Dear ImGui doesn't have a "graphics engine", the actual rendering is done by user-provided code which maps vertex- and index-arrays, and draw commands to system 3D APIs like D3D, Vulkan, Metal, GL etc...
Font handling is based on stb_truetype.h, but can be replaced with FreeType:
In any case, versatile text rendering is certainly not the design focus of Dear ImGui (AFAIK there's also no support for RTL layout), instead it is mainly targeted at quickly creating specialized UI tools (especially inhouse tooling for game development), less at creating end-user applications.
There's plenty of UI frameworks to create "end-user applications", but hardly any that fill the specific niche served by Dear ImGui.
Font handling is based on stb_truetype.h, but can be replaced with FreeType:
https://github.com/ocornut/imgui/blob/master/misc/freetype/R...
In any case, versatile text rendering is certainly not the design focus of Dear ImGui (AFAIK there's also no support for RTL layout), instead it is mainly targeted at quickly creating specialized UI tools (especially inhouse tooling for game development), less at creating end-user applications.
There's plenty of UI frameworks to create "end-user applications", but hardly any that fill the specific niche served by Dear ImGui.