Code-Beispiel

Zeichnen mit GooCanvas (ein Graph)

Lizenz:	Erster Autor:	Letzte Bearbeitung:
GPLv3	TJF	07.09.2012

Bildschirmausgabe

Dieses Code Beispiel öffnet ein Fenster und erzeugt die abgebildete Grafik darin. Beim Anklicken des Graphen ... ups, wir wollen doch nicht alles verraten.

Das Beispiel ist unter Windows und LINUX kompilierbar. Als GUI-Toolkit kommt GTK zum Einsatz (hier mal ohne Glade3) und die Zeichenfunktionen werden mit der Erweiterung GooCanvas (siehe Beschreibung auf gnome.org) realisiert. Dazu sind aktuelle Header erforderlich, wie sie in fbc-0.24.0 Aktuelle Compiler (oder neuer) enthalten sind. Hinweise zur Installation der Binaries finden sich in goocanvas.bih.

Für diesen Installationsaufwand wird man schließlich mit Grafik belohnt, die nicht nur mächtige Befehle bietet und durch Qualität und Geschwindigkeit überzeugt - sie ist auch überraschend einfach in Pixel- bzw. Vektorgrafik-Dateien zu exportieren (,z. B. im Dateiformat PostScript (*.ps) zur qualitativ hochwertigen Ausgabe auf dem Drucker).

#INCLUDE ONCE "gtk/gtk.bi"

#INCLUDE ONCE "goocanvas.bi"



' Some variables and types

CONST Xmax = 1000, Ymax = 1000, Smin = 0.1

CONST GridX = 100.0, GridY = GridX, GridW = 400.0, GridH = 300.0





' Initialize GTK+.

gtk_init (@__FB_ARGC__, @__FB_ARGV__)



' Create the window and widgets.

VAR win = gtk_window_new (GTK_WINDOW_TOPLEVEL)

gtk_window_set_default_size (GTK_WINDOW (win), 640, 600)

gtk_widget_show (win)

g_signal_connect (win, "delete_event", G_CALLBACK(@gtk_main_quit), NULL)



VAR scrolled_win = gtk_scrolled_window_new (NULL, NULL)

gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (scrolled_win), _

                                     GTK_SHADOW_IN)

gtk_widget_show (scrolled_win)

gtk_container_add (GTK_CONTAINER (win), scrolled_win)



VAR canvas = goo_canvas_new ()

gtk_widget_set_size_request (canvas, 600, 450)

goo_canvas_set_bounds (GOO_CANVAS (canvas), 0, 0, Xmax, ymax)

gtk_widget_show (canvas)

gtk_container_add (GTK_CONTAINER (scrolled_win), canvas)





VAR root = goo_canvas_get_root_item (GOO_CANVAS (canvas))



VAR title = goo_canvas_text_new(root, _

       "<span size=""xx-large"">GooCanvas FreeBasic-Example</span>", _

                                GridX + 0.5 * GridW, GridY - 25, -1, _

                                GTK_ANCHOR_S, _

                                "use-markup", 1, _

                                 "font", "Times bold 14", _

                                NULL)



VAR group = goo_canvas_group_new(root, _

                                 "font", "Sans 14", _

                                 NULL)



' calculate some values

VAR line_group = 0.8 ' basic line width

VAR az = 100, pi = 4.0 * ATN(1), n = 2 * az - 1

VAR fx = GridW / (n - 1), sx = (az - 1) / pi, dx = 0.25 * GridW

VAR fy = GridH * 0.45, oy = GridY + 0.5 * GridH



VAR grid = goo_canvas_grid_new(group, _

                               GridX, GridY, GridW, GridH, _

                               dx, fy * 0.5, dx * 1.001, 0.05 * GridH, _

                               "border-width", line_group * 2, _

                               "horz-grid-line-width", line_group, _

                               "vert-grid-line-width", line_group, _

                               "horz-grid-line-color", "gray", _

                               "vert-grid-line-color", "gray", _

                               NULL)



VAR CanPoi = goo_canvas_points_new(az), copo = CanPoi->coords

FOR i AS INTEGER = 0 TO n STEP 2

  copo[i] = GridX + i * fx

  copo[i + 1] = oy - SIN(i/sx) * fy

NEXT

VAR poly = goo_canvas_polyline_new(group, 0, 0, _

                                   "stroke-color", "red",_

                                   "line-width", line_group * 4,_

                                   "tooltip", "Test Polyline", _

                                   "points", CanPoi,_

                                   NULL)

goo_canvas_points_unref(CanPoi)



' and now some text, text, text, ...

