Daniel@0: #
Daniel@0: # data structures
Daniel@0: #
Daniel@0: length = 300;
Daniel@0: center = ['x' = 200; 'y' = 250;];
Daniel@0: radius = 2 * length / sqrt (12);
Daniel@0: fractalangle = 0;
Daniel@0: maxlevel = 2;
Daniel@0: sizes = [
Daniel@0:     'button' = [ 'x' = 100; 'y' = 40;  ];
Daniel@0:     'canvas' = [ 'x' = 400; 'y' = 500; ];
Daniel@0:     'view'   = [ 'x' = 400; 'y' = 600; ];
Daniel@0: ];
Daniel@0: sq = function (x) {
Daniel@0:     return x * x;
Daniel@0: };
Daniel@0: #
Daniel@0: # create view and other widgets
Daniel@0: #
Daniel@0: init = function () {
Daniel@0:     view = createwidget (-1, [
Daniel@0:         'type' = 'view'; 'name' = 'fractal'; 'size' = sizes.view;
Daniel@0:     ]);
Daniel@0: 
Daniel@0:     array1 = createwidget (view, [
Daniel@0:         'type' = 'array'; 'borderwidth' = 1; 'mode' = 'vertical';
Daniel@0:     ]);
Daniel@0:     widgets[array1].resize = resize;
Daniel@0: 
Daniel@0:     array2 = createwidget (array1, [
Daniel@0:         'type' = 'array'; 'borderwidth' = 1; 'mode' = 'horizontal';
Daniel@0:     ]);
Daniel@0:     widgets[array2].resize = resize;
Daniel@0: 
Daniel@0:     array3 = createwidget (array2, [
Daniel@0:         'type' = 'array'; 'borderwidth' = 1; 'mode' = 'vertical';
Daniel@0:     ]);
Daniel@0:     widgets[array3].resize = resize;
Daniel@0: 
Daniel@0:     morebutton = createwidget (array3, [
Daniel@0:         'type' = 'button'; 'text' = 'more';
Daniel@0:     ]);
Daniel@0:     widgets[morebutton].pressed = pressed;
Daniel@0:     lessbutton = createwidget (array3, [
Daniel@0:         'type' = 'button'; 'text' = 'less';
Daniel@0:     ]);
Daniel@0:     widgets[lessbutton].pressed = pressed;
Daniel@0:     setwidgetattr (morebutton, ['size' = sizes.button;]);
Daniel@0:     setwidgetattr (lessbutton, ['size' = sizes.button;]);
Daniel@0: 
Daniel@0:     atext = createwidget (array2, [
Daniel@0:         'type' = 'text'; 'mode' = 'oneline';
Daniel@0:     ]);
Daniel@0:     widgets[atext].oneline = oneline;
Daniel@0:     setwidgetattr (atext, [
Daniel@0:         'size' = ['x' = sizes.button.x; 'y' = sizes.button.y * 2;];
Daniel@0:     ]);
Daniel@0: 
Daniel@0:     scroll = createwidget (array1, ['type' = 'scroll';]);
Daniel@0:     canvas = createwidget (scroll, ['type' = 'canvas';]);
Daniel@0:     wrect = [0 = ['x' = 0; 'y' = 0;]; 1 = sizes.canvas;];
Daniel@0:     setwidgetattr (canvas, ['window' = wrect; 'viewport' = wrect[1];]);
Daniel@0: };
Daniel@0: #
Daniel@0: # drawing functions
Daniel@0: #
Daniel@0: # draw a Koch curve (a ``snowflake'' fractal)
Daniel@0: #
Daniel@0: # start with a triangle and keep replacing edges
Daniel@0: # with the construct: _/\_
Daniel@0: # until the recursion level reaches 'maxlevel'
Daniel@0: #
Daniel@0: fractal = function (level, length, angle) {
Daniel@0:     local nlength, newpenpos;
Daniel@0: 
Daniel@0:     if (level >= maxlevel) {
Daniel@0:         newpenpos.x = penpos.x + length * cos (angle);
Daniel@0:         newpenpos.y = penpos.y + length * sin (angle);
Daniel@0:         line (canvas, null, penpos, newpenpos, ['color' = 1;]);
Daniel@0:         penpos = newpenpos;
Daniel@0:         return;
Daniel@0:     }
Daniel@0:     nlength = length / 3;
Daniel@0:     fractal (level + 1, nlength, angle);
Daniel@0:     fractal (level + 1, nlength, angle + 60);
Daniel@0:     fractal (level + 1, nlength, angle - 60);
Daniel@0:     fractal (level + 1, nlength, angle);
Daniel@0: };
Daniel@0: redrawfractal = function () {
Daniel@0:     clear (canvas);
Daniel@0:     setpick (canvas, center, wrect);
Daniel@0:     penpos = [
Daniel@0:         'x' = center.x + cos (fractalangle + 210) * radius;
Daniel@0:         'y' = center.y + sin (fractalangle + 210) * radius;
Daniel@0:     ];
Daniel@0:     fractal (0, length, fractalangle +  60);
Daniel@0:     fractal (0, length, fractalangle -  60);
Daniel@0:     fractal (0, length, fractalangle - 180);
Daniel@0:     remove ('penpos');
Daniel@0: };
Daniel@0: #
Daniel@0: # editing functions
Daniel@0: #
Daniel@0: # transform the fractal.
