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.
Related
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.
I'm trying to recreate a text editor I've made but using the MVC design pattern; I'm not totally sure about certain parts of it.
For example, I have a tree view displaying my project directory, and a text editor showing the contents of a file, along with this i have output from compilation of files being displayed as well as a tabbed interface.
Would this be split into a few different models or under one big model? If it's under 1 big model how would I go about using the Qt model classes for such a thing?
Open up Qt Designer and drag and drop all the stuff you need. It should get you pretty far.
I think the only model/view you should worry about is the QFileSystemModel and pairing it up with a QTreeView. Everything else Qt has some nice examples showing how to do it.
If you are showing multiple files at once in separate tabs, then you might want to look into the Tabbed Browser Example to see how its done.
http://doc.qt.io/qt-5/examples-mainwindow.html
http://doc.qt.io/qt-5/qtwidgets-richtext-syntaxhighlighter-example.html
http://doc.qt.io/qt-5/qtwidgets-widgets-codeeditor-example.html
http://doc.qt.io/qt-5/qtwebkitexamples-webkitwidgets-browser-example.html
I like QDockWidgets and using QActions and putting them on the QToolbar in a QMainWindow.
http://doc.qt.io/qt-5/model-view-programming.html
http://doc.qt.io/qt-5/qfilesystemmodel.html#details
http://doc.qt.io/qt-5/qmdiarea.html#details
http://doc.qt.io/qt-5/qtextedit.html
For the compilation part you will just need to create a QProcess and connect its output to a QTextEdit.
Hope that helps.
I designed a Qt application by Qt creator. As you well know when you build a new form is possible to drag an drop the default items inside the main window. Instead of use classical "push button" I created a custom button by adding .qml file to the project. The problem now is that I don't know how I can use (or integrate) the new button inside the form of my project.
Thanks in advance
As long as your component is in the path of your application qml files, all you need to use your component is to place it somewhere. You don't need to include or import anything. Any user component is directly available to the entire project.
As long as the QML component is made from only built in components, it can even be safely loaded from arbitrary location on disk, over network or just from a source string. Check this answer for details on dynamic instantiation.
A friendly advice - type the code, do not use the visual editor - it is pretty weak.
EDIT: I don't know about you, but for me, seems like every custom qml file in the project qml folder is automatically added to the QML types in the designer library. So contrary to what I assumed, you shouldn't really need to do anything to get your custom type available for use in the designer.
I found this 1 year-old question when facing the same problem. This is what I found out:
If you save your custom button with an initial uppercase letter (CustomButton.qml instead of customButtom.qml), QtDesigner shows your component in the library panel correctly.
Sometimes you need to restart QtDesigner to work.
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
Currently, I am in the design phase of a Qt widget like what one would see in a typical hex editor. It seemed simple enough to begin with, but as I dig into its implementation details I’m having some confusion.
Basically, the widget would consist of 3 core components: It will inherit QAbstractScrollArea or QScrollArea to provide scrolling and, in the viewport margin, it will display the file offset of each line. Then there will be two text editors; one with the hexadecimal value of each byte of the file, and one with the plaintext character representation.
I, of course, first checked qt-apps.org for any existing widgets, but a search for “hex” only returned QHexEdit and qPHexEditor, neither of which are very complete. I then considered creating a widget completely from scratch as they had, but felt like there should be a more elegant solution. Qt already has much text-editor functionality built into QTextEdit and QPlainTextEdit; why reinvent the wheel?
Now, while the “plaintext view” would be as simple as using a QPlainTextEdit with a fixed-width font and a width of 16 characters, the “hex view” is giving me a headache. I’ve been poring over QTextEdit, QAbstractTextDocumentLayout, etc., trying to figure out a way to present the desired appearance. For those who have never used a hex editor, it should function like so: – Using a fixed-width font, widget should be the width of 47 characters – Widget should display 2 hexadecimal characters per byte, with a blank space between bytes—-16 bytes per line
Since that thought, I’ve been trying to figure out how to subclass any related classes to provide the desired formatting. Unfortunately, the text editing classes don’t seem to follow the model/view framework as closely as I’d hoped, so deriving a new “view” for it doesn’t seem easy. Ideally, the widget would function like so:
One document/model for both the “hex” and “plaintext” views. Editing either view would adjust this model and update the other view appropriately. Signals/Slots at its best.
Because QTextEdit and QPlainTextEdit already provide much of the functionality needed (visible cursor, selections, undo/redo, native look and feel, etc), it would be ideal to re-use this.
So, does anyone have any recommendations? I appreciate any input on this.
QHexEdit2 is a quite complete editor widget for binary data. It can edit very big files, is available for Qt4, Qt5, PyQt4, PyQt4 with python 2 and 3.
see https://github.com/Simsys/qhexedit2