Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Salvatore Coppola via lazarus]

Back to the first question. You can append your data with lb.items.text.
Just prepare your data in a string like this: 
strtmp:=data1+lineending+data2+lineending+.
And append lb.items.text:=lb.items.text+lineending+strtmp
Yes it is a workaround but do the trick like beginupdate
Ciao

⁣Ottieni BlueMail per Android ​

Il giorno 11 Nov 2022, 16:29, alle ore 16:29, Bo Berglund via lazarus 
 ha scritto:
>I am using a TListbox component on a form for displaying debug data
>arriving
>over a serial line at 115200 baud.
>The data are a set of MQTT telegram texts which arrive in packets of
>about 40
>lines each time (once per 10 seconds).
>I add them to the listbox as follows:
>
>procedure THanSimulatorMain.OnRxData(Sender: TObject; const Data:
>TBytes);
>var
>  len, oldlen: integer;
>  DataTxt: AnsiString;
>begin
>  len := Length(Data); //Incoming packet
>  oldlen := Length(DataBuffer);
>  SetLength(DataBuffer, oldlen + len);
>  Move(Data[0], DataBuffer[oldlen], len);
>  SetLength(DataTxt, Length(DataBuffer));
>  Move(DataBuffer[0], DataTxt[1], Length(DataBuffer));
>  lbxRxData.Items.Text := DataTxt;  //Add the text to the list
>  lbxRxData.ItemIndex := lbxRxData.Items.Count -1; //To make it visible
>end;
>
>DataBuffer is a global TBytes container where the incoming data are
>stuffed as
>they arrive (it grows during the session).
>You see that the buffer contains the complete log history from the
>start...
>
>I have noticed that after a while the display becomes very sluggish
>when data
>arrives and I think that is due to the way the component operates.
>
>Now I wonder if there is some way to do as I did when I worked in
>Delphi with
>TListView objects, where I could use the BeginUpdate and EndUpdate
>calls to make
>all screen updates wait until it was all put in place.
>This was MUCH faster!
>
>But I can not find a BeginUpdate on the TListBox object, only
>BeginUpdateBounds,
>which does not tell me much
>
>Any suggestions?
>
>
>--
>Bo Berglund
>Developer in Sweden
>
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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Jean SUZINEAU via lazarus]

Maybe you could add a buffer in your flow of data, storing the incoming 
data ?
When a line ending arrives, you can flush your buffer to Synedit up to 
the line ending, keeping in the buffer just the end of the data not yet 
terminated by a line ending.

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Vojtěch Čihák via lazarus]

It wouldn't be that hard to write custom component based on TGraphicControl + 
TBitmap with built-in bitmap font. Copying bitmap letters will be faster than 
rendering from ttf.
 
V.
__

Od: "Bo Berglund via lazarus" 
Komu: lazarus@lists.lazarus-ide.org
Datum: 11.11.2022 16:29
Předmět: [Lazarus] How to fix slow screen refresh of TListbox?



Now I wonder if there is some way to do as I did when I worked in Delphi with
TListView objects, where I could use the BeginUpdate and EndUpdate calls to make
all screen updates wait until it was all put in place.
This was MUCH faster!

But I can not find a BeginUpdate on the TListBox object, only BeginUpdateBounds,
which does not tell me much

Any suggestions?


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Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Sun, 20 Nov 2022 18:21:56 -0300, Flávio Etrusco via lazarus
 wrote:

>I see. My point is that you don't need to copy the whole DataBuffer and
>re-populate the whole SynEdit each time you receive new data. But this
>probably won't matter much unless you have hundreds of thousands of lines
>running on not so recent hardware.

Well, I tried at first to add incoming data to the bottom of the window, but it
turned out that when the transfer of data had been cut into parts by the serial
buffer such that the OnRxdata() triggered several times during the transfer then
the line at which the trigger happened was cut in two in the middle of the
screen.

