Re: [Qemu-devel] QEMU Video Driver for Win NT-based systems

[Filip Navara <xnavara@volny.cz>]

Grzegorz Kulewski wrote:

>On Wed, 12 May 2004, Filip Navara wrote:
>  
>
>>Natalia Portillo wrote:
>>    
>>
>>>DirectDraw is the accelerator for GDI.
>>>      
>>>
>>This is not correct. At the driver level GDI calls and DirectDraw calls 
>>are completly separate interfaces implemented different way.
>>    
>>
>
>You are unfortunatelly right. GDI was introduced a lot ealier than 
>DirectX (I think before win95).
>
Right, it was there since Windows 1.0.

> But GDI can be not accelerated by graphic 
>card but by qemu (using sdl or something like that) because today apps are 
>using GDI mainly for user interface and not for advanced drawing I think. 
>Right?
>  
>
Right, GDI is used mainly for UI drawing. It can be accelerated a bit. 
These GDI things can be *theoretically* optimized on the driver/HW level:
Alpha Blending, Gradient Fills, BitBlts/StretchBlts/TransparentBlts, 
Paths/Lines and HW Cursor. This is kind of what VMware does, their 
drivers pass some of the requests throught I/O ports (partially 
documented) to the emulator which executes the most common operations in 
the non-emulated host environment.

- Filip