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Mailing lists / lazarus / 2010-04

Patch for simple docking.

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Michael Van Canneyt

Hello,

I'm writing an article about docking in Lazarus.

The first - and most simple - example I tried, failed:
- Drop a panel on a form
- Set dragkind to dkDock
- Set dragmode to dkAutomatic.
- Run application
- Drag panel outside form, and let go.

expected behaviour: a small form should appear, and the panel should be on it.

Actual behaviour: 4 Access violations (fix one to get to the next ;) ).

Attached small patch fixes the 4 access violations, after which the expected behaviour occurs. They are all checks to see if a object pointer is not-nil.

Better would be to fix the root of the problem:
I think the automatic creation of a dockhost form probably uses createnew(), which maybe doesn't correctly allocate all structures (scrollbars/icons). But that is just a wild guess, which I currently don't have time to investigate.

Michael.
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Mattias Gaertner
to Michael Van Canneyt
Show quoted text 18 lines
Hello, I'm writing an article about docking in Lazarus. The first - and most simple - example I tried, failed: - Drop a panel on a form - Set dragkind to dkDock - Set dragmode to dkAutomatic. - Run application - Drag panel outside form, and let go. expected behaviour: a small form should appear, and the panel should be on it. Actual behaviour: 4 Access violations (fix one to get to the next ;) ). Attached small patch fixes the 4 access violations, after which the expected behaviour occurs. They are all checks to see if a object pointer is not-nil.

Thanks. Applied.

Mattias

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Michael Van Canneyt
to Mattias Gaertner
Mattias Gaertner wrote 23 lines
On Sun, 4 Apr 2010 13:31:10 +0200 (CEST) Michael Van Canneyt wrote: > > Hello, > > I'm writing an article about docking in Lazarus. > > The first - and most simple - example I tried, failed: > - Drop a panel on a form > - Set dragkind to dkDock > - Set dragmode to dkAutomatic. > - Run application > - Drag panel outside form, and let go. > > expected behaviour: a small form should appear, and the panel should be on it. > > Actual behaviour: 4 Access violations (fix one to get to the next ;) ). > > Attached small patch fixes the 4 access violations, after which the expected behaviour > occurs. They are all checks to see if a object pointer is not-nil. Thanks. Applied.

Great, thank you.

Maybe you can also have a look at the following bug:
- Create main form as above.
- Additionally Set docksite=true for the main form. Run program.
- Drop panel outside main form. DockForm appears, panel is on it :-)
- Now drop the panel back on the main form.

-> The panel disappears.

All properties I thought of check out OK: visible, parent (it is main form), it's size. (size of the form).

The same problem happens when you manually dock the panel back on the main form: I do this with the following code in a button on the main form:

   Panel1.ManualDock(Self,Self,alTop,true);

I tried debugging it, but the error escapes me. All seems to be working as it should, except that the control is not drawn on it's new location :/

It's not a panel problem, I tried with some other controls as well. (tested on GTK2, latest Lazarus and FPC)

Michael.

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Hans-Peter Diettrich
to Michael Van Canneyt: I'm writing an article about docking in Lazarus. The first - and most simple - example I…
I'm writing an article about docking in Lazarus.

First question: which DockManager do you use?

Did you see:
http://wiki.lazarus.freepascal.org/LCL_Drag_Drop#Common_Principles

Show quoted text 11 lines
The first - and most simple - example I tried, failed: - Drop a panel on a form - Set dragkind to dkDock - Set dragmode to dkAutomatic. - Run application - Drag panel outside form, and let go. expected behaviour: a small form should appear, and the panel should be on it. Actual behaviour: 4 Access violations (fix one to get to the next ;) ).

Sounds like new autosize bugs. Did you use -dOldAutoSize when building the LCL?

DoDi

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Michael Van Canneyt
to Hans-Peter Diettrich: First question: which DockManager do you use? Did you see:…
Hans-Peter Diettrich wrote 5 lines
Michael Van Canneyt schrieb: > I'm writing an article about docking in Lazarus. First question: which DockManager do you use?

The standard LCL dockmanager.

And, yes, I know about EasyDockingManager.

Did you see: http://wiki.lazarus.freepascal.org/LCL_Drag_Drop#Common_Principles

I didn't see, but there is nothing in there which is new to me.

Show quoted text 15 lines
> The first - and most simple - example I tried, failed: > - Drop a panel on a form > - Set dragkind to dkDock > - Set dragmode to dkAutomatic. > - Run application > - Drag panel outside form, and let go. > > expected behaviour: a small form should appear, and the panel should be on > it. > > Actual behaviour: 4 Access violations (fix one to get to the next ;) ). Sounds like new autosize bugs. Did you use -dOldAutoSize when building the LCL?

No.

But now I did, and in that case there is some noticeable improvement.

Michael.

