vkm.h

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/*
 * Virtual keyboard/mouse interface
 *
 * Copyright (C) 2026 Nirenjan Krishnan (nirenjan@nirenjan.org)
 *
 * SPDX-License-Identifier: GPL-2.0-only WITH Classpath-exception-2.0
 */
 
#ifndef VKM_H
#define VKM_H
 
#include <stdint.h>
#include <stdbool.h>
 
#ifndef VKM_API
# if defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) >= 303
#  define VKM_API __attribute__((visibility("default")))
# elif defined(_WIN32)
#  define VKM_API __declspec(dllexport)
# else
#  define VKM_API
# endif
#endif
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct vkm_context;
 
typedef struct vkm_context vkm_context;
 
typedef int32_t vkm_result;
 
typedef enum {
    VKM_FEAT_MOUSE = (1 << 0), 
    VKM_FEAT_KEYBOARD = (1 << 1),
 
    VKM_FEAT_KEYBOARD_MODIFIERS = (1 << 2),
 
    /* Additional flags may be added in the future */
} vkm_feature;
 
typedef enum {
    VKM_SUCCESS = 0,
 
    VKM_ERROR_UNKNOWN,
 
    VKM_ERROR_NOT_READY,
 
    VKM_ERROR_OUT_OF_MEMORY,
 
    VKM_ERROR_INVALID_PARAM,
 
    VKM_ERROR_NOT_SUPPORTED,
 
    VKM_ERROR_DEV_FAILURE,
 
    VKM_ERROR_EVENT,
 
    VKM_ERROR_NO_CHANGE,
 
    /* Maximum error states, do not use in external code*/
    VKM_ERROR_MAX,
} vkm_error_code;
 
VKM_API const char *vkm_strerror(vkm_result code);
 
typedef enum {
    VKM_OPT_HI_RES_SCROLL,
 
    VKM_OPT_HORIZONTAL_SCROLL,
 
    VKM_OPT_DEVICE_NAME,
 
    /* Max number of options, do not use in external code */
    VKM_OPT_MAX
} vkm_option;
 
typedef enum {
    VKM_BUTTON_RELEASED,
 
    VKM_BUTTON_PRESSED,
 
    /* Max number of button states, do not use in external code */
    VKM_BUTTON_STATE_MAX
} vkm_button_state;
 
typedef enum {
    VKM_MOUSE_BTN_LEFT,
 
    VKM_MOUSE_BTN_RIGHT,
 
    VKM_MOUSE_BTN_MIDDLE,
 
    /* Max number of mouse buttons, do not use in external code */
    VKM_MOUSE_BTN_MAX
} vkm_mouse_button;
 
typedef enum {
    VKM_MOUSE_SCROLL_UP,
 
    VKM_MOUSE_SCROLL_DOWN,
 
    VKM_MOUSE_SCROLL_LEFT,
 
    VKM_MOUSE_SCROLL_RIGHT,
 
    /* Maximum number of scroll states, do not use in external code */
    VKM_MOUSE_SCROLL_MAX
} vkm_mouse_scroll_direction;
 
