Re: [Lazarus] flickering on statusbar panel
I saw that the bug (ID 0012816) related to this thread has been closed.
But I still encounter the same problem as described in my first e-mail.
The statusbar panel still flickers.
Andrea
Sergei Gorelkin ha scritto:
> Michael Van Canneyt wrote:
>
>
>> As far as I know, in Delphi the statusbar updates immediatly, contrary to a
>> label.
>>
>>
> There is a bug in VCL that causes statusbars flicker. It can be fixed by
> something like not passing WM_ERASEBKGND to DefWindowProc ("something
> like" is because it was a long time ago, and I cannot remember exactly).
> All common controls are doublebuffered natively by Windows, so they
> shouldn't flicker even without doublebuffering in LCL.
>
> Regards,
> Sergei
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>
>
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Re: [Lazarus] flickering on statusbar panel
Michael Van Canneyt wrote:
> As far as I know, in Delphi the statusbar updates immediatly, contrary to a
> label.
>
There is a bug in VCL that causes statusbars flicker. It can be fixed by
something like not passing WM_ERASEBKGND to DefWindowProc ("something
like" is because it was a long time ago, and I cannot remember exactly).
All common controls are doublebuffered natively by Windows, so they
shouldn't flicker even without doublebuffering in LCL.
Regards,
Sergei
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Re: [Lazarus] flickering on statusbar panel
On Fri, 19 Dec 2008, Mattias Gaertner wrote:
> On Fri, 19 Dec 2008 11:52:18 +0100
> Andrea Mauri wrote:
>
> > The code I wrote in the e-mail is just a sample!
> > Anyway, create a new project, drop a label, a statusbar and a button
> > on the form. Create a panel on the statusbar.
> > On buttonclick drop the following code:
> >
> > procedure TForm1.Button1Click(Sender: TObject);
> > var
> > i: integer;
> > begin
> > i:= 0;
> > while i < 1 do
> > begin
> > // Application.ProcessMessages;
> > label1.Caption:= Format('Number: %d', [i]);
> > statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
> > Inc(i);
> > end;
> >
> > Clicking on the button the text in the statusbar panel start to be
> > updated, and it flickers. The text in the caption is updated only at
> > the end of the while do cycle.
>
> Great. There you have the bug. The statusbar should not update, just
> like the label.
As far as I know, in Delphi the statusbar updates immediatly, contrary to a
label.
Michael.
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Re: [Lazarus] flickering on statusbar panel
Bug report created.
Andrae
Mattias Gaertner ha scritto:
> On Fri, 19 Dec 2008 11:52:18 +0100
> Andrea Mauri wrote:
>
>
>> The code I wrote in the e-mail is just a sample!
>> Anyway, create a new project, drop a label, a statusbar and a button
>> on the form. Create a panel on the statusbar.
>> On buttonclick drop the following code:
>>
>> procedure TForm1.Button1Click(Sender: TObject);
>> var
>> i: integer;
>> begin
>> i:= 0;
>> while i < 1 do
>> begin
>> // Application.ProcessMessages;
>> label1.Caption:= Format('Number: %d', [i]);
>> statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
>> Inc(i);
>> end;
>>
>> Clicking on the button the text in the statusbar panel start to be
>> updated, and it flickers. The text in the caption is updated only at
>> the end of the while do cycle.
>>
>
> Great. There you have the bug. The statusbar should not update, just
> like the label.
>
>
>
>> If I uncomment the line Application.ProcessMessages both texts in
>> label and in statusbar panel are updated during the while do cycle.
>> The text in the label does not flicker while the text in the
>> statusbar panel flickers.
>>
>
> It probably flickers because of above bug.
>
>
>
>> I tested it on WinXP with lazarus v0.9.27 r17856
>> i386-win32-win32/win64 and fpc 2.2.2
>> The same code works on Linux with lazarus svn and fpc 2.2.2
>> (statusbar and label do not flicker).
>> I hope that I well explained the problem.
