thorvg/inc/thorvg_capi.h

/*!
* \file thorvg_capi.h
* \brief Function provides C bindings for thorvg library.
* Please refer to src/examples/Capi.cpp to find thorvg_capi examples.
*
* thorvg_capi module provides a set of functionality that allows to
* implement thorvg C client with following funcionalities
* - Drawing primitive paints: Line, Arc, Curve, Path, Shapes, Polygons
* - Filling: Solid, Linear, Radial Gradient
* - Scene Graph & Affine Transformation (translation, rotation, scale ...)
* - Stroking: Width, Join, Cap, Dash
* - Composition: Blending, Masking, Path Clipping, etc
* - Pictures: SVG, Bitmap
*/

#ifndef __THORVG_CAPI_H__
#define __THORVG_CAPI_H__

/*! Importation of librairies*/
#include <stdbool.h>

#ifdef TVG_EXPORT
    #undef TVG_EXPORT
#endif

#ifdef TVG_BUILD
    #define TVG_EXPORT __attribute__ ((visibility ("default")))
#else
    #define TVG_EXPORT
#endif


#ifdef __cplusplus
extern "C" {
#endif

typedef struct _Tvg_Canvas Tvg_Canvas;
typedef struct _Tvg_Paint Tvg_Paint;
typedef struct _Tvg_Gradient Tvg_Gradient;

/**
* \defgroup ThorVGCapi C APIs
* \brief ThorVG provides C interface.
*
* \{
*/

/**
* \defgroup ThorVGCapi_Initializer Initializer
* \brief Enables initialization and termination of the ThorVG engine.
*
* \{
*/

/*!
* \def TVG_ENGINE_SW
* Software raster engine type.
*/
#define TVG_ENGINE_SW (1 << 1)


/*!
* \def TVG_ENGINE_GL
* GL raster engine type.
*/
#define TVG_ENGINE_GL (1 << 2)

/*\}*/

/*!
* \ingroup ThorVGCapi_Canvas
* \def TVG_COLORSPACE_ABGR8888
* Colorspace used to fill buffer.
*/
#define TVG_COLORSPACE_ABGR8888 0


/*!
* \ingroup ThorVGCapi_Canvas
* \def TVG_COLORSPACE_ARGB8888
* Colorspace used to fill buffer.
*/
#define TVG_COLORSPACE_ARGB8888 1


/**
 * @brief Enumeration specifying the result from the APIs.
 */
typedef enum {
    TVG_RESULT_SUCCESS = 0,            ///< The value returned in case of the correct request execution.
    TVG_RESULT_INVALID_ARGUMENT,       ///< The value returned in the event of a problem with the arguments given to the API - e.g. empty paths or null pointers.
    TVG_RESULT_INSUFFICIENT_CONDITION, ///< The value returned in case the request cannot be processed - e.g. asking for properties of an object, which does not exist.
    TVG_RESULT_FAILED_ALLOCATION,      ///< The value returned in case of unsuccessful memory allocation.
    TVG_RESULT_MEMORY_CORRUPTION,      ///< The value returned in the event of bad memory handling - e.g. failing in pointer releasing or casting
    TVG_RESULT_NOT_SUPPORTED,          ///< The value returned in case of choosing unsupported options.
    TVG_RESULT_UNKNOWN                 ///< The value returned in all other cases.
} Tvg_Result;


/**
 * @brief A data structure representing a point in two-dimensional space.
 */
typedef struct
{
    float x, y;
} Tvg_Point;


/**
 * @brief A data structure representing a three-dimensional matrix.
 */
typedef struct
{
    float e11, e12, e13;
    float e21, e22, e23;
    float e31, e32, e33;
} Tvg_Matrix;

