[mkgmap-dev] Commit r3867: refactoring, no functional change: simplify code to add background polygon (type 0x4B)

Tue Mar 28 13:40:14 BST 2017

Hi Gerd,

cgpsmapper can create 3 types of map:
- transparent - TRE flag set and no background
- semi-transparent - TRE flag not set and no background
- normal - TRE flag not set and background exist

For normal maps, cgpsmapper creates background rectangle if no 
background object exist in source code. Background object is defined by 
explicit declaration "Background=Y". I'm not sure if this declaration 
could be added to any other object type than 0x4B. Probably marine maps 
use other type for background.

I think current algorithm in mkgmap is good enough. What you can add is 
an option to stop creating default background, like for example 
--background=no. But I don't think it would have much use.

I don't know if there is any peculiarity to background object in img. Is 
it marked as background somewhere in img data? If yes, then you can 
consider adding an ability in style to set this marking, for example 
like "set mkgmap:background=yes".

-- 
Best regards,
Andrzej