When scaling part of an image we need to specify the source coordinates
in transformed coordinates. For large magnifications this means
we will get pretty large values.
Now, if e.g. src_x * transform is larger than 32765, then the coordinate
ends up outside the pixman 16bit image size, so the rendering
will not work.
In order to work around this we generate a "sub-image" of the pixman
image such that the src_x/y values we have to specify are zero (or near
zero).
When scaling in pixman you give the source coordinates in transformed
space rather than in the source coordinates. This is a bit problematic
when both source and destination coordinates are at integer positions, but
the scaling factor is not an exact 16.16 fixed point value. We used
to calculate the transformed source based on the floating point
transformation, which gave the wrong answer sometimes. Now we do the
calculations based on the fixed point transform that we give pixman.
However, even with this patch I can still sometimes see issues related
to this, although they are less bad.
When a message has been read from the network we now pass it into
the generated demarshaller for the channel. The demarshaller converts
the network data to in-memory structures that is passed on to the
spice internals.
Additionally it also:
* Converts endianness
* Validates sizes of message and any pointers in it
* Localizes offsets (converts them to pointers)
* Checks for zero offsets in messages where they are not supported
Some of this was previously done using custom code in the client, this
is now removed.
