NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/sys/hp/14501

Internet Message Format | 1993-01-04 | 1.6 KB

From: [e-mail] (Howard Stroyan)
Date: Mon, 4 Jan 1993 21:24:06 GMT
Subject: Re: Using starbase in X
Message-ID: <[e-mail]>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Path: sparky!uunet!usc!sdd.hp.com!hpscit.sc.hp.com!hplextra!hpfcso!hstroyan
Newsgroups: comp.sys.hp
References: <[e-mail]>
Lines: 24

In comp.sys.hp, [e-mail] (Bob Sabiston) writes:

> The problem is that about half my graphics show up in the window and
> then the computer hangs.  I have a theory that the program is hanging
> at the points in my program where I access the frame buffer directly
> (using the gescape call R_LOCK_DEVICE).  I have to access the frame buffer
> in this way to draw icons, and to draw antialiased fonts and lines.
>
> Does anyone know if the R_LOCK_DEVICE gescape can be used in programs
> that run in Xwindows?  If so, anybody have any idea what could cause the
> program to hang my machine?

As John indicated, you can use direct frame buffer access in an X window,
but I would recommend that you modify your code to use X or Starbase to
perform the same functionality.  You could use either of these API's to
block_read the framebuffer's contents into a working buffer in memory,
perform your modifications and then block_write back the result.  This
method will deal with the issues of window clipping and offsets for you.
For the icons you mention, only a block_write should be necessary.

--
Howard Stroyan
Hewlett-Packard                                        [e-mail]
Systems Technology Division