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/*
  Copyright 2012-2019 David Robillard <http://drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/**
   @file pugl.h Public Pugl API.
*/

#ifndef PUGL_H_INCLUDED
#define PUGL_H_INCLUDED

#include <stdbool.h>
#include <stdint.h>

#ifdef PUGL_SHARED
#    ifdef _WIN32
#        define PUGL_LIB_IMPORT __declspec(dllimport)
#        define PUGL_LIB_EXPORT __declspec(dllexport)
#    else
#        define PUGL_LIB_IMPORT __attribute__((visibility("default")))
#        define PUGL_LIB_EXPORT __attribute__((visibility("default")))
#    endif
#    ifdef PUGL_INTERNAL
#        define PUGL_API PUGL_LIB_EXPORT
#    else
#        define PUGL_API PUGL_LIB_IMPORT
#    endif
#else
#    define PUGL_API
#endif

#if defined(__clang__)
#    define PUGL_DEPRECATED_BY(name) __attribute__((deprecated("", name)))
#elif defined(__GNUC__)
#    define PUGL_DEPRECATED_BY(name) __attribute__((deprecated("Use " name)))
#else
#    define PUGL_DEPRECATED_BY(name)
#endif

#ifdef __cplusplus
extern "C" {
#endif

/**
   @defgroup pugl Pugl
   A minimal portable API for OpenGL.
   @{
*/

/**
   A Pugl view.
*/
typedef struct PuglViewImpl PuglView;

/**
   Graphics backend interface.
*/
typedef struct PuglBackendImpl PuglBackend;

/**
   A native window handle.

   On X11, this is a Window.
   On OSX, this is an NSView*.
   On Windows, this is a HWND.
*/
typedef intptr_t PuglNativeWindow;

/**
   Handle for opaque user data.
*/
typedef void* PuglHandle;

/**
   Return status code.
*/
typedef enum {
	PUGL_SUCCESS,
	PUGL_ERR_CREATE_WINDOW,
	PUGL_ERR_SET_FORMAT,
	PUGL_ERR_CREATE_CONTEXT,
} PuglStatus;

/**
   Window hint.
*/
typedef enum {
	PUGL_USE_COMPAT_PROFILE,    /**< Use compatible (not core) OpenGL profile */
	PUGL_CONTEXT_VERSION_MAJOR, /**< OpenGL context major version */
	PUGL_CONTEXT_VERSION_MINOR, /**< OpenGL context minor version */
	PUGL_RED_BITS,              /**< Number of bits for red channel */
	PUGL_GREEN_BITS,            /**< Number of bits for green channel */
	PUGL_BLUE_BITS,             /**< Number of bits for blue channel */
	PUGL_ALPHA_BITS,            /**< Number of bits for alpha channel */
	PUGL_DEPTH_BITS,            /**< Number of bits for depth buffer */
	PUGL_STENCIL_BITS,          /**< Number of bits for stencil buffer */
	PUGL_SAMPLES,               /**< Number of samples per pixel (AA) */
	PUGL_DOUBLE_BUFFER,         /**< True if double buffering should be used */
	PUGL_RESIZABLE,             /**< True if window should be resizable */
	PUGL_IGNORE_KEY_REPEAT,     /**< True if key repeat events are ignored */
} PuglWindowHint;

/**
   Special window hint value.
*/
typedef enum {
	PUGL_DONT_CARE = -1,  /**< Use best available value */
	PUGL_FALSE     = 0,   /**< Explicitly false */
	PUGL_TRUE      = 1    /**< Explicitly true */
} PuglWindowHintValue;

/**
   Keyboard modifier flags.
*/
typedef enum {
	PUGL_MOD_SHIFT = 1,       /**< Shift key */
	PUGL_MOD_CTRL  = 1 << 1,  /**< Control key */
	PUGL_MOD_ALT   = 1 << 2,  /**< Alt/Option key */
	PUGL_MOD_SUPER = 1 << 3   /**< Mod4/Command/Windows key */
} PuglMod;

/**
   Special keyboard keys.

   All keys, special or not, are expressed as a Unicode code point.  This
   enumeration defines constants for special keys that do not have a standard
   code point, and some convenience constants for control characters.

