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80581c3011
2004-03-05 Federico Mena Quintero <federico@ximian.com> Fixes #136082 and #135265, patch by Morten Welinder. * configure.in: Use AC_SYS_LARGEFILE. * */*.c: #include <config.h>
324 lines
8.6 KiB
C
324 lines
8.6 KiB
C
/* Drawing Area
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*
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* GtkDrawingArea is a blank area where you can draw custom displays
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* of various kinds.
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*
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* This demo has two drawing areas. The checkerboard area shows
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* how you can just draw something; all you have to do is write
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* a signal handler for expose_event, as shown here.
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*
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* The "scribble" area is a bit more advanced, and shows how to handle
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* events such as button presses and mouse motion. Click the mouse
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* and drag in the scribble area to draw squiggles. Resize the window
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* to clear the area.
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*/
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#include <config.h>
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#include <gtk/gtk.h>
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static GtkWidget *window = NULL;
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/* Pixmap for scribble area, to store current scribbles */
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static GdkPixmap *pixmap = NULL;
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/* Create a new pixmap of the appropriate size to store our scribbles */
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static gboolean
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scribble_configure_event (GtkWidget *widget,
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GdkEventConfigure *event,
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gpointer data)
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{
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if (pixmap)
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g_object_unref (pixmap);
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pixmap = gdk_pixmap_new (widget->window,
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widget->allocation.width,
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widget->allocation.height,
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-1);
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/* Initialize the pixmap to white */
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gdk_draw_rectangle (pixmap,
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widget->style->white_gc,
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TRUE,
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0, 0,
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widget->allocation.width,
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widget->allocation.height);
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/* We've handled the configure event, no need for further processing. */
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return TRUE;
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}
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/* Redraw the screen from the pixmap */
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static gboolean
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scribble_expose_event (GtkWidget *widget,
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GdkEventExpose *event,
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gpointer data)
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{
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/* We use the "foreground GC" for the widget since it already exists,
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* but honestly any GC would work. The only thing to worry about
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* is whether the GC has an inappropriate clip region set.
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*/
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gdk_draw_drawable (widget->window,
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widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
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pixmap,
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/* Only copy the area that was exposed. */
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event->area.x, event->area.y,
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event->area.x, event->area.y,
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event->area.width, event->area.height);
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return FALSE;
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}
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/* Draw a rectangle on the screen */
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static void
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draw_brush (GtkWidget *widget,
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gdouble x,
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gdouble y)
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{
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GdkRectangle update_rect;
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update_rect.x = x - 3;
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update_rect.y = y - 3;
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update_rect.width = 6;
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update_rect.height = 6;
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/* Paint to the pixmap, where we store our state */
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gdk_draw_rectangle (pixmap,
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widget->style->black_gc,
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TRUE,
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update_rect.x, update_rect.y,
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update_rect.width, update_rect.height);
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/* Now invalidate the affected region of the drawing area. */
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gdk_window_invalidate_rect (widget->window,
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&update_rect,
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FALSE);
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}
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static gboolean
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scribble_button_press_event (GtkWidget *widget,
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GdkEventButton *event,
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gpointer data)
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{
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if (pixmap == NULL)
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return FALSE; /* paranoia check, in case we haven't gotten a configure event */
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if (event->button == 1)
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draw_brush (widget, event->x, event->y);
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/* We've handled the event, stop processing */
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return TRUE;
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}
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static gboolean
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scribble_motion_notify_event (GtkWidget *widget,
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GdkEventMotion *event,
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gpointer data)
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{
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int x, y;
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GdkModifierType state;
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if (pixmap == NULL)
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return FALSE; /* paranoia check, in case we haven't gotten a configure event */
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/* This call is very important; it requests the next motion event.
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* If you don't call gdk_window_get_pointer() you'll only get
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* a single motion event. The reason is that we specified
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* GDK_POINTER_MOTION_HINT_MASK to gtk_widget_set_events().
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* If we hadn't specified that, we could just use event->x, event->y
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* as the pointer location. But we'd also get deluged in events.
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* By requesting the next event as we handle the current one,
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* we avoid getting a huge number of events faster than we
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* can cope.
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*/
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gdk_window_get_pointer (event->window, &x, &y, &state);
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if (state & GDK_BUTTON1_MASK)
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draw_brush (widget, x, y);
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/* We've handled it, stop processing */
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return TRUE;
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}
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static gboolean
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checkerboard_expose (GtkWidget *da,
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GdkEventExpose *event,
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gpointer data)
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{
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gint i, j, xcount, ycount;
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GdkGC *gc1, *gc2;
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GdkColor color;
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#define CHECK_SIZE 10
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#define SPACING 2
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/* At the start of an expose handler, a clip region of event->area
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* is set on the window, and event->area has been cleared to the
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* widget's background color. The docs for
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* gdk_window_begin_paint_region() give more details on how this
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* works.
