MapTiler QGIS plugin - supported expressions

MapTiler plugin can convert any style.json containing GL JS style definition. However, the plugin does not support all of the style definition expressions. This article covers which expressions are supported and which are not.

Filter expression

Filter expression defines which features will be affected by a specific style layer definition.
Combining filters: all, any, none
Existential filters: has, !has, match, get
Set membership filters: in, !in
Comparison filters: !, ==, !=, >=, >, <=, <

Zoom function

zoom function changes a property of a style layer based on zoom level. Value must be literal values (i.e. not functions or expressions), and appropriate for the property. For example, stop output values for a fill-color function property must be colors.

{
  "base":1,
  "stops": [
    [zoom1, value1],
    [zoom2, value2],
    [zoom3, value3]
  ]
}

Interpolation

[
  "interpolate",
  [method]          // options: ["linear"], ["exponential", base]
  ["zoom"],
  zoom1, value1,
  zoom2, value2,
  zoom3, value3
]

[
"step",
input,          // e.g. ["get", "attribute"] or ["zoom"]
step_input_0, step_output_0,
stop_input_1, stop_output_1,
stop_input_n, stop_output_n,
...
]

"line-color": ["interpolate",
                ["linear"],
                ["zoom"],
                10, "rgba(138, 195, 229, 1)",
                16, [
                  "match",
                  ["get", "class"],
                  ["river","canal"],
                  "rgba(160, 205, 236, 1)",
                  "rgba(140, 185, 226, 1)"
                ]
              ]

Paint-properties

Fill

fill-color
Can be defined as a static value (string, hsl, hsla, RGB, rgba), using zoom function or interpolation.

fill-outline-color
Can be defined as a static value (string, hsl, hsla, RGB, rgba), using zoom function or interpolation.

fill-opacity
Can be defined as a static value, usingthe  zoom function or interpolation.
If opacity is already set in color asan  alpha channel, this property is skipped.

fill-translate
Can be defined as a static array or usinga  zoom function.

fill-pattern
Can be defined as a string or usinga  zoom function

Line

line-color
Can be defined as a static value (string, hsl, hsla, RGB, rgba), using zoom function or interpolation.

line-width
Can be defined as a static value, using zoom function or interpolation.

line-offset
Can be defined as a static value, using zoom function or interpolation.

line-opacity
Can be defined as a static value, using zoom function or interpolation.

line-dasharray
Can be defined as a static array or using a  zoom function.

line-cap
Can be round, square or flat (default).

line-join
Can be bevel, round or miter (default).

Labels

text-field
Can be defined as a static string, expression, list of expression or using zoom function.

text-size
an be defined as a static value, using zoom function or interpolation.

text-max-width
Can be defined as a static value, using zoom function or interpolation.

text-letter-spacing
Can be defined as a static value, using zoom function or interpolation.

text-font
Can be defined as a static value (string), list of string or zoom function.
If font not found on your system, the plugin will try to use fallback fonts:
Open Sans Regular, Arial Unicode MS

text-color
Can be defined as a static value (string, hsl, hsla, RGB, rgba), using zoom function or interpolation.

text-halo-color
Can be defined as a static value (string, hsl, hsla, RGB, rgba), using zoom function or interpolation.

text-halo-width
Can be defined as a static value (string, hsl, hsla, RGB, rgba), using zoom function or interpolation.

text-halo-blur
Must be defined as a static value.

text-transform
Must be uppercase or lowercase.

text-offset
Can be defined as a static array or using zoom function.

text-justify
Must be one of the following: left, right, follow, center (default).

text-anchor
Must be one of the following: center(default), left, right, top, bottom, top-left, top-right, bottom-left, bottom-right.

icon-image
Can be defined as a static string or using zoom function.

Background

background-color
Can be defined as a static value(string, hsl, hsla, RGB, rgba) or zoom function.

background-opacity
Can be defined as a static value or zoom function.

Useful links

Vector tile basemaps via QGIS plugin
Mapbox Styles - Expressions
Mapbox Styles - Layers
MapTiler QGIS plugin