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5,060 bytes added ,  10:42, 4 April 2018
Merge useful content from https://wiki.sugarlabs.org/go/Features/GTK3/Porting/GetBooks
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This is a guide to porting an existing activity from GTK2 to [http://developer.gnome.org/gtk3/stable/ GTK3]. It also shows the changes to use the new Sugar toolkit that also now uses [[Features/GTK3|GTK3]]. This guide uses the [https://github.com/sugarlabs/hello-world hello-world] activity as a simple example.
 
This is a guide to porting an existing activity from GTK2 to [http://developer.gnome.org/gtk3/stable/ GTK3]. It also shows the changes to use the new Sugar toolkit that also now uses [[Features/GTK3|GTK3]]. This guide uses the [https://github.com/sugarlabs/hello-world hello-world] activity as a simple example.
   −
There is another guide that uses this one as reference. It was made while porting GetBooks Activity [[Features/GTK3/Porting/GetBooks]]
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Here are some instances of porting activities, for reference:
 
  −
If you would like to reference other examples of GTK3 port:
   
* [https://github.com/sugarlabs/biorhythm/commit/c16de3b70cce2cc6f8af933e2b062c844a47c144/ Biorhythm]
 
* [https://github.com/sugarlabs/biorhythm/commit/c16de3b70cce2cc6f8af933e2b062c844a47c144/ Biorhythm]
 
* [https://github.com/sugarlabs/peru-learns-english-activity/commit/caa2cde526b3823a5a1f7d200a76ad5bc3502b0e Peru Learns English, includes GStreamer and GST update]
 
* [https://github.com/sugarlabs/peru-learns-english-activity/commit/caa2cde526b3823a5a1f7d200a76ad5bc3502b0e Peru Learns English, includes GStreamer and GST update]
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* [https://github.com/sugarlabs/jump/commit/b75410d2879d9829df942726f5465b7cf5a9d98d Port of Jump Activity]
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* [https://github.com/sugarlabs/iknowMadagascar/commit/44ba42645ac4fcd9e06b4add7fa3b6ce2e0d9c3d Port of I-know-Madagascar]
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=Steps to Port an Activity to Gtk3=
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#Read the [http://wiki.sugarlabs.org/go/Features/GTK3 Sugar Official Wiki]
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#Resolve any existing pull requests before porting to avoid conflicts at a later stage.
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#Run this [http://git.gnome.org/browse/pygobject/tree/pygi-convert.sh script] that will convert automatically things as much as it can. This is to avoid some stressful manually conversions that a "simple script" can do using ''sed'' :)
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#Convert all the <code>from sugar.* import</code> to <code>from sugar</code>'''3'''<code>.* import</code> using [http://dev.laptop.org/~manuq/sugar-convert.sh this script]
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#Follow the [[Development Team/Code guidelines|Code Guidelines]] during all the porting process
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#Make the API changes in sugar-toolkit-gtk3
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#Write comments on the code, by adding '''# README:''', '''# TODO:''' and '''# FIXME:''' explaining what are the problems that you are having with that chunk of code. Put a link if it's necessary
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Note: If you are considering to fix some ''pep8'' or ''pylint'' errors/warnings, please create two separate patch files (one for the port and one for the pylint/pep8 changes). If we follow this way it is easier to check the port patches, if not the information about the port itself it's difficult to follow
    
==Cleanup, adopt to API changes in sugar-toolkit-gtk3 ==
 
==Cleanup, adopt to API changes in sugar-toolkit-gtk3 ==
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* remove import of deprecated ActivityToolbox (see [http://git.sugarlabs.org/hello-world/mainline/commit/22060a3063b2d6fd38d6b1cd8d44946170255af3 hello-world])
 
* remove import of deprecated ActivityToolbox (see [http://git.sugarlabs.org/hello-world/mainline/commit/22060a3063b2d6fd38d6b1cd8d44946170255af3 hello-world])
 
* support for 'service_name' and 'class' has been removed from the activity.info make sure you are using: 'bundle_id' instead of 'service_name' and 'exec' instead of 'class' (see in [http://git.sugarlabs.org/record/mainline/commit/6e8968c71e474e2d8d86886badf5cf7d70217dc5 Record])
 
* support for 'service_name' and 'class' has been removed from the activity.info make sure you are using: 'bundle_id' instead of 'service_name' and 'exec' instead of 'class' (see in [http://git.sugarlabs.org/record/mainline/commit/6e8968c71e474e2d8d86886badf5cf7d70217dc5 Record])
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* <code>sugar3.activity.Activity</code> doesn't have the ''window'' attribute. Use the <code>.get_window()</code> method instead.
    
==Port the activity from GTK2 to GTK3==
 
==Port the activity from GTK2 to GTK3==
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The Gtk.Menu.popup function now works slightly differently.  
 
