I'm using QT 5.14, but cannot find they way to make Text component selectable..
Is there any way to do it?
What I need is to be able to select multiple blocks of texts (not within single text block only, but like in regular html page).
I tired with read only TextEdit, I can select only inside TextEdit, but not texts of multiple instances..
For context: I want to try to implement simple chat app with qt, and make chat messages selectable (like for example in Slack).
For chat history I'm thinking to use ListView with custom components which include Text and other components (Image, links, etc).
P.S: I don't want to use WebView or WebEngine
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I need to implement a specific text object in QEdit PyQt. I need rich objects that will content special information, capture the keyboard arrow keys only when cursor text is on these objects. They need support selection and copy / paste operations also. Outside of them, the cursor must act as normal behavior. At this time, the object does not need to show images or svg etc. Is only for capture text cursor purposes and to store specific information related with the object.
I read that I can implement a customized text object with this example:
textobject.py
but the example does not contain information about implement new html tags, how to capture focus, etc.
My questions are:
How can I add a new html tag related with my custom object for loading and saving documents?
How can I detect when text cursor is on the custom object to modify keyboard cursor behavior?
PyQt documentation says:
"Copy and Paste operations ignore custom text objects."
So is no way to implement copy / paste functionality?
How can I access to my custom object content?
I want to have specifics methods to navigate within the information contained in the object. I could save this information in another object, but I need to synchronize the information with the cursor because a document can contain many of these objects.
Context for my application: I'm developping a very specific application for blind users. I am blind myself. I need to make very specifics customizations to the Richttext area for accessibility. The goal is to develop an accessible math equation editor. For this, I need to add support for mathMl tag. I will process mathMl content inside these tags in my custom object, this part is already implemented at basic level without using any GUI framework. At this time I don't need to show the equation in the screen, I let to screen readers interact with my editor via a COM object. At this time, the equation box is functional, but I need to integrate this functionality in a rich text area. the idea is, a document can contain N math expressions that can be read, modified and saved in a document.
I plan to implement accessibility for sighted people also in the equation editor, but it is beyond my skills and is not a priority right now.
Also I need to accessibilize tables in rich text area, currently tables are not accesible in QT. Then I think to extend qt table functionality. Style elements like headings etc, does not exist in pyQt. OK, you can write a paragraph with heading style, but screen readers can't detect it. So I need to develop this functionality. I could solve it with customized objects I think.
Currently it need to work in windows only. Maybe later I'll consider other platforms.
I started to program in pyQt yesterday, but I already read a lot of documentation. I wrote a basic rich text editor to test my requirements.
I already tried to implement this application with wxPython phoenix because I've been using WX for a long time. But I couldn't implement custom text objects and I didn't find documentation about it.
If pyQt is limited for my requirements, could you recoment another gui framework?
Y could consider another languages, I chose Python because Python has many math tools like sympy or numpy, and implement user scripting functionality in the app is very easy.
Sorry for my bad english.
Is QML suitable for building a text editor with syntax highlighting (and maybe code folding)? Do you know of any text editors built using QML?
For building the whole editor UI: menus, buttons, file dialogs, it is totally up to the task.
As for exactly the main editor component that shows text, highlights, folding and stuff, technically QML could do it, but to my understanding you'd want to do it in C++ and just expose that C++ component to QML UI.
You will likely need to build the TextEdit component from scratch anyway and you can optimize C++ way more and QML isn't exactly made for the low level graphics/text nuances such as deciding how many pixels exactly to scroll the text on a new line or how to load bit-by-bit and show bit-by-but when you open a huge file. These things are possible with [mostly] QML, but unless you are building something simple, I suppose you'll want to just to C++ side for the main text editing component. And for OS-related operations such as file reading.
The LimeText editor has a QML frontend.
When it comes to designing a GUI in Qt, I am hesitating between using the designer in Qt Creator, or doing everything in source code. I'm using Qt widgets and not QML.
If I use the designer I can easily create a GUI using qt standard widgets. But as soon as I need to subclass a widget to extend its functionality I have to build a Designer plugin to support my new widget. Is that correct? Or is there another way to it?
You can build all the GUI in Designer including custom widgets, and you can also build your custom widgets in Designer.
Designer does not need to interpret your custom widgets. Just use the promote functionality. With promote, you start with a plain widget within Designer and then tell the "real" class of it (your custom one) and the header file where it is decleared. The only drawback is that within Designer, it will stay looking like an empty widget.
