| Flu_Button | This class extends Fl_Button to make a more attractive alternative that hilights as the mouse enters/leaves and automatically grayscales any image for deactivation |
| Flu_Chat_Buffer | A class for drawing text messages in the style of a "chat buffer" |
| Flu_Choice_Group | This class provides an alternative group to Fl_Tabs. It provides an Fl_Choice menu that is used to determine which child Fl_Group is visible |
| Flu_Collapsable_Group | This widget implements a collapsable group with a configurable framerate |
| Flu_Combo_Box | This is a generic base class for implementing widgets with combo-box-like behavior (i.e. a pulldown menu where the "input" area is editable |
| Flu_Combo_List | Just like the Fl_Choice widget except the input area is editable |
| Flu_Combo_Tree | Just like the Fl_Choice widget except the input area is editable and it can display a tree instead of a list (using Flu_Tree_Browser) |
| Flu_DND | This class augments the existing FLTK drag-n-drop feature, working with Flu_DND_Event to achieve new functionality |
| Flu_DND_Event | This class encapsulates the event state for a single dragged object, and is designed to work exclusively with Flu_DND |
| Flu_Dual_Progress_Meter | This class provides a simple meter showing both current and total progress that also provides canceling behavior |
| Flu_Dual_Slider | This class is essentially an Fl_Slider but with two handles. type() can be one of FL_HOR_SLIDER, FL_HOR_NICE_SLIDER, FL_VERT_SLIDER, FL_VERT_NICE_SLIDER |
| Flu_File_Chooser | A file and directory choosing widget that looks and acts similar to the stock Windows file chooser |
| Flu_File_Chooser::FileTypeInfo | Structure holding the info needed for custom file types |
| Flu_File_Chooser::PreviewWidgetBase | This class must be derived from to create a "preview" widget |
| Flu_Float_Input | This class simply extends Fl_Float_Input to allow getting/setting the widget value as floats instead of just strings |
| Flu_GL_Canvas | An easy to derive from class providing an OpenGL canvas for drawing |
| Flu_GL_Window | A class designed to supply an easier, more functional FLTK GL window, with callback functionality similar to GLUT |
| Flu_Int_Input | This class simply extends Fl_Int_Input to allow getting/setting the widget value as integers instead of strings |
| Flu_Label | This class just provides an easier interface to making labels in FLTK |
| Flu_Link_Button | This class extends Flu_Button to make a button that looks like a hyperlink |
| Flu_Output | This class simply extends Fl_Output to allow getting/setting the widget value as integers and floats in addition to strings |
| Flu_Progress | This class provides a simple progress widget similar to the way Fl_Slider is used for progress, except it is just for progress reporting and displays the progress value inside the widget |
| Flu_Progress_Meter | This class provides a simple progress meter with elapsed time, estimated time to completion, and optional canceling behavior |
| Flu_Return_Button | This class extends Flu_Button to make a button similar to Fl_Return_Button |
| Flu_Separator | A simple class that draws a separator line using the current box type |
| Flu_Simple_Group | This class provides a simple aesthetic alternative to Fl_Group |
| Flu_Spinner | This class provides a simple spinner widget similar to Fl_Counter, except the manipulator buttons are vertical and you can click, click and hold, or click and drag to change the value |
| Flu_Toggle_Group | This class provides a group that can be toggled active or inactive |
| Flu_Tree_Browser | This class provides a browser for hierarchical data representation (i.e. a "tree") |
| Flu_Tree_Browser::IntStack | Internal class holding a stack of integers |
| Flu_Tree_Browser::Node | This class holds a single entry in the tree |
| Flu_Tree_Browser::NodeList | Internal class holding an (alphabetically) ordered list of nodes |
| Flu_Tree_Browser::RData | Recursive data structure passed down through the node tree |
| Flu_Wrap_Group | This class provides an alternative to Fl_Group that automatically arranges the children either left to right and top to bottom (for type() == FL_VERTICAL), or top to bottom and left to right (for type() == FL_HORIZONTAL), within the available size of the group, with a scrollbar turning on if they don't all fit |
| FluSimpleString | A simple string object that works a lot like the STL string object |
