Re: gtk pixmap with transparent background question - What am I doing wrong???

[Tristan Van Berkom <vantr touchtunes com>]

        I'm not sure if there is a convinient way to
get transperency with Pixmaps (could be) but I know
you can easily do this with GdkPixbuf.

see:
http://developer.gnome.org/doc/API/2.0/gdk/gdk-Drawing-Primitives.html#gdk-draw-pixbuf


What I noticed in your code is that you dont
apply your image with transperency to anything.

>         gtk_pixmap_set(pixmapc,pmu,bmu);
>         gtk_widget_show(pixmapc);

Don't you need to render this pixmap and bitmask to a
background (that you need also to aquire) in order
to see the transperency ?

Cheers,
        -Tristan


Kimet Adil wrote:
> Hi,
>
> I am trying to witre an app that has animated gtkpixmaps crawling over the
> page. I am using Anjust+Glade, so there is a lot of code. It all works well
> except I want transparent backgrounds and they stay white, and cover each
> other if they collide. I know this is a long email but I just dont know how
> to ask the question completely without all the code Here are the key
> functions:
>
> struct pickies {
>
>         GdkPixmap *pm;
>         GdkBitmap *bm;
>         struct pickies *next;
>
> };
>
>         struct pickies p1,p2,p3,x1,x2,x3,x4,*xs,*s;
>         GdkPixmap *pm1;
>
>         int tx=250,ty=250;
>         static int vx=5, vy=0;
>
> /* load the pixmaps
>
> void on_button1_clicked  (GtkButton       *button,    gpointer   user_data)
> {
>  GtkStyle *style;
>         GtkWidget *pixmapa,*pixmapb;
>         GtkWidget *window;
>         pixmapa = lookup_widget(button,"pixmap2");
>         pixmapb = lookup_widget(button,"pixmap1");
>         window=lookup_widget(button,"window1");
>          style = gtk_widget_get_style( window );
>     p1.pm = gdk_pixmap_create_from_xpm( window->window,&p1.bm,NULL,"930e1.xpm"
> );
>     p1.next=&p2;
>         p2.pm = gdk_pixmap_create_from_xpm( window->window, &p2.bm,NULL,"930e2.xpm"
> );
>     p2.next=&p3;
>         p3.pm = gdk_pixmap_create_from_xpm( window->window,
> &p3.bm,&style->bg[GTK_STATE_NORMAL],"930e3.xpm" );
>     p3.next=&p1;
>         s=&p1;
>
>
>     x1.pm = gdk_pixmap_create_from_xpm( window->window,
> x1.bm,NULL,"XPB4100-1.xpm" );
>     x1.next=&x2;
>         x2.pm = gdk_pixmap_create_from_xpm( window->window,
> x2.bm,NULL,"XPB4100-2.xpm" );
>     x2.next=&x3;
>         x3.pm = gdk_pixmap_create_from_xpm( window->window,
> x3.bm,NULL,"XPB4100-3.xpm" );
>     x3.next=&x4;
>         x4.pm = gdk_pixmap_create_from_xpm( window->window,
> x4.bm,NULL,"XPB4100-4.xpm" );
>     x4.next=&x1;
>         xs=&x1;
>
>
>
> }
>
> void anim(GtkWidget *button2)
> {
>         GtkWidget *pixmapc;
>         GtkWidget *window;
>         GdkPixmap *pmu;
>         GdkBitmap *bmu;
>         s=s->next;
>         pmu=s->pm;
>         bmu=s->bm;
>         pixmapc = lookup_widget(button2,"pixmap2");
>         gtk_pixmap_set(pixmapc,pmu,bmu);
>         gtk_widget_show(pixmapc);
> }
>
> void movePM(GtkWidget *widget)
> {
> GtkPixmap *pixmap2;
> tx=tx+vx;
>         if(tx>500){
>         vx=vx*-1;
>         }
>         if(tx<50){
>         vx=vx*-1;
>         }
>         ty=ty+vy;
>         if(ty>500){
>         vy=vy*-1;
>         }
>         if(ty<50){
>         vy=vy*-1;
>         }
>         pixmap2 = lookup_widget(widget,"pixmap2");
>  gtk_widget_set_uposition (pixmap2, tx, ty);
> }
>
> void animXPB(GtkWidget *button2)
> {
>         GtkWidget *pixmapc;
>         GtkWidget *window;
>         GdkPixmap *pmu;
>         xs=xs->next;
>         pmu=xs->pm;
>         pixmapc = lookup_widget(button2,"pixmap1");
>         gtk_pixmap_set(pixmapc,xs->pm,xs->bm);
>         //gdk_pixmap_unref(pmu);
>         gtk_widget_show(pixmapc);
> }
>
> void on_button2_clicked (GtkButton       *button,
>                                         gpointer         user_data)
> {
>         GtkPixmap *pixmapc;
>         gtk_timeout_add(140,anim,button);
>         gtk_timeout_add(700,animXPB,button);
>         pixmapc = lookup_widget(button,"pixmap2");
>         gtk_timeout_add(90,movePM,button);
>
>         }
>
> Thanks,
> Kim
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