Re: [MiNT] WCOWORK implementation : conclusions.

[evan@coolrunningconcepts.com]

Quoting "olivier.landemarre@utbm.fr" <Olivier.Landemarre@utbm.fr>:

> Yes of course it's slower, does Odd wan't a vectorial offscreen for working
> area? I not think that possible. Of course it's possible for all draw 
> directly

Of course its possible.

> by AES (widgets, rsrc), but not for working area, except thinking the
> application component able to run throw network, especialy if this is use for
> AES be able redraw without asking it to the application, it's impossible with
> VDI because what is write on screen is made by a list of VDI instruction, but
> you not know when you, you erase all for redraw something else, so you can't
> erase buffer VDI instruction list. In my opinion only bitmap can be use for
> offscreen.

Well, it is true that the VDI doesn't really have a good erase.  Or rather the
use of any erase functions aren't common the screen.  However, I'm sure 
you can
find a way to make this work.   Perhaps by watching which calls affected the
entire area or something.

And while I'm on the subject, I've often mentioned the idea of a "canvas
widget".  This would be quite beneficial.  Basically it would be a new AES
object like you would put into a FORM, like a GBOX object.  You place this
CANVAS object into a window.  The canvas would open its own workstation 
and the
AES could automatically handle the redraws.  You then send VDI calls to the
CANVAS and it will remember them as well as draw them.  A "clear" command
allows a specific clearing of the internal display list to forget all previous
information (and should clear to whatever default color is defined by the
current theme - and default text color would be determined by theme, 
etc).  All
VDI calls sent to the CANVAS could be relative to the canvas itself, not the
screen, allowing the whole thing to be moved easily with the window.

Such an AES object would simplify quite a bit of programming and could be used
remotely quite easily.  Older apps could either use bitmaps to display
remotely, like VNC, or see how well detecting screen clears works.

> Do you think when I have done a small HTML viewer name "Gulliver" that I do a
> bitmap and then scroll it, I can't imagine do it, no but I not use 
> VDI to draw I
> have an offscreen redraw then do a vro_cpyfm() but this bitmap is 
> only the part
> I need redraw no more. This could be usefull to help display some 
> pictures in a
> windows but no more, it can't be universal.

RAM is cheap.  Unlike the majority of people on this list, I'm actually 
using a
system that has off-screen rendering.   XP does not.  OS X does, but OS X is
also all hardware accelerated.  Xorg using Xcomposite extensions is about the
same as what you are talking about - you draw off-screen and then blit the
changes to the window.   Scrolling is horrible!

Even if you can't keep the whole window off-screen, I would at least keep a
pretty sizable buffer off-screen to keep things sped up.

> I agree, in fact you are speeking about VDI feature, not really AES, you can
> wan't to open an handle for a Window, and said this to VDI that 
> coordinate send
> for this handle is relative to the left higher corner, and when this 
> windows is
> move the AES said to the VDI this new position. Notice this not new at all,
> Window have this for far, and Windom have this sort of facilities. We are not
> speeking offscreen. I agree this should exist, but it does not 
> because at this
> time there is no link between AES and VDI

Yup, I know.   Just wondering who's gonna jump in and do it :)

> AES can already know when application have draw something without 
> help of VDI,
> just wait for wind_update(END_UPDATE), but notice there is this for only do a
> cursor flash!

I don't want to know when the cursor flashes.  I want to know when the working
area has actually changed, and which portion of it has changed - 
similar to the
Xdamage extension.   Only way I can think of is for the VDI to keep a 
"damaged"
rectangle and then every drawing operation, it can add to the rectangle size.

Other applications (such as virtual desktop managers that show icons of the
window contents or network protocols, etc) can then use this information to
inquire exactly what has changed so they can make updates as efficient as
possible.

Redrawing a remote window every time the cursor flashes is just silly.
Speaking of which, any CANVAS widget or multi-line edit box should have an AES
controlled cursor so we don't have applications locking the screen to draw a
blinking cursor.   Some handling of insert-mode and over-write mode with
different cursors and things of that sort should be automatically handled by
the edit box, and shared with the canvas.

> RSC is vectorial, redraw it thorw network is not difficult, CICON can be send
> once (I don't know any software changing CICON at fly), but application can
> change some flags in RSC, and most not do it with AES functions 
> (should perhaps
> but it's slow), so you can't send the RSC, except RSC manage by AES itself.

With a compressed data channel, sending the parts of the RSC needed for that
specific AES call can be done at every call and it will still be faster than
sending the screen across.

> In fact there is an other way to do this, try MyAeS or Magic (and I suppose
> XAAES and NAES do it too), just ask "hide an application", all 
> software I have
> test it support it, Anyplayer too.

What message is sent to the Application?   And does the application 
KNOW that it
is hidden and shouldn't make any more attempts to draw anything?

> Yes soon after august!
> Olivier

Cool