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Make drawing example work again

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Using ::configure-event and ::draw on a drawing area
doesn't work anymore. Use ::size-allocate and a
draw function instead.
This commit is contained in:
Matthias Clasen 2018-01-01 09:15:59 -05:00
parent 4d6fbdd19e
commit bb568a51d4
1 changed files with 29 additions and 25 deletions
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54
examples/drawing.c
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@ -17,39 +17,44 @@ clear_surface (void)
}
/* Create a new surface of the appropriate size to store our scribbles */
static gboolean
configure_event_cb (GtkWidget *widget,
GdkEventConfigure *event,
gpointer data)
static void
size_allocate_cb (GtkWidget *widget,
GtkAllocation *alloc,
int baseline,
GdkRectangle *clip,
gpointer data)
{
if (surface)
cairo_surface_destroy (surface);
{
cairo_surface_destroy (surface);
surface = NULL;
}
surface = gdk_window_create_similar_surface (gtk_widget_get_window (widget),
CAIRO_CONTENT_COLOR,
gtk_widget_get_width (widget),
gtk_widget_get_height (widget));
if (gtk_widget_get_window (widget))
{
surface = gdk_window_create_similar_surface (gtk_widget_get_window (widget),
CAIRO_CONTENT_COLOR,
gtk_widget_get_width (widget),
gtk_widget_get_height (widget));
/* Initialize the surface to white */
clear_surface ();
/* We've handled the configure event, no need for further processing. */
return TRUE;
/* Initialize the surface to white */
clear_surface ();
}
}
/* Redraw the screen from the surface. Note that the ::draw
* signal receives a ready-to-be-used cairo_t that is already
* clipped to only draw the exposed areas of the widget
*/
static gboolean
draw_cb (GtkWidget *widget,
cairo_t *cr,
gpointer data)
static void
draw_cb (GtkDrawingArea *drawing_area,
cairo_t *cr,
int width,
int height,
gpointer data)
{
cairo_set_source_surface (cr, surface, 0, 0);
cairo_paint (cr);
return FALSE;
}
/* Draw a rectangle on the surface at the given position */
@ -162,11 +167,10 @@ activate (GtkApplication *app,
gtk_container_add (GTK_CONTAINER (frame), drawing_area);
/* Signals used to handle the backing surface */
g_signal_connect (drawing_area, "draw",
G_CALLBACK (draw_cb), NULL);
g_signal_connect (drawing_area,"configure-event",
G_CALLBACK (configure_event_cb), NULL);
gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (drawing_area), draw_cb, NULL, NULL);
g_signal_connect_after (drawing_area, "size-allocate",
G_CALLBACK (size_allocate_cb), NULL);
/* Event signals */
g_signal_connect (drawing_area, "motion-notify-event",