Basics

Go templates use{{ ... }} to embed expressions, variables, or functions.

Data Context (.)

The dot . refers to the current context. In rong, this includes:

• .Colors — a list of all material colors
• .Image — the source image or video path
• .<ColorName> — individual color values (e.g., .Background)

{{ .Background }}  {{/* Prints a hex color like "RRGGBB" */}}

Comments

Use {{/* ... */}} for comments.

{{/* This is a comment */}}

Loops

Use range to iterate over a slice or map.

{{ range .Colors }}
  {{ .Name.Snake }} = "{{ .Color }}"
{{ end }}

You can also use an index variable:

{{ range $i, $color := .Colors }}
  {{ $i }}: {{ $color.Name.Camel }}
{{ end }}

Conditionals

Use if, else, and end to control logic.

{{ if .Background }}
  Background: {{ .Background }}
{{ else }}
  No background color provided.
{{ end }}

You can nest conditions:

{{ if and .Background .Image }}
  Background and image are both available.
{{ end }}

Functions

Standard functions like index, print, and printf are supported. rong also adds:

• upper – Converts a string to uppercase.
• lower – Converts a string to lowercase.
• replace – Replaces all occurrences of a substring with another substring.
• parse – Parses a hex color string.
• chroma – Adjusts the chroma (color intensity) of a color.
• tone – Adjusts the tone (lightness/darkness) of a color.
• quote – Wraps the given value in double quotes as a string.
• json – Converts a value to its JSON string representation or "null" on error.
• sprig - A big list of templates functions: https://masterminds.github.io/sprig.

Examples:

{ "image": {{ .Image | json }} }

{{ replace .Title " " "_" | upper }}

{{ quote .Background }}

{{ printf "%s: %s" .Name .Value }}

Pipelining

You can chain multiple functions using the pipe |.

{{ .Primary | lower | quote }}