Apparently the extra line break that was not part of the transfer was added by
the control when the data was added to the end. Next data added to it was not
adjacent to the last previous character but placed on the start of the next
line...

So the data in the synedit always ended with a linefeed even though there was
not yet any such in the transfered data.

Therefore I decided to use a dynamic TBytes array, which I could expand the size
of whenever the data arrived to fit the new packet and put it at the end of the
buffer.
Then I just replaced the strings in the display control with the full buffer
every time.
This way lines are not visibly cut in half or worse

But it would be better if I could have kept the data in the SynEdit itself and
just expanded with new data as they arrived by putting them at the end...

Not so much to transfer then.
Just new arriving text.


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Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Flávio Etrusco via lazarus]

Em dom., 20 de nov. de 2022 04:23, Bo Berglund via lazarus <
lazarus@lists.lazarus-ide.org> escreveu:

> On Fri, 18 Nov 2022 18:40:57 -0300, Flávio Etrusco via lazarus
>  wrote:
>
> >Em dom., 13 de nov. de 2022 às 18:36, Luca Olivetti via lazarus <
> >lazarus@lists.lazarus-ide.org> escreveu:
> >
> >> El 12/11/22 a les 12:13, Bo Berglund via lazarus ha escrit:
> >> > On Sat, 12 Nov 2022 09:45:15 +0100, Luca Olivetti via lazarus
> >> >  wrote:
> >> >
> >> >> El 11/11/22 a les 23:37, Bo Berglund via lazarus ha escrit:
> >> >>
> >> >>> But how to jump to the end of the text on screen?
> >> >>>
> >> >>
> >> >> TheSynEdit.TopLine:=TheSynEdit.Lines.Count-TheSynEdit.LinesInWindow+1
> >> >>
> >> >
> >> > Did not work, but this does work:
> >>
> >> Strange, I've been using it for many years (and still use it) to ensure
> >> the last line is visible.
> >>
> >> (...)
> >> --
> >> Luca Olivetti
> >> Wetron Automation Technology http://www.wetron.es/
> >> Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007
> >>
> >
> > It should work. Or even straight
> >"TheSynEdit.TopLine:=TheSynEdit.Lines.Count;'.
>
> My current version of my logging tool application uses this to display
> incoming
> data on the serial port (where it ends up in the TBytes buffer DataBuffer[]
> before displaying):
>
> ...
>   SetLength(DataTxt, Length(DataBuffer)); //Set string length
>   Move(DataBuffer[0], DataTxt[1], Length(DataBuffer)); //Copy data to
> string
>   {$ifdef USESYNEDIT}
> synRxData.Lines.Beginupdate;
> synRxData.Lines.Text := DataTxt;
> synRxData.CaretY := synRxData.Lines.Count;
> synRxData.Lines.Endupdate;
> stxLineCount.Caption := IntToStr(synRxData.Lines.Count);
>   {$else}
> ...
>

I see. My point is that you don't need to copy the whole DataBuffer and
re-populate the whole SynEdit each time you receive new data. But this
probably won't matter much unless you have hundreds of thousands of lines
running on not so recent hardware.

Best regards,
Flávio

>
>
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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Fri, 18 Nov 2022 18:40:57 -0300, Flávio Etrusco via lazarus
 wrote:

>Em dom., 13 de nov. de 2022 às 18:36, Luca Olivetti via lazarus <
>lazarus@lists.lazarus-ide.org> escreveu:
>
>> El 12/11/22 a les 12:13, Bo Berglund via lazarus ha escrit:
>> > On Sat, 12 Nov 2022 09:45:15 +0100, Luca Olivetti via lazarus
>> >  wrote:
>> >
>> >> El 11/11/22 a les 23:37, Bo Berglund via lazarus ha escrit:
>> >>
>> >>> But how to jump to the end of the text on screen?
>> >>>
>> >>
>> >> TheSynEdit.TopLine:=TheSynEdit.Lines.Count-TheSynEdit.LinesInWindow+1
>> >>
>> >
>> > Did not work, but this does work:
>>
>> Strange, I've been using it for many years (and still use it) to ensure
>> the last line is visible.
>>
>> (...)
>> --
>> Luca Olivetti
>> Wetron Automation Technology http://www.wetron.es/
>> Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007
>>
>
> It should work. Or even straight
>"TheSynEdit.TopLine:=TheSynEdit.Lines.Count;'.

