In message <003501c08ab4$4d577ee0$ea57623e@e6z1t6>you write:
>Hi,
> I have a problem: I am in need of displaying a pixmap widget with a
>transparent area... but I want to control and change the shape of this area
>each time I create it. So, I have the non-trasparent pixmap in a file (png,
>let's say), and the 'mask' for the alpha channel in a bicolor one. Now, how
>can I assemble the two?? I've checked the header files of gdk_imlib, gdk_h
>and gtkpixmap, and it seems that nothing suits my need... well, I figured it
>could be done with imlib... apparently, not! So I wrote something like:
1) check the "shapes" example in the testgtk.c file
2) understand gtk_widget_shape_combine_mask()
2) the following code should give you some ideas, even though its in C++
/*
Copyright (C) 1999 Paul Barton-Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: shaped_window.cc,v 1.4 2000/06/20 16:50:13 pbd Exp $
*/
#include <gtk--.h>
#include <gtkmmext/pix.h>
#include <gtkmmext/shaped_window.h>
using namespace Gtkmmext;
ShapedWindow::ShapedWindow (Pix *pixset, Gtk::Widget *w)
{
pix = pixset;
current_pix = 0;
exposed = false;
shapeable_parent = w;
}
ShapedWindow::~ShapedWindow ()
{
finish_pix (pix);
}
void
ShapedWindow::set_current_pix (size_t n)
{
n = MIN(n,pix->max_pixmap());
if (n != current_pix) {
current_pix = n;
draw_pixmap ();
}
}
void
ShapedWindow::realize_impl ()
{
gint width, height;
Gtk::Widget *parent;
Gtk::DrawingArea::realize_impl ();
mystyle = get_style()->gtkobj();
if (!shapeable_parent) {
parent = this;
} else {
parent = shapeable_parent;
}
pix->generate (get_window(),
(GdkColor *) &mystyle->bg[GTK_STATE_NORMAL]);
gdk_window_get_size (pix->pixmap (0), &width, &height);
set_usize (width, height);
gtk_widget_shape_combine_mask (GTK_WIDGET(parent->gtkobj()),
pix->shape_mask (0),
0, 0);
exposed = true;
draw_pixmap ();
}
gint
ShapedWindow::expose_event_impl (GdkEventExpose *ev)
{
if (ev->count == 0) {
draw_pixmap ();
}
return TRUE;
}
void
ShapedWindow::state_changed_impl (GtkStateType somestate)
{
current_pix = (size_t) get_state() % pix->n_pixmaps();
draw_pixmap();
}
void
ShapedWindow::draw_pixmap ()
{
if (exposed) {
if (!pix->homogenous()) {
Gtk::Widget *parent;
if (!shapeable_parent) {
parent = this;
} else {
parent = shapeable_parent;
}
gtk_widget_shape_combine_mask
(GTK_WIDGET(parent->gtkobj()),
pix->shape_mask (current_pix),
0, 0);
}
gdk_draw_pixmap (get_window(),
mystyle->bg_gc[get_state()],
pix->pixmap (current_pix),
0, 0, 0, 0,
-1, -1);
}
}
/*
Copyright (C) 1999 Paul Barton-Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: shaped_window.h,v 1.5 2000/06/06 05:41:59 pbd Exp $
*/
#ifndef __gtkmm_shapedwindow_h__
#define __gtkmm_shapedwindow_h__
namespace Gtkmmext {
class Pix;
class ShapedWindow : public Gtk::DrawingArea
{
private:
Gtk::Widget *shapeable_parent;
Pix *pix;
const GtkStyle *mystyle;
int current_pix;
void draw_pixmap ();
bool exposed;
protected:
virtual void realize_impl ();
virtual gint expose_event_impl (GdkEventExpose *);
virtual void state_changed_impl (GtkStateType);
public:
ShapedWindow (Pix *pix, Gtk::Widget *shapeable_parent = 0);
virtual ~ShapedWindow();
void set_current_pix (size_t pixnum);
};
} /* namespace Gtkmmext */
#endif // __gtkmm_shapedwindow_h__
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