For a few months now I've been trying to have a random slideshow of images. I
used to do this either with
kscreensaver, which for completely different
reasons I can't use now, or
glslideshow, which, even when I
compiled it by hand, I can't find the way to give it the root dir of the images.
So, based on OMIT, I developed my own.
The differences with OMIT are minimal. It has to scan the whole tree for finding the appropriate files (its definition of "appropriate" could be improved, it's true); it goes into full screen mode with black background; and it (more) properly handles EXIF rotation. All that in 176 LOCs, including proper licensing (GPLv3), and developed in one day and refined the next one.
So, there you are. Like OMIT, it's in
PyQt4, but this time in Python3 (that's
why I used
includes porting it to
PyQt5 and a few other things. You can grab it
here. I plan to do a proper
release soon, but for the moment just drop it in your
PATH and be happy with
A few days ago someone said something that reminded me about my audio player, which I had abandoned for more than a year already. The reason was mostly that the two Phonon backends, VLC and gstreamer, for some reason or other couldn't play the files I had without any gaps between songs.
To be honest, the first bug end up being me not properly encoding the filenames.
If you first URL-encoded the filename and then built a Q/KURL with that, then
it's all fine. It took me more than 12 months and a few rereads of the thread
to realize it. Fixes apart, it seems that the bug still exists for other
instances of gstreamer errors, so we're not out of the woods. In any case, I
switched to the VLC backend and it seems that now is able to fire the
aboutToFinnish() signal properly, so for the moment I'm using that.
All that is fine, but that's not what I wanted to talk about in this post. Given
that this project largely precedes my interest on testing, it has no testing at
all. Most of the project is straightforward enough to almost no need any, but
there's a critic part that would not suffer at all if it had any, namely the
Collections handling, including passing files from one to another and
automatically updating new/removed
So after fixing the bug mentioned above I tried to figure out the current state
of affaires regarding
Collections, and boy, they're in bad shape. The code was
locally modified, never commited, deactivating any notifications of filesystem
changes (new or removed files), and other code I can't really understand the
Because if this last detail is that I decided to start testing three classes:
Collection, which handles a set a
Songs with a common root directory;
CollectionAggregator, which handles a set of collections and should coordinate
Song from one
Collection to another; and
CollectionIndexer, which scans
Collection's root dir to find
All went fine while I tested the first class, Collection. There was a tricky
part where I had to setup a
QApplication in order to make signals work. The
problems began when I started testing
CollectionIndexer. Tests started blocking
endlessly, signals stopped being either emited or firing the connected slots,
life was bad.
I tried to search the available documentation and mailing lists for a hint about the problem, but besides a quite complex example that didn't seem to properly converge to anything useful, I was mostly on my own.
This morning I got my eureka moment: I noticed that if I executed each test class
by itself, it worked, but both at the same time blocked and never finished. Then
I remembered something said in
For any GUI application using Qt, there is precisely one QApplication object, no matter whether the application has 0, 1, 2 or more windows at any given time.
That was it: I was creating the application, first in the
setUp() method, then
as a class attribute, but I had one test class per class to test, each in its
own file. Somehow this last fact lead me to think that somehow they were executed
in separate processes, which is not true. Luckily, even with this limitation, there's
none on the amount of times you can
quit() the same instance, so
that's what I did: I created only one instance and reused it everywhere. I was
already doing that for each test method, but again, somehow having several files
mislead me to think they were isolated from each other.
So now all my unit tests work without mysteriously blocking forever. Now I just
hope I can keep riding the success wave and bring
satyr into good shape. A new
release wouldn't hurt.
 No matter how much I try, I can't get any vaguer.
 Ok, maybe the
Playlist combo wouldn't hurt to have UTs either.
After several months thinking about it, and just two requests, I finally decided
satyr's code. I decided to use github because I already switched to
git, mainly for testing and understanding it. I think I
can live with
hg, althought branch management in
git seems to be given more
thought and a good implementation.