VAR ox = GridX - 8 * line_group

VAR text = goo_canvas_text_new(group, "1", _

                               ox, oy - fy, -1, _

                               GTK_ANCHOR_E, _

                               NULL)

text = goo_canvas_text_new(group, "-1", _

                           ox, oy + fy, -1, _

                           GTK_ANCHOR_E, _

                           NULL)

fy /= 2

text = goo_canvas_text_new(group, "<small>0.5</small>", _

                           ox, oy - fy, -1, _

                           GTK_ANCHOR_E, _

                           "use-markup", 1, _

                           NULL)

text = goo_canvas_text_new(group, "<small>-0.5</small>", _

                           ox, oy + fy, -1, _

                           GTK_ANCHOR_E, _

                           "use-markup", 1, _

                           NULL)

text = goo_canvas_text_new(group, "0", _

                           ox, oy, -1, _

                           GTK_ANCHOR_E, _

                           NULL)

ox -= 35

text = goo_canvas_text_new(group, "f(<i>&#966;</i>) = sin(<i>&#966;</i>)", _

                           ox, oy, -1, _

                           GTK_ANCHOR_S, _

                           "use-markup", 1, _

                           NULL)

goo_canvas_item_rotate(text, -90.0, ox, oy)



ox = GridX

oy = GridY + GridH + 8 * line_group

text = goo_canvas_text_new(group, "0", _

                           ox, oy, -1, _

                           GTK_ANCHOR_N, _

                           NULL)

ox += dx

text = goo_canvas_text_new(group, "<small>0.5&#960;</small>", _

                           ox, oy, -1, _

                           GTK_ANCHOR_N, _

                           "use-markup", 1, _

                           NULL)

ox += dx

text = goo_canvas_text_new(group, "&#960;", _

                           ox, oy, -1, _

                           GTK_ANCHOR_N, _

                           NULL)

text = goo_canvas_text_new(group, "This <i>&#966;</i> looks like an <i>angel</i>", _

                           ox, oy + 25, -1, _

                           GTK_ANCHOR_N, _

                           "use-markup", 1, _

                           NULL)

ox += dx

text = goo_canvas_text_new(group, "<small>1.5&#960;</small>", _

                           ox, oy, -1, _

                           GTK_ANCHOR_N, _

                           "use-markup", 1, _

                           NULL)

ox += dx

text = goo_canvas_text_new(group, "2&#960;", _

                           ox, oy, -1, _

                           GTK_ANCHOR_N, _

                           NULL)

text = goo_canvas_text_new(group, "<span size=""x-small""><span foreground=""blue"">" _

                           !"Click me!</span>\n<span background=""yellow"">" _

                           " l · m · r </span></span>", _

                           ox - 0.5 * dx, GridY + .05 * GridH + 0.5 * fy, -1, _

                           GTK_ANCHOR_CENTER, _

                           "use-markup", 1, _

                           "alignment", PANGO_ALIGN_CENTER, _

                           NULL)



' unvisible rect to make the grid clickable (not only lines)

VAR rect = goo_canvas_rect_new(group, _

                               GridX, GridY, GridW, GridH, _

                               "fill-color-rgba", &hFF000000, _

                               "stroke-pattern", NULL, _

                               NULL)



TYPE CbPointer

  AS GooCanvasItem PTR Title, Group

END TYPE



' signal handler (callback)

FUNCTION on_button_press CDECL(BYVAL item AS GooCanvasItem PTR, _

                               BYVAL target AS GooCanvasItem PTR, _

                               BYVAL event AS GdkEventButton PTR, _

                               BYVAL dat AS CbPointer PTR) AS gboolean

  STATIC AS INTEGER mo = 0

  IF event->button = 2 THEN

    goo_canvas_item_stop_animation(dat->Title) : mo = 0

    goo_canvas_item_set_simple_transform (dat->Title, 0.0, 0.0, 1.0, 0.0)

    goo_canvas_item_stop_animation(dat->Group) : mo = 0

    goo_canvas_item_set_simple_transform (dat->Group, 0.0, 0.0, 1.0, 0.0)

    RETURN TRUE

  ELSEIF mo = 0 THEN

    goo_canvas_item_animate (dat->Title, _

                             GridX + 0.5 * GridW, GridY - 25, _

                             Smin, -7.0, _

                             FALSE, 8 * 40, 40, _

                             GOO_CANVAS_ANIMATE_BOUNCE)

    goo_canvas_item_animate (dat->Group, _

                             Xmax, Ymax, _

                             Smin, 90, _

                             FALSE, event->button * 50 * 40, 40, _

                             GOO_CANVAS_ANIMATE_BOUNCE)

    mo = 1

  ELSE

    goo_canvas_item_stop_animation(dat->Title)

    goo_canvas_item_set_simple_transform (dat->Title, 0.0, 0.0, 1.0, 0.0)

    goo_canvas_item_stop_animation(dat->Group) : mo = 0

  END IF



  RETURN TRUE

END FUNCTION

g_signal_connect (group, "button_press_event", _

                  G_CALLBACK (@on_button_press), @TYPE<CbPointer>(title, group))



' Pass control to the GTK+ main event loop.

gtk_main ()



END 0

English

See english forum.

Zusätzliche Informationen und Funktionen

Das Code-Beispiel wurde am 23.09.2011 von TJF angelegt.
Die aktuellste Version wurde am 07.09.2012 von TJF gespeichert.

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