RE: transparent pixels with pixmap

[martyn 2 russell bt com]

This is how to do it, first I usually have a function to create the pixmap
(where the widget passed is the usually the window):

GtkWidget * getPixmapFromFile(GtkWidget *widget, const gchar *filename)
{
  GtkWidget *pixmap;
  GdkColormap *colormap;
  GdkPixmap *gdkpixmap;
  GdkBitmap *mask;

  if(!filename || !filename[0])
    return NULL;
  
  colormap = gtk_widget_get_colormap (widget);
  gdkpixmap = gdk_pixmap_colormap_create_from_xpm (NULL, colormap, &mask,
                                                   NULL, filename);
  if(gdkpixmap == NULL)
    {
      printf("**** couldn't create pixmap from file: '%s'\n",filename);
      return NULL;
    }

  pixmap = gtk_pixmap_new (gdkpixmap, mask);
  gdk_pixmap_unref (gdkpixmap);
  gdk_bitmap_unref (mask);
  return pixmap;
}

Then, I load the pixmap into the GtkObject:

.
.
.
  GtkWidget *window = ...
  GtkWidget *pixmap = NULL;

  /* get image */
  pixmap = getPixmapFromFile(window, filename);

  if(pixmap != NULL)
  {     
    gtk_pixmap_set(GTK_PIXMAP(mycontrol),
                 GTK_PIXMAP(pixmap)->pixmap,
                 GTK_PIXMAP(pixmap)->mask);
  }

  gtk_widget_show(mycontrol);

.
.
.

Hope this helps,

Regards,

Martyn

-----Original Message-----
From: Gregory Babusiaux [mailto:gbabusia ulb ac be] 
Sent: 19 March 2002 22:24
To: gtk-app-devel-list gnome org
Subject: transparent pixels with pixmap

Hi !

I have a .xpm with some transparent pixels (made with gimp) I wish to load
in a GdkPixmap but transparent pixels are white displayed.

Here is how I try to do that :

pixmap=gdk_pixmap_colormap_create_from_xpm(NULL,
gtk_widget_get_colormap(window), &trans_mask, NULL, "/.pic.xpm");

where 'window' is correctly initialised and trans_mask copied/pasted from a
.xbm made with gimp (representing the pixels I don't want to diplay, I
changed 'static unsigned short' with 'static unsigned char' to match the
second parameter of gdk_bitmap_create_from_data() )

I tried with a GdkColor as transparent color and change the .xpm to match
the color(transparent pixel -> white), doesn't work too.

Can you give me an advice please ?

Greg 
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