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/* GTK - The GIMP Toolkit
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GTK+ Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "gtkdrawingarea.h"
#include "gtkintl.h"
#include "gtkstylecontext.h"
/**
* SECTION:gtkdrawingarea
* @Short_description: A widget for custom user interface elements
* @Title: GtkDrawingArea
* @See_also: #GtkImage
*
* The #GtkDrawingArea widget is used for creating custom user interface
* elements. It’s essentially a blank widget; you can draw on it. After
* creating a drawing area, the application may want to connect to:
*
* - Mouse and button press signals to respond to input from
* the user. (Use gtk_widget_add_events() to enable events
* you wish to receive.)
*
* - The #GtkWidget::realize signal to take any necessary actions
* when the widget is instantiated on a particular display.
* (Create GDK resources in response to this signal.)
*
* - The #GtkWidget::configure-event signal to take any necessary
* actions when the widget changes size.
*
* - The #GtkWidget::draw signal to handle redrawing the
* contents of the widget.
*
* The following code portion demonstrates using a drawing
* area to display a circle in the normal widget foreground
* color.
*
* Note that GDK automatically clears the exposed area to the
* background color before sending the expose event, and that
* drawing is implicitly clipped to the exposed area.
*
* ## Simple GtkDrawingArea usage
*
* |[<!-- language="C" -->
* gboolean
* draw_callback (GtkWidget *widget, cairo_t *cr, gpointer data)
* {
* guint width, height;
* GdkRGBA color;
*
* width = gtk_widget_get_allocated_width (widget);
* height = gtk_widget_get_allocated_height (widget);
* cairo_arc (cr,
* width / 2.0, height / 2.0,
* MIN (width, height) / 2.0,
* 0, 2 * G_PI);
*
* gtk_style_context_get_color (gtk_widget_get_style_context (widget),
* 0,
* &color);
* gdk_cairo_set_source_rgba (cr, &color);
*
* cairo_fill (cr);
*
* return FALSE;
* }
* [...]
* GtkWidget *drawing_area = gtk_drawing_area_new ();
* gtk_widget_set_size_request (drawing_area, 100, 100);
* g_signal_connect (G_OBJECT (drawing_area), "draw",
* G_CALLBACK (draw_callback), NULL);
* ]|
*
* Draw signals are normally delivered when a drawing area first comes
* onscreen, or when it’s covered by another window and then uncovered.
* You can also force an expose event by adding to the “damage region”
* of the drawing area’s window; gtk_widget_queue_draw_area() and
* gdk_window_invalidate_rect() are equally good ways to do this.
* You’ll then get a draw signal for the invalid region.
*
* The available routines for drawing are documented on the
* [GDK Drawing Primitives][gdk3-Cairo-Interaction] page
* and the cairo documentation.
*
* To receive mouse events on a drawing area, you will need to enable
* them with gtk_widget_add_events(). To receive keyboard events, you
* will need to set the “can-focus” property on the drawing area, and you
* should probably draw some user-visible indication that the drawing
* area is focused. Use gtk_widget_has_focus() in your expose event
* handler to decide whether to draw the focus indicator. See
* gtk_render_focus() for one way to draw focus.
*/
static void gtk_drawing_area_realize (GtkWidget *widget);
static void gtk_drawing_area_size_allocate (GtkWidget *widget,
GtkAllocation *allocation);
static void gtk_drawing_area_send_configure (GtkDrawingArea *darea);
G_DEFINE_TYPE (GtkDrawingArea, gtk_drawing_area, GTK_TYPE_WIDGET)
static void
gtk_drawing_area_class_init (GtkDrawingAreaClass *class)
{
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
widget_class->realize = gtk_drawing_area_realize;
widget_class->size_allocate = gtk_drawing_area_size_allocate;
gtk_widget_class_set_accessible_role (widget_class, ATK_ROLE_DRAWING_AREA);
}
static void
gtk_drawing_area_init (GtkDrawingArea *darea)
{
}
/**
* gtk_drawing_area_new:
*
* Creates a new drawing area.
*
* Returns: a new #GtkDrawingArea
*/
GtkWidget*
gtk_drawing_area_new (void)
{
return g_object_new (GTK_TYPE_DRAWING_AREA, NULL);
}
static void
gtk_drawing_area_realize (GtkWidget *widget)
{
GtkAllocation allocation;
GdkWindow *window;
GdkWindowAttr attributes;
gint attributes_mask;
if (!gtk_widget_get_has_window (widget))
{
GTK_WIDGET_CLASS (gtk_drawing_area_parent_class)->realize (widget);
}
else
{
gtk_widget_set_realized (widget, TRUE);
gtk_widget_get_allocation (widget, &allocation);
attributes.window_type = GDK_WINDOW_CHILD;
attributes.x = allocation.x;
attributes.y = allocation.y;
attributes.width = allocation.width;
attributes.height = allocation.height;
attributes.wclass = GDK_INPUT_OUTPUT;
attributes.visual = gtk_widget_get_visual (widget);
attributes.event_mask = gtk_widget_get_events (widget) | GDK_EXPOSURE_MASK;
attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL;
window = gdk_window_new (gtk_widget_get_parent_window (widget),
&attributes, attributes_mask);
gtk_widget_register_window (widget, window);
gtk_widget_set_window (widget, window);
gtk_style_context_set_background (gtk_widget_get_style_context (widget),
window);
}
gtk_drawing_area_send_configure (GTK_DRAWING_AREA (widget));
}
static void
gtk_drawing_area_size_allocate (GtkWidget *widget,
GtkAllocation *allocation)
{
g_return_if_fail (GTK_IS_DRAWING_AREA (widget));
g_return_if_fail (allocation != NULL);
gtk_widget_set_allocation (widget, allocation);
if (gtk_widget_get_realized (widget))
{
if (gtk_widget_get_has_window (widget))
gdk_window_move_resize (gtk_widget_get_window (widget),
allocation->x, allocation->y,
allocation->width, allocation->height);
gtk_drawing_area_send_configure (GTK_DRAWING_AREA (widget));
}
}
static void
gtk_drawing_area_send_configure (GtkDrawingArea *darea)
{
GtkAllocation allocation;
GtkWidget *widget;
GdkEvent *event = gdk_event_new (GDK_CONFIGURE);
widget = GTK_WIDGET (darea);
gtk_widget_get_allocation (widget, &allocation);
event->configure.window = g_object_ref (gtk_widget_get_window (widget));
event->configure.send_event = TRUE;
event->configure.x = allocation.x;
event->configure.y = allocation.y;
event->configure.width = allocation.width;
event->configure.height = allocation.height;
gtk_widget_event (widget, event);
gdk_event_free (event);
}
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