This is a paid asset, but now you can download AltSDK (Professional) Free.
Detail this asset from Unity Store: Original Link
AltSDK (Professional) v1.00
Unity 4.6 – 5.X compatible
AltSDK Unity Asset forum discussion thread
AltSDK Professional Asset is for Professional developers.
AltGUI – Unity UI integrated Professional GUI Framework with Windows Forms like API. Based & include AltSketch – Vector Graphics Library with System.Drawing (GDI+) like API.
Unity Web Demo
– Includes source code of AltAssets
– GUI: Unity UI integration; Windows Forms like wide range of controls; Awesomium Browser integration
– Interactive Vector Graphics, Geometry Transformations, Clipping, Boolean Operations
– Brushes, Pens, Custom Shader Material Brushes, Graphics
– C# FreeType port, flexible Font Engine
– Direct Image Load/Save operations: PNG, JPEG, BMP, Animated Gif, TIFF, TGA
– AntiAliased and Solid Vector Data Triangulation
– HW Render to Texture, SW Render to Texture2D
– ZipFile & Folder storage Virtual File System
– Many integrated interactive packages: SVG, NPlot, OxyPlot, PieChart, GMap.NET, HTML/CSS, etc.
– Common Keyboard and Mouse Input Framework
– Pure C# code without native dependencies
– Hundreds of examples in Demo; Backend & Integration source code included (implementation does not depend on a specific version of the Unity)