   Keys that do not have a standard code point use values in the Private Use
   Area in the Basic Multilingual Plane (U+E000 to U+F8FF).  Applications must
   take care to not interpret these values beyond key detection, the mapping
   used here is arbitrary and specific to Pugl.
*/
typedef enum {
	// ASCII control codes
	PUGL_KEY_BACKSPACE = 0x08,
	PUGL_KEY_ESCAPE    = 0x1B,
	PUGL_KEY_DELETE    = 0x7F,

	// Unicode Private Use Area
	PUGL_KEY_F1 = 0xE000,
	PUGL_KEY_F2,
	PUGL_KEY_F3,
	PUGL_KEY_F4,
	PUGL_KEY_F5,
	PUGL_KEY_F6,
	PUGL_KEY_F7,
	PUGL_KEY_F8,
	PUGL_KEY_F9,
	PUGL_KEY_F10,
	PUGL_KEY_F11,
	PUGL_KEY_F12,
	PUGL_KEY_LEFT,
	PUGL_KEY_UP,
	PUGL_KEY_RIGHT,
	PUGL_KEY_DOWN,
	PUGL_KEY_PAGE_UP,
	PUGL_KEY_PAGE_DOWN,
	PUGL_KEY_HOME,
	PUGL_KEY_END,
	PUGL_KEY_INSERT,
	PUGL_KEY_SHIFT,
	PUGL_KEY_SHIFT_L = PUGL_KEY_SHIFT,
	PUGL_KEY_SHIFT_R,
	PUGL_KEY_CTRL,
	PUGL_KEY_CTRL_L = PUGL_KEY_CTRL,
	PUGL_KEY_CTRL_R,
	PUGL_KEY_ALT,
	PUGL_KEY_ALT_L = PUGL_KEY_ALT,
	PUGL_KEY_ALT_R,
	PUGL_KEY_SUPER,
	PUGL_KEY_SUPER_L = PUGL_KEY_SUPER,
	PUGL_KEY_SUPER_R,
	PUGL_KEY_MENU,
	PUGL_KEY_CAPS_LOCK,
	PUGL_KEY_SCROLL_LOCK,
	PUGL_KEY_NUM_LOCK,
	PUGL_KEY_PRINT_SCREEN,
	PUGL_KEY_PAUSE
} PuglKey;

/**
   The type of a PuglEvent.
*/
typedef enum {
	PUGL_NOTHING,              /**< No event */
	PUGL_BUTTON_PRESS,         /**< Mouse button press */
	PUGL_BUTTON_RELEASE,       /**< Mouse button release */
	PUGL_CONFIGURE,            /**< View moved and/or resized */
	PUGL_EXPOSE,               /**< View exposed, redraw required */
	PUGL_CLOSE,                /**< Close view */
	PUGL_KEY_PRESS,            /**< Key press */
	PUGL_KEY_RELEASE,          /**< Key release */
	PUGL_TEXT,                 /**< Character entry */
	PUGL_ENTER_NOTIFY,         /**< Pointer entered view */
	PUGL_LEAVE_NOTIFY,         /**< Pointer left view */
	PUGL_MOTION_NOTIFY,        /**< Pointer motion */
	PUGL_SCROLL,               /**< Scroll */
	PUGL_FOCUS_IN,             /**< Keyboard focus entered view */
	PUGL_FOCUS_OUT             /**< Keyboard focus left view */
} PuglEventType;

typedef enum {
	PUGL_IS_SEND_EVENT = 1
} PuglEventFlag;

/**
   Reason for a PuglEventCrossing.
*/
typedef enum {
	PUGL_CROSSING_NORMAL,      /**< Crossing due to pointer motion. */
	PUGL_CROSSING_GRAB,        /**< Crossing due to a grab. */
	PUGL_CROSSING_UNGRAB       /**< Crossing due to a grab release. */
} PuglCrossingMode;

/**
   Common header for all event structs.
*/
typedef struct {
	PuglEventType type;        /**< Event type. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
} PuglEventAny;

/**
   Button press or release event.

   For event types PUGL_BUTTON_PRESS and PUGL_BUTTON_RELEASE.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_BUTTON_PRESS or PUGL_BUTTON_RELEASE. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        time;        /**< Time in seconds. */
	double        x;           /**< View-relative X coordinate. */
	double        y;           /**< View-relative Y coordinate. */
	double        x_root;      /**< Root-relative X coordinate. */
	double        y_root;      /**< Root-relative Y coordinate. */
	uint32_t      state;       /**< Bitwise OR of PuglMod flags. */
	uint32_t      button;      /**< 1-relative button number. */
} PuglEventButton;

/**
   Configure event for when window size or position has changed.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_CONFIGURE. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        x;           /**< New parent-relative X coordinate. */
	double        y;           /**< New parent-relative Y coordinate. */
	double        width;       /**< New width. */
	double        height;      /**< New height. */
} PuglEventConfigure;

/**
   Expose event for when a region must be redrawn.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_EXPOSE. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        x;           /**< View-relative X coordinate. */
	double        y;           /**< View-relative Y coordinate. */
	double        width;       /**< Width of exposed region. */
	double        height;      /**< Height of exposed region. */
	int           count;       /**< Number of expose events to follow. */
} PuglEventExpose;

/**
   Window close event.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_CLOSE. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
} PuglEventClose;

/**
   Key press/release event.

