Paul Wratt skreiv:
That is my point (i think). Any virtual screen should be independent of physical hardware, and yes apps could be told about screen attribute changes. As long as it is not a fullscreen non-desktop app, then the virtual screen should not interfere with what is actually on the screen, especially if it is running under AES
This is a different concept than virtual workstations in VDI. In VDI, a virtual workstation is nothing but a set of stored parameters (colour, line style, fillpattern etc) attached to a handle we call a "virtual workstation". So when using a virtual workstation, you're only using those settings when drawing. The drawing is performed directly on the physical workstation (screen, printer, plotter...).
The concept you're suggesting can be compared to offscreen bitmaps in VDI. You could do all drawing to offscreen bitmaps in whatever size and resolution you like, and then blit it to the physical workstation when needed.
I am not sure of the use of multiple physical screens, except that more than one full screen non-desktop app could be running at the same time, and that would make sense, not interfering with each others
This is one use. Movie players, slideshows, art programs, text consoles etc. are other uses. The Amiga had a brilliant implementation of this 25 years ago.
On a hardware platform that support any form of graphics hardware, multiple cards and multiple monitor are inevitable, an need to be catered for from the start. If I ever get access to hardware that can use PCI graphics, I have 2 64Mb Voodoo 5000, and it would be a crying shame if I could not get direct access to there features. Note that there are still PCI cards being made at the moment, which may not be the case in years to come.
With direct framebuffer access it's hard to take advantage of multiple monitors. It's much better to use the VDI to blit to/from the desktop (or whatever you would call it), as the VDI would take care of the issues with framebuffer address, pixel format etc. As long as the screens have the same colour depth (well, the VDI could easily transform the bitmaps while blitting, so this is strictly not necessary) and height, this would be completely transparent to all existing apps that use VDI only and no direct framebuffer access. These apps will just see one huge screen :-)
Jo Even