/<w>/<h>/hex/<hex> - generate a solid color using a hex color code
/<w>/<h>/hex/<hex>/<hex> - generate a color gradient

/<w>/<h>/ral/<RAL> - generate a solid color using a RAL code (Design and Classic codes are supported)

/<w>/<h>/rgb/<r>/<g>/<b> - generate a solid color
/<w>/<h>/rgb/<r>/<g>/<b>/<r2>/<g2>/<b2> - generate a color gradient

/<w>/<h>/rgba/<r>/<g>/<b>/<a> - generate a solid color
/<w>/<h>/rgba/<r>/<g>/<b>/<a>/<r2>/<g2>/<b2>/<a2> - generate a color gradient