song editor window doesn't redraw properly at time of maximising

[Lx]

When maximising the song editor sub-window of LMMS, only the blocks visible before the maximise are redrawn. In order to cause all of the blocks to become visible, the window must be manually scrolled. Please refer to the two attached screen shots.

$ lmms --version
Linux MultiMedia Studio 1.0.3
(Linux x86_64, Qt 4.8.6, GCC 4.8.2)

$ dpkg -s lmms | grep Version:
Version: 1.0.3-src-0ubuntu1~ubuntu14.04.1

$ lsb_release -a
No LSB modules are available.
Distributor ID: LinuxMint
Description: Linux Mint 17 Qiana
Release: 17
Codename: qiana

Linux Mint 17 is a derivative of Ubuntu Trusty. Original Ubuntu bug report made here.

[tresf]

I'm not convinced it's a problem with LMMS (yet). It seems to happen only on some tracks for me making me believe it's a bug with QT's redraw methods (QT has a few redraw/GUI bugs that differ based on OS and QT version. For example, Apple won't scroll any MDI windows in the main QMdiArea, which is a terrible experience for newcomers to LMMS.) If you can locate a problem with the code, please point it out.

On a slightly unrelated note... how come your LMMS says 1.0.0 but your version information says 1.0.3?

-Tres

[Lx]

I initially prepared this bug report on Launchpad for Ubuntu using v1.0.0,
and was asked to test with a later version provided in an Ubuntu PPA. I've
experienced this behaviour across both versions. Your explanation
regarding QT aligns with that experience.

[tresf]

Looking at the source code, you can find a few examples of these strange bugs:
https://github.com/LMMS/lmms/blob/stable-1.1/src/gui/MainWindow.cpp#L880

And here's the Apple bug that was filed, where I've spent most of my time trying to understand the QMdiArea API:
#555

[tresf]

I just did some more testing... from what I can tell, this is reproducible, but it is extremely specific to the way the windows are open...

What I did to reproduce it:

1. Open LMMS
2. Maximize the Song Editor on the default blank template
3. Open a project that was previously saved (via Project, Recently opened projects)
4. When the project loads, it makes the default Song Editor window size incorrect (It's too small... one that does not make logical sense in terms of size)
5. Maximize the Song Editor, bug occurs.
   

Should be this:

Now do the same steps, but leave the Song Editor in a "restored" state before clicking on the recent project. The bug does not occur.

This leads me to believe the bug is related to the default "restore" behavior. Perhaps the loading of settings is in the wrong order (process the resize, then the restore, causing the resize to be forgotten).

Either way, it's a reproducible bug and probably can be fixed! :)

[Lx]

Thanks for your detailed analysis and milestone indication. I regret not having been able to provide you with the discrete list of steps that you found to reproduce the issue.

One observation I left out earlier (and which probably isn't too important since you've done more analysis): although not all blocks are shown when maximising, the blocks that are shown are at least fully drawn—there are no "partially-drawn" blocks.

I don't know whether this helps to determine whether or not an underlying Qt bug is contributing to the issue (hopefully it isn't—I can definitely sympathise with you on the matter of third-party toolkit providers being unresponsive to bug reports related to their components).

[Sti2nd]

Reproducible on windows, 1.0.93

[musikBear]

win32 xp 1.0.95
I can only replicate to the state of re-maximize

As you can see, i do get a wrong max-size after loading the existing project, but thetre are no option for maximize (grayed out) I have to first minimize, and then maximize, the result is a maximized error free song-editor -@Sti2nd -You had different context-options? How did you re-maximize the already maximized SE?
This could be much more interesting, because it could be a hint for the pesty 'lost handle' bug, where forms are unreachable from the gui. I get this idea, because one of the way to 'push' the lost form back, is to mini/maximize lmms. #765 So maybe a 'useful' bug :p

[tresf]

@musikBear I'm about ready to buy you a copy of Windows 7. :)

[Sti2nd]

What, @musikBear, context menu? I did not say how I reproduced it. Simply save your project with a small Song Editor window and open the project again. Then maximize the Song Editor window, tadaa.

[musikBear]

now 2 different ways to reproduce?
tresf says nothing about saving, and reopen nor anything about same project

Open LMMS
no shit sherlock 🐹 {joke :)
Maximize the Song Editor on the default blank template
empty new project maximized
Open a project that was previously saved (via Project, Recently opened projects)
any old project opend from "Recently.."
When the project loads, it makes the default Song Editor window size incorrect (It's too small... one that does not make logical sense in terms of size)
I have that too, as image shows
Maximize the Song Editor, bug occurs.
not possible, it is already maximized, as image shows

That is the procedure, and the result

[Sti2nd]

No, @musikBear you are on the one side talking about another bug where the Song Editor window itself is not maximized properly, whereas Tres, Lx and I are talking about the stuff inside the Song Editor is not drawn when you maximize the Song Editor.
And yeah there is different ways to reproduce it. This bug happens because LMMS doesn't "send a draw signal" when the Song Editor is maximized, so only the instrument patterns drawn in the window when loading the project is displayed after maximizing. If you scroll or resize the window with the mouse "the signal is sent" and the drawing is happening.

[tresf]

Possibly fixed via #1490.

[tresf]

Closing per #1490. Please reopen if you feel this bug was closed in error.