[mkgmap-dev] TREHeader.POI_FLAG_DETAIL, transparent and map background

Mon Mar 25 16:56:13 GMT 2019

Hi

I noticed a while ago that "test-map:all-elements" stopped working
correctly. The map it generated showed a box around the map area, but
within the map area, the device said 'no-map' and didn't show anything,
however POI searches did work.

I tracked it down to a couple of lines added to
mkgmap/build/MapBuilder.java : processInfo()

                if (!(src instanceof OverviewMapDataSource))
                        poiDisplayFlags |= TREHeader.POI_FLAG_DETAIL;

poiDisplayFlags is byte 0x3f in TRE

So:

Old maps and old all-elements, with poiDisplayFlags = 0 worked.

New maps, with poiDisplayFlags = POI_FLAG_DETAIL, work, but all
-elements doesn't.

One of differences between a typical map and all-elements is that all
-elements doesn't output a standard background (polygon 0x4b covering
the complete map area); changing it to do so, then all features get
displayed.

However, transparent maps don't have a standard background and they
work. Trying option --transparent with the original version of all
-elements makes it work. 

I don't know if this behaviour was known or expected, but I thought it
worth-while to note it down in this post.

I didn't want all-elements to have a standard background so I've added 
--transparent to the comment about how to invoke it, also a few other
option suggestions.

The other change I made was to show elements against a green background
as well as no background, as I was having trouble spotting many line
-types that my new device shows as white.

I've attached a patch for this.

Regards
Ticker

-------------- next part --------------
A non-text attachment was scrubbed...
Name: allElem.patch
Type: text/x-patch
Size: 1296 bytes
Desc: not available
URL: <http://www.mkgmap.org.uk/pipermail/mkgmap-dev/attachments/20190325/2ac52411/attachment.bin>