/************************************************************************/
/* Engine API                                                           */
/************************************************************************/
/*!
* \fn Tvg_Result tvg_engine_init(unsigned engine_method, unsigned threads)
* \brief The funciton initialises thorvg library. It must be called before the
* other functions at the beggining of thorvg client.
* \ingroup ThorVGCapi_Initializer Initializer
* \code
* tvg_engine_init(TVG_ENGINE_SW, 0); //Initialize software renderer and use 1 thread
* \endcode
* \param[in] engine_method renderer type
*   - TVG_ENGINE_SW: software renderer
*   - TVG_ENGINE_GL: opengl renderer (not supported yet)
* \param[in] threads number of threads used to perform rendering. If threads = 0, only one
* thread will be used for renderer
* \return Tvg_Result return values:
*   - TVG_RESULT_SUCCESS: if ok.
*   - TVG_RESULT_INSUFFICENT_CONDITION: multiple init calls.
*   - TVG_RESULT_INVALID_ARGUMENT: not known engine_method.
*   - TVG_RESULT_NOT_SUPPORTED: not supported engine_method.
*   - TVG_RESULT_UNKOWN: internal error.
*/
TVG_EXPORT Tvg_Result tvg_engine_init(unsigned engine_method, unsigned threads);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_engine_term(unsigned engine_method)
* \brief The funciton termiates renderer tasks. Used for cleanup.
* It should be called in case of termination of the thorvg library with same
* renderer types as it was passed in tvg_engine_init()
* \ingroup ThorVGCapi_Initializer Initializer
* \code
* tvg_engine_init(TVG_ENGINE_SW, 0);
* //define canvas and shapes, update shapes, general rendering calls
* tvg_engine_term(TVG_ENGINE_SW);
* \endcode
* \param engine_method renderer type
*   - TVG_ENGINE_SW: software renderer
*   - TVG_ENGINE_GL: opengl renderer (not supported yet)
* \return Tvg_Result return values:
*   - TVG_RESULT_SUCCESS: if ok.
*   - TVG_RESULT_INSUFFICENT_CONDITION: multiple terminate calls.
*   - TVG_RESULT_INVALID_ARGUMENT: not known engine_method.
*   - TVG_RESULT_NOT_SUPPORTED: not supported engine_method.
*   - TVG_RESULT_UNKOWN: internal error.
*/
TVG_EXPORT Tvg_Result tvg_engine_term(unsigned engine_method);


/**
* \defgroup ThorVGCapi_Canvas Canvas
* \brief Functions for drawing graphic elements.
* It stores all Paint objects (Shape, Scene, Picture) and creates the buffer, which can be drawn on the screen.
*
* \{
*/

/**
* \defgroup ThorVGCapi_SwCanvas SwCanvas
* \ingroup ThorVGCapi_Canvas
* \brief Functions for the rasterisation of graphic elements with a software engine.
*
* \{
*/

/************************************************************************/
/* SwCanvas API                                                         */
/************************************************************************/
/*!
* \fn TVG_EXPORT Tvg_Canvas* tvg_swcanvas_create()
* \brief The function creates a canvas, i.e. an object used for drawing shapes,
* scenes (Tvg_Paint objects)
* \code
* Tvg_Canvas *canvas = NULL;
*
* tvg_engine_init(TVG_ENGINE_SW, 4);
* canvas = tvg_swcavnas_create();
*
* //setup canvas buffer
* uint32_t *buffer = NULL;
* buffer = (uint32_t*) malloc(sizeof(uint32_t) * 100 * 100);
* if (!buffer) return;
*
* tvg_swcanvas_set_target(canvas, buffer, 100, 100, 100, TVG_COLORSPACE_ARGB8888);
*
* //add paints to canvas and setup them before draw calls
*
* tvg_canvas_destroy(canvas);
* tvg_engine_term(TVG_ENGINE_SW);
* \endcode
* \return Tvg_Canvas pointer to the canvas object, or NULL if something went wrong
*/