   This represents low-level key press and release events.  This event type
   should be used for "raw" keyboard handing (key bindings, for example), but
   must not be interpreted as text input.

   Keys are represented as Unicode code points, using the "natural" code point
   for the key wherever possible (see @ref PuglKey for details).  The `key`
   field will be set to the code for the pressed key, without any modifiers
   applied (by the shift or control keys).
*/
typedef struct {
	PuglEventType type;        /**< PUGL_KEY_PRESS or PUGL_KEY_RELEASE. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        time;        /**< Time in seconds. */
	double        x;           /**< View-relative X coordinate. */
	double        y;           /**< View-relative Y coordinate. */
	double        x_root;      /**< Root-relative X coordinate. */
	double        y_root;      /**< Root-relative Y coordinate. */
	uint32_t      state;       /**< Bitwise OR of PuglMod flags. */
	uint32_t      keycode;     /**< Raw key code. */
	uint32_t      key;         /**< Unshifted Unicode character code, or 0. */
} PuglEventKey;

/**
   Character input event.

   This represents text input, usually as the result of a key press.  The text
   is given both as a Unicode character code and a UTF-8 string.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_CHAR. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        time;        /**< Time in seconds. */
	double        x;           /**< View-relative X coordinate. */
	double        y;           /**< View-relative Y coordinate. */
	double        x_root;      /**< Root-relative X coordinate. */
	double        y_root;      /**< Root-relative Y coordinate. */
	uint32_t      state;       /**< Bitwise OR of PuglMod flags. */
	uint32_t      keycode;     /**< Raw key code. */
	uint32_t      character;   /**< Unicode character code */
	char          string[8];   /**< UTF-8 string. */
} PuglEventText;

/**
   Pointer crossing event (enter and leave).
*/
typedef struct {
	PuglEventType    type;     /**< PUGL_ENTER_NOTIFY or PUGL_LEAVE_NOTIFY. */
	uint32_t         flags;    /**< Bitwise OR of PuglEventFlag values. */
	double           time;     /**< Time in seconds. */
	double           x;        /**< View-relative X coordinate. */
	double           y;        /**< View-relative Y coordinate. */
	double           x_root;   /**< Root-relative X coordinate. */
	double           y_root;   /**< Root-relative Y coordinate. */
	uint32_t         state;    /**< Bitwise OR of PuglMod flags. */
	PuglCrossingMode mode;     /**< Reason for crossing. */
} PuglEventCrossing;

/**
   Pointer motion event.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_MOTION_NOTIFY. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        time;        /**< Time in seconds. */
	double        x;           /**< View-relative X coordinate. */
	double        y;           /**< View-relative Y coordinate. */
	double        x_root;      /**< Root-relative X coordinate. */
	double        y_root;      /**< Root-relative Y coordinate. */
	uint32_t      state;       /**< Bitwise OR of PuglMod flags. */
	bool          is_hint;     /**< True iff this event is a motion hint. */
	bool          focus;       /**< True iff this is the focused window. */
} PuglEventMotion;

/**
   Scroll event.

   The scroll distance is expressed in "lines", an arbitrary unit that
   corresponds to a single tick of a detented mouse wheel.  For example, `dy` =
   1.0 scrolls 1 line up.  Some systems and devices support finer resolution
   and/or higher values for fast scrolls, so programs should handle any value
   gracefully.
 */
typedef struct {
	PuglEventType type;        /**< PUGL_SCROLL. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	double        time;        /**< Time in seconds. */
	double        x;           /**< View-relative X coordinate. */
	double        y;           /**< View-relative Y coordinate. */
	double        x_root;      /**< Root-relative X coordinate. */
	double        y_root;      /**< Root-relative Y coordinate. */
	uint32_t      state;       /**< Bitwise OR of PuglMod flags. */
	double        dx;          /**< Scroll X distance in lines. */
	double        dy;          /**< Scroll Y distance in lines. */
} PuglEventScroll;

/**
   Keyboard focus event.
*/
typedef struct {
	PuglEventType type;        /**< PUGL_FOCUS_IN or PUGL_FOCUS_OUT. */
	uint32_t      flags;       /**< Bitwise OR of PuglEventFlag values. */
	bool          grab;        /**< True iff this is a grab/ungrab event. */
} PuglEventFocus;

/**
   Interface event.

