Chartmaker version 1.57

This release adds a new feature to output charts in grayscale, which is controlled by a new settings value: "outputgrayscale": true

From settings.json:

"outputgrayscale": true,
"tileimagequality" : 40,
"blendpixels" : 30,
"zoomrange" : "0-11",
"centerzoomlevel": "7",
"dbextension": "mbtiles",
"externaldbfolder": "",
"addoverviews": true,
"usecommandline": true,
"timezone": "America/Chicago",
"debug": true,

Note that the WEBP driver in GDAL cannot translate RGB images to grayscale, so the index value setting for tiledriverindex should be set to either 0 (png) or 1 (jpeg) . If the value is left at the default of 2 (webp) then the application will automatically default to 0 (png)

Tile driver index set to png:

"tiledriverindex": 0,
"tiledrivers": [
    "png",
    "jpeg",
    "webp"
]