nanogui: Thread: regions

The region code for Microwindows builds a dynamic
array of non-overlapping rectangles which can completely
specify any set of pixels on a display surface.  Both
the Nano-X API and Win32 fully support user-based
regions as well as the visible clip region for a window.  When
a user-based region is used, it is intersected with the 
window's visible clip region for the final clip region.

In addition, Microwindows' win32 API keeps up the
notion of an "update region" which is a potential subset
of the visible region that has been invalidated through
InvalidateRect or InvalidateRegion.  This additional
feature allows flicker-free redrawing for areas of a window
when a window is fully repainted but doesn't need it.

Regards,

Greg



Greg,

Can a Region likes these:

-------------          ---------------   
|     0     |          |       1     |
--------------------------------------
        |        2        |
        -------------------

        OR

            ----------------
            |       0      |
  -------------------------------------
  |         |              |     2    |
  |    1    |              ------------  
  |         |
  -----------

       OR
                          -----------
  -----------------       |         |
  |       0       |       |    1    |
  -----------------       ----------- 

                          -----------------
                          |       2       |
                          -----------------

And what a Region will the Global ClipRegion likes ?

Regards,

FindSun

Sr,

I don't know how the 'Bands' arraying in a 'Region' ,
and how the 'Rectangles' arraying in a 'Band' .

I have studied the source code ,
but it's much difficult to master the arithmetic .

For example ,
Can the Regions can array like that :

                00000000000000000000
                0                                    0
0000000000000000000000000000     0000000000
0              0                                           0
0
0              0                                           0000000000
0              0
000000000

Or like this:

                00000000000000000000
BAND 0
                0                                    0
0000000000000000000000000000     0000000000                    BAND 1
0              0                                           0
0
000000000                                           0000000000
BAND 2
0              0
000000000

Regards,

FindSun

----- Original Message -----
From: "Greg Haerr" ####@####.####
To: ####@####.####
Cc: "nanogui" ####@####.####
Sent: Wednesday, December 20, 2000 8:19 AM
Subject: regions


> The region code for Microwindows builds a dynamic
> array of non-overlapping rectangles which can completely
> specify any set of pixels on a display surface.  Both
> the Nano-X API and Win32 fully support user-based
> regions as well as the visible clip region for a window.  When
> a user-based region is used, it is intersected with the
> window's visible clip region for the final clip region.
>
> In addition, Microwindows' win32 API keeps up the
> notion of an "update region" which is a potential subset
> of the visible region that has been invalidated through
> InvalidateRect or InvalidateRegion.  This additional
> feature allows flicker-free redrawing for areas of a window
> when a window is fully repainted but doesn't need it.
>
> Regards,
>
> Greg