typedef enum {
    VKM_KEY_NONE = 0x00, 
    VKM_KEY_A = 0x04, 
    VKM_KEY_B,        
    VKM_KEY_C,        
    VKM_KEY_D,        
    VKM_KEY_E,        
    VKM_KEY_F,        
    VKM_KEY_G,        
    VKM_KEY_H,        
    VKM_KEY_I,        
    VKM_KEY_J,        
    VKM_KEY_K,        
    VKM_KEY_L,        
    VKM_KEY_M,        
    VKM_KEY_N,        
    VKM_KEY_O,        
    VKM_KEY_P,        
    VKM_KEY_Q,        
    VKM_KEY_R,        
    VKM_KEY_S,        
    VKM_KEY_T,        
    VKM_KEY_U,        
    VKM_KEY_V,        
    VKM_KEY_W,        
    VKM_KEY_X,        
    VKM_KEY_Y,        
    VKM_KEY_Z,        
    VKM_KEY_1 = 0x1E, 
    VKM_KEY_2,        
    VKM_KEY_3,        
    VKM_KEY_4,        
    VKM_KEY_5,        
    VKM_KEY_6,        
    VKM_KEY_7,        
    VKM_KEY_8,        
    VKM_KEY_9,        
    VKM_KEY_0,        
    VKM_KEY_ENTER = 0x28,       
    VKM_KEY_ESCAPE,             
    VKM_KEY_BACKSPACE,          
    VKM_KEY_TAB,                
    VKM_KEY_SPACE,              
    VKM_KEY_MINUS,              
    VKM_KEY_EQUAL,              
    VKM_KEY_LEFT_BRACKET,       
    VKM_KEY_RIGHT_BRACKET,      
    VKM_KEY_BACKSLASH,         
    VKM_KEY_NONUS_HASH,        
    VKM_KEY_SEMICOLON,         
    VKM_KEY_APOSTROPHE,        
    VKM_KEY_GRAVE_ACCENT,      
    VKM_KEY_COMMA,             
    VKM_KEY_PERIOD,            
    VKM_KEY_SLASH,             
    VKM_KEY_CAPS_LOCK = 0x39,   
    VKM_KEY_F1 = 0x3A, 
    VKM_KEY_F2,        
    VKM_KEY_F3,        
    VKM_KEY_F4,        
    VKM_KEY_F5,        
    VKM_KEY_F6,        
    VKM_KEY_F7,        
    VKM_KEY_F8,        
    VKM_KEY_F9,        
    VKM_KEY_F10,       
    VKM_KEY_F11,       
    VKM_KEY_F12,       
    VKM_KEY_PRINT_SCREEN = 0x46, 
    VKM_KEY_SCROLL_LOCK,         
    VKM_KEY_PAUSE,               
    VKM_KEY_INSERT,         
    VKM_KEY_HOME,           
    VKM_KEY_PAGE_UP,        
    VKM_KEY_DELETE_FORWARD, 
    VKM_KEY_END,            
    VKM_KEY_PAGE_DOWN,      
    VKM_KEY_RIGHT_ARROW, 
    VKM_KEY_LEFT_ARROW,  
    VKM_KEY_DOWN_ARROW,  
    VKM_KEY_UP_ARROW,    
    VKM_KEY_KEYPAD_NUM_LOCK = 0x53, 
    VKM_KEY_KEYPAD_DIVIDE,          
    VKM_KEY_KEYPAD_MULTIPLY,        
    VKM_KEY_KEYPAD_MINUS,           
    VKM_KEY_KEYPAD_PLUS,            
    VKM_KEY_KEYPAD_ENTER,           
    VKM_KEY_KEYPAD_1,               
    VKM_KEY_KEYPAD_2,               
    VKM_KEY_KEYPAD_3,               
    VKM_KEY_KEYPAD_4,               
    VKM_KEY_KEYPAD_5,               
    VKM_KEY_KEYPAD_6,               
    VKM_KEY_KEYPAD_7,               
    VKM_KEY_KEYPAD_8,               
    VKM_KEY_KEYPAD_9,               
    VKM_KEY_KEYPAD_0,               
    VKM_KEY_KEYPAD_DECIMAL,        
    VKM_KEY_INTL_BACKSLASH, 
    VKM_KEY_APPLICATION,    
    VKM_KEY_KEYPAD_COMMA = 0x85, 
    VKM_KEY_LEFT_CTRL = 0xE0,  
    VKM_KEY_LEFT_SHIFT,        
    VKM_KEY_LEFT_ALT,          
    VKM_KEY_LEFT_GUI,          
    VKM_KEY_RIGHT_CTRL,        
    VKM_KEY_RIGHT_SHIFT,       
    VKM_KEY_RIGHT_ALT,         
    VKM_KEY_RIGHT_GUI,         
    VKM_KEY_MAX 
} vkm_key;
 
typedef enum {
    VKM_KEY_MOD_NONE = 0, 
    VKM_KEY_MOD_LCTRL = (1 << 0),  
    VKM_KEY_MOD_LSHIFT = (1 << 1), 
    VKM_KEY_MOD_LALT = (1 << 2),   
    VKM_KEY_MOD_LGUI = (1 << 3),   
    VKM_KEY_MOD_RCTRL = (1 << 4),  
    VKM_KEY_MOD_RSHIFT = (1 << 5), 
    VKM_KEY_MOD_RALT = (1 << 6),   
    VKM_KEY_MOD_RGUI = (1 << 7),   
} vkm_key_modifiers;
 
#define VKM_KEY_MOD_CTRL VKM_KEY_MOD_LCTRL
#define VKM_KEY_MOD_SHIFT VKM_KEY_MOD_LSHIFT
#define VKM_KEY_MOD_ALT VKM_KEY_MOD_LALT
#define VKM_KEY_MOD_GUI VKM_KEY_MOD_LGUI
 
typedef enum {
    VKM_KEY_STATE_RELEASED, 
    VKM_KEY_STATE_PRESSED,  
    VKM_KEY_STATE_MAX       
} vkm_key_state;
 
VKM_API vkm_result vkm_init(vkm_context **ctx);
 
VKM_API void vkm_exit(vkm_context *ctx);
 
VKM_API vkm_result vkm_reset(vkm_context *ctx);
 
VKM_API vkm_result vkm_start(vkm_context *ctx);
 
VKM_API bool vkm_is_ready(vkm_context *ctx);
 
VKM_API bool vkm_platform_supported(void);
 
VKM_API bool vkm_feature_supported(vkm_feature feat);
 
VKM_API vkm_result vkm_set_option(vkm_context *ctx, vkm_option option, ...);
 
VKM_API vkm_result vkm_mouse_move(vkm_context *ctx, int dx, int dy);
 
VKM_API vkm_result vkm_mouse_click(vkm_context *ctx, vkm_mouse_button button, vkm_button_state state);
 
VKM_API vkm_result vkm_mouse_scroll(vkm_context *ctx, vkm_mouse_scroll_direction dir);
 
VKM_API vkm_result vkm_keyboard_send(vkm_context *ctx, vkm_key key, vkm_key_modifiers modifiers, vkm_key_state state);
 
VKM_API vkm_result vkm_sync(vkm_context *ctx);
 
#ifdef __cplusplus
}
#endif
 
#endif // !defined VKM_H