I am designing a form in Qt Creator Designer. I want to make a QWidget that will always keep 4:3 aspect ratio and will keep the remaining space around itself empty.
I put it in a grid layout and surounded it with spacers which I thought would consume any extra space:
After that, I set it's minimum size to 48x32 and it's size increment to 2x3:
I tried all size policies but it never respects the aspect ratio. It also doesn't properly try to fit the whole area.
How do I set it up correctly?
Related
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.
For exemple, I want the value of the layoutLeftMargin property to be equal to 1/3 of the parent widget. So when I will resize the windows, the ratio of the widget will still stay the same.
Else, if it's not possible with QtDesigner, how can I do it with code ?
No, Margins are specified in pixels, they can't be relative to the parent widget's size.
However, You can do that in the designer by putting your whole current layout in a Horizontal Layout, add a Horizontal Spacer to the left of it, assign suitable layoutStretch values in the horizontal layout (In your example, this should be 1,2, meaning the original layout will take up twice the space taken up by the spacer, so that the spacer gets 1/3 of the parent widget).
I am now trying to resize a qgraphicsview to a preffered size:
I am using layouts:
this->layout()->addWidget(&qtview);
I have layouts everywhere, so thet the size of my main widow is adjusted depending on its contents.
If I use:
qtview.setMinimumWidth(500);
qtviewSetMinimumHeight(500);
Then my view is scaled to the given size, but I am not able to shrink the main window. (which makes sense as I set a minimum soze)
I would like to tell qt my preferred (not minimum or maximum) size for the view, letting the view use scrollbars when needed (i.e. if the preferred size does not fit in my screen), or letting qt have a smaller view than my preferred size if the scene is smaller than my view, (or enlarge the scene to fit the view in this case)
I am searching for something looking like an hypothetical method setPreferredWidth().
What can I do to get this behaviour?
It sounds like you're looking for the QGraphicsView function setSizePolicy: -
setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred));
I have 3 subviews(UILabel, UIImageview, UIButton) to be laid out on a container view. All the subviews are laid out using visual format language (VFL). The subview have padding from the leading , top edges etc. The content of the subview are dynamic so their sizes changes all the time. i want to resize the superview(container view) to exactly fit all the subviews. Is this possible by auto layout? i have seen some of the link here which suggest intrinsic size which i am not able to understand. can someone suggest a better way to achieve this.
Yes, it's possible. If you plan to resize the superview according to subview content, then intrinsic content size is the way to go.
The ever excellent Ray Wenderlich site has a tutorial that covers this well. It's Beginning Auto Layout in iOS 6: Part 2/2:
Intrinsic Content Size
Before Auto Layout, you always had to tell buttons and other controls
how big they should be, either by setting their frame or bounds
properties or by resizing them in Interface Builder. But it turns out
that most controls are perfectly capable of determining how much space
they need, based on their content.
A label knows how wide and tall it is because it knows the length of
the text that has been set on it, as well as the font size for that
text. Likewise for a button, which might combine the text with a
background image and some padding for the rounded corners.
The same is true for segmented controls, progress bars, and most other
controls, although some may only have a predetermined height but an
unknown width.
This is known as the intrinsic content size, and it is an important
concept in Auto Layout. You have already seen it in action with the
buttons. Auto Layout asks your controls how big they need to be and
lays out the screen based on that information.
It is possible.
In my case, I wanted to give rounded corners to segmented control. For that, I embedded segmented control in UIView. Now I was required to resize that container view as per size of segmented control.
I gave only following constraint and everything was taken care itself.
(1) Chose container view and give it X and Y constraints.
Leading space to Super view.
Top space to Super view.
(2) Chose container view and give Leading | Trailing | Top | Bottom constraint.
Leading space to segmented control.
Top space to segmented control.
Trailing space to segmented control.
Bottom space to segmented control.
(3) Chose segmented control and give it Height and Width constraints.
Height : 30 // Whatever
Width : 250 // Whatever
Now if I change the height and width of my segmented control, it automatically adjust container view's size (super-view of segmented control).
I can't quite figure out what the best way of displaying an image is in my particular case, so hopefully someone on here has a few tips.
I want to display an image that gets re-sized automatically to fit inside the space that is available. I currently do this by creating a class derived from QLabel that implements void resizeEvent(QResizeEvent*) where I do a QPixmap::scaled to re-size the image. The problem is that this only works when the widget is enlarged because the widget doesn't get a resizeEvent when I try to make the widget smaller. I guess that because I set the image to the same size as the widget, it isn't allowed to be sized smaller again? I guess I could try to create a smaller image therefor introducing a sort of "border" around the image which would perhaps allow re-size events to occur when making the area smaller. Any thoughts?
resizeEvent is sent whenever size is changed. It doesn't matter whether it is enlarged or not.
But you can set Policy and Max/Min size to constraint widget in shrinking/enlarging. So if you have your widget not getting resizeEvent AND it doesn't shrink either, then look at your size policy and min width/height. If it shrinks but you doesn't have resizeEvent then you have some error in you logic, I believe.
Alternatively you can use paintEvent for image painting and use QWidget::rect() for your widget width/height.
Try changing the size policy of the label to QSizePolicy::Preferred.
Have a look at size policies in general.