>>
>
> Yes, although I'm not a win32 intf developer. Please create a bug
> report with the above example.
>
>
> Mattias
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>
>
--
Dr. Andrea Mauri, PhD
Milano Chemometrics and QSAR Research Group
Department of Environmental Sciences
University of Milano-Bicocca
P.zza della Scienza, 1
20126 Milano - Italy
Tel: ++39 02 64482801
mailto:andrea.mauri...@gmail.com
http://michem.disat.unimib.it/chm/
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Re: [Lazarus] flickering on statusbar panel
On Fri, 19 Dec 2008 11:52:18 +0100
Andrea Mauri wrote:
> The code I wrote in the e-mail is just a sample!
> Anyway, create a new project, drop a label, a statusbar and a button
> on the form. Create a panel on the statusbar.
> On buttonclick drop the following code:
>
> procedure TForm1.Button1Click(Sender: TObject);
> var
> i: integer;
> begin
> i:= 0;
> while i < 1 do
> begin
> // Application.ProcessMessages;
> label1.Caption:= Format('Number: %d', [i]);
> statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
> Inc(i);
> end;
>
> Clicking on the button the text in the statusbar panel start to be
> updated, and it flickers. The text in the caption is updated only at
> the end of the while do cycle.
Great. There you have the bug. The statusbar should not update, just
like the label.
> If I uncomment the line Application.ProcessMessages both texts in
> label and in statusbar panel are updated during the while do cycle.
> The text in the label does not flicker while the text in the
> statusbar panel flickers.
It probably flickers because of above bug.
> I tested it on WinXP with lazarus v0.9.27 r17856
> i386-win32-win32/win64 and fpc 2.2.2
> The same code works on Linux with lazarus svn and fpc 2.2.2
> (statusbar and label do not flicker).
> I hope that I well explained the problem.
Yes, although I'm not a win32 intf developer. Please create a bug
report with the above example.
Mattias
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Re: [Lazarus] flickering on statusbar panel
The code I wrote in the e-mail is just a sample!
Anyway, create a new project, drop a label, a statusbar and a button on
the form. Create a panel on the statusbar.
On buttonclick drop the following code:
procedure TForm1.Button1Click(Sender: TObject);
var
i: integer;
begin
i:= 0;
while i < 1 do
begin
// Application.ProcessMessages;
label1.Caption:= Format('Number: %d', [i]);
statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
Inc(i);
end;
Clicking on the button the text in the statusbar panel start to be
updated, and it flickers. The text in the caption is updated only at the
end of the while do cycle.
If I uncomment the line Application.ProcessMessages both texts in label
and in statusbar panel are updated during the while do cycle. The text
in the label does not flicker while the text in the statusbar panel
flickers.
I tested it on WinXP with lazarus v0.9.27 r17856 i386-win32-win32/win64
and fpc 2.2.2
The same code works on Linux with lazarus svn and fpc 2.2.2 (statusbar
and label do not flicker).
I hope that I well explained the problem.
Best regards,
Andrea
Reenen Laurie ha scritto:
i:= 0;
while condition do
begin
readln(f, str);
label1.Caption:= Format('Number: %d', [i]);
statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
Inc(i);
end;
If condition stays true, then statusbar will flicker continuously...
(being updated continuously)
you don't have an "exit" condition here (like "while not EOF(F) do")
Maybe this will help?
Also, just for information:
Which OS are you on, which version of that OS and which SVN version
(or Lazarus release version)?
Regards,
-Reenen
On Fri, Dec 19, 2008 at 11:17 AM, Andrea Mauri
mailto:andrea.mauri...@gmail.com>> wrote:
Mattias Gaertner ha scritto:
> On Thu, 18 Dec 2008 14:58:58 +0100
> Andrea Mauri mailto:andrea.mauri...@gmail.com>> wrote:
>
>
>> But why, same monitor, same application, labels do not flicker
while
>> statusbar flickers?
