Does 'TMemo' have no OnPrepareCanvas / OnPaint / OnDraw-Event or so?

[Hartmut]

I wanted to draw some lines of a TMemo in a different color. I hoped to find an Event like OnPrepareCanvas / OnPaint / OnDraw or something like that, which I could use to manipulate the color, before a certain line is drawed. But I could not find some Event like this... does nothing like this exist?

I'm on Linux with Lazarus 2.2.4. Thanks in advance.

[jamie]

Use a different component.

TListBox for example has an owner draw, you can color each line as you wish.

[paweld]

Use TSynEdit - read this thread: https://forum.lazarus.freepascal.org/index.php/topic,65987.0.html

[indydev]

Could you use Richmemo? Here's what I am thinking to color specific lines:

Use the TRichMemo.SelStart and TRichMemo.SelLength properties to select the specific line.
Set the TRichMemo.SelAttributes.Color property to change the color of the selected text.
Create a procedure to color a line and apply it in the onChange event.

Here's an example:

Code: Pascal  [Select][+][-]

1. uses
2.   StrUtils  //  ...and your other units
3.  
4. procedure ColorLine(RichMemo: TRichMemo; LineIndex: Integer; Color: TColor);
5. var
6.   StartPos, EndPos, LineCount: Integer;
7.   Text: string;
8. begin
9.   LineCount := RichMemo.Lines.Count;
10.  
11.   // Check if the requested line exists
12.   if (LineIndex < 0) or (LineIndex >= LineCount) then
13.     Exit;
14.  
15.   // Get the full text
16.   Text := RichMemo.Text;
17.  
18.   // Find the start position of the line
19.   StartPos := 1;
20.   for var i := 0 to LineIndex - 1 do
21.     StartPos := PosEx(LineEnding, Text, StartPos) + Length(LineEnding);
22.  
23.   // Find the end position of the line
24.   if LineIndex = LineCount - 1 then
25.     EndPos := Length(Text) + 1
26.   else
27.     EndPos := PosEx(LineEnding, Text, StartPos);
28.  
29.   // Select the line
30.   RichMemo.SelStart := StartPos - 1; // Adjusting for 0-based index
31.   RichMemo.SelLength := EndPos - StartPos;
32.  
33.   // Set the color
34.   RichMemo.SelAttributes.Color := Color;
35.  
36.   // Clear the selection
37.   RichMemo.SelLength := 0;
38. end;

You can then use this procedure to color a specific line in the onChange event:

Code: Pascal  [Select][+][-]

1. ColorLine(RichMemo1, 8, clRed); // Colors the 9th line (index 8) red

This should allow you to color entire lines. If you need more granular control (e.g., coloring parts of lines), you would need to adjust the selection range.

[Hartmut]

Thanks a lot to all for your answers. Seems that 'TMemo' does not have an appropriate Event. I will investigate your suggestions to find the best fitting solution for me.