Quite new to wxWidgets and ran into an issue with sizers, in my program I got quite a few buttons in a custom panel which I would like to add a horizontal scrollbar too. However the different sizers that I've tried all got auto layout which re-arranges my buttons upon start and change the distance between them while resizing, I would like to disable all of this behaviour but can't find any documentation on how to do so. Is it not possible or have I just been going about this the wrong way?
If you use sizers, you should let them manage the layout, of course.
You can use absolute positions if you really want to, but this is strongly not recommended and will not allow you to create the layouts that work in all configurations. But if you do decide to do this (again, you really shouldn't), then you wouldn't be using sizers at all.
Related
I'm writing a messenger, and there is a message feed there. As you all know message feeds usually look like lists and go from bottom to top, the keep the scrolling positions anchored to the bottom when a new element is added, they grow upwards when resized and all kinds of fancy behavior like that.
So, I wanted to use QListView to make the feed, I have a model written elsewhere, it's absolutely under my control. But it doesn't seem like QListView supports this mode. There is a trick of how to do it with QML, but I don't have QML used anywhere else in my project and I'm not sure of how to interact with it, like how to set there my model, how to listen for signals or if it's going to behave well in my QGridLayout where I want it to place.
I can't believe no one ever faced the same situation. I'm trying to find the most standard solution, involving as little of my rookie code as possible, keeping in mind that Qt guys are much more experienced in layouting elements in list view and handling all corner cases. If I'm correct my options are
Use QML for the feed
Try to rotate QListView with QGraphicScene tricks
Reimplement QListView
Which of those you think is a better solution? Or, may be, someone knows some better way to do it?
I am using Ubuntu OS.
I am new to GTKMM GUI building application.
I am following the tutorials which they have on their websites.
https://developer.gnome.org/gtkmm-tutorial/stable/sec-helloworld.html.en
I can resize the window with helloworld.set_default_size(500,500);
but I cannot move the position of button("hello world").
It is always aligned at center.
I tried with m_button.set_alignment(0.0,0.0) but nothing seems to be working.
Why it is that much difficult to move button to any position.?
kindly suggest some solution if available.
If you want to place a widget like a button, you have to use some container widget like Gtk::Boxor Gtk::Grid. Inside such container widgets you can place you child widget as you like, but typically not directly per point position.
The container widgets use some internal logic to order and resize the contained widgets.
From the documentation:
Many GUI toolkits require you to precisely place widgets in a window, using absolute positioning, often using a visual editor. This leads to several problems: ...
gtkmm uses the packing system to solve these problems.
You can find the full documentation here:
Multi-item widgets
I did not know if there is a container widget which allows direct positioning by giving a point position. If someone has an additional hint, let us know!
Sometimes automatic is better than manual handling, but sometimes it is not :-)
I want to resize everything when i show it in full screen automatically keeping aspect ratio. How can i do it. i use PyQt4 but if you know of C++ then also please tell me.
Hope the code will be not more than 2-3 lines.
Thanks
I suppose you've implemented static layouts with fixed widget sizes and positions in your dialogs/windows. In order to resize the widgets with the window, what you need to do is using dynamic layouts. You best use Qt Designer for the dialog design, else setting up any non-trivial layout can get rather toilsome.
I'm having all sorts of size problems with Qt. I am creating my own widgets and using different layouts (generally, I need my own to make them work properly without spending hours on the "powerful" default layouts... which don't lay things out as intended.)
Once I'm done with a widget and its layout though, it doesn't work right. The size is never getting set properly unless I call widget->resize(1, 1); which finally forces a "resize" and makes the widget look correct (i.e. recompute the geometry.) Even the updateGeometry() call has no effect.
This is a dreadful problem when the resize() needs to be called on the parent widget (yuck!) and from what I'm reading should not be necessary were the layouts properly programmed.
Is there a sample that works and is not several thousand of lines long, or does Qt require several thousand lines to make anything work perfectly, even the simplest widget?
What are the minimal functions to be called to make a widget & its layout work at once?
Thank you.
Alexis
P.S. I tried to implement the sizeHint(), minimumSize(), maximumSize(), others that I'm missing? I was hoping that would be enough. Obviously, I also implement the setGeometry() on the layout to resize the children appropriately.
--- addition 1
There is a sample image with a layout that clearly isn't available as is in Qt. The positioning, functions, and colors of the different keys is XML driven and works for any keyboard in the world.
(note, this sample doesn't show the Enter key displayed on two rows and wider below than at the top; more or less, not doable at all with the regular layouts; of course, it works with my version.)
--- clarification
I'm not too sure how to describe the problem better. I was thinking to write a test widget next to see how I can reproduce the problem and then post that and eventually fix it. 8-)
The default layout function that the internal Qt layouts make use of require a lot of coding. I would like to avoid having to copy/paste all of that because for maintenance, it makes it close to impossible.
--- today's findings
As I needed to tweak one of the widgets, I decided to add a VBoxLayout and make it work.
I actually found the problem... One of the widgets in my tree is a QScrollArea and that sizeHint() returns (-1, -1). Not exactly what I'd expect but... whatever you put inside that widget has better know how to compute its width and height or else... it fails.
Looking at the code closely, I could actually compute the width by using the widest width found. Once I used that, the widget would appear (and it actually resizes itself as things change in the list, kinda cool.)
This being said, my earlier comment about having a tree of widgets that auto-resize themselves stands. From the root up to the parents of the leaves in your tree, all of those widgets will need a valid layout. Once I added one in the top widget it resized itself and its children properly (well... in my case up to the QScrollArea, the rest required a bottom to top resizing. Funny how that works!)
