error with Layout.alignment vertical bar in vertical bar .qml file - qt

Background: I have a side project that I'm working on that's gonna be a "rolling" project that I'll be updating as I learn and grow as a programmer. Since this project will be growing with me I wanted to learn how to create a GUI that can be simple but also gives me the ability to really customize the GUI once I really feel comfortable with it. After feeling overwhelmed with options I landed on PySide6 and QML but I'm running into an issue with the QML file.
The tutorial I'm following is Python-QML integration (https://doc.qt.io/qtforpython/tutorials/qmlintegration/qmlintegration.html) and I'm using the .py and .qml files linked at the bottom of the tutorial page. For an IDE if it matters I'm using Pycharm and have PySide6 package added to the project as well as the QML Editor plug-in.
Problem: The issue that I'm having is with the .qml file. For some reason, it's not recognizing the vertical bar used in the two-dimensional flag to center my RowLayout vertically and horizontally. When I hover my cursor over the vertical bar I get a tip saying that one of multiple different symbols like commas, parenthesis, or braces were expected but instead got '|'.
ColumnLayout {
id: rightcolumn
spacing: 2
Layout.columnSpan: 1
Layout.preferredWidth: 400
Layout.preferredHeight: 400
Layout.fillWidth: true
RowLayout {
Layout.alignment: Qt.AlignVCenter | Qt.AlignHCenter
Button {
id: red
text: "Red"
highlighted: true
Material.accent: Material.Red
onClicked: {
leftlabel.color = bridge.getColor(red.text)
}
}
}
I feel like I've checked everywhere Reddit, stack overflow, the documentation on the QT site, but can't find anyone else that's experienced this.

The main issue is that setting Qt.AlignVCenter in a child of a ColumnLayout doesn't make sense since Layouts only honor alignment orthogonal to the direction of their layout. So, setting a vertical alignment on a vertically oriented layout won't do anything.
In this case, since you've simplified the example (specifically, all of your layouts only have one child), you don't really need any layouts at all. Instead, I would convert the ColumnLayout to an Item and then anchor the Button in the center of it like this:
Item {
id: rightcolumn
Layout.columnSpan: 1
Layout.preferredWidth: 400
Layout.preferredHeight: 400
Layout.fillWidth: true
Button {
id: red
anchors.centerIn: parent
text: "Red"
highlighted: true
Material.accent: Material.Red
onClicked: {
leftlabel.color = bridge.getColor(red.text)
}
}
}

Related

QML Tumbler looses vertical mouse focus

When I create a tumbler widget in QML, I can grab it, and change the contents. As soon as I leave the widget with my mouse in vertical direction, the tumbler stops changing its contents. It works fine if I leave the widget to the left or right. In that case, I can operate the tumbler even when the mouse leaves the QML window.
Is there anything I missed?
Example code:
import QtQuick 2.5
import QtQuick.Controls 2.5
Rectangle {
width: 1000
height: 600
Tumbler {
anchors.centerIn: parent
model: 24
width: 30
height: 100
}
}
I'm using QT 6.2.1 and tried it on Kubuntu 20.04 and Yocto Dunfell.
I tried the same thing with a QML Dial. Herewith I can leave the widget in all directions, and it still reacts to my mouse movement.

QML/Qt: Make displayed text as large as possible depending on the parent containing it

I am trying to make a very simple KDE-Plasma Widget where only a certain number is displayed. I want to make this displayed number have a font size as large as possible depending on the parent containing it.
Here is what it looks right now:
As you can see, the text inside has a lot of space around it. What I actually want it to be is something like the "Date And Time" Widget found in KDE Plasma (my widget is right next to it for comparison):
Here, the time displayed has much lesser space around it while also auto-resizing whenever the panel height is changed.
Here is what the current code looks like:
import QtQuick 2.6
import QtQuick.Layouts 1.0
import org.kde.plasma.components 2.0 as PlasmaComponents
import org.kde.plasma.plasmoid 2.0
Item {
id: main
anchors.fill: parent
Layout.minimumWidth: units.iconSizes.large
Layout.minimumHeight: units.iconSizes.large
Plasmoid.preferredRepresentation: Plasmoid.fullRepresentation
PlasmaComponents.Label {
id: display
anchors {
fill: parent
margins: Math.round(parent.width * 0.1)
}
verticalAlignment: Text.AlignVCenter
horizontalAlignment: Text.AlignHCenter
text: foobar
font.pixelSize: 1000;
minimumPointSize: theme.smallestFont.pointSize
fontSizeMode: Text.Fit
font.bold: true
}
Timer {
some stuff
}
}
I tried looking into the code of the above Date and Time widget and wrote down the exact same layouts/controls (which is what you are seeing in the above code) with the same positioning/styling properties and yet I get a lot of space around my text/or the font size continues to remain small.
I tried your code and it resized the font correctly. For the spacing around the text, there are two points:
The spacing on the left and right is easily controlled by adjusting the margins value that you are using. For less space, try Math.round(parent.width * 0.05).
The spacing on the top and bottom is larger because the shape of your parent object is square, while the shape of the text is rectangular. In order to make the text fit the height of the square without exceeding the width of the square, the text would not just need to resize, it would need to be stretched vertically. But QML does not have an easy way to do that, and I doubt that's really what you want anyway.
EDIT:
And if you do want font stretching, I'll point you to this answer.
Thanks to #JarMan's input I was able to realize that my text was being rendered in small font because of lack of space due to the root (item) element being square in shape.
I have now figured that to change the layout sizes of the root element inside the KDE-Plasma panel, one needs to mess with Layout.preferredWidth and Layout.preferredHeight.
Here is what I did:
item {
.
.
Layout.preferredWidth: 150 * units.devicePixelRatio
Layout.preferredHeight: 50 * units.devicePixelRatio
.
.
}
Note: the 150 and 50 values aren't final. It basically gives an idea about the ratio at which the root element's width and height should be in (and I wanted a rectangle). It automatically resizes the inner content too as the Plasma Panel is resized.

