libx52/vkm

Virtual keyboard/mouse infrastructure

The virtual keyboard/mouse infrastructure (or VKM), is an API used by an application to inject keyboard and mouse events into the OS stack. The advantage of using a separate API for this is so that this can be handled in a cross-platform manner without having to sprinkle #ifdef's throughout the program.

Base API

The API is based around a context, which is an opaque pointer returned by vkm_init. All subsequent VKM calls will take in this pointer as the first argument, and return a signed 32-bit status code. Once done, vkm_exit will clean up any data structures and close any file descriptors that were opened as part of the VKM calls.

VKM can also be configured through the vkm_config API call.

Device handling

vkm_new_device is the API to use when creating a new VKM device. While VKM will support both keyboard and mouse events from a single device, there may be cases where the application needs to separate out keyboard and mouse events into different devices. The flags will enable keyboard and/or mouse support.

Note that the supported event codes (on Linux) are fixed, and cannot be updated. The keyboard will emulate a standard US keyboard, while the mouse will emulate a standard 3 button mouse with a scroll wheel.

Mouse handling

The mouse is handled as a single API call that passes in dx and dy to move the mouse in the relative X and Y axes. VKM will take care of internally translating the calls to the appropriate framework. This is handled in vkm_mouse_move

The scroll wheel is handled through vkm_mouse_scroll. By default, the mouse motion uses standard scrolling, but high resolution scrolling may be enabled.

The buttons are handled by vkm_mouse_click. The API will send the state, depending on the input (pressed or not)

Keyboard handling

The keyboard is handled through a single call vkm_keyboard_send. This sends a single key event, with modifiers enabled (Ctrl, Shift, Alt, GUI).