So, without further ado: satyr in github
Remember, it's still a test software, by no means polished or ready for human
consumption, and with very low development force. Still, I think it has some
nice features, like interchangeable skins and a well defined backend,
support, quick tag edition, reasonable collection managment, and, thanks to
Phonon, almost-gapless playback and things like «stop after playing the
current this file» (but not «after any given file» yet).
In Debian Sid it mostly works only with the
GStreamer backend; I haven't tried
xine one and I know
VLC does not emit a signal needed for queueing the
next song, so you have to press «next» after each song. AFAIK this is fixed
satyr-0.3.2 "I should install my own food" is out. The Changelog is not very impressive:
- We can save the list of queued Songs on exit and load it at startup.
- The queue position is not presented when editing the title of a Song that is queued.
- Setting the track number works now (was a bug).
- Fixed a bug in setup.py.
but the last one is somewhat important (Thanks Chipaca). Also, 2 months ago, I made the satyr-0.3.1 "freudian slip" release, when user 'dglent' from http://kde-apps.org/ found a packaging bug. It was not only a bugfixing revision, it also included new features:
- nowPlaying(), exported via dbus.
- 'now playing' plugin for irssi.
- Changes in tags is copied to selected cells (in the same column). This allows 'Massive tag writing'.
- Fixed "NoneType has no attribute 'row'" bug, but this is just a workaround.
- Forgot to install complex.ui.
Now go get it!
Since a long ago I'm looking for a media player for listening my music. In that aspect I'm really exigent. Is not that I need lots of plugins and eye candy, no, I just need a media player that fits my way to listen music.
How do I listen to music? All day long, for starters. I have a collection of
.ogg files, which I normally listen in random mode. From time to time I
want to listen certain song, so I either queue it or simply stop the current
one and start the one I want. Sometimes I enqueue several songs, which might
not be related between them (maybe only in my head they are).
I've been using
Amarok, I really like its random albums feature; that is,
I listen to a whole album, and when it finishes, another album is picked at
random and I listen to all its songs. The last feature, a really important
one: My collection is my playlist and viceversa. I don't build playlists; if
I want to listen to certain songs I just queue them. One feature I like also
is a tag editor and the posibility to rearrange the songs based on its tags
(with support for albums with songs from various authors, like OST's). Last
but no least, reacting to new files in the collection is also well regarded.
I used to use
xmms. I still think it's a very good player for me, but it
lacks utf support and doesn't react when I add songs to the collection. Then
Audacious (I was using it up to
today) and probably a couple more. None of them support all the features, so
today, completely tired of this situation, I started writing my own. I
Satyr. Another reason to do it is to play a little more with
PyKDE. Talking about
KDE, I know the existence of
minirok, but it uses
GStreamer, and I wanted to play with
So, what's different in this media player? If you think about it, if you have a CD (vinyl, cassettes maybe?) collection in your home, what you have is exactly that: a collection of Albums. Most media players manage Songs, grouping them in Albums and by Author too. Notably Amarok used to manage Albums with several artists (what's called a 'Various artists' Album), but since Amarok 2 it doesn't do it anymore, nor the queuing works. So the basic idea is exactly that: you have a Collection of Albums, most of them with songs from the same Author (and sometimes Featuring some other Authors), but sometimes with Songs from different Authors. Of course I will try to implement all the features I mentioned above.
Ok, enough introduction. This post was aimed to show some code, and that's what I'm going to do now. This afternoon I was testing the Phonon Python bindings, trying to make a script to play a simple file. This snippet works:
# qt/kde related from <span class="createlink">PyKDE4</span>.kdecore import KCmdLineArgs, KAboutData, i18n, ki18n from <span class="createlink">PyKDE4</span>.kdeui import KApplication # from <span class="createlink">PyKDE4</span>.phonon import Phonon from <span class="createlink">PyQt4</span>.phonon import Phonon from <span class="createlink">PyQt4</span>.QtCore import SIGNAL media= Phonon.MediaObject () ao= Phonon.AudioOutput (Phonon.MusicCategory, app) print ao.outputDevice ().name () Phonon.createPath (media, ao) media.setCurrentSource (Phonon.MediaSource ("/home/mdione/test.ogg") media.play () app.connect (media, SIGNAL("finished ()"), app.quit) app.exec_ ()
Of course, this must be preceded by the bureaucratic creation of a
KApplication, but it basically plays an ogg file and quits. You just have
to define a
MediaObject as the source, an
AudioOutput as the sink, and
createPath between them. As you can see, with Phonon you don't
even have to worry about where the output will be going: that is defined by
the system/user configuration. You only have to declare that your
AudioOutput is going to play Music (the second actual line of code).