   This is a union of all event structs.  The `type` must be checked to
   determine which fields are safe to access.  A pointer to PuglEvent can
   either be cast to the appropriate type, or the union members used.
*/
typedef union {
	PuglEventType      type;       /**< Event type. */
	PuglEventAny       any;        /**< Valid for all event types. */
	PuglEventButton    button;     /**< PUGL_BUTTON_PRESS, PUGL_BUTTON_RELEASE. */
	PuglEventConfigure configure;  /**< PUGL_CONFIGURE. */
	PuglEventExpose    expose;     /**< PUGL_EXPOSE. */
	PuglEventClose     close;      /**< PUGL_CLOSE. */
	PuglEventKey       key;        /**< PUGL_KEY_PRESS, PUGL_KEY_RELEASE. */
	PuglEventText      text;       /**< PUGL_TEXT. */
	PuglEventCrossing  crossing;   /**< PUGL_ENTER_NOTIFY, PUGL_LEAVE_NOTIFY. */
	PuglEventMotion    motion;     /**< PUGL_MOTION_NOTIFY. */
	PuglEventScroll    scroll;     /**< PUGL_SCROLL. */
	PuglEventFocus     focus;      /**< PUGL_FOCUS_IN, PUGL_FOCUS_OUT. */
} PuglEvent;

/**
   @name Initialization
   Configuration functions which must be called before creating a window.
   @{
*/

/**
   Create a Pugl view.

   To create a window, call the various puglInit* functions as necessary, then
   call puglCreateWindow().

   @param pargc Pointer to argument count (currently unused).
   @param argv  Arguments (currently unused).
   @return A newly created view.
*/
PUGL_API PuglView*
puglInit(int* pargc, char** argv);

/**
   Set a hint before creating a window.
*/
PUGL_API void
puglInitWindowHint(PuglView* view, PuglWindowHint hint, int value);

/**
   Set the window class name before creating a window.
*/
PUGL_API void
puglInitWindowClass(PuglView* view, const char* name);

/**
   Set the parent window before creating a window (for embedding).
*/
PUGL_API void
puglInitWindowParent(PuglView* view, PuglNativeWindow parent);

/**
   Set the window size before creating a window.
*/
PUGL_API void
puglInitWindowSize(PuglView* view, int width, int height);

/**
   Set the minimum window size before creating a window.
*/
PUGL_API void
puglInitWindowMinSize(PuglView* view, int width, int height);

/**
   Set the window aspect ratio range before creating a window.

   The x and y values here represent a ratio of width to height.  To set a
   fixed aspect ratio, set the minimum and maximum values to the same ratio.

   Note that setting different minimum and maximum constraints does not
   currenty work on MacOS (the minimum is used), so only setting a fixed aspect
   ratio works properly across all platforms.
*/
PUGL_API void
puglInitWindowAspectRatio(PuglView* view,
                          int       min_x,
                          int       min_y,
                          int       max_x,
                          int       max_y);

/**
   Enable or disable resizing before creating a window.

   @deprecated Use puglInitWindowHint() with @ref PUGL_RESIZABLE.
*/
PUGL_API PUGL_DEPRECATED_BY("puglInitWindowHint") void
puglInitResizable(PuglView* view, bool resizable);

/**
   Set transient parent before creating a window.

   On X11, parent must be a Window.
   On OSX, parent must be an NSView*.
*/
PUGL_API void
puglInitTransientFor(PuglView* view, uintptr_t parent);

/**
   Set the graphics backend to use.

   This needs to be called once before creating the window to set the graphics
   backend.  There are two backend accessors included with pugl:
   puglGlBackend() and puglCairoBackend(), declared in pugl_gl_backend.h and
   pugl_cairo_backend.h, respectively.
*/
PUGL_API int
puglInitBackend(PuglView* view, const PuglBackend* backend);

/**
   @}
   @name Windows
   Functions for creating and managing a visible window for a view.
   @{
*/

/**
   Create a window with the settings given by the various puglInit functions.

