Obtaining a netsurf bitmap buffer may fail on some frontends (RISC OS
especially) as the bitmap allocation is not performed until the
buffer is requested. The PNG image handler failed to check for this
when populating the row pointer structure.
On some OS the ftruncate operation can take some time so move it to
occour in the background maintinance operations instead of when data
blocks are initialy opened. This should improve browsing responsiveness.
This makes the box_move_xy function return a value on all code
paths. This was not really necessary as there is an assert in the path
that could have returned without a value. The gcc optimiser seems
unable to reason about this in this case causing a warning.
It seems many filesystems are greatly more efficient if the block file
is allocated its entire extent once rather than trying to
continuously grown the file later.
The size of the block files is known at their creation time so this
change ensures they are grown to the full possible extent hence removing
future inefficient writes.
The ftell call in the html renderer handling of drag and drop was not
checking its return value for errors which could have resulted in
attempting to read -1 bytes.
coverity 1251038
Add a new interface to the content to allow automaticaly scaled
content redraws. This is intended to replace the thumbnail_redraw
interface with something more generic.
The bitmap and image handling interfaces have changed within NetSurf
and the webp image handling has not been fixed up appropriately to
cope.
After discussion with the other developers it has been decided that
the webp support is not worth the necessary development effort to
rewrite and maintain.
The webp format is not in wide usage and Mozilla, Microsoft and Apple
have not adopted it. This means the removal will not adversely impact
NetSurf.
Resolves:2310
The RISC OS bitmap header was including several headers it simply did
not require. This removed those includes and also cleans up the
documentation comments to completely cover the exported interface.