TVG_EXPORT Tvg_Canvas* tvg_swcanvas_create();
/*!
* \fn TVG_EXPORT Tvg_Result tvg_swcanvas_set_target(Tvg_Canvas* canvas, uint32_t* buffer, uint32_t stride, uint32_t w, uint32_t h, uint32_t cs)
* \brief The function sets memory buffer used by renderer and define colorspace used for renderering. For optimisation reasons, the library
* does not allocate memory for the output buffer on its own. Buffer is used to integrate thorvg with external libraries. Please refer to examples/Capi.cpp
* where thorvg is integrated with the EFL lib.
* \param[in] canvas The pointer to Tvg_Canvas object.
* \param[in] buffer The uint32_t pointer to allocated memory.
* \param[in] stride The buffer stride - in most cases width.
* \param[in] w The buffer width
* \param[in] h The buffer height
* \param[in] cs The buffer colorspace, defines position of color in raw pixel data.
* - TVG_COLORSPACE_ABGR8888
* - TVG_COLORSPACE_ARGB8888
* \return Tvg_Result return values:
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_MEMORY_CORRUPTION: A canvas is not valid.
* - TVG_RESULT_INVALID_ARGUMENTS: invalid buffer, stride = 0, w or h = 0
*/
TVG_EXPORT Tvg_Result tvg_swcanvas_set_target(Tvg_Canvas* canvas, uint32_t* buffer, uint32_t stride, uint32_t w, uint32_t h, uint32_t cs);