In my experience, it is much better to use Designer for the GUI than writing source code yourself. You can easily change all the properties afterwards etc., and it is helpful even if you rely on custom widgets. Source code is not a good declarative language for GUI objects, with all the properties etc. Also you cannot play around, you would need to compile all the time just to tell "Is it better to have this text label in bold font?".
Sometimes I edit the XML files that are created by Designer by hand. For example, if I want to put a widget somewhere else in the object tree. If you don't mess up the XML, Designer will still read it and not destroy your changes. The only reason I see for writing GUI in source code is when you have repetitive elements, or dynamic changes based on data input, e.g. a for()-loop that produces elements. In my project I have some Selector Boxes that are filled with options in the source code.
And btw: If you prefer to write your GUI in code instead of using Designer, maybe you are not the right person to craft the GUI. Most programmers don't understand that while they are technically able to design a GUI, they are not always also competent in doing it.
http://hallofshame.gp.co.at/index.php?file=shame.htm&mode=original
It is a bit of a shortcut, but I often use a simple QWidget as a container for my custom widget. This way, I can setup sizing policies, put the whole thing in the layout I want before my custom widget is even in. Then, in C++, I add the custom widget as a child of the container widget.
edit: As ypnos mentioned you can promote the placeholder directly. You can find guidelines here
I'm new with Qt and am looking for advice on how to structure this.
I want a flexible widget that can display a set of images (normally read from a directory but other sources too) and let the user select images with the arrow keys and/or mouse and also apply custom tags.
For example there might be 5 tags defined by the application. A user can press a key to select one, and then a little icon would appear in or near the image preview showing that it was selected for that tag.
Would I need to implement this from scratch via drawing on a QWidget or is there something that would make a sensible base class? Thanks!
I would use a QListView base class, and then subclass QStyledItemDelegate.
There is an example here which might help you.
I'm new to QT, and am trying to figure out the best means of creating a WYSIWYG editor widget for a custom markup language that displays simple text, images, and links. I need to be able to propagate changes from the WYSIWYG editor to the custom markup representation.
As a concrete example of the problem domain, imagine that the custom markup might have a "player" tag which contains a player name and a team name. The markup could look like this:
Last week, <player id="1234"><name>Aaron Rodgers</name><team>Packers</team></player> threw a pass.
This text would display in the editor as:
Last week, Aaron Rodgers of the Packers threw a pass.
The player name and the team name would be editable directly within the editor in standard WYSIWYG fashion, so that my users do not have to learn any markup. Also, when the player name is moused-over, a details pop-up will appear about that player, and similarly for the team.
With that long introduction, I'm trying to figure out where to start with QT. It seems that the most logical option would be the Rich Text API using a QTextDocument. This approach seems less than ideal given the limitations of a QTextDocument:
I can't figure out how to capture navigation events from clicking on links.
Following links on click seems to only be enabled when the QTextEdit is readonly.
Custom objects that implement QTextObjectInterface are ignored in copy-and-paste operations
Any HTML-based markup that is passed to it as Rich Text is retranslated into a series of span tags and lots of other junk, making it extremely difficult to propagate changes from the editor back to the original custom markup.
A second option appears to be QWebKit, which allows for live editing of HTML5 markup, so I could specify a two-way translation between the custom markup and HTML5. I'm not clear on how one would propagate changes from the editor back to the original markup in real-time without re-translating the entire document on every text change. The QWebKit solutions looks like awfully bulky to me (Learning WebKit along with QT) to what should be a relatively simple problem.
I have also considered implementing the WYSIWYG with a custom class using native QT containers, labels, images, and other widgets manually. This seems like the most flexible approach, and the one most likely not to run into unresolvable problems. However, I'm pretty sure that implementing all the details of a normal text editor (selecting text, font changes, cut-and-paste support, undo/redo, dragging of objects, cursor placement, etc.) will be incredibly time consuming.
So, finally, my question: are there any QT gurus out there with some advice on where to start with this sort of project?
BTW, I am using QT because the application is a desktop application that needs platform independence.
Given that I got no advice here, I decided to go with the QTextEdit approach, although I'm actually using a QTextBrowser that is set to be editable so that I can capture link navigation events. I will be using QTextCharFormat's with the link names set to unique identifiers in order to convert from the QTextEdit back to the custom markup. The QTextEdit supports images already, so I won't have to deal with those.
I think I will hit the biggest roadblocks with the fact that I need to be able to insert/grow/shrink tables whose cells can have Excel-style functionality. I have not yet figured that whole process out.