Preventing layouts from expanding beyond the window size - qt

I'm trying to make my UI content expand nicely when the user resizes the window. I'm doing this in Qt Designer and learning about layouts and size policies.
Seems that everything is working fine for now: one layout stays within its maximum size, while another expands with the window resize, and they all stay above their minimum sizes. That's great and all, but the problem is that if I have a list with a lot of items, or if I am displaying a very large image, it will expand beyond the available window space and cause the window to be huge.
How can I specify something along the lines of "do not expand beyond the available window space"? I've played around with the size policies, but I couldn't get it to work. Is this something I need to set for the form itself rather than the layouts it contains?
I should specify this is the desired behavior: Display the widget as large as the available window, even if the widget content is too small. Expand/Shrink the widget to fill the window when the window is resized. Do not expand beyond the available window space. The widgets in question are 2 images (labels) and 1 list view.

I set the size policy to "ignored" for the respective widgets. That fixed it.

Or you can set the window maximum size.

Related

How do you prevent labels and buttons scaling?

I am testing a godot app, where there is a text heading along the top, and there are buttons along the bottom. For now I have a spacer in the middle to keep the heading at the top and the buttons at the bottom.
If I set Project Settings -> Display -> Stretch to disabled, then I can set a font and button size that looks reasonable for my laptop, and the font size for the heading and button doesnt shrink smaller and larger when the window is adjusted.
How do I guarantee and/or test that the size will be appropriate when the application is exported to iOS and Android? Is there some kind of guide that will help choose appropriate (non scaleable) button sizes for all devices?
How Controls are positioned
There are three intended ways to position a Control in Godot:
Placed in a Container. In this case the Container will control position and sizing of the child Control, taking into account "Size Flags".
See also Using Containers, and Containers.
By anchors (anchor_*) and margins (margin_*). They determine the position of the edges of the Control. The anchors are factors, and the margins are offsets.
For example, the leftmost part of the Control will be positioned at anchor_left * parent_width + margin_left, relative to the parent Control.
You will find presets in the "Layout" menu that appears in the tool bar when you have a Control selected.
See also Size and anchors.
By rect_position and rect_size. These are relative to the top left corner of the parent Control.
Ultimately the other ways to position the Control are changing these. And you can also change these even if you positioned the Control by other means… Which is not intended, but supported (because it is useful to add animations to the UI among other things).
Regardless of which one you use, Godot will respect rect_min_size. And yes, there is also rect_rotation and rect_scale which throw a wrench on the above explanation, but they works as you would expect.
And yes, it is not the easier to use system. Because of that, the designer is being improved for Godot 4 (currently on Alpha 3 at the time of writing).
To answer the question the title: If your stretch mode is set to disabled, and your UI is anchored to the top left (which is the default), you would resize the window and the UI would not scale or adapt to that change. I don't think you don't want the UI to adapt.
Making a top and bottom bars with containers
You can use a VBoxContainer, since we will have three bars stacked one on top of the other, vertically. And yes, the second one is a spacer.
First of all, you want the VBoxContainer to take the whole screen. So set it to the Layout preset "Full Rect". So, yes, we are placing the Container by anchors and margins.
And second, we want the spacer to take as much space as possible. To archive this we set "Expand" flag on size_flags_vertical of the spacer. This is what Size Flags are for.
And, of course, what you place inside the Container might or might not be more Containers.
Making a top and bottom bars with anchors and margins
Give the top bar the "Top Wide" preset. It will set the margins and anchors to have it stay at the top, take the full width, and take its minimum height.
And give the bottom bar the "Bottom Wide" preset. It will set the margins and anchors to have it stay at the bottom, take the full width, and take its minimum height.
You would need no spacer.
And, by the way, I remind you that anchors are margins are relative to the parent. So you can nest this approach. And yes, Controls that are not containers can also have children Controls
About stretch modes
As you know you have a choice between:
viewport: All the sizes will be computed with the original resolution, and then the resulting sizes are scaled to the resolution of the device.
2D: will also compute all the sizes with the original resolution, but instead of scaling the resulting sizes, it renders at that size and scales the image.
disabled: It will compute all the sizes with the actual resolution of the device. No scaling will happen.
Since both viewport and 2D, the size of the UI will not be computed with the actual resolution of the device. This makes the approaches I described to have the UI adapt less effective (less useful or less necessary, depending how you look at it). And thus, if we want to use those approaches effectively we will want the stretch mode set to disabled.
And, of course, there is also the aspect setting.
See also Multiple resolutions and Support multiple form factors and screen sizes.
Designing for small resolution
You can test on the editor how the UI adapts to the resolution, either by resizing the window, or by setting the Test Width and Test Height in Project Settings. You can, of course, also test on an actual smartphone. For instance, I often launch the game in my Android from the Godot editor when developing mobile games.
Circling back to the stretch modes, this is what happens with the text:
disabled: The text stays the same size. This means that the UI can become too small for the text.
viewport: the text scales. This means that the text can become too small to be legible.
2d: the text scales too… except since it is a image scaling it can become blurry, even harder to read.
If we only consider the text, there is no good option. Now, either design the UI for the specific target resolution… Or make one that can adapt. And for one that can adapt, I believe disabled is the best stretch mode as I was arguing above.
And of course you can script it
If you need to run some code when the resolution changes, you can connect to the "size_changed" signal of the root Viewport. And if you need to figure out if the device is in landscape or portrait mode you OS.screen_orientation, and if you really have to, you can create a custom Container.

