Feature request: ability to set default out-of-bounds background color

[wilkesreid]

My map, which has an opaque white background, shows the following when being tiled at its edge:

It's a bit hard to tell, but this is a square image with the white background of the map's right edge, and the black is the background that is automatically added by TileUp when in order to make the image square.

Could we have some option to specify that color and/or to make it transparent if exporting in a file format that supports transparency (e.g. PNG)?

[wilkesreid]

Lines 137 - 148 of tiler.rb:

    # unless told to do otherwise, extend tiles in the last row and column
    # if they do not fill an entire tile width and height.
    
    is_edge = (c[:row] == num_rows - 1 || c[:column] == num_columns - 1)
    needs_extension = ci.rows != tile_height || ci.columns != tile_width
    if @options.extend_incomplete_tiles && is_edge && needs_extension
      # defaults to white background color, but transparent is probably 
      # a better default for our purposes.
      ci.background_color = "none"
      # fill to width height, start from top left corner.
      ci = ci.extent(tile_width, tile_height, 0, 0)
    end

I think choosing to set the background color to "none" in all cases is causing the black background when exporting to filetypes that do not support transparency (e.g. JPEG).

[moiristo]

Hi,

Just fyi, I added this to my fork of tileup: https://github.com/moiristo/tileup