[Solved] TRichMemo - Adjust Scrolling Speed

[OLLI_S]

Hello,

I am using Lazarus 1.8.4 in Windows 10 Professional x64.

I have a form where I used a TMemo control to display some text.
Now I switched to a TRichMemo control, because I needed some text in red color.
But I recognized a scrolling issue in the TRichMemo.

When I scroll one step using the mouse wheel in the TMemo control, then a full line of text is scrolled.
When I scroll in the TRichMemo then only a part of the line is scrolled (I have to scroll 5-6 steps to scroll one complete line).

Both controls have the same font and font size.
And both have the same text (content).

So how can I increase the scrolling speed of the TRichMemo?
Thank you!

Best regards

OLLI

[OLLI_S]

Hello,

some of my users complained about the scrolling speed of my two TRichMemo controls.
Is there a way to change the scrolling behavior?
Thank you for your help.

Best regards

OLLI

[sstvmaster]

Hi OLLI,

for scrolling you can use this:

Code: Pascal  [Select][+][-]

1. procedure TForm1.RichMemo1MouseWheel(Sender: TObject; Shift: TShiftState;
2.   WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
3. begin
4.   case WheelDelta of
5.     120: begin
6.       SendMessage(RichMemo1.Handle, EM_LINESCROLL,0,-1);
7.     end;
8.     -120: begin
9.       SendMessage(RichMemo1.Handle, EM_LINESCROLL,0,1);
10.     end;
11.   end;
12. end;

[skalogryz]

I have a form where I used a TMemo control to display some text.
Now I switched to a TRichMemo control, because I needed some text in red color.
But I recognized a scrolling issue in the TRichMemo.

It's not an issue, it's intentional.
Since RichMemo can have different font sizes per line, scrolling by lines makes little to not sense.
(You might want to add wordwrapping problems).

Thus RichMemo always scrolls by pixels (on all platforms)

[OLLI_S]

Hello,

if the TRichMemo is scrolling by pixels, can I somehow adjust the number of pixels that are scrolled?
My problem is that I show here a Change-Log in RTF text and if users want to read the Change-Log they have to scroll a lot.

Best regards

OLLI

[sstvmaster]

@OLLI
Did you read my post?

[OLLI_S]

@OLLI
Did you read my post?

 
When I posted my answer I must have overseen it (I really can not explain why).
But thank you, your code is working perfectly.

I have two TRichMemo controls, so I made a common procedure that is called by both TRichMemo controls.
I just had to cast the sender so it is working:

Code: Pascal  [Select][+][-]

1. procedure TfrmMainForm.TRichMemoMouseWheel(Sender: TObject; Shift: TShiftState; WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
2. begin
3.   case WheelDelta of
4.     120: begin
5.       SendMessage(TRichMemo(Sender).Handle, EM_LINESCROLL,0,-1);
6.     end;
7.     -120: begin
8.       SendMessage(TRichMemo(Sender).Handle, EM_LINESCROLL,0,1);
9.     end;
10.   end;
11. end;  

Thank you again sstvmaster !

Best regards

OLLI

[jamie]

Now if you want to get fancy with that, you can check the SHIFT value and have it do page jumps or
smooth scroll when you want them by holding a key down on the board like the shift, control alt etc..