This library provides the wxAccordion class, which as the name suggests, is an accordion style container control for the wxWidgets library. This is a very simple implementation: the expanding and collapsing mechanism uses nothing but sizers and panels. The control is derived from wxBookCtrlBase so that a programmer familiar wxNotebook or wxAuiNotebook should already be comfortable this class as well. The documentation for this class can be viewed here.
Although this class can't provide all the freedom a programmer would have for building an accordion with HTML/CSS, there is a wide variety of commands for modifying the behavior, layout, and appearance of the control. For example, the caption bars can be drawn with a gradient of 2 or more colors or can use an image file for the background. The caption bars can optionally contain expand/collapse buttons and icons. Here are a few examples of accordions that can be produced with this library:
