFrame: controlFrame];
}
[self.backgroundImage
drawInRect: [controlView bounds]
fromRect: NSZeroRect
operation: NSCompositeSourceOver
fraction: 1.0
respectFlipped: YES
hints: NULL];
[self drawKnob];
}
Related
Background: I wanted to animate the change in my content along with the orientation. My content position is relative to the self.view.bounds.
Problem: In order to animate the content along with the bounds, I would need to know what would the bounds of the view be at the end. I can hard code it but I hope to find a more dynamic way.
Codes: So all animation takes place in willRotateToInterfaceOrientation as per following:
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
//centering the image
imageView.frame = CGRectMake(self.view.bounds.origin.x + (self.view.bounds.size.width - image.size.width)/2 , self.view.bounds.origin.y + (self.view.bounds.size.height - image.size.height)/2, image.size.width, image.size.height);
NSLog(#"%d",[[UIDevice currentDevice] orientation]);
NSLog(#"%f", self.view.bounds.origin.x);
NSLog(#"%f", self.view.bounds.origin.y);
NSLog(#"%f", self.view.bounds.size.width);
NSLog(#"%f", self.view.bounds.size.height);
}
The bounds are before the orientation change. Thus, this only works if the transformation is 180 degrees. If I were to use didRotateFromInterfaceOrientation, the animation will be after the orientation change which looks awful.
Use willAnimateRotationToInterfaceOrientation:duration: instead. This method gets called from within the rotation animation block, and all the bounds have been set correctly at this point. Docs.
If you want it dynamic then when you initialize imageView, set the autoresizingMask property so that when the imageView's superview resizes on the rotate the margins can auto resize themselves...
imageView = //init imageView
imageView.autoresizingMask = UIViewAutoresizingFlexibleTopMargin|UIViewAutoresizingFlexibleBottomMargin|UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleRightMargin;
//addtional config
This means you only need to set the frame once then the imageView will always adjust itself to stay in the middle.
Check out the UIView class reference http://developer.apple.com/library/ios/ipad/#documentation/uikit/reference/uiview_class/uiview/uiview.html to see what else you can do with the autoresizingMask property
If I'm understanding you correctly, you just need to swap the X/Y coordinates and width/height in you're CGRectMake, to get your future layout for a 90 degree change. If it's 180 degree change, then it's the same as current
CGRectMake(self.view.bounds.origin.y + (self.view.bounds.size.height - image.size.height)/2 , self.view.bounds.origin.x + (self.view.bounds.size.width - image.size.width)/2, image.size.height, image.size.width);
I have a UIView that contains another UIView. The outer UIView draws a border around the inner UIView via drawRect. (The border is too complicated to be drawn via CALayer properties.)
At present, when I animate the resizing of the outer UIView, its drawRect method is called once at the beginning of the animation and the result is stretched or shrunk. This does not look good.
I am looking for a way to either redraw the content at every step of the animation, or find a way to achieve the same visual effect. (The result should be similar to the resizing of a stretchable UIImage.)
You should change view's content type to:
your_view.contentMode = UIViewContentModeRedraw;
And it will redraw each time its frame changes.
I ended up adding subviews with autoresizing masks that kept them positioned correctly during the animation.
You need to send a [UIView setNeedsToDisplay] to the view for every time the frame size is changed, you could try overriding the setFrame: method like
- (void)setFrame:(CGRect)r
{
[super setFrame:r];
[self setNeedsToDisplay];
}
I created a custom view to a button, as I need to implement some highlighting when the mouse is over. The class is very simple, and I already implemented mouseEntered: as well as mouseExited:. The view was registered for tracking in the init method (not sure if it's the best place).
The problem is drawing. I keep an ivar mouseOver, set to YES on mouse enter and NO on mouse exited. The other ivar is for the image, called image. The difference between mouse over or not when it comes to drawing, is the transparency. Here is my drawRect::
- (void)drawRect:(NSRect)dirtyRect
{
[image drawAtPoint:NSMakePoint(0.0,0.0)
fromRect:dirtyRect
operation:NSCompositeCopy
fraction:((mouseOver) ? 1.0 : 0.0)];
}
It works nicely, but only when the mouse first entered, apparently. I guess the problem is that the view is not cleared before drawing the other image. I tried adding:
[[NSColor clearColor] set];
NSRectFillUsingOperation(dirtyRect, NSCompositeClear);
But without success. How can I fix this?
[NSColor clearColor] is a purely transparent color. You probably want to fill using a color with some opacity, like, say, [NSColor whiteColor].