The Gtk.Menu.popup function now works slightly differently.  
 
The user supplied positioning function now takes different parameters. These are menu, x, y, push_in and user_data.  
 
The user supplied positioning function now takes different parameters. These are menu, x, y, push_in and user_data.  
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=== Gdk ===
 
=== Gdk ===
 
Previously, gdk was an attribute of the gtk module, which means that it can be called through gtk. For example, if we want to use color_parse():
 
Previously, gdk was an attribute of the gtk module, which means that it can be called through gtk. For example, if we want to use color_parse():
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gtk.JUSTIFY_CENTER became Gtk.Justification.CENTER
 
gtk.JUSTIFY_CENTER became Gtk.Justification.CENTER
 
gtk.RELIEF_NONE became Gtk.ReliefStyle.NONE
 
gtk.RELIEF_NONE became Gtk.ReliefStyle.NONE
      
=== Pixbufs ===
 
=== Pixbufs ===
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  GdkPixbuf.Pixbuf.new_from_file()
 
  GdkPixbuf.Pixbuf.new_from_file()
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==Releasing activities (for maintainers)==
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Once an activity is ported, a new release can be made. The major version should be greater than the existing one.
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Please follow [https://github.com/sugarlabs/sugar-docs/blob/master/src/contributing.md#checklist---maintainer this] guide for releasing a new version
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==Port to Python 3==
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We are migrating towards Python 3. Python 3 does not support GTK+ 2. Hence, once the activity is ported to GTK+ 3, please also continue porting the activity from Python 2 to Python 3.
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  −
Ref: [https://github.com/sugarlabs/sugar-docs/blob/master/src/python-porting-guide.md Guide to port activities to Python 3]
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  −
== Tips to Activity Developers ==
      
===Changes to the Clipboard===
 
===Changes to the Clipboard===
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===Going from Cairo in GTK-2 to Cairo in GTK-3===
 
===Going from Cairo in GTK-2 to Cairo in GTK-3===
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(See http://developer.gnome.org/pangomm/2.28/annotated.html for more details)
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(For more detailes, see http://developer.gnome.org/pangomm/2.28/annotated.html)
Not much changes, but...
      
The Cairo/Pango interaction is a little different:
 
The Cairo/Pango interaction is a little different:
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==== Replacing pixmaps with Cairo ====
 
==== Replacing pixmaps with Cairo ====
You need to replace your pixmaps with Cairo in GTK3. See http://developer.gnome.org/gtk3/3.5/ch24s02.html#idp129615008 for example code.
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You need to replace your pixmaps with Cairo in GTK3. For an example on how this is done, see: http://developer.gnome.org/gtk3/3.5/ch24s02.html#idp129615008  
    
===Taking a screenshot and making a thumbnail===
 
===Taking a screenshot and making a thumbnail===
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===Creating a video widget===
 
===Creating a video widget===
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Haven't gotten this working yet, but some necessary changes include:
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Some necessary changes include:
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Using
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get_property('window').get_xid()
    
Instead of
 
Instead of
 
  window.xid
 
  window.xid
use
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Using
  get_property('window').get_xid()
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  set_double_buffered(False)
 
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set_app_paintable(True)
 
Instead of
 
Instead of
 
  unset_flags(gtk.DOUBLE_BUFFERED)
 
  unset_flags(gtk.DOUBLE_BUFFERED)
 
  set_flags(gtk.APP_PAINTABLE)
 
  set_flags(gtk.APP_PAINTABLE)
use
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set_double_buffered(False)
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set_app_paintable(True)
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A more basic question is whether or not we migrate to gstreamer-1.0. If we do, some helpful documentation is found here [https://wiki.ubuntu.com/Novacut/GStreamer1.0].
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=Hacks to help in porting=
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=== Use the same keyboard and mouse ===
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If you have an XO, I'm sure you want to take a look at [[User:Humitos/x2x|this]]...
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===Use Extended Python debugger===
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'''epdb''' library is useful to inspect the code while the Activity is running.
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sudo yum install python-epdb
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After that I put some trace point in the code where I can stop and make my tests by doing this:
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import epdb;epdb.set_trace()
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Finally I run Get Books Activity from the Terminal Activity to be able to write some code on a shell. This is the command that I use:
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sugar-launch org.laptop.sugar.GetBooksActivity
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See also [[Development Team/Debugging]].
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===Check logs with ''multitail''===
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Here is a really useful command to open new logs automatically: [[User:Humitos/MultiTail]]
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===Use the pygobject code as example===
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[https://live.gnome.org/PyGObject pygobject] is what we use to make Gtk3 activities. So, it's really useful to take a look at the code examples that are there. Even more, you can run some demo application that show how to use something specific about the library.
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*Clone the code:
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git clone git://git.gnome.org/pygobject
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*Run an example
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cd pygobject
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cd demos/gtk-demo/demos
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python pixbuf.py
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*Grep the code to search for something useful
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cd pygobject
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git grep GdkPixbuf
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===Monitoring DBus===
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Not sure how this command works, but it can give us an interesting information. If you run this command and plug an USB drive you will see useful information
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dbus-monitor --system
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=Port to Python 3=
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We are migrating towards Python 3. Python 3 does not support GTK+ 2. Hence, once the activity is ported to GTK+ 3, please consider porting the activity from Python 2 to Python 3.
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 +
Ref: [https://github.com/sugarlabs/sugar-docs/blob/master/src/python-porting-guide.md Guide to port activities to Python 3]
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=Releasing activities (for maintainers)=
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Once an activity is ported, a new release can be made. The major version should be greater than the existing one.
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Please follow [https://github.com/sugarlabs/sugar-docs/blob/master/src/contributing.md#checklist---maintainer this] guide for releasing a new version
 +
 