   @return 1 (pugl does not currently support multiple windows).
*/
PUGL_API int
puglCreateWindow(PuglView* view, const char* title);

/**
   Show the current window.
*/
PUGL_API void
puglShowWindow(PuglView* view);

/**
   Hide the current window.
*/
PUGL_API void
puglHideWindow(PuglView* view);

/**
   Return the native window handle.
*/
PUGL_API PuglNativeWindow
puglGetNativeWindow(PuglView* view);

/**
   @}
*/

/**
   Set the handle to be passed to all callbacks.

   This is generally a pointer to a struct which contains all necessary state.
   Everything needed in callbacks should be here, not in static variables.
*/
PUGL_API void
puglSetHandle(PuglView* view, PuglHandle handle);

/**
   Get the handle to be passed to all callbacks.
*/
PUGL_API PuglHandle
puglGetHandle(PuglView* view);

/**
   Return true iff the view is currently visible.
*/
PUGL_API bool
puglGetVisible(PuglView* view);

/**
   Get the current size of the view.
*/
PUGL_API void
puglGetSize(PuglView* view, int* width, int* height);

/**
   @name Context
   Functions for accessing the drawing context.
   @{
*/

/**
   Get the drawing context.

   The context is only guaranteed to be available during an expose.

   For OpenGL backends, this is unused and returns NULL.
   For Cairo backends, this returns a pointer to a `cairo_t`.
*/
PUGL_API void*
puglGetContext(PuglView* view);

/**
   Enter the drawing context.

   Note that pugl automatically enters and leaves the drawing context during
   configure and expose events, so it is not normally necessary to call this.
   However, it can be used to enter the drawing context elsewhere, for example
   to call any GL functions during setup.

   @param view The view being entered.
   @param drawing If true, prepare for drawing.
*/
PUGL_API void
puglEnterContext(PuglView* view, bool drawing);

/**
   Leave the drawing context.

   This must be called after puglEnterContext() with a matching `drawing`
   parameter.

   @param view The view being left.
   @param drawing If true, finish drawing, for example by swapping buffers.
*/
PUGL_API void
puglLeaveContext(PuglView* view, bool drawing);

/**
   @}
   @name Event Handling
   @{
*/

/**
   A function called when an event occurs.
*/
typedef void (*PuglEventFunc)(PuglView* view, const PuglEvent* event);

/**
   Set the function to call when an event occurs.
*/
PUGL_API void
puglSetEventFunc(PuglView* view, PuglEventFunc eventFunc);

/**
   Ignore synthetic repeated key events.

   @deprecated Use puglInitWindowHint() with @ref PUGL_IGNORE_KEY_REPEAT.
*/
PUGL_API PUGL_DEPRECATED_BY("puglInitWindowHint") void
puglIgnoreKeyRepeat(PuglView* view, bool ignore);

/**
   Grab the input focus.
*/
PUGL_API void
puglGrabFocus(PuglView* view);

/**
   Request user attention.

   This hints to the system that the window or application requires attention
   from the user.  The exact effect depends on the platform, but is usually
   something like flashing a task bar entry.
*/
PUGL_API void
puglRequestAttention(PuglView* view);

/**
   Block and wait for an event to be ready.

   This can be used in a loop to only process events via puglProcessEvents when
   necessary.  This function will block indefinitely if no events are
   available, so is not appropriate for use in programs that need to perform
   regular updates (e.g. animation).
*/
PUGL_API PuglStatus
puglWaitForEvent(PuglView* view);

/**
   Process all pending window events.

   This handles input events as well as rendering, so it should be called
   regularly and rapidly enough to keep the UI responsive.  This function does
   not block if no events are pending.
*/
PUGL_API PuglStatus
puglProcessEvents(PuglView* view);

/**
   @}
*/

/**
   OpenGL extension function.
*/
typedef void (*PuglGlFunc)(void);

/**
   Return the address of an OpenGL extension function.
*/
PUGL_API PuglGlFunc
puglGetProcAddress(const char* name);

/**
   Return the time in seconds.

   This is a monotonically increasing clock with high resolution.  The returned
   time is only useful to compare against other times returned by this
   function, its absolute value has no meaning.
*/
PUGL_API double
puglGetTime(PuglView* view);

/**
   Request a redisplay on the next call to puglProcessEvents().
*/
PUGL_API void
puglPostRedisplay(PuglView* view);

/**
   Destroy a GL window.
*/
PUGL_API void
puglDestroy(PuglView* view);

/**
   @}
*/

#ifdef __cplusplus
}  /* extern "C" */
#endif

#endif  /* PUGL_H_INCLUDED */