User manual:
- Left click to add new drop of color
- Hold right click and drag it to the direction desired
- Customization window:
- Layer: choose the drop, layer 0 for first drop, layer 1 for second drop, and so on
- Radius: drop radius
- Center: the drop center x, and center y. Use this to re-position the drop
- Color: change drop's color, floating point from 0 to 1 is used
- Marble selection: select the marbling type, please refer to Mathematical Marbling by Shufang Lu et al.