[Spice-devel] RFC: Render support in the protocol

[Soeren Sandmann]

Yonit Halperin <yhalperi at redhat.com> writes:

> Hi,
> It looks like Render overlaps QXL_DRAW_ROP3. Maybe QXLRop3 can be
> exploited?

I'm not sure it's possible to wedge the Render semantics into
QXLRop3. Here are some differences between the two commands:

- Render supports full affine transformations, not just scaling

- The mask in Render can be (and usually is) an a8 type image, whereas
  the existing Mask can only be a1 as far as I understand.

- The mask can have a separate transformation from the source

- The operator in Render is a porter/duff operator (See
  http://cairographics.org/operators/), not a ternary raster operator.

- In Render, the mask is multiplied with the source, and the result is
  then composited with the destination. For some operators, this is
  different from limited the operation to the mask.


Soren