/* \} */


/************************************************************************/
/* Common Canvas API                                                    */
/************************************************************************/
/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_destroy(Tvg_Canvas* canvas)
* \brief The function clears canvas internal data (e.g all paints stored by canvas)
* and destroy canvas object. There is no need to call tvg_paint_del API manually for
* each paint. This function releases stored paints data. If there is a need to destroy
* paint manually in thorvg client runtime tvg_canvas_clear(canvas, false) API should be
* called, but in that case all shapes should be deleted by thorvg client.
* \code
* static Tvg_Canvas *canvas = NULL;
* static uint32_t *buffer = NULL;
*
* static void _init() {
*   canvas = tvg_swcavnas_create();
*   buffer = (uint32_t*) malloc(sizeof(uint32_t) * 100 * 100);
*   tvg_swcanvas_set_target(canvas, buffer, 100, 100, 100, TVG_COLORSPACE_ARGB8888);
* }
*
* //a task called from main function in a loop
* static void _job(const int cmd) {
*   switch (cmd) {
*     case CMD_EXIT: return 0;
*     case CMD_ADD_RECT:
*       //define valid rectangle shape
*       tvg_canvas_push(canvas, rect);
*       break;
*     case CMD_DEL_RECT:
*       tvg_shape_del(rect);
*       //now to safely delete Tvg_Canvas, tvg_canvas_clear() API have to be used.
*       break;
*     default:
*       break;
*   }
* }
*
* int main(int argc, char **argv) {
*   int cmd = 0;
*   int stop = 1;
*
*   tvg_engine_init(TVG_ENGINE_SW, 4);
*
*   while (stop) {
*      //wait for command e.g. from console
*      stop = _job(cmd);
*   }
*   tvg_canvas_clear(canvas, false);
*   tvg_canvas_destroy(canvas);
*   tvg_engine_term(TVG_ENGINE_SW);
*   return 0;
* }
*
*
* tvg_canvas_destroy(canvas);
* tvg_engine_term()
* \endcode
* \param[in] canvas Tvg_Canvas pointer
* \return Tvg_Result return values:
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_ARGUMENT: if canvas is a NULL pointer.
*/
TVG_EXPORT Tvg_Result tvg_canvas_destroy(Tvg_Canvas* canvas);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_push(Tvg_Canvas* canvas, Tvg_Paint* paint)
* \brief The function inserts paint object in the canvas.
* \param[in] canvas Tvg_Canvas pointer
* \param[in] paint Tvg_Paint pointer
* \return Tvg_Result return values:
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas or if paint are NULL pointers.
* - TVG_RESULT_MEMORY_CORRUPTION: if paint is not a valid Tvg_Paint object.
*/
TVG_EXPORT Tvg_Result tvg_canvas_push(Tvg_Canvas* canvas, Tvg_Paint* paint);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_reserve(Tvg_Canvas* canvas, uint32_t n)
* \brief The function reserves a memory for objects. It might be used to reduce
* reallocations in any cases when number of Tvg_Paints stored in canvas is known
* or it can be estimated.
* \code
* Tvg_Canvas *canvas = NULL;
*
* tvg_engine_init(TVG_ENGINE_SW, 4);
* canvas = tvg_swcavnas_create();
*
* uint32_t *buffer = NULL;
* buffer = (uint32_t*) malloc(sizeof(uint32_t) * 100 * 100);
* if (!buffer) return;
*
* tvg_swcanvas_set_target(canvas, buffer, 100, 100, 100, TVG_COLORSPACE_ARGB8888);
* tvg_canvas_reserve(canvas, 100); //reserve array for 100 paints in canvas.
*
* tvg_canvas_destroy(canvas);
* tvg_engine_term()
* \endcode
* \param[in] canvas Tvg_Canvas pointer.
* \param[in] n uint32_t reserved space.
* \return Tvg_Result return values:
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalid.
*/
TVG_EXPORT Tvg_Result tvg_canvas_reserve(Tvg_Canvas* canvas, uint32_t n);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_clear(Tvg_Canvas* canvas, bool free)
* \brief The function clears a Tvg_Canvas from pushed paints. If free is set to true,
* Tvg_Paints stored in canvas also will be released. If free is set to false,
* all paints should be released manually to avoid memory leaks.
* \param canvas Tvg_Canvas pointer.
* \param free boolean, if equals true, function release all paints stored in given canvas.
* \return
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalid
*/
TVG_EXPORT Tvg_Result tvg_canvas_clear(Tvg_Canvas* canvas, bool free);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_update(Tvg_Canvas* canvas)
* \brief The function update all paints in given canvas. Should be called before draw to
* prepare shapes for rendering.
* \code
* //A frame drawing example. Thread safety and events implementation is skipped to show only thorvg code.
*
* static Tvg_Canvas *canvas = NULL;
* static Tvg_Paint *rect = NULL;
*
* int _frame_render(void) {
*   tvg_canvas_update(canvas);
*   tvg_canvas_draw(canvas);
*   tvg_canvas_sync(canvas);
* }
*
* //event handler from your code or third party library
* void _event_handler(event *event_data) {
*   if (!event_data) return NULL;
*     switch(event_data.type) {
*       case EVENT_RECT_ADD:
*         if (!rect) {
*           tvg_shape_append_rect(shape, 10, 10, 50, 50, 0, 0);
*           tvg_shape_set_stroke_width(shape, 1.0f);
*           tvg_shape_set_stroke_color(shape, 255, 0, 0, 255);
*           tvg_canvas_push(canvas, shape);
*         }
*         break;
*       case EVENT_RECT_MOVE:
*         if (rect) tvg_paint_translate(rect, 10.0, 10.0);
*           break;
*         default:
*           break;
*   }
* }
*
* int main(int argc, char **argv) {
*   //example handler from your code or third party lib
*   event_handler_add(handler, _event_handler);
*
*   //create frame rendering process which calls _frame_render() function.
*   app_loop_begin(_frame_render);
*   app_loop_finish();
*   cleanup();
* }
* \endcode
* \param[in] canvas Tvg_Canvas pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalid]
*/
TVG_EXPORT Tvg_Result tvg_canvas_update(Tvg_Canvas* canvas);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_update_paint(Tvg_Canvas* canvas, Tvg_Paint* paint)
* \brief The funciton updates shape before rendering. If a client application using the
* thorvg library does not update the entire canvas (tvg_canvas_update()) in the frame
* rendering process, Tvg_Paints previosly added to the canvas should be updated manually
* using this function.
* \param[in] canvas Tvg_Canvas pointer
* \param[in] paint Tvg_Paint pointer to update
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalid
*/
TVG_EXPORT Tvg_Result tvg_canvas_update_paint(Tvg_Canvas* canvas, Tvg_Paint* paint);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_draw(Tvg_Canvas* canvas)
* \brief The function start rendering process. All shapes from the given canvas will be rasterized
* to the buffer.
* \param[in] canvas
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INSUFFICIENT_CONDITION: interna rendering errors.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalid.
*/
TVG_EXPORT Tvg_Result tvg_canvas_draw(Tvg_Canvas* canvas);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_canvas_sync(Tvg_Canvas* canvas)
* \brief The function finalize rendering process. It should be called after tvg_canvas_draw(canvas).
* \param[in] canvas
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalids.
*/
TVG_EXPORT Tvg_Result tvg_canvas_sync(Tvg_Canvas* canvas);