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*/
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/* It would be a bit more efficient to keep these
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* GC's around instead of recreating on each expose, but
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* this is the lazy/slow way.
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*/
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gc1 = gdk_gc_new (da->window);
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color.red = 30000;
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color.green = 0;
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color.blue = 30000;
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gdk_gc_set_rgb_fg_color (gc1, &color);
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gc2 = gdk_gc_new (da->window);
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color.red = 65535;
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color.green = 65535;
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color.blue = 65535;
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gdk_gc_set_rgb_fg_color (gc2, &color);
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xcount = 0;
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i = SPACING;
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while (i < da->allocation.width)
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{
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j = SPACING;
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ycount = xcount % 2; /* start with even/odd depending on row */
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while (j < da->allocation.height)
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{
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GdkGC *gc;
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if (ycount % 2)
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gc = gc1;
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else
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gc = gc2;
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/* If we're outside event->area, this will do nothing.
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* It might be mildly more efficient if we handled
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* the clipping ourselves, but again we're feeling lazy.
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*/
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gdk_draw_rectangle (da->window,
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gc,
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TRUE,
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i, j,
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CHECK_SIZE,
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CHECK_SIZE);
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j += CHECK_SIZE + SPACING;
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++ycount;
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}
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i += CHECK_SIZE + SPACING;
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++xcount;
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}
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g_object_unref (gc1);
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g_object_unref (gc2);
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/* return TRUE because we've handled this event, so no
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* further processing is required.
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*/
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return TRUE;
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}
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GtkWidget *
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do_drawingarea (GtkWidget *do_widget)
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{
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GtkWidget *frame;
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GtkWidget *vbox;
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GtkWidget *da;
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GtkWidget *label;
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if (!window)
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{
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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gtk_window_set_screen (GTK_WINDOW (window),
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gtk_widget_get_screen (do_widget));
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gtk_window_set_title (GTK_WINDOW (window), "Drawing Area");
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g_signal_connect (window, "destroy", G_CALLBACK (gtk_widget_destroyed), &window);
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gtk_container_set_border_width (GTK_CONTAINER (window), 8);
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vbox = gtk_vbox_new (FALSE, 8);
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gtk_container_set_border_width (GTK_CONTAINER (vbox), 8);
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gtk_container_add (GTK_CONTAINER (window), vbox);
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/*
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* Create the checkerboard area
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*/
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label = gtk_label_new (NULL);
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gtk_label_set_markup (GTK_LABEL (label),
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"<u>Checkerboard pattern</u>");
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gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);
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frame = gtk_frame_new (NULL);
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gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
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gtk_box_pack_start (GTK_BOX (vbox), frame, TRUE, TRUE, 0);
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da = gtk_drawing_area_new ();
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/* set a minimum size */
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gtk_widget_set_size_request (da, 100, 100);
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gtk_container_add (GTK_CONTAINER (frame), da);
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g_signal_connect (da, "expose_event",
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G_CALLBACK (checkerboard_expose), NULL);
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/*
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* Create the scribble area
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*/
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label = gtk_label_new (NULL);
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gtk_label_set_markup (GTK_LABEL (label),
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"<u>Scribble area</u>");
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gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);
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frame = gtk_frame_new (NULL);
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gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
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gtk_box_pack_start (GTK_BOX (vbox), frame, TRUE, TRUE, 0);
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da = gtk_drawing_area_new ();
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/* set a minimum size */
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gtk_widget_set_size_request (da, 100, 100);
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gtk_container_add (GTK_CONTAINER (frame), da);
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/* Signals used to handle backing pixmap */
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g_signal_connect (da, "expose_event",
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G_CALLBACK (scribble_expose_event), NULL);
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g_signal_connect (da,"configure_event",
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G_CALLBACK (scribble_configure_event), NULL);
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/* Event signals */
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g_signal_connect (da, "motion_notify_event",
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G_CALLBACK (scribble_motion_notify_event), NULL);
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g_signal_connect (da, "button_press_event",
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G_CALLBACK (scribble_button_press_event), NULL);
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/* Ask to receive events the drawing area doesn't normally
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* subscribe to
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*/
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gtk_widget_set_events (da, gtk_widget_get_events (da)
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| GDK_LEAVE_NOTIFY_MASK
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| GDK_BUTTON_PRESS_MASK
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| GDK_POINTER_MOTION_MASK
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| GDK_POINTER_MOTION_HINT_MASK);
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}
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if (!GTK_WIDGET_VISIBLE (window))
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{
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gtk_widget_show_all (window);
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}
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else
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{
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gtk_widget_destroy (window);
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window = NULL;
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}
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return window;
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}
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