[Visualpython-users] keyboard release

[Frank W. S. <fr...@me...>]

I am interested in using vpython to make some simple games.  Apparently there 
are a few others like me based on some internet posts that I found.  To make 
games we need to know when keyboard buttons are released as well as pressed. 
To facilitate this happening, I made a couple small code changes represented by 
the below patch on the visual-5.71 release.  You are welcome to incorporate or 
ignore them.  When keys are released, the generated keyboard events are 
proceeded with the string "Released: " in front of them.

The good:
-The patch is very small
-This hack is backwards compatible for people who use code like
     s = scene.kb.getkey()
     if s == 'k': ...
-Processing of keyboard events is still easy string comparisons

The bad:
-The code is currently only for gtk.  I don't have "Windows" or Mac computer on 
which to test any change that I make.

Thanks for all your work on vpython.  It's great.

-Frank


--- src/gtk2/display.cpp.~1.58.~	2009-10-11 17:33:43.000000000 -0400
+++ src/gtk2/display.cpp	2011-06-11 07:24:54.176217104 -0400
@@ -133,6 +133,8 @@
  	area->set_size_request( w, h );
  	area->signal_key_press_event().connect(
  		sigc::mem_fun( *this, &display::on_key_pressed));
+	area->signal_key_release_event().connect(
+		sigc::mem_fun( *this, &display::on_key_pressed));

  	// Glade-based UI.
  	// Turned off toolbar in display initialization for now; not yet available on Windows or Mac
@@ -270,6 +272,11 @@
  	// other than a US keyboard.
  	guint k = key->keyval;
  	std::string ctrl_str;
+
+	// Is this a press or release?
+	if (key->type == GDK_KEY_RELEASE) {
+		ctrl_str += "Released: ";
+	}
  	// First trap for shift, ctrl, and alt.
  	if (key->state & GDK_CONTROL_MASK) {
  		ctrl_str += "ctrl+";