Using BOSS GT-10 with Linux

written by Jonas Wagner, on 1/10/09 2:36 PM.

Today I hooked up my BOSS GT-10 to my computer. And do you know what? It just works. So here's what I've tested so far:

Ubuntu and Arch Linux
Play it Slowly (of course!)
Ardour / jack

Everything works as expected so far. There are some xruns when using jack at low latencies (~ 5ms). I guess one could get rid of them using a realtime kernel or some fiddling. But doesn't matter anyway because I do monitoring using the GT-10.

MIDI Support for the GT-10 seems to be included in the Linux Kernel since 2.6.28

I'll try to do some re-amping and midi later

Play it slowly 1.1

written by Jonas Wagner, on 1/8/09 1:14 PM.

And there it is, a new version of play it slowly. It fixes all known bugs and even adds some features

Saving of state (file, speed, ..)
Improved error handling
Pitch scale is using semitones
Speed scale allows steps of 0.05
New command line argument --sink
Fixes all known bugs

If you've got suggestions please write a comment

screenshot

Get it Now

PyGTK Exception Hook

written by Jonas Wagner, on 1/8/09 9:03 AM.

screenshot I wrote a little exception hook for pygtk applications. When an exception occurs it will show a dialog with a full stack trace obtained using cgitb.

import gtk, gobject
import sys

_ = lambda s: s

def scrolled(widget, shadow=gtk.SHADOW_NONE):
    window = gtk.ScrolledWindow()
    window.set_shadow_type(shadow)
    window.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC)
    if widget.set_scroll_adjustments(window.get_hadjustment(),
                                      window.get_vadjustment()):
        window.add(widget)
    else:
        window.add_with_viewport(widget)
    return window


class ExceptionDialog(gtk.MessageDialog):
    def __init__(self, etype, evalue, etb):
        gtk.MessageDialog.__init__(self, buttons=gtk.BUTTONS_CLOSE, type=gtk.MESSAGE_ERROR)
        self.set_resizable(True)
        self.set_markup(_("An error has occured:\n%r\nYou should save "
                "your work and restart the application. If the error "
                "occurs again please report it to the developer." % evalue))
        import cgitb
        text = cgitb.text((etype, evalue, etb), 5)
        expander = gtk.Expander(_("Exception Details"))
        self.vbox.pack_start(expander)
        textview = gtk.TextView()
        textview.get_buffer().set_text(text)
        expander.add(scrolled(textview))
        self.show_all()

def install_exception_hook(dialog=ExceptionDialog):
    old_hook = sys.excepthook
    def new_hook(etype, evalue, etb):
        if etype not in (KeyboardInterrupt, SystemExit):
            d = dialog(etype, evalue, etb)
            d.run()
            d.destroy()
        old_hook(etype, evalue, etb)
    new_hook.old_hook = old_hook
    sys.excepthook = new_hook

if __name__ == "__main__":
    install_exception_hook()
    gobject.idle_add(lambda: 1/0)
    gobject.idle_add(gtk.main_quit)
    gtk.main()

Stepped scales with pygtk

written by Jonas Wagner, on 1/6/09 10:56 PM.

The Scale Widgets that come with gtk ignore step_incr from the adjustment when the user drags the slider. So there is no way to specify that you only want to use increments of 0.5 or 1.0. So here's how to do it:

class Scale(object):
    """A scale that adheres to increment steps"""
    def __init__(self):
        self.connect("change-value", self.adjust)

    def adjust(self, range, scroll, value):
        adj = self.get_adjustment()
        lower = adj.get_property('lower')
        upper = adj.get_property('upper')
        incr = adj.get_property('step-increment')
        value -= (value % incr)
        self.set_value(min(max(lower, value), upper))
        return True


class VScale(gtk.VScale, Scale):
    def __init__(self, *args):
        gtk.VScale.__init__(self, *args)
        Scale.__init__(self)

class HScale(gtk.HScale, Scale):
    def __init__(self, *args):
        gtk.HScale.__init__(self, *args)
        Scale.__init__(self)

Make timidity use dmix

written by Jonas Wagner, on 1/5/09 2:51 AM.

It annoyed me for quite some time now that playback in TuxGuitar only worked when I closed all other audio applications. The reason for this was that timidity, the midi software synthesizer I use didn't use the software mixing (dmix) provided by alsa. The solution to this is quite simple. Edit /etc/default/timidity and replace this line: