Different text styles

[Atarion12]

Please help, cannot make for example one line of text bold other is regular.
Or for example user selection make bold. How i can do it in avaloniaedit?

[danipen]

You can do it through TextTransformations you can see an example here:

AvaloniaEdit/src/AvaloniaEdit.TextMate/TextTransformation.cs

Line 9 in daf4320

public abstract class TextTransformation : TextSegment

[Atarion12]

Yes i was check this. But i do not understand how i can transform current selection in fact.

Lets imagine: user select any text. It is accessible now in Editor.SelectedText (where Editor is my object of avaloniaedit) and how i can transform this selection in different style?

[danipen]

I think background and foreground for selection can be customized via styled properties, but if you want to do something more advanced you can probably atatch the selection changed event and combine it with a text transformation (there are primitives to get the selected chunk)

[Atarion12]

This logic is oblivous, yes. But I am do not understand yet how to write the appropriate code.

[danipen]

This is the selection event

AvaloniaEdit/src/AvaloniaEdit/Editing/TextArea.cs

Line 432 in daf4320

public event EventHandler SelectionChanged;

Combining that with a line transformer could work for you.

[Atarion12]

thanks i will trying.

[Atarion12]

i am trying but still cannot do it.
so I have ready selection on that handler. And how I can change style of selection? Do not realize, yet, soryy

[danipen]

        internal class SelectionLineTransformer : GenericLineTransformer
        {
            internal SelectionLineTransformer(TextArea textArea) : base(null)
            {
                _textArea = textArea;
            }

            protected override void TransformLine(DocumentLine line, ITextRunConstructionContext context)
            {
                if (_textArea.Selection.StartPosition.Line == _textArea.Selection.EndPosition.Line &&
                    line.LineNumber == _textArea.Selection.StartPosition.Line)
                {
                    var startColumn = _textArea.Selection.StartPosition.Column - 1;
                    var endColumn = _textArea.Selection.EndPosition.Column - 1;

                    SetTextStyle(
                        line,
                        startColumn,
                        endColumn - startColumn,
                        null,
                        Brushes.Red,
                        FontStyle.Normal,
                        FontWeight.Normal,
                        false);
                }
            }

            TextArea _textArea;
        }

[Atarion12]

Thanks! I am trying like this:

SelectionLineTransformer sl = new SelectionLineTransformer(Editor.TextArea);
sl.SetTextStyle(Editor.Document.Lines[0], 0, 3, Avalonia.Media.Brushes.Red, Avalonia.Media.Brushes.Green, Avalonia.Media.FontStyle.Italic, FontWeight.Bold, false);

Where is Editor - it is my editor on the form.
But on the string sl.SetTextStyle... it is write error "System.NullReferenceException: "Object reference not set to an instance of an object.""

[danipen]

This is not the usage of the transformer. You shouldn't call sl.SetTextStyle directly.

You only should register the transformer using
_yourEditor.TextArea.TextView.LineTransformers.Add.

See an example here:

AvaloniaEdit/src/AvaloniaEdit.Demo/MainWindow.xaml.cs

Line 98 in daf4320

_textEditor.TextArea.TextView.LineTransformers.Add(new UnderlineAndStrikeThroughTransformer());

[Atarion12]

it is just change my selection style!

Editor.TextArea.TextView.LineTransformers.Add(new SelectionLineTransformer(Editor.TextArea));

but i need completly other thing!

I whant change bold of any part of the text! Like in richtextbox like this: sdfsdfsdfdsf

[danipen]

You can do that using SetTextStyle, for the line, start column and length you're interested in, setting the FontWeight.

[Atarion12]

Can you write direct example that makes part of text bold?

[danipen]

This should work...

        internal class SelectionLineTransformer : GenericLineTransformer
        {
            internal SelectionLineTransformer(TextArea textArea) : base(null)
            {
                _textArea = textArea;
            }

            protected override void TransformLine(DocumentLine line, ITextRunConstructionContext context)
            {
                if (_textArea.Selection.StartPosition.Line == _textArea.Selection.EndPosition.Line &&
                    line.LineNumber == _textArea.Selection.StartPosition.Line)
                {
                    var startColumn = _textArea.Selection.StartPosition.Column - 1;
                    var endColumn = _textArea.Selection.EndPosition.Column - 1;

                    SetTextStyle(
                        line,
                        startColumn,
                        endColumn - startColumn,
                        null,
                        null,
                        FontStyle.Normal,
                        FontWeight.Bold,
                        false);
                }
            }

            TextArea _textArea;
        }

Note that if you're using Avalonia.TextMate integration, it seems that the grammars there are already setting the text in bold, so maybe you need to disable in order to notice the difference when selecting text.

[danipen]

Take into account that the open-source project doesn't have the support you require for free. However, Avalonia offers paid support through our Avalonia project website, You may visit their website for more information on our paid support options.

[Atarion12]

If you do not what give support - so just don't do it. But for what we have here discussion board? For discussions isn't it? Mabe other users will be more kind and have less formality

You give separate class, then some other comments. Then again separate class. I do not understand how USE this class FROM my own object. Real object. Myedit.... doings. But you give me abstractions again and again...