forked from AuroraMiddleware/gtk
f7a50c4dc2
Thu Aug 19 14:43:08 1999 Owen Taylor <otaylor@redhat.com> * gdk/tmpl/gcs.sgml gdk/gdk-sections.txt: Added section. (Written a while ago but fell through the cracks) * gtk/gtk-docs.sgml: Add a &hash; entity here as a temporary hack. (There is no standard entity for '#', and no way of escaping '#' in gtk-doc) * gtk/tmpl/gtkrc.sgml: Use the above to fix up #rrggbb string literals. * gtk/tmpl/gtkdrawingarea.sgml: Fixed a couple of errors in the example. (pointed out by Nick Lamb)
113 lines
3.0 KiB
Plaintext
113 lines
3.0 KiB
Plaintext
<!-- ##### SECTION Title ##### -->
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GtkDrawingArea
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<!-- ##### SECTION Short_Description ##### -->
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a widget for custom user interface elements.
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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The #GtkDrawingArea widget is used for creating custom
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user interface elements. After creating a drawing
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area, the application may want to connect to:
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<itemizedlist>
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<listitem>
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<para>
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Mouse and button press signals to respond to input from
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the user.
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</para>
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</listitem>
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<listitem>
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<para>
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The "realize" signal to take any necessary actions
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when the widget
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</para>
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</listitem>
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<listitem>
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<para>
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The "size_allocate" signal to take any necessary actions
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when the widget changes size.
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</para>
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</listitem>
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<listitem>
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<para>
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The "expose_event" signal to handle redrawing the
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contents of the widget.
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</para>
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</listitem>
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</itemizedlist>
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As a convenience, the #GtkDrawingArea widget synthesizes
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a "configure_event" when the widget is realized
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and any time the size of a widget changes when it
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is realized. It often suffices to connect to this
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signal instead of "realize" and "size_allocate".
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</para>
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<para>
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The following code portion demonstrates using a drawing
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area to implement a widget that draws a circle.
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As this example demonstrates, an expose handler should
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draw only the pixels within the requested area and
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should draw or clear all these pixels.
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</para>
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<programlisting>
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gboolean
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expose_event (GdkWidget *widget, GdkEventExpose *event, gpointer data)
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{
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gdk_window_clear_area (widget->window,
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event->area.x, event->area.y,
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event->area.width, event->area.height);
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gdk_gc_set_clip_rectangle (widget->style->fg_gc[widget->state],
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&event->area);
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gdk_draw_arc (widget->window,
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widget->style->fg_gc[widget->state],
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TRUE,
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0, 0, widget->allocation.width, widget->allocation.height,
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0, 64 * 360);
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gdk_gc_set_clip_rectangle (widget->style->fg_gc[widget->state],
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NULL);
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return TRUE;
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}
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[...]
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GtkWidget *drawing_area = gdk_drawing_area_new ();
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gdk_drawing_area_size (GTK_DRAWING_AREA (drawing_area),
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100, 100);
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gtk_signal_connect (GTK_OBJECT (drawing_area),
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</programlisting>
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<!-- ##### SECTION See_Also ##### -->
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<para>
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</para>
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<!-- ##### STRUCT GtkDrawingArea ##### -->
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<para>
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The #GtkDrawingArea-struct struct contains private data only, and
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should be accessed using the functions below.
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</para>
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@widget:
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@draw_data:
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<!-- ##### FUNCTION gtk_drawing_area_new ##### -->
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<para>
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Create a new drawing area.
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</para>
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@Returns:
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<!-- ##### FUNCTION gtk_drawing_area_size ##### -->
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<para>
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Set the size that the drawing area will request
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in response to a "size_request" signal. The
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drawing area may actually be allocated a size
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larger than this depending on how it is packed
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within the enclosing containers.
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</para>
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@darea: a #GtkDrawingArea.
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@width: the width to request.
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@height: the height to request.
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