Help with this design issue - c++

I'm making a game GUI API. It is coming along very nicely except for one aspect. I want themes similar to how GTK works. The way I want it to work is that every GUI element will have a default Windows9X-like way of drawing themselves. If it is found that a theme is set for that type of widget, it will be drawn with those bitmaps.
My original concept was to create a Theme class which would have getters and setters for the bitmaps.
for example:
themeManager.setButtonHover(Bitmap *bitmap);
The problem with this, is that it is not flexable if I want to create new types of Widgets. I may eventually want to create a superButton which would use a different theme than a button. This is the flaw with that concept. The concept I'm thinking of going with is that each widget type has static methods to set the theme for itself and the constructor uses that.
Are there better ways of doing this that I'm not thinking of? Since it is an API, I want to avoid reading text files, so reading the theme from a text document is not an option.
Thanks


May be template the superButton on a policy and then have a default policy which does the default and the user has the option of providing a different policy? The policy could then define the attributes of the button (such as the hover image etc.) - does what I describe make sense?

Related

How to add an action to the default context menu of a QSpinBox?

I am using Qt 5.7 (C++) and want to add custom functionality like a reset option to a QSpinBox (as well as QDoubleSpinBox and maybe some other input widgets). This functionality should be accessible via the context menu. However I do not want to replace the default context menu. Instead I want to add my custom actions on top or below the already existing actions.
I found almost matching answers to this question:
https://forum.qt.io/topic/81946/add-item-to-top-of-standard-context-menu-at-right-click
How to add an entry to toolbar context menu in qt?
However, these do not help in my case since it relies on the Widget to have a method that creates and returns the standard context menu (like QLineEdit::createStandardContextMenu()). The spin boxes do not have such a method.
I also tried to go the cheap way and copy the code that creates the default options directly from source (https://github.com/qt/qtbase/blob/5.7/src/widgets/widgets/qabstractspinbox.cpp line 1249). This is also not really satisfactory since it uses private members of the underlying line edit.
Is there a (standard) way to reuse and augment the default context menu of a Q(Double)SpinBox or any QWidget in general? Or do I have to manually re-implement the default behavior?

https://code.qt.io/cgit/qt/qtbase.git/tree/src/widgets/widgets/qabstractspinbox.cpp#n1315
Yeah it doesn't look like we have any easy "hook" for customizing it (and you can make a feature request if you like); OTOH it's not that much code to copy, since most of the menu entries are added by QLineEdit::createStandardContextMenu()

Menu designed for use without mouse. What is the best way to implement?

I'm writing a GUI using QT for embedded system with linux. This device has no mouse. Only display and specific keyboard with keys: up, down, return and 7 number keys.
The software will be used to set some parameters of device and read them (some charts also).
Example of how menu could look:
after OPTION 1 selected
After SUBOPTION 1 selected some table with data is loaded.
Sometimes after selecting option i need to load specific widget and sometimes just another set of options.
I think it is possible to implement custom labels and kind of list widget that aligns them.
I guess it is also possible to use Qt's MVC classes for it. They are highly customizable, but i never made custom views and delegates.
Maybe i just need to create QtListView with stringlist model and apply stylesheet to it so it gets look more like buttons. And based on selection in list load next widget.
Which way is better and why?
Is there any easier ways to accomplish this?
Any ideas would be appreciated.

PopUp Menus in a custom GUI API?

I have made my own GUI API for games. One assumption that must be made is the user may want to use a derived version of a Widget I have made.
An example of how I dealt with this with ToolTips is, the user allocates a new ToolTip and sets a global one for the GUI. Ex: getGui().setToolTip(customToolTip);
The GUI then calls toolTip->show() when necessary. The problem with menus in general is that you can have many of them appearing at a given time.
I also would hate to have the user implement an interface:
PopUpFactory::createPopUp()
PopUpFactory::destroyPopup()
How is this usually dealt with? Who or how is the memory also managed for these?
There is always the option of limiting to something like 9 nested menus and have the user set an array of 9 PopUps but that seems messy.
Thanks

Making a game in Qt regarding GUI windows

I've been wanting to program a simple game with a simple GUI using Qt (Its will be a VERY simple game, nothing fancy). What I've been wondering is, how can I create multiple windows and display them when needed? For an example, a battle screen and an inventory screen. The user should only see one of them, but should be able to access the other one when needed. I was using stacked widget but I'm not sure if that's the proper way. Also, is it better to design the windows in the designer or to code them?

A StackWidget certainly would accomplish what you want to do. The reason why it is not always used for this kind of thing, is that it all the screens are pre-created at the beginning and always exist. This means it takes a little longer to initialize, and you are using more resources than you need at any one time
But as you are saying, if this is a simple game, then I don't see a big problem with it. Just as easily, you could also, create an empty layout and swap the inventory and game panels as needed.
Add my vote to everyone else suggesting to use the designer. It is so much easier to manipulate layouts, actions, and such using the designer then through code.
You can see the Designer manual here
So this is what I would suggest:
Create your "battleScreen.ui" - which is the designer file for your battle screen and everything in it, and then create your "inventory.ui". Both of these could be QWidgets, or QFrames, or whatever makes sense.
Then create your "Game.ui" which will be your QMainWindow.
In your Game main window, you can then add your QStackWidget, and place your inventory, and battle screens in the stack widget.
If you don't know how to do that...
1) drag a QWidget into your form (into the stack widget)
2) select the new QWidget and right-click.
3) Select "Promote to..."
4) Fill out the information to promote the QWidget to your inventory class
Promoted Class Name: The name of your inventory class
Header File: The header file of your inventory class
5) Click add
6) Click Promote.
Hope that helps.

Since I'm not sure what your goals are I can't advise whether or not the stacked widget is appropriate but I think you can accomplish quite a lot using the designer and style sheets. If you need to code some parts of the GUI, you can always drop in a place holder widget and either replace it with coded items or make them children of the place holders.

A general answer for a general question:
Use the Designer to create your windows; hide and show the auxiliary windows as needed.
Use a flow manager class to manage the visibility of a related set of windows.
The stacked widget is useful for managing a button/icon whose appearance changes based on state; the different representations live in the stack.

Customising a Qt library class

Qt's QTabBar has functionality to set the colour of text on each tab.
I'd like my application to be able to set the background colour of each tab. From what I can see, QTabBar isn't easily modifiable (e.g. by inheritance or changing a property) to do this.
This leaves me with the option of copying the QTabBar code wholesale into my (GPL) application, then modifying the class name (i.e. MyQTabBar), then adding my functionality. Is this the preferred method, or is there a better way?

There is definitely a better way :) You should be able to do what you want using stylesheets. This article covers some of this with a QTabWidget which contains a QTabBar.