My current version of my logging tool application uses this to display incoming
data on the serial port (where it ends up in the TBytes buffer DataBuffer[]
before displaying):

...
  SetLength(DataTxt, Length(DataBuffer)); //Set string length
  Move(DataBuffer[0], DataTxt[1], Length(DataBuffer)); //Copy data to string
  {$ifdef USESYNEDIT}
synRxData.Lines.Beginupdate;
synRxData.Lines.Text := DataTxt;
synRxData.CaretY := synRxData.Lines.Count;
synRxData.Lines.Endupdate;
stxLineCount.Caption := IntToStr(synRxData.Lines.Count);
  {$else}
...


Right now it has been running since 2022-11-19 01:20:05 and contains 11936 log
lines and whenever new data arrive it is almost instant on screen when it loads
the new lines and displays the very bottom of the list...


-- 
Bo Berglund
Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Flávio Etrusco via lazarus]

Em dom., 13 de nov. de 2022 às 18:36, Luca Olivetti via lazarus <
lazarus@lists.lazarus-ide.org> escreveu:

> El 12/11/22 a les 12:13, Bo Berglund via lazarus ha escrit:
> > On Sat, 12 Nov 2022 09:45:15 +0100, Luca Olivetti via lazarus
> >  wrote:
> >
> >> El 11/11/22 a les 23:37, Bo Berglund via lazarus ha escrit:
> >>
> >>> But how to jump to the end of the text on screen?
> >>>
> >>
> >> TheSynEdit.TopLine:=TheSynEdit.Lines.Count-TheSynEdit.LinesInWindow+1
> >>
> >
> > Did not work, but this does work:
>
> Strange, I've been using it for many years (and still use it) to ensure
> the last line is visible.
>
> (...)
> --
> Luca Olivetti
> Wetron Automation Technology http://www.wetron.es/
> Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007
>

 It should work. Or even straight
"TheSynEdit.TopLine:=TheSynEdit.Lines.Count;'.

Best regards,
Flávio
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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Flávio Etrusco via lazarus]

Em sex., 11 de nov. de 2022 às 12:29, Bo Berglund via lazarus <
lazarus@lists.lazarus-ide.org> escreveu:
>
> I am using a TListbox component on a form for displaying debug data
arriving
> over a serial line at 115200 baud.
> The data are a set of MQTT telegram texts which arrive in packets of
about 40
> lines each time (once per 10 seconds).
> I add them to the listbox as follows:
>
> procedure THanSimulatorMain.OnRxData(Sender: TObject; const Data: TBytes);
> var
>   len, oldlen: integer;
>   DataTxt: AnsiString;
> begin
>   len := Length(Data); //Incoming packet
>   oldlen := Length(DataBuffer);
>   SetLength(DataBuffer, oldlen + len);
>   Move(Data[0], DataBuffer[oldlen], len);
>   SetLength(DataTxt, Length(DataBuffer));
>   Move(DataBuffer[0], DataTxt[1], Length(DataBuffer));
>   lbxRxData.Items.Text := DataTxt;  //Add the text to the list
>   lbxRxData.ItemIndex := lbxRxData.Items.Count -1; //To make it visible
> end;
>
> DataBuffer is a global TBytes container where the incoming data are
stuffed as
> they arrive (it grows during the session).
> You see that the buffer contains the complete log history from the
start...
>
> I have noticed that after a while the display becomes very sluggish when
data
> arrives and I think that is due to the way the component operates.
>
> Now I wonder if there is some way to do as I did when I worked in Delphi
with
> TListView objects, where I could use the BeginUpdate and EndUpdate calls
to make
> all screen updates wait until it was all put in place.
> This was MUCH faster!
>
> But I can not find a BeginUpdate on the TListBox object, only
BeginUpdateBounds,
> which does not tell me much
>
> Any suggestions?
>
>
> --
> Bo Berglund
> Developer in Sweden

