Here is picture form QGIS. 
There are three layers. Blue dotted lines are warehouse rack layer.
Green one is rack sections layer (routable network, created with pgr_createTopology).
And third layer is points (from _vertices_pgr table) with sections names.
It is saved as project. And the picture is generated with the command:
qgis-bin-g7.exe --snapshot print_points_wh.png --width 300 --height 1000 --project print_points.qgz --nologo --noversioncheck --noplugins
Layer three data source is table. When I need new plan, I just fill the table with required point ID`s. And then run command above. The problem is that a GUI is required.
Then I tried to generate image with PostGIS tools.
select ST_AsPNG(ST_AsRaster((select ST_Union(the_geom) from print_points_geo), 400,1000))
Result is 
Also these image dots are very small and only 3 points are visible. Two are missing.
If I add table print_points_geo to QGIS, result is 
Is it possible to generate image like in first example from PostgreSQL without GUI tools?
Better would be to do it with PostGIS tools. An option is to generate racks in one image, sections in another, and points in third image and then combine all images together. But I cannot figure out how to enlarge points in ST_AsRaster function. Basically rack and section images are static.
