nanogui: Patch for Shared Memory Pixmaps
Subject:
Re: [nanogui] Patch for Shared Memory Pixmaps
From:
Jordan Crouse ####@####.####
Date:
9 Aug 2001 15:55:18 -0000
Message-Id: <01080909552802.01574@cosmic>
I would add a new client function called GrNewSharedPixmap() and keep the old
GrNewPixmap() (for compatibility), and then just have them both make the same
server call with different paremeters. That would allow programs to maintain
compatibility, while at the same time saving you the effort of writing two
different server calls.
And of course, throw a #ifdef HAVE_SHAREDMEM_SUPPORT around all the shared
memory calls to avoid any issues with less capable libcs.
Jordan
On Thursday 09 August 2001 09:45, David T Eger mentioned:
> I've made a modification to nano-X to support the following mode of
> interaction:
>
> + User program shmget()s and shmat()s a portion of shared memory to use as
> a pixmap in the same format as the screen (i.e. if the screen is 16bpp,
> this buffer is 16bpp)
> + User program sends GrNewPixmap the shm id of this region.
> + nano-X shmat()s the region, and uses it later on with Pixmap functions
>
> One problem is that to support this patch, the format of GrNewPixmap
> changes, possibly breaking a number of programs. It goes from:
>
> < GR_WINDOW_ID GrNewPixmap(GR_SIZE width, GR_SIZE height, void * addr);
> ----
>
> > GR_WINDOW_ID GrNewPixmap(GR_SIZE width, GR_SIZE height, int shmid);
>
> and the default of "No, this isn't shared memory, just a regular old Pixmap
> request" goes from addr=0 to shmid=-1, since shmget() specifies -1 as the
> invalid value for the id of a System V shared memory region.
>
> Is this useful? Is it the same intent as the FIXME comments for shared
> memory? Should I clean it up and post it somewhere?
>
> -David
>
>
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