Hi,

What size is your data? The biggest problem regarding Windows' TListBox
(and TMemo and others) was it used a contiguous buffer for its whole text
and increased capacity by doubling the buffer or something, thus it got
ugly easily; the parsing did seem to have some problems too. Microsoft
alleviated this problem for TMemo at least at some point but I don`t know
about TListBox.
When you set/replace the whole text for a control (ex. using
ListBox1.Items.Text) there`s (usually) no need to use Begin/EndUpdate; if
you're appending a bunch of lines, though, you should use
ListBox1.Items.BeginUpdate.
Do you really need to keep 'DataBuffer' around for other reasons? Otherwise
you could just:

procedure TForm1.OnRxData(Sender: TObject; const Data: TBytes);
var
  buf: TStringList;
  DataTxt: ansistring;
begin
  SetLength(DataTxt, Length(Data));
  Move(Data[0], DataTxt[1], Length(Data));

  buf := TStringList.Create;
  buf.Text := DataTxt;
  SynEdit1.Lines.AddStrings(buf);
  buf.Free;
  SynEdit1.CaretY := SynEdit1.Lines.Count;
end;

Too bad TStrings don`t have a method to add text parsing the linebreaks...
IMHO even a PChar overload with offsets would be deserved.

Best regards,
Flávio
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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Luca Olivetti via lazarus]

El 12/11/22 a les 12:13, Bo Berglund via lazarus ha escrit:

On Sat, 12 Nov 2022 09:45:15 +0100, Luca Olivetti via lazarus
 wrote:


El 11/11/22 a les 23:37, Bo Berglund via lazarus ha escrit:


But how to jump to the end of the text on screen?



TheSynEdit.TopLine:=TheSynEdit.Lines.Count-TheSynEdit.LinesInWindow+1



Did not work, but this does work:


Strange, I've been using it for many years (and still use it) to ensure 
the last line is visible.





synRxData.CaretY := synRxData.Lines.Count;



--
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Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Sat, 12 Nov 2022 09:45:15 +0100, Luca Olivetti via lazarus
 wrote:

>El 11/11/22 a les 23:37, Bo Berglund via lazarus ha escrit:
>
>> But how to jump to the end of the text on screen?
>> 
>
>TheSynEdit.TopLine:=TheSynEdit.Lines.Count-TheSynEdit.LinesInWindow+1
>

Did not work, but this does work:

synRxData.CaretY := synRxData.Lines.Count;

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Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Luca Olivetti via lazarus]

El 11/11/22 a les 23:37, Bo Berglund via lazarus ha escrit:


But how to jump to the end of the text on screen?



TheSynEdit.TopLine:=TheSynEdit.Lines.Count-TheSynEdit.LinesInWindow+1

Bye
--
Luca Olivetti
Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Fri, 11 Nov 2022 23:37:14 +0100, Bo Berglund via lazarus
 wrote:

Concerning TSynEdit:

>I have a couple of questions:
>
>1) Is there a way to make sure that when adding text to synedit the view 
>shifts such that the last line is visible?
>I.e. Automatically scroll the text up when new text is added

This was my most acute problem with the synedit object, but see below...

>2) The reason I am not adding incoming data to the listbox as they arrive is
>that I don't know if the serial component provides the data at line endings or
>in the middle of a line, so I add the data to the old data in the TBytes array
>and then dump the content of the TBytes into the text property of the box.

I have dug down into the serial component and found that it actually dumps data
at a rather high pace with small packets every time...

Example:
One transmission contains 16 lines of data totalling 1130 bytes, but the serial
port component triggered an ondata event for a lot less, more like less than 10
bytes so the transmission triggered a big number of events, each updating the
listbox which totally overloaded the system.

