--- /dev/null
+/*
+ * zavai - simple interface to the OpenMoko (or to the FSO stack)
+ *
+ * Copyright (C) 2009 Enrico Zini <enrico@enricozini.org>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+using GLib;
+
+public class FisheyeList : Gtk.DrawingArea
+{
+ private string[] list;
+ protected int cur_el;
+
+ public FisheyeList()
+ {
+ list = new string[300];
+ for (int i = 0; i < 300; ++i)
+ list[i] = "Antani %d".printf(i);
+
+ cur_el = 50;
+
+ add_events(Gdk.EventMask.POINTER_MOTION_MASK
+ | Gdk.EventMask.BUTTON_PRESS_MASK
+ | Gdk.EventMask.BUTTON_RELEASE_MASK);
+ }
+
+ /* Mouse button got pressed over widget */
+ public override bool button_press_event(Gdk.EventButton event)
+ {
+ // ...
+ return false;
+ }
+
+ /* Mouse button got released */
+ public override bool button_release_event(Gdk.EventButton event)
+ {
+ // ...
+ return false;
+ }
+
+ /* Mouse pointer moved over widget */
+ public override bool motion_notify_event(Gdk.EventMotion event)
+ {
+ cur_el = (int)Math.round(event.y * list.length / allocation.height);
+ stderr.printf("MOTION %f %f CE %d\n", event.x, event.y, cur_el);
+ queue_draw();
+ return false;
+ }
+
+ /* Widget is asked to draw itself */
+ public override bool expose_event (Gdk.EventExpose event) {
+
+ // Create a Cairo context
+ var cr = Gdk.cairo_create (this.window);
+
+ // Set clipping area in order to avoid unnecessary drawing
+ cr.rectangle(event.area.x, event.area.y,
+ event.area.width, event.area.height);
+ cr.clip();
+
+ draw(cr);
+
+ return false;
+ }
+
+ protected double el_y(int idx)
+ {
+ double layout_min = 0;
+ double layout_max = 1;
+ double distortion_factor = 30;
+ // Anchor point
+ double anchor = (double)cur_el/list.length;
+ // Undistorted Y
+ double undy = (double)idx/list.length;
+ // Distorted position
+ double pos = fisheye(undy, anchor, distortion_factor, layout_min, layout_max);
+ //stderr.printf("%d %f %f\n", idx, undy, pos);
+ return pos;
+ }
+
+ protected void draw(Cairo.Context context)
+ {
+ context.set_source_rgb(1, 1, 1);
+ context.paint();
+ context.set_source_rgb(0, 0, 0);
+
+ context.translate (0, 0);
+ context.scale(allocation.width, allocation.height);
+
+
+ // Layout items
+ // item_pos(idx) = idx/list.length
+
+ context.set_line_width (0.001);
+ context.select_font_face("Sans", Cairo.FontSlant.NORMAL, Cairo.FontWeight.NORMAL);
+ for (int idx = 0; idx < list.length; ++idx)
+ {
+ double posprev = idx == 0 ? 0 : el_y(idx-1);
+ double pos = el_y(idx);
+ double posnext = idx == list.length-1 ? 1 : el_y(idx+1);
+ double y0 = (pos+posprev)/2;
+ double y1 = (pos+posnext)/2;
+
+ //stderr.printf(" %f->%f (%f)\n", y0, y1, y1-y0);
+
+ context.set_source_rgba(idx%2, 1-idx%2, 0, 1);
+ context.new_path();
+ context.rectangle(0, y0, 1, y1-y0);
+ context.fill();
+ context.stroke();
+
+ context.set_source_rgba(0, 0, 0, 1);
+ context.new_path();
+ context.move_to(0, pos);
+ context.set_font_size(y1-y0);
+ context.text_path(list[idx]);
+ context.fill();
+ context.stroke();
+ }
+ }
+
+ /*
+ * The following function is adapted from Prefuse's FisheyeDistortion.java.
+ *
+ * A relevant annotation from Prefuse:
+ *
+ * For more details on this form of transformation, see Manojit Sarkar and
+ * Marc H. Brown, "Graphical Fisheye Views of Graphs", in Proceedings of
+ * CHI'92, Human Factors in Computing Systems, p. 83-91, 1992. Available
+ * online at <a href="http://citeseer.ist.psu.edu/sarkar92graphical.html">
+ * http://citeseer.ist.psu.edu/sarkar92graphical.html</a>.
+ */
+
+ /*
+ * Distorts an item's coordinate.
+ * @param x the undistorted coordinate
+ * @param coordinate of the anchor or focus point
+ * @param d disortion factor
+ * @param min the beginning of the display
+ * @param max the end of the display
+ * @return the distorted coordinate
+ */
+ private double fisheye(double x, double a, double d, double min, double max)
+ {
+ if ( d != 0 ) {
+ bool left = x<a;
+ double v;
+ double m = (left ? a-min : max-a);
+ if ( m == 0 ) m = max-min;
+ v = Math.fabs(x - a) / m;
+ v = (d+1)/(d+(1/v));
+ return (left?-1:1)*m*v + a;
+ } else {
+ return x;
+ }
+ }
+}
+
+public class Fisheye : Gtk.Window
+{
+ public Fisheye()
+ {
+ title = "Fisheye";
+ destroy += Gtk.main_quit;
+
+ var list = new FisheyeList();
+ add(list);
+ }
+}
+
+static int main (string[] args) {
+ Gtk.init (ref args);
+
+ var fe = new Fisheye();
+ fe.set_size_request(300, 500);
+ fe.show_all();
+
+ Gtk.main();
+
+ return 0;
+}