Having trouble resizing a QLabel in a QScrollArea

I'm trying to follow the example at the below link to have a picture (in a qlabel) shown in a scrollable area.
https://doc.qt.io/qt-5/qtwidgets-widgets-imageviewer-example.html
I'm using Qt Designer to make the ui instead of hardcoding everything. So I have a QLabel, in a QWidget (with a grid layout assigned to it), in a QScrollArea.
From the tutorial, they state the following for the sizepolicy of the QLabel:
We set imageLabel's [QLabel] size policy to ignored, making the users able to scale the image to whatever size they want when the Fit to Window option is turned on. Otherwise, the default size policy (preferred) will make scroll bars appear when the scroll area becomes smaller than the label's minimum size hint.
Setting it to ignored fits to the window, as expected and as stated. Setting it to preferred provides scroll bars when the image is larger than the scroll area, also as expected and as stated. My issue is that when the sizepolicy is set to preferred, the resize function of the QLabel doesn't work. It always stays at the default size of the loaded image. The only way that I'm able to get the resize function to work is when I don't assign a layout/break the layout to the widget in the QScrollArea, but then no scrollbars will appear when the image is larger than the QScrollArea.
Does anyone have any ideas of how to make the resize function and scrollbars work at the same time?
Thanks in advance for any help. I'm trying to learn qt5 still and this seems like it'd be a simple thing to do, but it's slowly driving me crazy.

How to restrict growth (size) of layout in Qt Designer?

When I maximize my window, I want to restrict a vertical layout (and the entire row below it also) so that it has a specific size (lets say a width of 200). How can I achieve this? Below is what I get now. The buttons are stretched too far. I want them to keep a width of 200.
To stop the buttons stretching, use the following steps in Qt Designer:
click on scrollArea in the Object Inspector
click on Break Layout on the toolbar
click on scrollArea in the Object Inspector
click on Lay Out in a Grid on the toolbar
click on scrollAreaWidgetContents in the Object Inspector
scroll down to the bottom of the Property Editor
change layoutColumnStretch to 0,1
These steps should remove an empty column from the scroll-area grid-layout, and make the second column stretch to take up the available space when the window is resized.
You just need to restrict the maximum width of all widgets (in this case the buttons) within the layouts of this grid column to the expected size, else they'll just keep expanding. You may also have to fiddle the horizontal size policy; I seem to remember that buttons were a bit tricky in this regard (or was that the height?), but can't test it right now.
The layout size contraint you tried only applies to the layout's direct parent widget, if it has one, which isn't the case for the vertical layouts here.

How to set the desired size of a QMainWindow with QScrollArea?

I am working on a project where I have to display a pretty large (vertically) main Widget.
In the initial Version of my GUI it was just added as the central Widget of a QMainWindow, which caused the Problem that on small screen resolutions the controls on the Bottom of the Widget are unreachable.
To solve this i wrapped a QScrollArea around the main Widget, but now the main window is always relatively small even if it doesn't have to.
What do i need to change so the Main Windows (vertical) size is large enough to show all the contents unless it would be too large for the screen resolution? Also I don't want it to be stretched, so simply always using the whole vertical screen resolution is not an option. Ideally the size should be fixed to the size needed by the contents (w/o the scroll area) and only smaller where needed.
Overriding the sizeHint method did only resulted in a small enlargement of the Window and setting the minimal height brings me back to the beginning where some of the controls are not assessable on small resolutions.
Since i am new to QT I am actually out of ideas how to google the solution because most Solutions I can find are about sizing components inside a Window and not the Window itself.
By default a QScrollArea will not attempt to expand to fit its contents. In order to do this you will need to re-implement QScrollArea's sizeHint() to return the size of QScrollArea's child widgets.
In your question it sounds like you were trying to re-implement MainWindow's sizeHint? re-implementing sizeHint on the top-level window will have no effect as sizeHint designed for use with widgets inside layouts.

qt unexpandable layout?

Ok, here is my problem:
I have a vertical layout which contains a QPlainTextEdit and a horizontal layout (containing 2 QPushButtons) below the text edit.
The vertical layout is just a part of GUI, and gets resized depending on screen resolution. Btw. it is a mobile app, so I don't have a lot of space on screen.
Push buttons have some text which is dynamically set, I don't know it from the beginning to code it manually.
My problem occurs when the text in push buttons is big, and my whole vertical layout is expanded to fit the buttons.
How can I make the vertical layout unexpandable? note, that this is different from "fixed" because of different screen resoulutions.
I'd just like the clip the buttons if they do not fit, but keep the layout width untouched.
Anyway to do this?
You'll need to set the maximum width for the buttons, not the layout, which is only widening to fit the wider buttons. Check out the docs on QPushButton and look for QWidget inherited functions called setMaximumSize or setMaximumWidth.
You can always GetWidth() on the button when it is an appropriate size, then setMaximumWidth using that value since you wouldn't ordinarily know this. Pick an appropriate default text size/val and use that to create your "dynamic" default since this is going on screens of varying size.

Resources