489 lines
15 KiB
C
489 lines
15 KiB
C
/* GTK - The GIMP Toolkit
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* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
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* file for a list of people on the GTK+ Team. See the ChangeLog
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* files for a list of changes. These files are distributed with
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* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
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*/
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#include "config.h"
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#include "gtkdrawingarea.h"
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#include "gtkmarshalers.h"
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#include "gdk/gdkmarshalers.h"
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#include "gtkprivate.h"
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#include "gtksnapshot.h"
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#include "gtkwidgetprivate.h"
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typedef struct _GtkDrawingAreaPrivate GtkDrawingAreaPrivate;
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struct _GtkDrawingAreaPrivate {
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int content_width;
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int content_height;
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GtkDrawingAreaDrawFunc draw_func;
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gpointer draw_func_target;
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GDestroyNotify draw_func_target_destroy_notify;
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};
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enum {
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PROP_0,
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PROP_CONTENT_WIDTH,
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PROP_CONTENT_HEIGHT,
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LAST_PROP
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};
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static GParamSpec *props[LAST_PROP] = { NULL, };
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enum {
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RESIZE,
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LAST_SIGNAL
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};
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static guint signals[LAST_SIGNAL] = { 0, };
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/**
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* GtkDrawingArea:
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*
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* `GtkDrawingArea` is a widget that allows drawing with cairo.
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*
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* 
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*
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* It’s essentially a blank widget; you can draw on it. After
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* creating a drawing area, the application may want to connect to:
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*
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* - The [signal@Gtk.Widget::realize] signal to take any necessary actions
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* when the widget is instantiated on a particular display.
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* (Create GDK resources in response to this signal.)
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*
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* - The [signal@Gtk.DrawingArea::resize] signal to take any necessary
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* actions when the widget changes size.
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*
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* - Call [method@Gtk.DrawingArea.set_draw_func] to handle redrawing the
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* contents of the widget.
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*
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* The following code portion demonstrates using a drawing
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* area to display a circle in the normal widget foreground
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* color.
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*
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* ## Simple GtkDrawingArea usage
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*
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* ```c
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* static void
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* draw_function (GtkDrawingArea *area,
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* cairo_t *cr,
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* int width,
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* int height,
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* gpointer data)
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* {
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* GdkRGBA color;
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*
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* cairo_arc (cr,
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* width / 2.0, height / 2.0,
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* MIN (width, height) / 2.0,
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* 0, 2 * G_PI);
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*
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* gtk_widget_get_color (GTK_WIDGET (area),
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* &color);
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* gdk_cairo_set_source_rgba (cr, &color);
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*
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* cairo_fill (cr);
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* }
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*
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* int
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* main (int argc, char **argv)
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* {
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* gtk_init ();
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*
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* GtkWidget *area = gtk_drawing_area_new ();
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* gtk_drawing_area_set_content_width (GTK_DRAWING_AREA (area), 100);
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* gtk_drawing_area_set_content_height (GTK_DRAWING_AREA (area), 100);
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* gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (area),
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* draw_function,
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* NULL, NULL);
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* return 0;
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* }
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* ```
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*
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* The draw function is normally called when a drawing area first comes
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* onscreen, or when it’s covered by another window and then uncovered.
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* You can also force a redraw by adding to the “damage region” of the
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* drawing area’s window using [method@Gtk.Widget.queue_draw].
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* This will cause the drawing area to call the draw function again.
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*
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* The available routines for drawing are documented in the
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* [Cairo documentation](https://www.cairographics.org/manual/); GDK
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* offers additional API to integrate with Cairo, like [func@Gdk.cairo_set_source_rgba]
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* or [func@Gdk.cairo_set_source_pixbuf].
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*
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* To receive mouse events on a drawing area, you will need to use
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* event controllers. To receive keyboard events, you will need to set
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* the “can-focus” property on the drawing area, and you should probably
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* draw some user-visible indication that the drawing area is focused.
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*
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* If you need more complex control over your widget, you should consider
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* creating your own `GtkWidget` subclass.