There are a couple of peculiarities with the
Python bindings. First of
Phonon comes both with Qt and separately. The separate one has a
binding in the
PyKDE4 package, but it seems that it doesn't work very
well, so I used the
PyQt binding. For that, I had to install the
python-pyqt4-phonon package. Second, the bindings don't support to call
setCurrentSource() with a string; you have to wrap it in a
The original API supports it. Third, it seems that
is not supported by the bindings either, so I had to build the
by hand. I don't care, it's just a couple lines more.
This code also shows the name of the selected
OutputDevice. I my machine
HDA Intel (STAC92xx Analog).
In the following days I'll be posting more info about what comes out of this project. I will only reveal that right now the code has classes called Player,and Collection. It can scan a Collection from a path given in the command line and play all the files found there. Soon more features will come.
 I'm not planing to do anything about it... yet.
Satyr handles paths. There are some problems with paths and (sigh)
encondings. Of those, here are two: there's no way to know in which encoding
the filenames in a filesystem are enconded (f.i., there's no way to ask the
filesystem), and even if that were possible, the filenames might not even be
enconded in that enconding. In these (still!) transitioning times, lots and
lots and shitloads of filesystems are used in UTF-8 environments, but some
filenames are still in old ISO-8859-1 or whatever the system was using
QString. I'm taking a path from the command line; this path is
the location of the (right now only)
Collection for the player. I'm
handling the command line using
KCmdLineOptions, which returns
As we all know,
QString, just like the
unicode type in
all the data internally as Unicode, which is The Right Thing™. If you
really need the internal data, say as bytes, you can always call the
constData() method and be happy with it. This would be the case for paths;
you need the bytes.
PyQt4. For some reason, which maybe I will ask in the pyqt
constData() is not available. What to do? Well, that's what this post is
about. What you're about to read is hacky as it can be, but then it works. I
might feel dirty, but I can live with it. As long as I mark it as a
utter/über hack and promise to revert it once that's possible...
# path is a QString qba= QByteArray () qba.append (path) path= str (qba) # now path is a list of bytes/string.
Even if this part of the bug is fixed, then
Phonon.MediaObject.play() fails when feeded that same path with this
ERROR: backend <span class="createlink">MediaObject</span> reached <span class="createlink">ErrorState</span> after 1 . It seems a <span class="createlink">KioMediaStream</span> will not help here, trying anyway.
or simply refusing to continue. Sure, in my case I should simply ignore the filename and inform the user what's going on, but sometimes you can't be so gentle.
 but then it doesn't make much sense now since Phil wants to get rid of QString (for several reasons, which might most possibly include this one).
satyr got the possibility to queue songs for playing very early. At that
moment there wasn't any GUI, so the only way to (de)queue songs was via
dbus. Once the GUI was there, we had to provide a way to queue songs. As
satyr aims to be fully usable only using the keyboard, the obvious way was to
setup some shortcut for the action.
Qt and then
KDE have a very nice API for defining 'actions' that can be
fired by the user. The ways to fire them include a shortcut, a menu entry or a
button in a toolbar. I decided to go with the
According to [the
classKAction.html#_details), to create an action is just a matter of creating
the action and to add it to an
actionCollection(). The problem is that nowhere
it says where this collection comes from. There's the
but creating one and adding the actions to it seems to be not enough.