strange visual behavior on maximized qml window

I've got a qml based application which renders fine as long as it is not maximized. The error occurs to different extend on different platforms and on resizing/unmaximizing the window everything goes back to normal. On linux it looks like the window freezed but if you resize it you will see that e.g. previous button clicking indeed triggered something but no visual update was shown during that time. On windows (7), updates and reacting to user input is shown but there are a lot of artifacts duplicating the state before the window was maximized that wont disappear until resizing, so a portion of the window is not refreshed here too
Does somebody have any idea by what may cause this behavior? Can I - in the worstcase - disable that the window can be maximized?
Edit:
I tested it with a minimal qt quick controls 2 template application again without modification and i have the same behavior (tested on ubuntu)
The example I used is quite simple and still the issue is still present:
import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.3
ApplicationWindow {
visible: true
width: 640
height: 480
title: qsTr("Hello World")
SwipeView {
id: swipeView
anchors.fill: parent
currentIndex: tabBar.currentIndex
Page1 {
}
Page {
Label {
text: qsTr("Second page")
anchors.centerIn: parent
}
}
}
footer: TabBar {
id: tabBar
currentIndex: swipeView.currentIndex
TabButton {
text: qsTr("First")
}
TabButton {
text: qsTr("Second")
}
}
}
Its the simple template from New Project > Applications > Qt Quick Controls 2 Application in Qt Creator. I tested it with Qt 5.9.1 and 5.10.0
Maybe a general qt problem in conjuction with graphics drivers?

QML tab occasionally stretches off-screen

I have a QML-based GUI with a fixed width that uses the TabView type in several places.
On one page, I have something like this (leaving out most properties except for lateral anchors):
ColumnLayout {
MyTabsViewSubmenu { // defined below
Layout.fillWidth: true
Tab {
id: someId
title: someString
anchors.fill: parent
SomeCustomClass {
id: someId2
anchors.fill: parent
}
}
// three more tabs defined the same way, with the same anchors...
}
// another item below the tabs...
}
MyTabsViewSubmenu is something like this:
TabView {
Rectanble {
anchors.fill: parent
}
style: TabViewStyle {
// miscellaneous style stuff
}
}
One of my four tabs in the ColumnLayout above sometimes stretches off the screen when selected. As far as I can tell, there is nothing special about it compared to the other items used as tabs throughout the GUI. The layout of this tab is something like this:
Item {
MyTabsViewSubmenu {
anchors.top: parent.top
anchors.left: parent.left
anchors.right: parent.right
anchors.bottom: sibling.top
Tab {
// no anchors (see below)
SomeItem {
anchors.fill: parent
}
// ... other tabs....
}
Rectangle {
id: sibling
anchors.left: parent.left
anchors.right: parent.right
// ... stuff....
}
}
The entire page stretches off the screen: both the sub-tab content and the content in the Rectangle I've shown here as sibling.
I would suspect that possibly the missing anchors.fill: parent in the innermost Tabs might be the problem, except that sibling is not (as far as I can tell* missing any anchors, and I've never seen the tabs stretched offscreen without the sibling being stretched offscreen as well.
It seems entirely unpredictable whether the stretching occurs or the layout is done correctly. Once the layout has stretched off the screen, I can sometimes get it to correct itself by navigating away from that page and back.
I'm using Qt 5.6.1-1 on Debian 7.
EDIT: When I navigate to the "stretched" tab and the bug occurs causing the stretching, the tabs themselves at the top of the page also get "stretched" somewhat. Returning to a different tab un-stretches the tabs.
The fix
Setting Layout.maximumWidth (as per Velkan's comment) appears to resolve the issue. Additionally, it appears to make the page load faster.
Observations and testing
It's now about a week and a half since I introduced this change to the code, and the product has been heavily tested since then.
We have discovered a second component that needs Layout.maximumWidth set in order to keep from stretching off the screen, and indeed applying this fix to both the original problematic components has prevented the screen-stretching bug. So this is definitely a valid fix.
Possible root cause (i.e. groundless speculation)
I suspect that the QML engine attempts to size "Layout" objects by starting with the maximum width, then shrinking them to fit (or something like this). If the maximum width is unset, it's set to something like "infinity". Without a maximumWidth, it appears that the auto-shrinking operation sometimes fails, leaving the component stretched offscreen. I suspect that the automatic-resizing code may be impacted by some kind of nondeterminism in the order in which the sizes of different QML components are computed.

QML : If condition in delegate?

I'm designing a spinner list control, which displays 3 items at a time.
Its working fine as required behaviour the only issue am facing is I need the central element appearance little bigger.
The approach which I can think as of now is to have an if condition in the delegate, which on the basis of current index increases the font size.
Is the above approach is possible? Any suggestions to achieve the particular behaviour
Below is the code snippet
SpinnerData {
id: spinner
focus: true
model: 20
delegate: Text { font.pixelSize: spinner.height/4.5; text: index; height: spinner.height }
}
I don't know the details of your component but here you can see implementation of the same control in Qt Quick Components.

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