>>
>
> If statusbar text and properties do not change and it still flickers
> when it is repainted, then there is a bug in the double buffering.
> Please create a bug report.
>
> Mattias
>
As I wrote in my first e-mail in this thread the statusbar
flickers when
the text changes.
This is what I wrote in my first e-mail:
"
Dear all,
I encountered a flickering problem when using a statusbar under winxp
(lazarus v0.9.27 r17839 i386-win32-win32/win64 fpc 2.2.2)
Using a code similar to the following:
i:= 0;
while condition do
begin
readln(f, str);
label1.Caption:= Format('Number: %d', [i]);
statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
Inc(i);
end;
The text in the status bar panel flickers a lot while the same text in
the label does not flicker.
On Linux Ubuntu also the statusbar works fine.
Another issue, but I am not sure because I made just some few
tests, it
seems that writing on the statusbar is a little slower than
writing on a
label.
"
So the text changes (not all the text, 'Number: ' string is fixed)
in the statusbar, no other properties change.
I encounter this problem only on windows. Labels work properly.
Confirm that I have to create a bug report.
Thanks,
Andrea
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> Lazarus mailing list
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> http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
>
>
--
Dr. Andrea Mauri, PhD
Milano Chemometrics and QSAR Research Group
Department of Environmental Sciences
University of Milano-Bicocca
P.zza della Scienza, 1
20126 Milano - Italy
Tel: ++39 02 64482801
mailto:andrea.mauri...@gmail.com
http://michem.disat.unimib.it/chm/
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Dr. Andrea Mauri, PhD
Milano Chemometrics and QSAR Research Group
Department of Environmental Sciences
University of Milano-Bicocca
P.zza della Scienza, 1
20126 Milano - Italy
Tel: ++39 02 64482801
mailto:andrea.mauri...@gmail.com
http://michem.disat.unimib.it/chm/
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Re: [Lazarus] flickering on statusbar panel
i:= 0;
while condition do
begin
readln(f, str);
label1.Caption:= Format('Number: %d', [i]);
statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
Inc(i);
end;
If condition stays true, then statusbar will flicker continuously... (being
updated continuously)
you don't have an "exit" condition here (like "while not EOF(F) do")
Maybe this will help?
Also, just for information:
Which OS are you on, which version of that OS and which SVN version (or
Lazarus release version)?
Regards,
-Reenen
On Fri, Dec 19, 2008 at 11:17 AM, Andrea Mauri wrote:
>
> Mattias Gaertner ha scritto:
> > On Thu, 18 Dec 2008 14:58:58 +0100
> > Andrea Mauri wrote:
> >
> >
> >> But why, same monitor, same application, labels do not flicker while
> >> statusbar flickers?
> >>
> >
> > If statusbar text and properties do not change and it still flickers
> > when it is repainted, then there is a bug in the double buffering.
> > Please create a bug report.
> >
> > Mattias
> >
>
> As I wrote in my first e-mail in this thread the statusbar flickers when
> the text changes.
> This is what I wrote in my first e-mail:
>
> "
> Dear all,
> I encountered a flickering problem when using a statusbar under winxp
> (lazarus v0.9.27 r17839 i386-win32-win32/win64 fpc 2.2.2)
> Using a code similar to the following:
>
> i:= 0;
> while condition do
> begin
> readln(f, str);
> label1.Caption:= Format('Number: %d', [i]);
> statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
> Inc(i);
> end;
>
> The text in the status bar panel flickers a lot while the same text in
> the label does not flicker.
> On Linux Ubuntu also the statusbar works fine.
> Another issue, but I am not sure because I made just some few tests, it
> seems that writing on the statusbar is a little slower than writing on a
> label.
> "
>
> So the text changes (not all the text, 'Number: ' string is fixed) in the
> statusbar, no other properties change.
> I encounter this problem only on windows. Labels work properly.
> Confirm that I have to create a bug report.