Daniel@0: #
Daniel@0: # map point 'prevpoint' to point 'currpoint'
Daniel@0: # with respect to the center of the fractal.
Daniel@0: #
Daniel@0: transformfractal = function (prevpoint, currpoint) {
Daniel@0:     local prevtan, currtan, prevradius, currradius;
Daniel@0: 
Daniel@0:     prevtan = atan (prevpoint.y - center.y, prevpoint.x - center.x);
Daniel@0:     currtan = atan (currpoint.y - center.y, currpoint.x - center.x);
Daniel@0:     fractalangle = fractalangle + (currtan - prevtan);
Daniel@0:     prevradius = sqrt (
Daniel@0:         sq (prevpoint.y - center.y) + sq (prevpoint.x - center.x)
Daniel@0:     );
Daniel@0:     currradius = sqrt (
Daniel@0:         sq (currpoint.y - center.y) + sq (currpoint.x - center.x)
Daniel@0:     );
Daniel@0:     radius = radius / prevradius * currradius;
Daniel@0:     length = radius / 2 * sqrt (12);
Daniel@0: };
Daniel@0: #
Daniel@0: # main actions
Daniel@0: #
Daniel@0: redraw = function (data) {
Daniel@0:     redrawfractal ();
Daniel@0: };
Daniel@0: changemaxlevel = function (dn) {
Daniel@0:     maxlevel = maxlevel + dn;
Daniel@0:     if (maxlevel < 0)
Daniel@0:         maxlevel = 0;
Daniel@0:     redrawfractal ();
Daniel@0: };
Daniel@0: resize = function (data) {
Daniel@0:     local ret;
Daniel@0:     if (data.widget == array1) {
Daniel@0:         ret = [
Daniel@0:             array2 = [
Daniel@0:                 'x' = data.size.x;
Daniel@0:                 'y' = sizes.button.y * 2;
Daniel@0:             ];
Daniel@0:             scroll = [
Daniel@0:                 'x' = data.size.x;
Daniel@0:                 'y' = data.size.y - sizes.button.y * 2;
Daniel@0:             ];
Daniel@0:         ];
Daniel@0:     } else if (data.widget == array2) {
Daniel@0:         ret = [
Daniel@0:             array3 = [
Daniel@0:                 'x' = sizes.button.x;
Daniel@0:                 'y' = 2 * sizes.button.y;
Daniel@0:             ];
Daniel@0:             atext = [
Daniel@0:                 'x' = data.size.x - sizes.button.x;
Daniel@0:                 'y' = 2 * sizes.button.y;
Daniel@0:             ];
Daniel@0:         ];
Daniel@0:     } else if (data.widget == array3) {
Daniel@0:         ret = [
Daniel@0:             morebutton = sizes.button;
Daniel@0:             lessbutton = sizes.button;
Daniel@0:         ];
Daniel@0:     }
Daniel@0:     return ret;
Daniel@0: };
Daniel@0: #
Daniel@0: # user interface functions
Daniel@0: #
Daniel@0: # bind changes to the fractal to user actions
Daniel@0: #
Daniel@0: leftup = function (data) {
Daniel@0:     transformfractal (data.ppos, data.pos);
Daniel@0:     redrawfractal ();
Daniel@0: };
Daniel@0: menu = [
Daniel@0:     0 = 'more';
Daniel@0:     1 = 'less';
Daniel@0: ];
Daniel@0: domenu = function (i) {
Daniel@0:     local s;
Daniel@0:     s = menu[i];
Daniel@0:     if (s == 'more')
Daniel@0:         changemaxlevel (1);
Daniel@0:     else if (s == 'less')
Daniel@0:         changemaxlevel (-1);
Daniel@0: };
Daniel@0: rightdown = function (data) {
Daniel@0:     domenu (displaymenu (canvas, menu));
Daniel@0: };
Daniel@0: pressed = function (data) {
Daniel@0:     if (data.widget == morebutton)
Daniel@0:         changemaxlevel (1);
Daniel@0:     else if (data.widget == lessbutton)
Daniel@0:         changemaxlevel (-1);
Daniel@0: };
Daniel@0: oneline = function (data) {
Daniel@0:     local dn;
Daniel@0:     dn = ston (data.text);
Daniel@0:     if (dn > 0 | dn < 0)
Daniel@0:         changemaxlevel (dn - maxlevel);
Daniel@0: };
Daniel@0: #
Daniel@0: # postscript generation
Daniel@0: #
Daniel@0: dops = function () {
Daniel@0:     local r;
Daniel@0: 
Daniel@0:     r = [0 = ['x' = 0; 'y' = 0;]; 1 = ['x' = 8 * 300; 'y' = 10.5 * 300;];];
Daniel@0:     canvas = opencanvas ('pscanvas', '', r);
Daniel@0:     setwidgetattr (canvas, ['window' = wrect;]);
Daniel@0:     redraw ();
Daniel@0:     closecanvas (canvas);
Daniel@0:     canvas=defcanvas;
Daniel@0: };
Daniel@0: init ();
Daniel@0: #txtview ('off');