Update README.md

README.md

@@ -2,3 +2,40 @@
 
 Converts a simple list of color definitions to asset catalogs for Xcode, resource XML for Android or an HTML preview.
 
+## Input format
+
+Each line in your input contains one color definition. That is a name followed by the actual color. We support RGB colors in a few formats similar to CSS:
+
+```
+Color/Color1 #fff
+Color/Color2 #abcdeff0
+Color/Color3 rgb(12, 13, 53)
+Color/Color4 rgba(250, 250, 250, 128)
+```
+
+Colors can also reference other colors by prefixing them with an `@` sign:
+
+```
+ColorAlias @Color/Color1
+```
+
+## Output format
+
+### Xcode Asset Catalogs (`--ios`)
+
+The optional prefix followed by a `/` is added in front of the color name. Then for each part separate by / a new folder that provides namespace is inserted in the asset catalogs. Spaces are inserted between CamelCase words. Color references are inserted as copies of the original color.
+
+### Android resource XML (`--android`)
+
+The optional prefix, followed by a underscore is added in front of the name. Names are converted from CamelCase to snake_case and / is replaced by underscores as well. Color references the generated color resource also references the original color.
+
+### HTML preview (`--html`)
+
+Generates a simple HTML table with the color names, values and a sample.
+
+## Future work
+
+- Support other color formats (HSV, ...)
+- Calculate derived colors (blend, change hue/saturation/brightness/alpha)
+- Support for dark/light mode
+- Improved error reporting in the parser