I'm wondering what the dropdown "Mode" is about? It contains "Scale to fill", "Aspect fit" and so on. I never had to change it so far, still I'm curious what it can be used for. Can somebody explain?
The content mode property of a view tells how its content should be laid out. In the Interface Builder, the various modes can be selected in the Attributes Inspector.
Let's use two image views to see how the various modes work.
Scale to Fill
The image heights and widths are stretched to match the size of the UIImageView.
Aspect Fit
The longest side (either height or width) of the image is stretched to match the view. This makes the image as big as possible while still showing the entire image and not distorting the height or width. (I set the UIImageView background to blue so that its size is clear.)
Aspect Fill
The shortest side (either height or width) of the image is stretched to match the view. Like "Aspect Fit", the proportions of the image are not distorted from their original aspect ratio.
Redraw
Redraw is only for custom views that need to do their own scaling and resizing. We aren't using a custom view, so we shouldn't use Redraw. Notice that here UIImageView just gives us the same result as Scale to Fill, but it is doing more work behind the scenes.
About Redraw, the documentation says:
Content modes are good for recycling the contents of your view, but you can also set the content mode to the UIViewContentModeRedraw value when you specifically want your custom views to redraw themselves during scaling and resizing operations. Setting your view’s content mode to this value forces the system to call your view’s drawRect: method in response to geometry changes. In general, you should avoid using this value whenever possible, and you should certainly not use it with the standard system views.
Center
The image is centered in the view, but the length and width of the image are not stretched.
Top
The top edge of the image is centered horizontally at the top of the view, and the length and width of the image are not stretched.
Bottom
The bottom edge of the image is centered horizontally at the bottom of the view, and the length and width of the image are not stretched.
Left
The left edge of the image is centered vertically at the left of the view, and the length and width of the image are not stretched.
Right
The right edge of the image is centered vertically at the right of the view, and the length and width of the image are not stretched.
Top Left
The top left corner of the image is placed at the top left corner of the view. The length and width of the image are not stretched.
Top Right
The top right corner of the image is placed at the top right corner of the view. The length and width of the image are not stretched.
Bottom Left
The bottom left corner of the image is placed at the bottom left corner of the view. The length and width of the image are not stretched.
Bottom Right
The bottom right corner of the image is placed at the bottom right corner of the view. The length and width of the image are not stretched.
Notes
If the content (in our case the image) is the same size as the view (in our case the UIImageView), then changing the content mode will make no noticeable difference.
See this and this question for a discussion about content modes for views other than UIImageView.
In Swift, to set to set the content mode programmatically you do the following:
imageView.contentMode = UIViewContentMode.ScaleToFill
imageView.contentMode = UIViewContentMode.ScaleAspectFit
imageView.contentMode = UIViewContentMode.ScaleAspectFill
imageView.contentMode = UIViewContentMode.Redraw
imageView.contentMode = UIViewContentMode.Center
imageView.contentMode = UIViewContentMode.Top
imageView.contentMode = UIViewContentMode.Bottom
imageView.contentMode = UIViewContentMode.Left
imageView.contentMode = UIViewContentMode.Right
imageView.contentMode = UIViewContentMode.TopLeft
imageView.contentMode = UIViewContentMode.TopRight
imageView.contentMode = UIViewContentMode.BottomLeft
imageView.contentMode = UIViewContentMode.BottomRight
View Programming Guide goes into details of what you're asking about. If you scroll down to the section called "Content Modes" you'd find what you're looking for.
Basically according to Apple:
"Each view has a content mode that controls how the view recycles its content in response to changes in the view’s geometry [...] the value in the contentMode property determines whether the bitmap should be scaled to fit the new bounds or simply pinned to one corner or edge of the view."
http://vocaro.com/trevor/blog/2009/10/12/resize-a-uiimage-the-right-way/
should give you the basic ideas very well.
Related
What is the correct formula for the location of an NSRulerMarker on a vertical NSRulerView, if the client view is flipped?
The situation: I have a view (let's call it the "main view") that is embedded in an NSScrollView with rulers, and it has subviews. The user can drag these subviews around, and while dragging, I want to indicate the current position on the rulers.
The main view is flipped: The zero point is top-left.
The horizontal position is pretty simple:
NSPoint scroll = myScrollView.documentVisibleRect.origin;
NSRect rect = mySubView.frame;
rulerMarkerDragLeft.markerLocation = rect.origin.x - scroll.x;
However the same method for the vertical position...
rulerMarkerDragTop.markerLocation = rect.origin.y - scroll.y;
does not work. The marker is only in the correct position when the scrollview has been scrolled down to the extreme bottom. For every n points scrolled back up, the marker location is n points too high. This is independent of the main view's size or the size of the visible area.