If you instead follow the
see that it refers to a
KXmlGuiWindow, which I revised when I was desperately
looking for the misterious
actionCollection(). I don't know why, but the
documentation generated by
PyKDE does not include that method. All in all, the
tutorial code works, so I just ported my
class MainWindow (KXmlGuiWindow): def __init__ (self, parent=None): KXmlGuiWindow.__init__ (self, parent) uipath= __file__[:__file__.rfind ('.')]+'.ui' UIMainWindow, _= uic.loadUiType (uipath) self.ui= UIMainWindow () self.ui.setupUi (self) [...] self.ac= KActionCollection (self) actions.create (self, self.actionCollection ())
def create (parent, ac): '''here be common actions for satyr skins''' queueAction= KAction (parent) queueAction.setShortcut (Qt.CTRL + Qt.Key_Q) ac.addAction ("queue", queueAction) # FIXME? if we don't do this then the skin will be able to choose whether it # wants the action or not. with this it will still be able to do it, but via # implementing empty slots queueAction.triggered.connect (parent.queue)
Very simple, really. But then the action doesn't work! I tried different approaches, but none worked.
The tutorial I mentioned talks about some capabilities of the
one of them, the ability to have the inclusion of actions in menues and
toolbars dumped and loaded from XML file (hence, the XML part of the class
name), and that is handled by the
setupGUI() method. From its documentation:
«Configures the current windows and its actions in the typical
[...] Typically this function replaces
createGUI()». In my case the GUI is
already built by that
self.ui.setupUi() that you see up there, so I ignored
this method. But the thing is that if you don't call this method, the actions
will not be properly hooked, so they don't work; hence, my problem. But just
calling it make the actions work! I'll check later what's the magic behind this
method. For now just adding
self.setupGUI() at the end of the
So, that's it with actions. As a result I also get several things: a populated menu bar with Settings and Help options (but no File; that'll come later with standard actions, of which I'll talk about later, I think), with free report bug, about satyr and configure shortcuts options, among others. The later does work but its state is not saved. That also will come in the same post that standard actions.
PD: First post from my new internet connection. Will
satyr suffer from this?
Only time will tell...
 then you had to pick the index of the songs either by guessing or looking at the dump of the playlist.
Tal vez ya lo leyeron en otro lado, pero bueno: el otro día fue el día de los tutoriales de Kubuntu. Básicamente fueron tutoriales por IRC. Los logs los pueden encontrar en el wiki de Kubuntu. En particular hay 3 que me parecen bastante piolas:
Cómo usar bazaar (con Launchpad, esa bonga de project server cerrado que usan los *buntu guys).
Empaquetando para Kubuntu (obvio, sirve para Debian también).
Tutorial de , el cual lamebtablemente es muy corto.
Como para salir masomenos andando están muy piolas.
A couple of days ago Marcelo Fernández wrote a simple image viewer in
less than 200 lines long, and I thought that it would be nice to compare how
the same app would be written in
PyKDE4. But then I though that it would not
be fair, as
KDE is a whole desktop environment and
GTK is 'only' a widget
library, so I did it in
To make this even more fair, I hadn't had a good look at the code itself, I only run it to see what it looks like: a window with only the shown image in it, both scrollbars, no menu or statusbar, and no external file, so I assume he builds the ui 'by hand'. He mentions these features:
- Pan the image with the mouse.
- F1 to F5 handle the zoom from 'fit to window', 25%, 50%, 75% and 100%.
- Zooming with the mouse wheel doesn't work.