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*/
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G_DEFINE_TYPE_WITH_PRIVATE (GtkDrawingArea, gtk_drawing_area, GTK_TYPE_WIDGET)
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static void
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gtk_drawing_area_set_property (GObject *gobject,
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guint prop_id,
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const GValue *value,
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GParamSpec *pspec)
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{
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GtkDrawingArea *self = GTK_DRAWING_AREA (gobject);
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switch (prop_id)
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{
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case PROP_CONTENT_WIDTH:
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gtk_drawing_area_set_content_width (self, g_value_get_int (value));
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break;
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case PROP_CONTENT_HEIGHT:
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gtk_drawing_area_set_content_height (self, g_value_get_int (value));
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
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}
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}
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static void
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gtk_drawing_area_get_property (GObject *gobject,
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guint prop_id,
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GValue *value,
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GParamSpec *pspec)
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{
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GtkDrawingArea *self = GTK_DRAWING_AREA (gobject);
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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switch (prop_id)
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{
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case PROP_CONTENT_WIDTH:
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g_value_set_int (value, priv->content_width);
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break;
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case PROP_CONTENT_HEIGHT:
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g_value_set_int (value, priv->content_height);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
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}
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}
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static void
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gtk_drawing_area_dispose (GObject *object)
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{
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GtkDrawingArea *self = GTK_DRAWING_AREA (object);
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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if (priv->draw_func_target_destroy_notify != NULL)
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priv->draw_func_target_destroy_notify (priv->draw_func_target);
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priv->draw_func = NULL;
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priv->draw_func_target = NULL;
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priv->draw_func_target_destroy_notify = NULL;
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G_OBJECT_CLASS (gtk_drawing_area_parent_class)->dispose (object);
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}
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static void
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gtk_drawing_area_measure (GtkWidget *widget,
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GtkOrientation orientation,
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int for_size,
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int *minimum,
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int *natural,
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int *minimum_baseline,
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int *natural_baseline)
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{
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GtkDrawingArea *self = GTK_DRAWING_AREA (widget);
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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if (orientation == GTK_ORIENTATION_HORIZONTAL)
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{
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*minimum = *natural = priv->content_width;
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}
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else
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{
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*minimum = *natural = priv->content_height;
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}
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}
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static void
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gtk_drawing_area_size_allocate (GtkWidget *widget,
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int width,
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int height,
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int baseline)
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{
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g_signal_emit (widget, signals[RESIZE], 0, width, height);
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}
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static void
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gtk_drawing_area_snapshot (GtkWidget *widget,
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GtkSnapshot *snapshot)
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{
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GtkDrawingArea *self = GTK_DRAWING_AREA (widget);
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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cairo_t *cr;
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int width, height;
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if (!priv->draw_func)
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return;
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width = gtk_widget_get_width (widget);
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height = gtk_widget_get_height (widget);
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cr = gtk_snapshot_append_cairo (snapshot,
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&GRAPHENE_RECT_INIT (
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0, 0,
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width, height
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));
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priv->draw_func (self,
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cr,
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width, height,
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priv->draw_func_target);
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cairo_destroy (cr);
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}
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static void
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gtk_drawing_area_class_init (GtkDrawingAreaClass *class)
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{
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GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
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GObjectClass *gobject_class = G_OBJECT_CLASS (class);
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gobject_class->set_property = gtk_drawing_area_set_property;
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gobject_class->get_property = gtk_drawing_area_get_property;
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gobject_class->dispose = gtk_drawing_area_dispose;
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widget_class->measure = gtk_drawing_area_measure;
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widget_class->size_allocate = gtk_drawing_area_size_allocate;
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widget_class->snapshot = gtk_drawing_area_snapshot;
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/**
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* GtkDrawingArea:content-width: (attributes org.gtk.Property.get=gtk_drawing_area_get_content_width org.gtk.Property.set=gtk_drawing_area_set_content_width)
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*
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* The content width.
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*/
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props[PROP_CONTENT_WIDTH] =
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g_param_spec_int ("content-width", NULL, NULL,
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0, G_MAXINT, 0,
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GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
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/**
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* GtkDrawingArea:content-height: (attributes org.gtk.Property.get=gtk_drawing_area_get_content_height org.gtk.Property.set=gtk_drawing_area_set_content_height)
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*
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* The content height.
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*/
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props[PROP_CONTENT_HEIGHT] =
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g_param_spec_int ("content-height", NULL, NULL,
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0, G_MAXINT, 0,
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GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
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g_object_class_install_properties (gobject_class, LAST_PROP, props);
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/**
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* GtkDrawingArea::resize:
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* @area: the `GtkDrawingArea` that emitted the signal
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* @width: the width of the viewport
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* @height: the height of the viewport
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*
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* Emitted once when the widget is realized, and then each time the widget
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* is changed while realized.
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*
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* This is useful in order to keep state up to date with the widget size,
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* like for instance a backing surface.
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*/
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signals[RESIZE] =
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g_signal_new (I_("resize"),
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G_TYPE_FROM_CLASS (class),
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G_SIGNAL_RUN_LAST,
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G_STRUCT_OFFSET (GtkDrawingAreaClass, resize),
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NULL, NULL,
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_gdk_marshal_VOID__INT_INT,
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G_TYPE_NONE, 2, G_TYPE_INT, G_TYPE_INT);
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g_signal_set_va_marshaller (signals[RESIZE],
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G_TYPE_FROM_CLASS (class),
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_gdk_marshal_VOID__INT_INTv);
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}
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static void
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gtk_drawing_area_init (GtkDrawingArea *darea)
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{
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gtk_widget_set_focusable (GTK_WIDGET (darea), FALSE);
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}
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/**
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* gtk_drawing_area_new:
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*
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* Creates a new drawing area.