/* \} */

/**
* \defgroup ThorVGCapi_Paint Paint
* \brief Functions for managing graphic elements. It enables duplication, transformation and composition.
*
* \{
*/

/************************************************************************/
/* Paint API                                                            */
/************************************************************************/
/**
 * @brief Enumeration indicating the method used in the composition of two objects - the target and the source.
 */
typedef enum {
    TVG_COMPOSITE_METHOD_NONE = 0,           ///< No composition is applied.
    TVG_COMPOSITE_METHOD_CLIP_PATH,          ///< The intersection of the source and the target is determined and only the resulting pixels from the source are rendered.
    TVG_COMPOSITE_METHOD_ALPHA_MASK,         ///< The pixels of the source and the target are alpha blended. As a result, only the part of the source, which intersects with the target is visible.
    TVG_COMPOSITE_METHOD_INVERSE_ALPHA_MASK, ///< The pixels of the source and the complement to the target's pixels are alpha blended. As a result, only the part of the source which is not covered by the target is visible.
} Tvg_Composite_Method;

/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_del(Tvg_Paint* paint)
* \brief The function releases given paint object. The tvg_canvas_clear(canvas, true) or tvg_canvas_del(canvas)
* releases previously pushed paints internally. If this function is used, tvg_canvas_clear(canvas, false) should
* be used to avoid unexpected behaviours.
* \code
* //example of cleanup function
* Tvg_Paint *rect = NULL; //rectangle shape added in other function
*
* //rectangle delete API
* int rectangle_delete(void) {
*   if (rect) tvg_paint_del(rect);
*   rect = NULL;
* }
*
* int cleanup(void) {
*   tvg_canvas_clear(canvas, false);
*   tvg_canvas_del(canvas);
*   canvas = NULL;
* }
* \endcode
* \param[in] paint Tvg_Paint pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_del(Tvg_Paint* paint);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_scale(Tvg_Paint* paint, float factor)
* \brief The function scales given paint using given factor.
* \param[in] paint Tvg_Paint pointer
* \param[in] factor double scale factor
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INSUFFICENT_CONDITION: if invalid factor is used.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_scale(Tvg_Paint* paint, float factor);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_rotate(Tvg_Paint* paint, float degree)
* \brief The function rotates the givent paint by the given degree.
* \param[in] paint Tvg_Paint pointer
* \param[in] degree double rotation degree
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INSUFFICENT_CONDITION: if invalid degree is used.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid.
*/
TVG_EXPORT Tvg_Result tvg_paint_rotate(Tvg_Paint* paint, float degree);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_translate(Tvg_Paint* paint, float x, float y)
* \brief The function moves the given paint in the X,Y coordinate system.
* \param[in] paint Tvg_Paint pointer
* \param[in] x float x shift
* \param[in] y float y shift
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_translate(Tvg_Paint* paint, float x, float y);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_transform(Tvg_Paint* paint, const Tvg_Matrix* m)
* \brief The function transforms given paint using transformation matrix. It could
* be used to move, rotate in 2d coordinates system and rotate in 3d coordinates system
* \param[in] paint Tvg_Paint pointer
* \param[in] m Tvg_Matrix pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint or m is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_transform(Tvg_Paint* paint, const Tvg_Matrix* m);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_set_opacity(Tvg_Paint* paint, uint8_t opacity)
* \brief The function sets opacity of paint. It could be used in Tvg_Scene to implement
* translucent layers of shapes.
* \param[in] paint Tvg_Paint pointer
* \param[in] opacity uint8_t opacity value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_set_opacity(Tvg_Paint* paint, uint8_t opacity);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_get_opacity(Tvg_Paint* paint, uint8_t* opacity)
* \brief The function gets opacity of given paint
* \param[in] paint Tvg_Paint pointer
* \param[out] opacity uint8_t pointer to store opacity
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if canvas is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_get_opacity(Tvg_Paint* paint, uint8_t* opacity);