Here's my take:
#! /usr/bin/python # -*- coding: utf-8 -*- # - Example image viewer in # Marcos Dione <email@example.com> - http://grulicueva.homelinux.net/~mdione/glob/ # TODO: # * add licence! (GPLv2 or later) from .QtGui import QApplication, QMainWindow, QGraphicsView, QGraphicsScene from .QtGui import QPixmap, QGraphicsPixmapItem, QAction, QKeySequence import sys class OMITGraphicsView (QGraphicsView): def __init__ (self, pixmap, scene, parent, *args): QGraphicsView.__init__ (self, scene) self.zoomLevel= 1.0 self.win= parent self.img= pixmap self.setupActions () def setupActions (self): # a factory to the right! zoomfit= QAction (self) zoomfit.setShortcuts ([QKeySequence.fromString ('F1')]) zoomfit.triggered.connect (self.zoomfit) self.addAction (zoomfit) zoom25= QAction (self) zoom25.setShortcuts ([QKeySequence.fromString ('F2')]) zoom25.triggered.connect (self.zoom25) self.addAction (zoom25) zoom50= QAction (self) zoom50.setShortcuts ([QKeySequence.fromString ('F3')]) zoom50.triggered.connect (self.zoom50) self.addAction (zoom50) zoom75= QAction (self) zoom75.setShortcuts ([QKeySequence.fromString ('F4')]) zoom75.triggered.connect (self.zoom75) self.addAction (zoom75) zoom100= QAction (self) zoom100.setShortcuts ([QKeySequence.fromString ('F5')]) zoom100.triggered.connect (self.zoom100) self.addAction (zoom100) def zoomfit (self, *ignore): winSize= self.size () imgSize= self.img.size () print winSize, imgSize hZoom= 1.0*winSize.width ()/imgSize.width () vZoom= 1.0*winSize.height ()/imgSize.height () zoomLevel= min (hZoom, vZoom) print zoomLevel self.zoomTo (zoomLevel) def zoom25 (self, *ignore): self.zoomTo (0.25) def zoom50 (self, *ignore): self.zoomTo (0.5) def zoom75 (self, *ignore): self.zoomTo (0.75) def zoom100 (self, *ignore): self.zoomTo (1.0) def zoomTo (self, zoomLevel): scale= zoomLevel/self.zoomLevel print "scaling", scale self.scale (scale, scale) self.zoomLevel= zoomLevel if __name__=='__main__': # this code is enough for loading an image and show it! app= QApplication (sys.argv) win= QMainWindow () pixmap= QPixmap (sys.argv) qgpi= QGraphicsPixmapItem (pixmap) scene= QGraphicsScene () scene.addItem (qgpi) view= OMITGraphicsView (pixmap, scene, win) view.setDragMode (QGraphicsView.ScrollHandDrag) view.show() app.exec_ () # up to here! # end
Things to note:
- The code for loading, showing the image and pan support is only 13 lines of
Pythoncode, including 3 imports. The resulting app is also able to handle vector graphics, but of course I didn't exploit that, I just added a
- Zooming is implemented via
QGraphicsView.scale(), which is accumulative (scaling twice to 0.5 actually scales to 0.25 of the original size), so I have to keep the zoom level all the time. There should be a
- The code for calculating the scale level is not very good: scaling between 75% and 50% or 25% produces scales of 0.666 and 0.333, which I think at the end of the day will accumulate a lot of error.
- For the same reason,
zoomToFit()has to do some magic. I also got hit by the integer division of
Python(I was getting zoom factors of 0) so I had to add
1.0*to the claculations. It's good that this is fixed in
- The size reported by the
QMainWindowwas any vegetable (it said 640x480 when it actually was 960x600), so I used the
- For some strange reason
zoomToFit()scales the image a little bigger than it should, so a scrollbar appears in the direction of the constraining dimension.
- Less that 100 lines! Even if
setupActions()could surely be improved.
- In Marcelo's favor I should mention that he writes docstrings for most of his methods both in english and spanish (yes, of course I read his code after I finished mine). I barely put a couple of comments, but doing the same should add 10 more lines, tops. Also, I don't want to convert this into a who-has-it-smaller contest (the code, I mean :).
- It took me approx 3 hours, with no previous knowledge of how to do it and no internet connection, so no asking around. I just used the «Qt Reference Documentation», going to the «Gropued Classes» page and to the «Graphics View Classes» from there.
- It doesn't zoom with the mouse wheel either.
- The default colors of
formatplugin are at most sucky, but better than nothing.
 Unluckly he didn't declared which license it has, so I'm not sure if I really can do this. I GPL'ed mine.