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*
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* Returns: a new `GtkDrawingArea`
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*/
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GtkWidget*
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gtk_drawing_area_new (void)
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{
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return g_object_new (GTK_TYPE_DRAWING_AREA, NULL);
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}
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/**
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* gtk_drawing_area_set_content_width: (attributes org.gtk.Method.set_property=content-width)
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* @self: a `GtkDrawingArea`
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* @width: the width of contents
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*
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* Sets the desired width of the contents of the drawing area.
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*
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* Note that because widgets may be allocated larger sizes than they
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* requested, it is possible that the actual width passed to your draw
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* function is larger than the width set here. You can use
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* [method@Gtk.Widget.set_halign] to avoid that.
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*
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* If the width is set to 0 (the default), the drawing area may disappear.
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*/
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void
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gtk_drawing_area_set_content_width (GtkDrawingArea *self,
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int width)
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{
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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g_return_if_fail (GTK_IS_DRAWING_AREA (self));
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g_return_if_fail (width >= 0);
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if (priv->content_width == width)
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return;
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priv->content_width = width;
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gtk_widget_queue_resize (GTK_WIDGET (self));
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g_object_notify_by_pspec (G_OBJECT (self), props[PROP_CONTENT_WIDTH]);
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}
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/**
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* gtk_drawing_area_get_content_width: (attributes org.gtk.Method.get_property=content-width)
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* @self: a `GtkDrawingArea`
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*
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* Retrieves the content width of the `GtkDrawingArea`.
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*
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* Returns: The width requested for content of the drawing area
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*/
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int
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gtk_drawing_area_get_content_width (GtkDrawingArea *self)
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{
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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g_return_val_if_fail (GTK_IS_DRAWING_AREA (self), 0);
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return priv->content_width;
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}
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/**
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* gtk_drawing_area_set_content_height: (attributes org.gtk.Method.set_property=content-height)
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* @self: a `GtkDrawingArea`
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* @height: the height of contents
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*
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* Sets the desired height of the contents of the drawing area.
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*
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* Note that because widgets may be allocated larger sizes than they
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* requested, it is possible that the actual height passed to your draw
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* function is larger than the height set here. You can use
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* [method@Gtk.Widget.set_valign] to avoid that.
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*
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* If the height is set to 0 (the default), the drawing area may disappear.
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*/
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void
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gtk_drawing_area_set_content_height (GtkDrawingArea *self,
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int height)
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{
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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g_return_if_fail (GTK_IS_DRAWING_AREA (self));
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g_return_if_fail (height >= 0);
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if (priv->content_height == height)
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return;
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priv->content_height = height;
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gtk_widget_queue_resize (GTK_WIDGET (self));
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g_object_notify_by_pspec (G_OBJECT (self), props[PROP_CONTENT_HEIGHT]);
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}
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/**
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* gtk_drawing_area_get_content_height: (attributes org.gtk.Method.get_property=content-height)
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* @self: a `GtkDrawingArea`
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*
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* Retrieves the content height of the `GtkDrawingArea`.
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*
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* Returns: The height requested for content of the drawing area
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*/
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int
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gtk_drawing_area_get_content_height (GtkDrawingArea *self)
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{
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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g_return_val_if_fail (GTK_IS_DRAWING_AREA (self), 0);
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return priv->content_height;
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}
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/**
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* gtk_drawing_area_set_draw_func:
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* @self: a `GtkDrawingArea`
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* @draw_func: (nullable): callback that lets you draw
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* the drawing area's contents
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* @user_data: (closure): user data passed to @draw_func
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* @destroy: destroy notifier for @user_data
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*
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* Setting a draw function is the main thing you want to do when using
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* a drawing area.
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*
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* The draw function is called whenever GTK needs to draw the contents
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* of the drawing area to the screen.
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*
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* The draw function will be called during the drawing stage of GTK.
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* In the drawing stage it is not allowed to change properties of any
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* GTK widgets or call any functions that would cause any properties
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* to be changed. You should restrict yourself exclusively to drawing
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* your contents in the draw function.
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*
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* If what you are drawing does change, call [method@Gtk.Widget.queue_draw]
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* on the drawing area. This will cause a redraw and will call @draw_func again.
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*/
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void
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gtk_drawing_area_set_draw_func (GtkDrawingArea *self,
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GtkDrawingAreaDrawFunc draw_func,
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gpointer user_data,
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GDestroyNotify destroy)
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{
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GtkDrawingAreaPrivate *priv = gtk_drawing_area_get_instance_private (self);
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g_return_if_fail (GTK_IS_DRAWING_AREA (self));
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if (priv->draw_func_target_destroy_notify != NULL)
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priv->draw_func_target_destroy_notify (priv->draw_func_target);
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priv->draw_func = draw_func;
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priv->draw_func_target = user_data;
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priv->draw_func_target_destroy_notify = destroy;
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gtk_widget_queue_draw (GTK_WIDGET (self));
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}
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