/*!
* \fn TVG_EXPORT Tvg_Paint* tvg_paint_duplicate(Tvg_Paint* paint)
* \brief The function duplicates given paint. Returns newly allocated paint with the
* same properties (stroke, color, path). It could be used to duplicate scenes too.
* \param[in] paint Tvg_Paint pointer
* \return Tvg_Paint pointer to duplicatede paint
*/
TVG_EXPORT Tvg_Paint* tvg_paint_duplicate(Tvg_Paint* paint);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_get_bounds(const Tvg_Paint* paint, float* x, float* y, float* w, float* h)
* \brief The function returns paint path bounds.
* \param[in] paint Tvg_Paint pointer
* \param[out] x float x position
* \param[out] y float y position
* \param[out] w float paint width
* \param[out] h float paint height
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_get_bounds(const Tvg_Paint* paint, float* x, float* y, float* w, float* h);

/*!
* \fn TVG_EXPORT Tvg_Result tvg_paint_set_composite_method(Tvg_Paint* paint, Tvg_Paint* target, Tvg_Composite_Method method)
* \brief The function set composition method.
* \param[in] paint Tvg_Paint composition source
* \param[in] target Tvg_Paint composition target
* \param[in] method Tvg_Composite_Method used composite method
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_paint_set_composite_method(Tvg_Paint* paint, Tvg_Paint* target, Tvg_Composite_Method method);

/** \}*/

/**
* \defgroup ThorVGCapi_Shape Shape
* \brief Functions representing two-dimensional figures and their properties.
* The shapes of the figures in the Shape object are stored as the sub-paths in the path.
* The data to be saved in the path can be read directly from the svg file or through the provided APIs.
*
* \{
*/

/************************************************************************/
/* Shape API                                                            */
/************************************************************************/

/**
 * @brief Enumeration specifying the values of the path commands accepted by ThorVG.
 *
 * Not to be confused with the path commands from the svg path element (like M, L, Q, H and many others).
 * ThorVG interprets all of them and translates to the ones from the PathCommand values.
 */
typedef enum {
    TVG_PATH_COMMAND_CLOSE = 0, ///< Ends the current sub-path and connects it with its initial point - corresponds to Z command in the svg path commands.
    TVG_PATH_COMMAND_MOVE_TO,   ///< Sets a new initial point of the sub-path and a new current point - corresponds to M command in the svg path commands.
    TVG_PATH_COMMAND_LINE_TO,   ///< Draws a line from the current point to the given point and sets a new value of the current point - corresponds to L command in the svg path commands.
    TVG_PATH_COMMAND_CUBIC_TO   ///< Draws a cubic Bezier curve from the current point to the given point using two given control points and sets a new value of the current point - corresponds to C command in the svg path commands.
} Tvg_Path_Command;


/**
 * @brief Enumeration determining the ending type of a stroke in the open sub-paths.
 */
typedef enum {
    TVG_STROKE_CAP_SQUARE = 0, ///< The stroke is extended in both endpoints of a sub-path by a rectangle, with the width equal to the stroke width and the length equal to the half of the stroke width. For zero length sub-paths the square is rendered with the size of the stroke width.
    TVG_STROKE_CAP_ROUND,      ///< The stroke is extended in both endpoints of a sub-path by a half circle, with a radius equal to the half of a stroke width. For zero length sub-paths a full circle is rendered.
    TVG_STROKE_CAP_BUTT        ///< The stroke ends exactly at each of the two endpoints of a sub-path. For zero length sub-paths no stroke is rendered.
} Tvg_Stroke_Cap;


/**
 * @brief Enumeration specifying how to fill the area outside the gradient bounds.
 */
typedef enum {
    TVG_STROKE_JOIN_BEVEL = 0, ///< The outer corner of the joined path segments is bevelled at the join point. The triangular region of the corner is enclosed by a straight line between the outer corners of each stroke.
    TVG_STROKE_JOIN_ROUND,     ///< The outer corner of the joined path segments is rounded. The circular region is centered at the join point.
    TVG_STROKE_JOIN_MITER      ///< The outer corner of the joined path segments is spiked. The spike is created by extension beyond the join point of the outer edges of the stroke until they intersect. In case the extension goes beyond the limit, the join style is converted to the Bevel style.
} Tvg_Stroke_Join;