Let's say I have an NSImage that's 100x100. I also have an NSImageView that's 50x50. Is there a way I can place the NSImage at coordinates inside the NSImageView, so I can control which part of it shows? It didn't seem like NSImage had an initWithFrame method...
I did this in my NSImageView subclass, as Andrew suggested.
- (void)drawRect:(NSRect)rect
{
[super drawRect:rect];
NSRect cropRect = NSMakeRect(x, y, w, h);
[image drawAtPoint:NSZeroPoint
fromRect:cropRect
operation:NSCompositeCopy
fraction:1];
}
I don't believe so, but it's trivial to roll your own NSImageView equivalent that supports center/stretch options by drawing the image yourself.
Make your imageview as big as the image, and put it inside a scrollview. Hide the scrollers if you want. No need for subclassing in this case.
NSImageView has a method -setImageAlignment: which lets you control how the image is aligned within the image view. Unfortunately, if you want to display part of the image that doesn't correspond to any of the NSImageAlignment values, you're going to have to draw the image programmatically.
Depends on what your eventual goal is but the easiest thing to me seems to put your NSImageView inside an NSView (or a subclass – doesn't have to be NSScrollView as "#NSResponder" user suggests but this should work well too), set its imageScaling to NSImageScaleProportionallyUpOrDown and its frameSize to image's size. Then you can move your NSImageView freely around the upper view using setFrame:myDesiredFrame. No subclassing, no manual redrawing, etc.
I have a UIImageView that is displaying an image that is wider and taller than the UIImageView is. I would like to pan the image within the view using an animation (so that the pan is nice and smooth).
It seems to me that I should be able to just adjust the bounds.origin of the UIImageView, and the image should move (because the image should paint inside the view with that as its origin, right?) but that doesn't seem to work. The bounds.origin changes, but the image draws in the same location.
What almost works is to change the contentsRect of the view's layer. But this begins as a unit square, even though the viewable area of the image is not the whole image. So I'm not sure how I would detect that the far edge of the image is being pulled into the viewable area (which I need to avoid, since it displays by stretching the edge out to infinity, which looks, well, sub-par).
My view currently has its contentsGravity set to kCAGravityTopLeft via Interface Builder, if that makes a difference (Is it causing the image to move?). No other options seemed to be any better, though.
UPDATE: to be clear, I want to move the image inside the view, while keeping the view in the same spot.
I'd highly recommend enclosing your UIImageView in a UIScrollView. Have the UIImageView display the full image, and set the contentSize on the UIScrollView to be the same as your UIImageView's size. Your window into the image will be the size of the UIScrollView, and by using scrollRectToVisible:animated: you can pan to particular areas on the image in an animated fashion.
If you don't want scroll bars to appear, you can set the showsHorizontalScrollIndicator and showsVerticalScrollIndicatorproperties to NO.
UIScrollView also provides pinch-zooming functionality, which may or may not be useful to you.
Brad Larson pointed me down the right road with his suggestion to put the UIImageView inside a UIScrollView.
In the end I put the UIImageView inside of a UIScrollView, and set the scrollView's contentSize and the imageView's bounds to be the same size as the image in the UIImage:
UIImage* image = imageView.image;
imageView.bounds = CGRectMake(0, 0, image.size.width, image.size.height);
scrollView.contentSize = image.size;
Then, I can animate the scrollView's contentOffset to achieve a nice panning effect:
[UIView beginAnimations:#"pan" context:nil];
[UIView setAnimationDuration:animationDuration];
scrollView.contentOffset = newRect.origin;
[UIView commitAnimations];
In my particular case, I'm panning to a random space in the image. In order to find a proper rect to pan to and a proper duration to get a nice constant speed, I use the following:
UIImage* image = imageView.image;
float xNewOrigin = [TCBRandom randomIntLessThan:image.size.width - scrollView.bounds.size.width];
float yNewOrigin = [TCBRandom randomIntLessThan:image.size.height - scrollView.bounds.size.height];
CGRect oldRect = scrollView.bounds;
CGRect newRect = CGRectMake(
xNewOrigin,
yNewOrigin,
scrollView.bounds.size.width,
scrollView.bounds.size.height);
float xDistance = fabs(xNewOrigin - oldRect.origin.x);
float yDistance = fabs(yNewOrigin - oldRect.origin.y);
float hDistance = sqrtf(powf(xDistance, 2) + powf(yDistance, 2));
float hDistanceInPixels = hDistance;
float animationDuration = hDistanceInPixels / speedInPixelsPerSecond;
I'm using a speedInPixelsPerSecond of 10.0f, but other applications might want to use a different value.