Re: panning using xrandr

[T o n g <mlist4suntong@yahoo.com>]

On Tue, 01 Feb 2011 20:38:50 +0000, Camaleón wrote:

>> all virtual display. I tried below, but it didn't work as I expected:
>> 
>>  xrandr -s 640x480 --output VGA-1 --panning 1920x1080
> 
> Hum... if I understood correctly the xrandr man page, you should run
> something like:
> 
> xrandr --output VGA-1 --mode 640x480 --fb 1920x1080 --panning 1920x1080

OMG! That's perfect!

Thanks a thousand!!! 

Just FTA, the --fb 1920x1080 is not really necessary. The relation 
between mode, panning and framebuffer can be illustrated below,

	┌──┳━━━━━━━━━━━━━━┳─────┬ ─ ─ ─ ─ ─ ┐
	│  ┃     CRTC     ┃     │
	│  ┃              ┃     │           │
	│  ┃             X┃→    │
	│  ┃              ┃     │           │  framebuffer
	│  ┗━━━━━━━━━━━━━━┛     │
	│                       │           │
	│panning area           │
	└───────────────────────┴ ─ ─ ─ ─ ─ ┘

If now  --fb is specified, it default to the same size as panning:

	┌──┳━━━━━━━━━━━━━━┳────────────┐
	│  ┃     CRTC     ┃            │
	│  ┃              ┃            │
	│  ┃              ┃→           │
	│  ┃           X←→┃            │
	│  ┃       border_right        │
	│  ┗━━━━━━━━━━━━━━┛            │
	│                              │
	│panning area                  │
	└──────────────────────────────┘

Credit: 
http://cgit.freedesktop.org/xorg/proto/randrproto/tree/randrproto.txt

Thanks again

-- 
Tong (remove underscore(s) to reply)
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