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=Notes=
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These are the changes implemented by developers while porting activities
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*<code>Gtk.Widget.hide_all()</code> does not exist anymore. We should use just <code>.hide</code>
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**Ref: http://developer.gnome.org/gtk3/3.5/GtkWidget.html#gtk-widget-hide
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== Resources ==
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*If the code creates some own object, and it defines some properties, you should use '''__gproperties__''' dictionary: http://python-gtk-3-tutorial.readthedocs.org/en/latest/objects.html#GObject.GObject.__gproperties__
PyGI Documentation: https://lazka.github.io/pgi-docs/
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*<code>Gtk.ListStore</code> doesn't have the method '''.reorder'''. There is a [https://bugzilla.gnome.org/show_bug.cgi?id=677941 ticket] reported upstream about this.
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*I replaced the use of <code>dbus</code> by [http://developer.gnome.org/gio/unstable/pt02.html Gio] to monitor the (dis)connection of pen drives
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*Migrate custom signals:
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**If you have defined custom gtk objects with custom signal you should migrate them to [http://python-gtk-3-tutorial.readthedocs.org/en/latest/objects.html the new way] to do this.  You should replace this:  from gobject import signal_new, TYPE_INT, TYPE_STRING, TYPE_BOOLEAN, \ TYPE_PYOBJECT, TYPE_NONE, SIGNAL_RUN_LAST  signal_new('extlistview-modified', gtk.TreeView, SIGNAL_RUN_LAST, TYPE_NONE,            ()) by adding the signal definition inside the object that you are creating using the <code>__gsignals__</code> dictionary like this (in this case Gtk.TreeView is the class that our object inherits):  from gi.repository import GObject  class ExtListView(Gtk.TreeView):    __gsignals__ = {      'extlistview-modified': (GObject.SignalFlags.RUN_LAST, None,                              ()),        } The last argument of the signal definition are the argument types that the callback will receive.
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* Change the mouse cursor
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** Example use case: When the activity is working and we want to show a ''work in progress'' cursor.
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** Replace this:
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self.window.set_cursor(gtk.gdk.Cursor(gtk.gdk.WATCH))
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with:
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from gi.repository import Gdk
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self.get_window().set_cursor(Gdk.Cursor(Gdk.CursorType.WATCH))
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=Resources=
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*PyGI Documentation: https://lazka.github.io/pgi-docs/
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*PyGtk documentation
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**Gtk3: [http://python-gtk-3-tutorial.readthedocs.org/ http://python-gtk-3-tutorial.readthedocs.org]
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**gtk2: http://www.pygtk.org/docs/pygtk/
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*Reference Manual
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**Gtk3: http://developer.gnome.org/gtk3/3.4/
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*Gdk documentation:
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**Gdk3: http://developer.gnome.org/gdk/2.24/
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*OLPC Documentation: http://wiki.laptop.org/go/Activities/PortingToGtk3
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*Used to know the arguments of <code>GdkPixbuf.Pixbuf.save_to_bufferv</code> https://mail.gnome.org/archives/javascript-list/2011-March/msg00001.html
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gtk2: http://www.pygtk.org/docs/pygtk/
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* Pango documentation: http://developer.gnome.org/pangomm
* Reference Manual
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:: Gtk3: http://developer.gnome.org/gtk3/3.4/
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* Gdk documentation:
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:: Gdk3: http://developer.gnome.org/gdk/2.24/
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* Pango documentation:
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:: GTK3: http://developer.gnome.org/pangomm
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* Gst-1.0 documentation
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:: Gst-1: http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/index.html
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* Gst-1.0 porting hints
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:: https://wiki.ubuntu.com/Novacut/GStreamer1.0
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* Gst-1.0 documentation: http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/index.html
    +
* Gst-1.0 porting hints: https://wiki.ubuntu.com/Novacut/GStreamer1.0
 
[[Category:Developer]]
 
[[Category:Developer]]
  
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