> Thanks,
> Andrea
>
>
> > ___
> > Lazarus mailing list
> > Lazarus@lazarus.freepascal.org
> > http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
> >
> >
>
> --
> Dr. Andrea Mauri, PhD
> Milano Chemometrics and QSAR Research Group
> Department of Environmental Sciences
> University of Milano-Bicocca
> P.zza della Scienza, 1
> 20126 Milano - Italy
>
> Tel: ++39 02 64482801
> mailto:andrea.mauri...@gmail.com
> http://michem.disat.unimib.it/chm/
>
> ___
> Lazarus mailing list
> Lazarus@lazarus.freepascal.org
> http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
>
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Re: [Lazarus] flickering on statusbar panel
Mattias Gaertner ha scritto:
> On Thu, 18 Dec 2008 14:58:58 +0100
> Andrea Mauri wrote:
>
>
>> But why, same monitor, same application, labels do not flicker while
>> statusbar flickers?
>>
>
> If statusbar text and properties do not change and it still flickers
> when it is repainted, then there is a bug in the double buffering.
> Please create a bug report.
>
> Mattias
>
As I wrote in my first e-mail in this thread the statusbar flickers when
the text changes.
This is what I wrote in my first e-mail:
"
Dear all,
I encountered a flickering problem when using a statusbar under winxp
(lazarus v0.9.27 r17839 i386-win32-win32/win64 fpc 2.2.2)
Using a code similar to the following:
i:= 0;
while condition do
begin
readln(f, str);
label1.Caption:= Format('Number: %d', [i]);
statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
Inc(i);
end;
The text in the status bar panel flickers a lot while the same text in
the label does not flicker.
On Linux Ubuntu also the statusbar works fine.
Another issue, but I am not sure because I made just some few tests, it
seems that writing on the statusbar is a little slower than writing on a
label.
"
So the text changes (not all the text, 'Number: ' string is fixed) in the
statusbar, no other properties change.
I encounter this problem only on windows. Labels work properly.
Confirm that I have to create a bug report.
Thanks,
Andrea
> ___
> Lazarus mailing list
> Lazarus@lazarus.freepascal.org
> http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
>
>
--
Dr. Andrea Mauri, PhD
Milano Chemometrics and QSAR Research Group
Department of Environmental Sciences
University of Milano-Bicocca
P.zza della Scienza, 1
20126 Milano - Italy
Tel: ++39 02 64482801
mailto:andrea.mauri...@gmail.com
http://michem.disat.unimib.it/chm/
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Re: [Lazarus] flickering on statusbar panel
On Thu, 18 Dec 2008 14:58:58 +0100 Andrea Mauri wrote: > But why, same monitor, same application, labels do not flicker while > statusbar flickers? If statusbar text and properties do not change and it still flickers when it is repainted, then there is a bug in the double buffering. Please create a bug report. Mattias ___ Lazarus mailing list Lazarus@lazarus.freepascal.org http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] flickering on statusbar panel
But why, same monitor, same application, labels do not flicker while statusbar flickers? Andrea Mattias Gärtner ha scritto: > Zitat von Andrea Mauri : > > >> Yes, but the flickering remains both with DoubleBuffered:= True and >> DoubleBuffered:= False. >> The only difference is that using DoubleBuffered:= True the statusbar >> seems to be repainted faster. >> > > TWinControl.DoubleBuffered can only fix the flickering when repainting the > same > (erasing plus painting the same content as the last time). > It can not fix the flickering when the text on the statusbar changes. To fix > this flickering your painting must be in sync with your monitor. See the > vertical sync option for your graphic card. > > > Mattias > > ___ > Lazarus mailing list > Lazarus@lazarus.freepascal.org > http://www.lazarus.freepascal.org/mailman/listinfo/lazarus > > -- Dr. Andrea Mauri, PhD Milano Chemometrics and QSAR Research Group Department of Environmental Sciences University of Milano-Bicocca P.zza della Scienza, 1 20126 Milano - Italy Tel: ++39 02 64482801 mailto:andrea.mauri...@gmail.com http://michem.disat.unimib.it/chm/ ___ Lazarus mailing list Lazarus@lazarus.freepascal.org http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] flickering on statusbar panel
