lib/cairo: Add cairo status to error message

[wenzeslaus]

The original message about failing to initialize a Cairo surface does not include any reason. This adds size and status from Cairo.

Comparison

Original

ERROR: Failed to initialize Cairo surface

New

ERROR: Failed to initialize Cairo surface (width: 100000, height: 100000):
       invalid value (typically too big) for the size of the input
       (surface, pattern, etc.)

The result depends on what message is generated by Cairo.

In action

> d.mon stop=cairo; d.mon start=cairo width=10000 height=10000 --o; d.rast map=dsm; d.mon stop=cairo
WARNING: File <map.png> already exists and will be overwritten
Output file: /home/vpetras/Projects/grass/code/grass/map.png
 100%
> d.mon start=cairo width=100000 height=10000 --o; d.rast map=dsm; d.mon stop=cairo
Current region rows: 1991, cols: 2027
ERROR: G_malloc: unable to allocate 18446744073414584320 bytes of memory at
       lib/cairodriver/graph.c:210
> d.mon start=cairo width=100000 height=100000 --o; d.rast map=dsm; d.mon stop=cairo
ERROR: Failed to initialize Cairo surface (width: 100000, height: 100000):
       invalid value (typically too big) for the size of the input
       (surface, pattern, etc.)

[neteler]

This is a nice improvement, I just tested it locally:

which looks much better than before (compare #2376 (comment)).

[wenzeslaus]

Thanks @neteler. Given the context of your test, I take it you vote for backporting this to 8.2. The cairo function is available since 1.0 and otherwise it is minimal and after-error code only, so backporting to 8.2 is reasonable.