I can't seem to wrap my head around this problem; I guess there is a value I need to subtract from my result that expresses how far up the scrollview has been scrolled (or rather, how much further it can be scrolled down), but I don't think I can derive that value from myScrollView.documentVisibleRect...?
I may have overlooked something simple, but I can't find the solution.
Edit 2022-11-02 17:17 CET: Found the problem. I had set the NSRulerViews clientView to the contentView of the window. I am now setting it to the "main view" (ie. the view inside the scroll view), and now it works "automagically": I just set the marker locations to the subviews frame, no correction for scroll position or anything else needed.
The solution was simple: the ruler views' clientView needs to be set to the view that is inside the scroll view, not the main content view of the window.
The positioning of the ruler markers is now very straightforward: you just use the local coordinates inside the view, ie. the subviews' frame values.
No correction for scroll position, view height or such necessary.
My mistake was assigning the window's main content view as the rulers' clientView.
I'm trying to make an NSTextField with only two rounded corners on the top-left and bottom-left. I tried to do the following, but in this case I get all corners rounded:
[self.myTextField:YES];
self.myTextField.layer.cornerRadius = 5;
What should I do to have only two (or for example one) rounded corners?
I'm a little out of my lane in OS X, but what you want to do is embed whatever corner art you like into an image and present those on an image view behind the NSTextField.
Resize the image view exactly as you do the text field, but first set the image's capInsets property. Size the insets to exclude the corners from scaling as the extent of the image changes. (Make sure your corner art is placed at the extreme edges of the image).
I want to create a close button which will look like a circle with an x in the middle. In x code I set the button's size and width to be large so that the touchable area is larger (50 x 50 with a font of just 22).
I create a button, change the title to X and then set the following:
[self.closeButton.layer setBorderWidth:2.0f];
[self.closeButton.layer setBorderColor:[[UIColor whiteColor] CGColor]];
[self.closeButton.layer setCornerRadius:self.closeButton.bounds.size.width/2];
The circle border is too far from the X. How would I bring the borders in tighter to the X but not decrease the size of the clickable area?
assign image to a button. and make tappable area as you want. then set image location in button by setting inset value of that button as top, bottom, left, right. change the value of this according to your requirements. You can set inset value from interface builder as shown in image here. change the value and see the difference to place your image in button at exact location you want.
exactly like this image
I'd suggest exactly what Max has done. He has shown how to do this via IB, this is how you do it through code:
myButton.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 25, 25);// UIButton
myBarButtonItem.imageInsets = UIEdgeInsetsMake(0, 0, 25, 25);// UIBarButtonItem
EDIT:
Sorry for not reading your question properly the first time. I think you will run into the same issue with this approach : the border/cornerRadius of the button will not respect any insets. It will be drawn according to the frame of the button. Only (easy) workaround at the top of my head, is to create an image with the border and corners in it, and then set it as the image. The image will respect the insets, and you will have your desired tappable area, with the borders exactly where you want them.
There might be a more elegant workaround through subclassing, but unless you change the border width/color, or corner radius of your button at any stage, I'd suggest sticking with custom image.
EDIT 2:
Instead of using an image you might want to use this unicode character.
I am trying to render the image of a scroll view even to the areas which is outside the visible area of the screen. I am resizing the frame of the scroll view to include the content size width and height.After resizing, I am doing a renderInContext and finally taking the image by UIGraphicsGetImageFromCurrentImageContext.
All I am getting is a square box of black color of certain bytes. If i do not resize the frame of the view, i get the image with incorrect frame.
Does changing the frame affect renderInContext? What can i do to get the correct image after resizing?
I am using a crop tool in my app and I need to modify a UIImageView so that it fits an image exactly after inserting the image in aspect fit mode.
So an image is selected and added to the UIImageView in aspect fit mode. The problem is that this then leaves "blank space" around the image inside the UIImageView that needs trimming. I was wondering how I could then go and resize the holding UIImageView based upon the image inside.
Is this possible?
The Easy way is simply using the following code on your "imageView"
imageView.contentMode = UIViewContentModeScaleAspectFit;
Assuming you want to cut a "zoomed" section of your image to fit fully into your imageView
check your original image width and height
Assuming width is bigger in size then height , scale the image width to the holder width
center the image on your holder , the width will fit perfectly (section2) and the height will simply be cropped follow above and below the holder.
It turns out that a better approach is to use the following idea.
How to get the size of a scaled UIImage in UIImageView?
Instead of trimming the UIImageView, insert the image and then get the dimensions of the image inside the UIImageView, from there you can then resize the UIImageView to match the dimensions of the image inside.