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Some updates for the drawing section. (#161414, Robert Ancell)

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2005-01-03  Matthias Clasen  <mclasen@redhat.com>

	* docs/tutorial/gtk-tut.sgml: Some updates for the drawing
	section.  (#161414, Robert Ancell)
This commit is contained in:
Matthias Clasen 2005-01-03 19:16:20 +00:00 committed by Matthias Clasen
parent 600e5b4721
commit 6803d93d38
5 changed files with 47 additions and 21 deletions
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3
ChangeLog
View File

@ -1,5 +1,8 @@
2005-01-03 Matthias Clasen <mclasen@redhat.com>
* docs/tutorial/gtk-tut.sgml: Some updates for the drawing
section. (#161414, Robert Ancell)
* docs/tutorial/gtk-tut.sgml: Make it build.
* gtk/gtkdialog.c (gtk_dialog_run): Some clarification

3
ChangeLog.pre-2-10
View File

@ -1,5 +1,8 @@
2005-01-03 Matthias Clasen <mclasen@redhat.com>
* docs/tutorial/gtk-tut.sgml: Some updates for the drawing
section. (#161414, Robert Ancell)
* docs/tutorial/gtk-tut.sgml: Make it build.
* gtk/gtkdialog.c (gtk_dialog_run): Some clarification

3
ChangeLog.pre-2-6
View File

@ -1,5 +1,8 @@
2005-01-03 Matthias Clasen <mclasen@redhat.com>
* docs/tutorial/gtk-tut.sgml: Some updates for the drawing
section. (#161414, Robert Ancell)
* docs/tutorial/gtk-tut.sgml: Make it build.
* gtk/gtkdialog.c (gtk_dialog_run): Some clarification

3
ChangeLog.pre-2-8
View File

@ -1,5 +1,8 @@
2005-01-03 Matthias Clasen <mclasen@redhat.com>
* docs/tutorial/gtk-tut.sgml: Some updates for the drawing
section. (#161414, Robert Ancell)
* docs/tutorial/gtk-tut.sgml: Make it build.
* gtk/gtkdialog.c (gtk_dialog_run): Some clarification

56
docs/tutorial/gtk-tut.sgml
View File

@ -12772,7 +12772,7 @@ static gboolean
configure_event( GtkWidget *widget, GdkEventConfigure *event )
{
if (pixmap)
gdk_pixmap_unref(pixmap);
g_object_unref(pixmap);
pixmap = gdk_pixmap_new(widget->window,
widget->allocation.width,
@ -12801,12 +12801,12 @@ to redraw by using the event->area field of the exposure event):</para>
static gboolean
expose_event( GtkWidget *widget, GdkEventExpose *event )
{
gdk_draw_pixmap(widget->window,
widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
pixmap,
event->area.x, event->area.y,
event->area.x, event->area.y,
event->area.width, event->area.height);
gdk_draw_drawable(widget->window,
widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
pixmap,
event->area.x, event->area.y,
event->area.x, event->area.y,
event->area.width, event->area.height);
return FALSE;
}
@ -12818,28 +12818,36 @@ large number of calls in GTK's GDK library for drawing on
<emphasis>drawables</emphasis>. A drawable is simply something that can be drawn
upon. It can be a window, a pixmap, or a bitmap (a black and white
image). We've already seen two such calls above,
<literal>gdk_draw_rectangle()</literal> and <literal>gdk_draw_pixmap()</literal>. The
<literal>gdk_draw_rectangle()</literal> and <literal>gdk_draw_drawable()</literal>. The
complete list is:</para>
<programlisting role="C">
gdk_draw_point ()
gdk_draw_line ()
gdk_draw_rectangle ()
gdk_draw_arc ()
gdk_draw_polygon ()
gdk_draw_string ()
gdk_draw_text ()
gdk_draw_pixmap ()
gdk_draw_bitmap ()
gdk_draw_image ()
gdk_draw_points ()
gdk_draw_segments ()
gdk_draw_lines ()
gdk_draw_pixbuf ()
gdk_draw_glyphs ()
gdk_draw_layout_line ()
gdk_draw_layout ()
gdk_draw_layout_line_with_colors ()
gdk_draw_layout_with_colors ()
gdk_draw_glyphs_transformed ()
gdk_draw_glyphs_trapezoids ()
</programlisting>
<para>See the reference documentation or the header file
<literal>&lt;gdk/gdk.h&gt;</literal> for further details on these functions.
<literal>&lt;gdk/gdkdrawable.h&gt;</literal> for further details on these functions.
These functions all share the same first two arguments. The first
argument is the drawable to draw upon, the second argument is a
<emphasis>graphics context</emphasis> (GC). </para>
<emphasis>graphics context</emphasis> (GC).</para>
<para>A graphics context encapsulates information about things such as
foreground and background color and line width. GDK has a full set of
@ -12887,11 +12895,13 @@ draw_brush (GtkWidget *widget, gdouble x, gdouble y)
update_rect.width = 10;
update_rect.height = 10;
gdk_draw_rectangle (pixmap,
widget->style->black_gc,
TRUE,
widget->style->black_gc,
TRUE,
update_rect.x, update_rect.y,
update_rect.width, update_rect.height);
gtk_widget_draw (widget, &amp;update_rect);
gtk_widget_queue_draw_area (widget,
update_rect.x, update_rect.y,
update_rect.width, update_rect.height);
}
</programlisting>
@ -12899,14 +12909,18 @@ draw_brush (GtkWidget *widget, gdouble x, gdouble y)
we call the function:</para>
<programlisting role="C">
void gtk_widget_draw (GtkWidget *widget,
GdkRectangle *area);
void gtk_widget_queue_draw_area (GtkWidget *widget,
gint x,
gint y,
gint width,
gint height)
</programlisting>
<para>which notifies X that the area given by the <literal>area</literal> parameter
<para>which notifies X that the area given by the <literal>x</literal>,
<literal>y</literal>, <literal>width</literal> and <literal>height</literal> parameters
needs to be updated. X will eventually generate an expose event
(possibly combining the areas passed in several calls to
<literal>gtk_widget_draw()</literal>) which will cause our expose event handler
<literal>gtk_widget_queue_draw_area()</literal>) which will cause our expose event handler
to copy the relevant portions to the screen.</para>
<para>We have now covered the entire drawing program except for a few
@ -15743,8 +15757,8 @@ static void draw_brush( GtkWidget *widget,
update_rect.x, update_rect.y,
update_rect.width, update_rect.height);
gtk_widget_queue_draw_area (widget,
update_rect.x, update_rect.y,
update_rect.width, update_rect.height);
update_rect.x, update_rect.y,
update_rect.width, update_rect.height);
}
static gboolean button_press_event( GtkWidget *widget,