Zitat von Andrea Mauri : > Yes, but the flickering remains both with DoubleBuffered:= True and > DoubleBuffered:= False. > The only difference is that using DoubleBuffered:= True the statusbar > seems to be repainted faster. TWinControl.DoubleBuffered can only fix the flickering when repainting the same (erasing plus painting the same content as the last time). It can not fix the flickering when the text on the statusbar changes. To fix this flickering your painting must be in sync with your monitor. See the vertical sync option for your graphic card. Mattias ___ Lazarus mailing list Lazarus@lazarus.freepascal.org http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] flickering on statusbar panel
Yes, but the flickering remains both with DoubleBuffered:= True and DoubleBuffered:= False. The only difference is that using DoubleBuffered:= True the statusbar seems to be repainted faster. Andrea Bart ha scritto: > On 12/17/08, Andrea Mauri wrote: > >> any suggestions? >> > > Does TStatusBar have a DoubleBuffer property (I cannot test here at > this place: no Lazarus available) > > Bart > ___ > Lazarus mailing list > Lazarus@lazarus.freepascal.org > http://www.lazarus.freepascal.org/mailman/listinfo/lazarus > > -- Dr. Andrea Mauri, PhD Milano Chemometrics and QSAR Research Group Department of Environmental Sciences University of Milano-Bicocca P.zza della Scienza, 1 20126 Milano - Italy Tel: ++39 02 64482801 mailto:andrea.mauri...@gmail.com http://michem.disat.unimib.it/chm/ ___ Lazarus mailing list Lazarus@lazarus.freepascal.org http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] flickering on statusbar panel
On 12/17/08, Andrea Mauri wrote: > any suggestions? Does TStatusBar have a DoubleBuffer property (I cannot test here at this place: no Lazarus available) Bart ___ Lazarus mailing list Lazarus@lazarus.freepascal.org http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] flickering on statusbar panel
any suggestions?
Andrea Mauri ha scritto:
> Dear all,
> I encountered a flickering problem when using a statusbar under winxp
> (lazarus v0.9.27 r17839 i386-win32-win32/win64 fpc 2.2.2)
> Using a code similar to the following:
>
> i:= 0;
> while condition do
> begin
> readln(f, str);
> label1.Caption:= Format('Number: %d', [i]);
> statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
> Inc(i);
> end;
>
> The text in the status bar panel flickers a lot while the same text in
> the label does not flicker.
> On Linux Ubuntu also the statusbar works fine.
> Another issue, but I am not sure because I made just some few tests, it
> seems that writing on the statusbar is a little slower than writing on a
> label.
> Regards,
> Andrea
> ___
> Lazarus mailing list
> Lazarus@lazarus.freepascal.org
> http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
>
>
--
Dr. Andrea Mauri, PhD
Milano Chemometrics and QSAR Research Group
Department of Environmental Sciences
University of Milano-Bicocca
P.zza della Scienza, 1
20126 Milano - Italy
Tel: ++39 02 64482801
mailto:andrea.mauri...@gmail.com
http://michem.disat.unimib.it/chm/
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[Lazarus] flickering on statusbar panel
Dear all,
I encountered a flickering problem when using a statusbar under winxp
(lazarus v0.9.27 r17839 i386-win32-win32/win64 fpc 2.2.2)
Using a code similar to the following:
i:= 0;
while condition do
begin
readln(f, str);
label1.Caption:= Format('Number: %d', [i]);
statusbar1.Panels[0].Text:= Format('Number: %d', [i]);
Inc(i);
end;
The text in the status bar panel flickers a lot while the same text in
the label does not flicker.
On Linux Ubuntu also the statusbar works fine.
Another issue, but I am not sure because I made just some few tests, it
seems that writing on the statusbar is a little slower than writing on a
label.
Regards,
Andrea
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