Add fingerscroll.py

Fingerscroll is a python/gtk module to display text
and allow it to be scrolled easily with a finger.

No throwing, just dragging.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/lib/fingerscroll.py b/lib/fingerscroll.py
new file mode 100644 (file)
index 0000000..685aa8e
--- /dev/null
+++ b/lib/fingerscroll.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python
+
+# Copyright (C) 2011-2012 Neil Brown <neilb@suse.de>
+#
+#    This program is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation; either version 2 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License along
+#    with this program; if not, write to the Free Software Foundation, Inc.,
+#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# FingerScroll is a simple widget to wrap around TextView
+# so that the TextBuffer can be scrolled with finger-wipes.
+# Each wipe is either horizontal or vertical, not both.
+
+import gtk
+
+class FingerScroll(gtk.TextView):
+    def __init__(self, wrap=gtk.WRAP_NONE):
+        gtk.TextView.__init__(self)
+        self.hadj = gtk.Adjustment()
+        self.vadj = gtk.Adjustment()
+        self.set_size_request(1,1)
+        self.set_wrap_mode(wrap)
+        self.set_scroll_adjustments(self.hadj, self.vadj)
+
+        self.add_events(gtk.gdk.POINTER_MOTION_MASK
+                        | gtk.gdk.POINTER_MOTION_HINT_MASK
+                        | gtk.gdk.BUTTON_PRESS_MASK
+                        | gtk.gdk.BUTTON_RELEASE_MASK)
+        self.connect("button_press_event", self.press)
+        self.connect("button_release_event", self.release)
+        self.connect("motion_notify_event", self.motion)
+        self.drag_start = None
+
+    def press(self, w, ev):
+        w.stop_emission("button_press_event")
+
+        self.drag_start = int(ev.x), int(ev.y)
+        self.xstart = self.hadj.value
+        self.ystart = self.vadj.value
+
+    def release(self, w, ev):
+        self.drag_start = None
+        w.stop_emission("button_release_event")
+
+    def motion(self, w, ev):
+        if self.drag_start == None:
+            return
+
+        if ev.is_hint:
+            x, y, state = ev.window.get_pointer()
+        else:
+            x = ev.x
+            y = ev.y
+        x = int(x)
+        y = int(y)
+        dx = x - self.drag_start[0]
+        dy = y - self.drag_start[1]
+        newx, newy = self.xstart, self.ystart
+        if abs(dx) > abs(dy):
+            newx = newx - dx
+        else:
+            newy = newy - dy
+
+        if newx >= self.hadj.upper - self.hadj.page_size:
+            newx = self.hadj.upper - self.hadj.page_size
+        if newx <= self.hadj.lower: newx = self.hadj.lower
+        if newy >= self.vadj.upper - self.vadj.page_size:
+            newy = self.vadj.upper - self.vadj.page_size
+        if newy <= self.vadj.lower: newy = self.vadj.lower
+        self.hadj.value = newx
+        self.vadj.value = newy
+        w.stop_emission("motion_notify_event")
+
+if __name__ == "__main__":
+    # test app for FingerScroll
+    import sys
+    w = gtk.Window(gtk.WINDOW_TOPLEVEL)
+    w.connect("destroy", lambda w: gtk.main_quit())
+    w.set_title("FingerScroll test")
+    w.show()
+    w.set_default_size(200,200)
+    
+    sw = FingerScroll(); sw.show()
+    w.add(sw)
+
+    b = sw.get_buffer()
+
+    f = open(sys.argv[-1], "r")
+    l = f.readline()
+    while len(l):
+        b.insert(b.get_end_iter(), l)
+        l = f.readline()
+
+    gtk.main()
+
+