Selecting Memo lines drifts selection

[munair]

Selecting a line with the following code in the OnKeyUp event of a Memo drifts the selection past the beginning of each line > 0. So I adjusted the line break offset to -2 and the line length offset to -1. First I thought this was a Linux problem due to line ending differences with Windows (#10 vs #13#10), but the code seems to fix the same problem on both Linux (Debian 12/GTK2+) and Windows (7).

Code: Pascal  [Select][+][-]

1.   // Get current line number
2.   Line := Memo.CaretPos.Y;
3.  
4.   // prevent selection drift (both Windows and Linux)
5.   LineBreakOffset := Length(sLineBreak) - 2;
6.   LineLengthOffset := -1;
7.  
8.   // Calculate the starting character position of the line
9.   LineStart := 0;
10.   for I := 0 to Line - 1 do
11.     LineStart := LineStart + Length(Memo.Lines[I]) + LineBreakOffset;
12.  
13.   // Get the length of the current line
14.   LineLength := Length(Memo.Lines[Line]) + LineLengthOffset;
15.   if LineLength < 0 then
16.     LineLength := 0; // Prevent negative length
17.  
18.   // Select the line
19.   Memo.SelStart := LineStart;
20.   Memo.SelLength := LineLength;
21.   Memo.SetFocus;

This seems more like an LCL issue.

[ASerge]

Code: Pascal  [Select][+][-]

1. procedure SelectLine(AMemo: TMemo; ALine: Integer);
2. var
3.   iEnd: Integer;
4. begin
5.   AMemo.CaretPos := Point(0, ALine + 1);
6.   iEnd := AMemo.SelStart;
7.   AMemo.CaretPos := Point(0, ALine);
8.   AMemo.SelLength := iEnd - AMemo.SelStart;
9. end;

[munair]

Line is undefined upon entry. Here is the procedure, which incorrectly assumed a difference between Linux and Windows.

Code: Pascal  [Select][+][-]

1. function SelectMemoLine(Memo: TMemo; key: word = 0): string;
2. var
3.   Line: Integer;
4.   LineStart: Integer;
5.   LineLength: Integer;
6.   I: Integer;
7.   LineBreakOffset: Integer;
8.   LineLengthOffset: Integer;
9. begin
10.  
11.   result := '';
12.  
13.   if key = VK_DOWN then
14.     Memo.CaretPos := Point(0, Memo.CaretPos.Y - 1);
15.  
16.   // Get the current line number from CaretPos
17.   Line := Memo.CaretPos.Y;
18.  
19.   // Ensure the line number is valid
20.   if (Line < 0) or (Line >= Memo.Lines.Count) then
21.     Exit;
22.  
23.   // Platform-specific adjustments (no use; Linux settings must also be applied to Windows)
24.   {$IFDEF LINUX}
25.   LineBreakOffset := Length(sLineBreak) - 2;
26.   LineLengthOffset := -1;
27.   {$ELSE}
28.   LineBreakOffset := Length(sLineBreak);
29.   LineLengthOffset := 0;
30.   {$ENDIF}
31.  
32.   // Calculate the starting character position of the line
33.   LineStart := 0;
34.   for I := 0 to Line - 1 do
35.     LineStart := LineStart + Length(Memo.Lines[I]) + LineBreakOffset;
36.  
37.   // Get the length of the current line
38.   LineLength := Length(Memo.Lines[Line]) + LineLengthOffset;
39.   if LineLength < 0 then
40.     LineLength := 0; // Prevent negative length
41.  
42.   // Select the line
43.   Memo.SelStart := LineStart;
44.   Memo.SelLength := LineLength;
45.   Memo.SetFocus;
46.  
47.   result := Memo.Lines[Line];
48. end;

[PascalDragon]

Line is undefined upon entry. Here is the procedure, which incorrectly assumed a difference between Linux and Windows.

Please use [code=pascal][/code]-tags as otherwise the forum software will interpret your code and also it improves readability.

[munair]

Line is undefined upon entry. Here is the procedure, which incorrectly assumed a difference between Linux and Windows.

Please use [code=pascal][/code]-tags as otherwise the forum software will interpret your code and also it improves readability.

Apologies, I corrected it.