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Michael Van Canneyt
to Michael Van Canneyt: Great, thank you. Maybe you can also have a look at the following bug: - Create main form…
Michael Van Canneyt wrote 27 lines
Great, thank you. Maybe you can also have a look at the following bug: - Create main form as above. - Additionally Set docksite=true for the main form. Run program. - Drop panel outside main form. DockForm appears, panel is on it :-) - Now drop the panel back on the main form. -> The panel disappears. All properties I thought of check out OK: visible, parent (it is main form), it's size. (size of the form). The same problem happens when you manually dock the panel back on the main form: I do this with the following code in a button on the main form: Panel1.ManualDock(Self,Self,alTop,true); I tried debugging it, but the error escapes me. All seems to be working as it should, except that the control is not drawn on it's new location :/ It's not a panel problem, I tried with some other controls as well. (tested on GTK2, latest Lazarus and FPC)

Follow-up, after tip from Hans-Peter Diettrich:

When building the LCL with -dOldAutoSize, the panel is shown.

Michael.

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Mattias Gaertner
to Hans-Peter Diettrich: First question: which DockManager do you use? Did you see:…
Show quoted text 23 lines
Michael Van Canneyt schrieb: > I'm writing an article about docking in Lazarus. First question: which DockManager do you use? Did you see: http://wiki.lazarus.freepascal.org/LCL_Drag_Drop#Common_Principles > The first - and most simple - example I tried, failed: > - Drop a panel on a form > - Set dragkind to dkDock > - Set dragmode to dkAutomatic. > - Run application > - Drag panel outside form, and let go. > > expected behaviour: a small form should appear, and the panel should be > on it. > > Actual behaviour: 4 Access violations (fix one to get to the next ;) ). Sounds like new autosize bugs. Did you use -dOldAutoSize when building the LCL?

The patch checks Iconnil, which is a good thing in an event.

The new autosize algorithm unhid many bugs, that worked by luck not by design.

Mattias

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Mattias Gaertner
to Michael Van Canneyt: Follow-up, after tip from Hans-Peter Diettrich: When building the LCL with -dOldAutoSize,…
Show quoted text 35 lines
On Sun, 4 Apr 2010, Michael Van Canneyt wrote: > Great, thank you. > > Maybe you can also have a look at the following bug: > - Create main form as above. > - Additionally Set docksite=true for the main form. > Run program. > - Drop panel outside main form. DockForm appears, panel is on it :-) > - Now drop the panel back on the main form. > > -> The panel disappears. > > All properties I thought of check out OK: visible, parent (it is main form), > it's size. > (size of the form). > > The same problem happens when you manually dock the panel back on the main > form: > I do this with the following code in a button on the main form: > > Panel1.ManualDock(Self,Self,alTop,true); > > I tried debugging it, but the error escapes me. All seems to be working as it > should, > except that the control is not drawn on it's new location :/ > > It's not a panel problem, I tried with some other controls as well. > (tested on GTK2, latest Lazarus and FPC) Follow-up, after tip from Hans-Peter Diettrich: When building the LCL with -dOldAutoSize, the panel is shown.

This has been fixed.

Mattias

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Michael Van Canneyt
to Mattias Gaertner: On Sun, 4 Apr 2010 20:02:51 +0200 (CEST) What improvement? Mattias
Mattias Gaertner wrote 12 lines
On Sun, 4 Apr 2010 20:02:51 +0200 (CEST) Michael Van Canneyt wrote: > [...] >> Sounds like new autosize bugs. Did you use -dOldAutoSize when building the >> LCL? > > No. > > But now I did, and in that case there is some noticeable improvement. What improvement?

When the panel is dropped back on the form, it is shown again. (but with weird alignments)

Michael.

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Michael Van Canneyt
to Mattias Gaertner: On Sun, 4 Apr 2010 20:04:38 +0200 (CEST) This has been fixed. Mattias
Mattias Gaertner wrote 40 lines
On Sun, 4 Apr 2010 20:04:38 +0200 (CEST) Michael Van Canneyt wrote: > > > On Sun, 4 Apr 2010, Michael Van Canneyt wrote: > >> Great, thank you. >> >> Maybe you can also have a look at the following bug: >> - Create main form as above. >> - Additionally Set docksite=true for the main form. >> Run program. >> - Drop panel outside main form. DockForm appears, panel is on it :-) >> - Now drop the panel back on the main form. >> >> -> The panel disappears. >> >> All properties I thought of check out OK: visible, parent (it is main form), >> it's size. >> (size of the form). >> >> The same problem happens when you manually dock the panel back on the main >> form: >> I do this with the following code in a button on the main form: >> >> Panel1.ManualDock(Self,Self,alTop,true); >> >> I tried debugging it, but the error escapes me. All seems to be working as it >> should, >> except that the control is not drawn on it's new location :/ >> >> It's not a panel problem, I tried with some other controls as well. >> (tested on GTK2, latest Lazarus and FPC) > > Follow-up, after tip from Hans-Peter Diettrich: > > When building the LCL with -dOldAutoSize, the panel is shown. This has been fixed.

Great, thank you very much.

Michael.

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