Qt Creator plugin - how to modify current editor margins

SebastianM

Hi,
I've created ZenMode plugin. It hides sidebars, menubar and Modes View and make Creator fullscreen.
By default current editor align text/code to left side.
What I need is ... to make code horizontally centered. Let's make left margin different for active ZenMode.
I tried with

// Get the current editor
Core::IEditor *currentEditor = Core::EditorManager::currentEditor();
if (currentEditor) {
    // Cast to text editor
    TextEditor::BaseTextEditor *textEditor = 
        qobject_cast<TextEditor::BaseTextEditor*>(currentEditor);
    
    if (textEditor) {
        // Access the widget
        QPlainTextEdit *editorWidget = 
            qobject_cast<QPlainTextEdit*>(textEditor->editorWidget());
        
        if (editorWidget) {
            // Apply centered margins
            int margin = 200; // Or calculate dynamically
            editorWidget->setViewportMargins(margin, 0, margin, 0);
        }
    }
}

but linking fails on qobject_cast<TextEditor::BaseTextEditor*>(currentEditor); .
What other solution are available?

PS: Second problem is that setViewportMargins is protected method and requries some additional hacks to be called.

aha_1980

@SebastianM Does your plugin depend on/ link to the TextEditor plugin?

SebastianM

Yes, you right.
I added QtCreator::TextEditor in CMakeLists.txt to PLUGIN_DEPENDS section in add_qtc_plugin and linking problem is gone.

SebastianM

Still, I can't find way to modify TextEditor margins.

    Core::IEditor *currentEditor = Core::EditorManager::currentEditor();
    TextEditor::BaseTextEditor *textEditor = qobject_cast<TextEditor::BaseTextEditor*>(currentEditor);
    TextEditor::TextEditorWidget * editorWidget = textEditor->editorWidget();
//how to do it?

Tried casting edditorWidget to class CustomTextEditorWidget : public TextEditor::TextEditorWidget with custom virtual int extraAreaWidth(int *markWidthPtr = nullptr) const override. qobject_cast fails, after static_cast there's exception.

Accessor approach

    class TextEditorWidgetAccessor : public TextEditor::TextEditorWidget
    {
    public:
        static void setMargins(TextEditor::TextEditorWidget *widget, int left, int top, int right, int bottom)
        {
            // Cast to accessor to get access to protected method
            TextEditorWidgetAccessor *accessor = static_cast<TextEditorWidgetAccessor*>(widget);
            accessor->setViewportMargins(left, top, right, bottom);
        }
};
....
TextEditorWidgetAccessor::setMargins(editorWidget, 300, 0, 0, 0);

doesn't change viewportMargins - before and after setting they return the same original value.