More than two months ago I globed about QStrings and
The problem was this: my app accepts paths via command line, which are
KCmdLineOptions; which in turn converts everything to
QStrings. What I wanted were paths, which are more like
QStrings (because the latter have internally an unicode representation;
more on that later). Including
PyQt4 in the equation forced me to resort
QByteArray to get the path as a
str instead of using
PyQt4 doesn't export that function). But that's
only the beginning of the problem.
Take for instance this situation. I have a music collection that I've been
building for years now (more that 10, I think). In the old times of this
collection the filenames were encoded in
iso-8859-1. Then the future came
and converted all my machines to
utf-8. But only the software; the
filesystems were in one way or another inherited from system to system, from
machine to machine. So I ended with a mixture of utf and iso filenames, to
the point where I have a file whose filename is in iso, but the directory
where it is is in utf. Yes, I know, it is a mess. But if I take any decent
media player, I can play the file allright. That's because the filesystem
knows nothing of encodings (otherwise it would reject badly encoded
I just spent last saturday making sure that
satyr only stored filepaths in
QStrings. It took concentration, but having just
a bunch of classes and only 3 or 4 points where the filepaths are managed it
wasn't that difficult. Still, it took a day. But then, as I mentioned in
Phonon the is not able to play such files... or so I thought.
If you run
satyr after executing
export PHONON_XINE_DEBUG=1 you'll see a
Phonon debug info in the console (not that there is another way to
satyr right now anyways). Among all that info you'll see lines such as
void Phonon::Xine::XineStream::setMrl(const QByteArray&, Phonon::Xine::XineStream::StateForNewMrl) ... bool Phonon::Xine::XineStream::xineOpen(Phonon::State) xine_open succeeded for m_mrl = ...
If you're sharp enough (I'm not; sandsmark from
#phonon had to tell me)
you'll note the mention of MRL's. MRL's are
xine's URL for media. As any
URL, they can (and most of the time must) encode 'strange' characters with
the so-called "percent encoding". This means that no matter what encodings
the different parts of a filepath is in, I just add
file:// at the
beginning and then I can safely encode it scaping non-ascii characters to
%xx representations... or that's what the theory says. One thing to note is
file:// part must not be scaped;
xine complains that the file
does not exist in that case.
Looking for help in
Qt's classes one can find
QUrl and the already known
QByteArray. I can call
QByteArray.toPercentEnconding() from my
feed that to
QUrl.fromPercentEncoding() (which strangely returns a
QString, which is exactly what we're avoiding) or
But then the first function encodes too much, replacing
%3A%2F%2F. No fun.
Ok, let's try creating a
QByteArray with only the
file:// and then
toPercentEncoding() of the path only. It works:
But then calling
<span class="createlink">PyQt4</span>.QtCore.QUrl("file://xn--/home/mdione.../ltimo bondi a finisterre/07- la pequea novia del carioca-wkmz60758d.wav")
The URL got somehow puny-encoded,
which of course
xine doesn't recognize for local files.
Another option is to create an empty
QUrl.StrictMode so we avoid 50 lines of code that start
that try to escape everything all over again (and I already had some
double-or-even-triple-enconding nightmares parsing RSS/Atom feeds last year,
thank you), but we get puny-encoded again (maybe it is 'pwny-encoded'?).
Last resort: backtrack to the point were we created only one
with the path and call
toPercentEncoding(); feed that to the method
setEncodedPath() of an empty
QUrl. Then we add the last piece calling
setScheme('file') and we're ready! Of course we're not:
Notice the lack of the two
xine doesn't like it;
hence, I don't either.
Ok, this post got too long. I hope I can resolve this soon, I already spent too much time on it. At least a good part of it was expaining it, so others don't have to suffer the same as I did.
satyr will shortly be released, whether I fix this bug or not.
 Look at the size of that file! 6k lines to handle URL's! Who would say it was so difficult... Once more I'm remembered of how lucky I am to have this libraries at the tips of my fingers, yay!