dl23+@andrew.cmu.edu (Damon Wayne Lipparelli) (04/15/89)
Hello. On the hp 835's there is a program called "xseethru" which allows you to
see the full color planes if you are running in the overlay planes. I'm trying
to write something similar only on a more specific scale. Does anyone know how
it works?
I've tried various things with varying results. The program that comes the
closest is this one:
#include <stdio.h>
#include <starbase.c.h>
main(argc,argv)
int argc;
char **argv;
{
int fd,f2;
float p_l[2][3],r[3],p1[3],p2[3];
int c;
gescape_arg a,b;
system("xwcreate -geometry =600x600 foo -bw 0");
if ((fd = gopen("/dev/screen/foo",OUTINDEV,"sox11",0)) == -1)
{
fprintf(stderr,"Error: Couldn't open window.\n");
exit(-1);
}
if ((f2 = gopen("/dev/ocrt0",OUTDEV,"hp98731",0)) == -1)
{
fprintf(stderr,"Error: Couldn't open overlay planes.\n");
exit(-2);
}
inquire_sizes(fd,p_l,r,p1,p2,&c);
background_color_index(fd,c-1);
clear_control(fd,CLEAR_DISPLAY_SURFACE);
clear_view_surface(fd);
make_picture_current(fd);
a.i[0] = FALSE;
gescape(f2,SWITCH_SEMAPHORE,&a,&b);
a.i[0] = c-1;
gescape(f2,R_TRANSPARENCY_INDEX,&a,&b);
a.i[0] = TRUE;
gescape(f2,SWITCH_SEMAPHORE,&a,&b);
while (1)
;
gclose(fd);
system("xwdestroy foo");
}
This opens a window which _does_ show the full color planes, but as soon as the
mouse is moved, or a key is hit, X disables the transparency. What magic does
xseethru do?
Damon Lipparelli
Graphics Support Staff
Engineering Design Research Centerkam@hpcvlx.HP.COM (Keith Marchington) (04/18/89)
/ hpcvlx:comp.sys.hp / dl23+@andrew.cmu.edu (Damon Wayne Lipparelli) / 2:59 pm Apr 14, 1989 / > Hello. On the hp 835's there is a program called "xseethru" which > allows you to see the full color planes if you are running in the > overlay planes. I'm trying to write something similar only on a more > specific scale. Does anyone know how it works? > <Program deleted> > > Damon Lipparelli > Graphics Support Staff > Engineering Design Research Center > ---------- I guess the big question here is which version of X are you running? If it is Version 10, then the way xseethru works is magic (if I remember correctly.) If it is Version 11, then you should be able to actually create windows with a background color of "Transparent" that will allow you to see thru to the image planes. In fact, you can actually set the root window to transparent on X 11 with the command xsetroot -solid transparent assuming that you have a color cell in the colormap available. In fact that is the mode that I prefer to work in (in that configuration.) This makes it seem as though the windows are simply "floating" over whatever image you have in the image planes. Keith Marchington Hewlett-Packard Corvallis, OR USA
steve@hpcvlx.HP.COM (Steve Hiebert) (04/18/89)
What OS level are you at? Mixing X and Starbase calls to the same device isn't supported before 3.1. (The overlay and image planes are considered two devices unless one is running in Combined Mode in 3.1). If you're running 3.1, you shouldn't be making Starbase calls directly to the overlay planes hardware when X is running there. You should be going to a window. When X wakes up it restores the transparency registers to the values it thinks they should have; modifying the hardware directly doesn't give X a chance to know that something has changed. The SRX and TSRX don't really have a transparent color - we "borrowed" a color (0,0,1) that would normally be a blue so close to black as to be indistinguishable and therefore probably useless. Whenever the server gets a pixel value of (0,0,1) it sets the the overlays to black and the image planes to dominant thereby making the overlays transparent (they actually blend). How about setting "-bg transparent" in your call to xwcreate()? I often do an "xsetroot -solid transparent". It makes the windows in the overlays appear to float over the image planes. It seems more intuitive to me than to have to punch a hole in the overlay planes to get to the image planes. Steve Hiebert Hewlett-Packard Corvallis Workstation Operation
stroyan@hpfcdc.HP.COM (Mike Stroyan) (04/18/89)
> Hello. On the hp 835's there is a program called "xseethru" which > allows you to see the full color planes if you are running in the > overlay planes. I'm trying to write something similar only on a more > specific scale. Does anyone know how it works? There is a magic color in the rgb database called "transparent". The rgb data would correspond to a very dark blue, but it is actually rendered as transparency to the full color planes. For instance, "xterm -bg transparent" will produce a terminal window with a transparent background. Mike Stroyan, stroyan@hpfcla.hp.com