So now I have changed two properties on the serial component:
- ReadPacketSize := 1500 (default is 16)
- ReadTimeout := 200 (default is 2 ms)

Since most transfers are shorter than 1500 the timeout of 200 ms will trigger
and by then the complete message *is* available, hence only one call to update
the screen display with new text.
This helps to make it more responsive...

>What happens if one adds the text as a block to this synedit where the block
>does not end in a line feed?
>Will the end of it be some way into the last line such that if I then add the
>next transmission it will start at that position and not on a new line?

It is my belief that even though there is no data following the end of the last
line (like an explicit linefeed), the next data added will start on a new
line...

Unless of course one could do the following (pseudocode):

synedit.lines[lastline] := synedit.lines[lastline] + incomingdata;

This would extend the last line with the incoming data...

>
>If that is possible then the handling will become a lot easier since I just 
>have
>to add the few new lines at the end directly in synedit...

No just simply adding incoming data to the lines does not work, they will start
on a new line (see above)...


>But how to jump to the end of the text on screen?

Right now this was my one remaining issue, since the Lines property does not
have a settable "ItemIndex" value that will move a line into the visible area.

But I found out that there is another useful property:

synRxData.CaretY := synRxData.Lines.Count;

This tries to put the cursor 1 line beyond the end and it does exactly what I
need to do by showing the incoming new data and scrolling up the display
visibly.
This is how it is now done in full:

  SetLength(DataTxt, Length(DataBuffer)); //Set string length
  Move(DataBuffer[0], DataTxt[1], Length(DataBuffer)); //Copy data to string
  {$ifdef USESYNEDIT}
synRxData.Lines.Beginupdate;
synRxData.Lines.Text := DataTxt;
synRxData.CaretY := synRxData.Lines.Count;
synRxData.Lines.Endupdate;
  {$else}
lbxRxData.Items.Beginupdate;
lbxRxData.Items.Text := DataTxt;
lbxRxData.ItemIndex := lbxRxDataBak.Items.Count -1;
lbxRxData.Items.Endupdate;
  {$endif}


-- 
Bo Berglund
Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Fri, 11 Nov 2022 18:49:15 +0100, Luca Olivetti via lazarus
 wrote:

>Play with the properties in the project inspector, you can remove the 
>gutter (gutter.visible -> false), the margin (by setting RightEdge to a 
>very big value, say 800) and customize much of its appearance..
>
I replaced the TListBox with a TSynEdit as suggested and I have "played with"
the properties a bit.
Seems to work quite well so far.

>
>Me too. Just set the readonly property to true and that's it.
>Then just treat it like a TMemo (using the Lines property). It has some 
>more goodies that aren't available in a Tmemo.
>As I said, I was using a TMemo for logging and it was too slow under 
>windows, I switched to a TSynEdit and had great improvement in performance.
>
I have a couple of questions:

1) Is there a way to make sure that when adding text the view shifts such that
the last line is visible?
I.e. Automatically scroll the text up when new text is added.

2) The reason I am not adding incoming data to the listbox as tyhey arrive is
that I don't know if the serial component provides the data at line endings or
in the middle of a line, so I add the data to the old data in the TBytes array
and then dump the content of the TBytes into the text property of the box.

What happens if one adds the text as a block to this synedit where the block
does not end in a line feed?
Will the end of it be some way into the last line such that if I then add the
next transmission it will start at tahat position and not on a new line?

If that is possible then the handling will become a lot easier since I just have
to add the few new lines at the end directly in synedit...

I'll test that too.
But how to jump to the end of the text on screen?

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Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Luca Olivetti via lazarus]

El 11/11/22 a les 17:56, Bo Berglund via lazarus ha escrit:


I have never used TSynEdit before so I tried dropping one onto my form and it
looked a bit "strange" with a wide margin to the left... > How does it work 
(especially the margin that steals space)?