--- ah! ha! moment (or: what you find reading the implementation code!)
Today I bumped in another problem which just needed the correct call... I just couldn't find anything worth it in the documentation.
All the objects have a layout now, but a certain parent would not resize properly. Plain simple.
I had a call to the parent as following:
// changes to the children are changing the geometry
parentWidget()->updateGeometry();
Yeah. The docs says that's what you have to do. Nothing happens at all with that call. No idea what it's supposed to do, I did not look at that function. It never did anything for me anyway.
So... I looked at the layout to try to understand how it would send the info up/down. I did not see much except for one interesting comment:
// will trigger resize
This is said of the SetFixedSize mode. To reach that function you need to make the layout for update. Ah! Yes... the layout, not the parent widget... let's try that instead:
parentWidget()->layout()->update();
And voila! It resizes correctly in all cases I have. Quite incredible that the widget updateGeometry() doesn't trigger the same effect...
Although it's possible to do what you want it sounds like the problems you are having are because you're using Qt in a way that it's not meant to be used. Why do you need separate widgets for each key represented on the keyboard?
I see two options, both of which are better in some way:
Use QGraphicsScene and QGraphicsView.
A single custom widget that uses custom drawing to display the keyboard (and likely uses hover for hints).
The first option is probably better. Your keys could then be represented by QGraphicsSimpleTextItem's or even a QGraphicsSvgItem. It also provides a number of standard layouts or you could choose to write your own layout. By default you can use the keyPressEvent or mouseReleaseEvent to respond to user interactions.
I'd highly recommend you take a look at the QGraphicsView examples to get an idea what you can do.
If you go the second route you'll need to record the different key locations so you can respond accordingly as the user moves the mouse around, clicks, etc.
This won't help you with your immediate issue but I wanted to show you a keyboard I made using standard layouts and buttons. It's not perfect and it still won't help you with an enter key that spans two rows but it's not bad. It's resizable too by resizing the window, although I'm not sure if that will be apparent from the images below as SO may be scaling them. (you can view the actual images by opening them in their own tab)
Anyway, this was done using only Qt Designer with no manual coding. It consists of a top level vertical layout with 5 horizontal layouts in it. The buttons are then inserted into one of the 5 horizontal layouts. The size of the keys can be controlled by setting the horizontal and vertical size policies to "ignored" for most of the buttons and then horizontal "minimum" for buttons that you want to be wider. Things can be tweaked by setting min and max size restrictions to buttons. When resized, the buttons will not maintain their relative proportions though, that would probably take some custom programming.
The styling in your example could be approximated pretty well using css style sheets and background images. Still not a minor effort but you should be able to get most of the way there without custom layouts and buttons.
I'm looking for a really good dialog resizer class that will stretch and shrink individual items as needed as the screen is resized. Stephan Keil has a good one (DlgResizeHelper) which basically resizes everything by a set ratio, but I'm looking for something smarter.
For example:
Icons should not resize
Single-line text boxes should not be stretched vertically
Buttons should probably stay the same size
Basically I'm looking for something to look at all of the controls, figure out that a static text field is related to a control next/below it and anchor the two together, and resize large controls in a 'smart' way so it looks good.
Are there such frameworks out there? I've been working on one but something ready-made would probably be better.
FOLLOW UP: I'm looking at the suggested solutions. Many of them require you to go in an anchor each control on the dialog. I'm looking for something smart that will figure out what the anchors ought to be, with the ability to manually anchor if the guesses are wrong. Seems like it should be possible -- most humans would agree a static text field next to an edit field should be anchored together. Guess I'm almost looking for a little AI here :)
You can use wxWidgets. It completely replaces MFC, is multi-platform, and gives you a layout-based dialog mechanism.
I use ResizableLib (also does PropertySheets and Pages) off codeproject, IIRC. You set anchor points that determine how the dialog and controls resize or move as the dialog moves.
You can set up to 2 anchors per control, (left, right) so you can move them as the dialog moves, or resize them as it moves. Its very easy to understand, if difficult to get perfectly right :)
I've tried many and finally settled on http://www.codeproject.com/KB/dialog/layoutmgr.aspx. It doesn't do the 'intelligent' layouting that you suggest though. I've never seen that in any library, on any platform - I don't see how it would work without having lots of under the hood magic that'd have to be overridden half of the time anyway.
The Ultimate Toolbox MFC library (here on CodeProject) includes a layout manager. I haven't used it myself, but it looks like it does what you want.
You can look at Professional GUI we use their class library for resizing our dialog controls. I think that is part of their free version.
We use CResize class from CodeGuru to resize all controls automatically. You tell how you want each control to be resized and it does the job for you.
The resize paradigm is to specify how much each side of a control will move when the dialog is resized.
SetResize(IDC_EDIT1, 0, 0, 0.5, 1);
SetResize(IDC_EDIT2, 0.5, 0, 1, 1);
Very handy when you have a large number of dialog controls.
Source code
This is a free solution also from CodeProject
http://www.codeproject.com/KB/dialog/dlgresizearticle.aspx
It's just a set of simple macros that position controls as the dialog resizes.
Edit - following the OPs comments. I don't know of any general sizer support like QT/WX for MFC, it doesn't seem to be present in new frameworks like Winforms either.
It is in QT/WX because it is necessary for multiplatform where widgets may be a different size, which explains MS lack of it. But it is also vital for multi-language ports, eg. where the German for cancel is 30 characters long.