Play with the properties in the project inspector, you can remove the 
gutter (gutter.visible -> false), the margin (by setting RightEdge to a 
very big value, say 800) and customize much of its appearance..




Note that I do not need an editor as such, just somewhere to show the log lines,
and possibly also a way to copy certain lines or text sections to paste
somewhere else.


Me too. Just set the readonly property to true and that's it.
Then just treat it like a TMemo (using the Lines property). It has some 
more goodies that aren't available in a Tmemo.
As I said, I was using a TMemo for logging and it was too slow under 
windows, I switched to a TSynEdit and had great improvement in performance.




BTW this application is on Windows and I am using Lazarus 2.0.12 and FPC 3.2.0


So you'll probably see an improvement by using a TSynEdit (or maybe not, 
the only way to know is to try it).


Bye
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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Werner Pamler via lazarus]

Am 11.11.2022 um 16:29 schrieb Bo Berglund via lazarus:

You see that the buffer contains the complete log history from the start...


When the first block of data has arrived I would store the length of the 
buffer at this time. Then next time when new data come in, I would 
extract the "new data", i.e. the bytes between the stored length and the 
new length of the buffer and add them to the listbox. And store the 
current length for the next round. Etc... This avoids moving all the 
data to the listbox, which it already has, again and again. Because 
extraction of the individual lines in lbxRxdata.Items.Text := DataTxt is 
a length process.



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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Fri, 11 Nov 2022 17:10:08 +0100, Luca Olivetti via lazarus
 wrote:

>El 11/11/22 a les 16:29, Bo Berglund via lazarus ha escrit:
>> I have noticed that after a while the display becomes very sluggish when data
>> arrives and I think that is due to the way the component operates.
>
>You could try using a TSynEdit instead of a TListBox: some years ago I 
>switched from TMemo to TSynEdit to do some logging in a similar (though 
>I add lines instead of assigning the complete text, also, I delete the 
>oldest line when there are 5000 lines) because I found that, under 
>windows, TSynEdit is an order of magnitude (or more) faster than TMemo.
>No difference under linux though, and maybe it's no longer true nowadays.
>

I have never used TSynEdit before so I tried dropping one onto my form and it
looked a bit "strange" with a wide margin to the left...
How does it work (especially the margin that steals space)?

Note that I do not need an editor as such, just somewhere to show the log lines,
and possibly also a way to copy certain lines or text sections to paste
somewhere else.

BTW this application is on Windows and I am using Lazarus 2.0.12 and FPC 3.2.0


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Bo Berglund
Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Bo Berglund via lazarus]

On Fri, 11 Nov 2022 16:29:31 +0100, Bo Berglund via lazarus
 wrote:

>Now I wonder if there is some way to do as I did when I worked in Delphi with
>TListView objects, where I could use the BeginUpdate and EndUpdate calls to 
>make
>all screen updates wait until it was all put in place.
>This was MUCH faster!
>
>But I can not find a BeginUpdate on the TListBox object, only 
>BeginUpdateBounds,
>which does not tell me much

In fact I found TListbox.Items.Beginupdate/EndUpdate, but it did not do much to
improve the handling, too slow anyway


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Bo Berglund
Developer in Sweden

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Re: [Lazarus] How to fix slow screen refresh of TListbox?

[Luca Olivetti via lazarus]

El 11/11/22 a les 16:29, Bo Berglund via lazarus ha escrit:

I have noticed that after a while the display becomes very sluggish when data
arrives and I think that is due to the way the component operates.


You could try using a TSynEdit instead of a TListBox: some years ago I 
switched from TMemo to TSynEdit to do some logging in a similar (though 
I add lines instead of assigning the complete text, also, I delete the 
oldest line when there are 5000 lines) because I found that, under 
windows, TSynEdit is an order of magnitude (or more) faster than TMemo.

No difference under linux though, and maybe it's no longer true nowadays.

Bye
--
Luca Olivetti
Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007

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