/**
 * @brief Enumeration specifying how to fill the area outside the gradient bounds.
 */
typedef enum {
    TVG_STROKE_FILL_PAD = 0, ///< The remaining area is filled with the closest stop color.
    TVG_STROKE_FILL_REFLECT, ///< The gradient pattern is reflected outside the gradient area until the expected region is filled.
    TVG_STROKE_FILL_REPEAT   ///< The gradient pattern is repeated continuously beyond the gradient area until the expected region is filled.
} Tvg_Stroke_Fill;


/**
 * @brief Enumeration specifying the algorithm used to establish which parts of the shape are treated as the inside of the shape.
 */
typedef enum {
    TVG_FILL_RULE_WINDING = 0, ///< A line from the point to a location outside the shape is drawn. The intersections of the line with the path segment of the shape are counted. Starting from zero, if the path segment of the shape crosses the line clockwise, one is added, otherwise one is subtracted. If the resulting sum is non zero, the point is inside the shape.
    TVG_FILL_RULE_EVEN_ODD     ///< A line from the point to a location outside the shape is drawn and its intersections with the path segments of the shape are counted. If the number of intersections is an odd number, the point is inside the shape.
} Tvg_Fill_Rule;

/*!
* \fn TVG_EXPORT Tvg_Paint* tvg_shape_new()
* \brief The function creates a new shape
* \return Tvg_Paint pointer or NULL if something went wrong
*/
TVG_EXPORT Tvg_Paint* tvg_shape_new();


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_reset(Tvg_Paint* paint)
* \brief The function resets shape properties like path, stroke properties, fill color
* \param[in] paint Tvg_Paint pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_reset(Tvg_Paint* paint);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_move_to(Tvg_Paint* paint, float x, float y)
* \brief The funciton moves the current point to the given point.
* \param[in] paint Tvg_paint pointer
* \param[in] x move x coordinate
* \param[in] y move y coordinate
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_move_to(Tvg_Paint* paint, float x, float y);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_line_to(Tvg_Paint* paint, float x, float y)
* \brief The funciton adds straight line from the current point to the given point.
* \param[in] paint Tvg_Paint pointer
* \param[in] x line end x position
* \param[in] y line end y position
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_line_to(Tvg_Paint* paint, float x, float y);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_cubic_to(Tvg_Paint* paint, float cx1, float cy1, float cx2, float cy2, float x, float y)
* \brief The function adds a cubic Bezier curve between the current point and given end point (x, y) specified by control
points (cx1, cy1) and (cx2, cy2).
* \param[in] paint Tvg_Paint pointer
* \param[in] cx1 First control point x coordinate
* \param[in] cy1 First control point y coordinate
* \param[in] cx2 Second control point x coordinate
* \param[in] cy2 Second control point y coordinate
* \param[in] x Line end x coordinate
* \param[in] y Line end y coordinate
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_cubic_to(Tvg_Paint* paint, float cx1, float cy1, float cx2, float cy2, float x, float y);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_close(Tvg_Paint* paint)
* \brief The function closes current path by drawing line to the start position of it.
* \param[in] paint
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_close(Tvg_Paint* paint);
/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_append_rect(Tvg_Paint* paint, float x, float y, float w, float h, float rx, float ry)
* \brief The function appends rectangle in start position specified by x and y parameters, size spiecified by w and h parameters
* and rounded rectangles specified by rx, ry parameteres
* \param[in] paint Tvg_Paint pointer
* \param[in] x start x position
* \param[in] y start y position
* \param[in] w rectangle width
* \param[in] h rectangle height
* \param[in] rx rectangle corner x radius
* \param[in] ry rectangle corner y radius
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_append_rect(Tvg_Paint* paint, float x, float y, float w, float h, float rx, float ry);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_append_circle(Tvg_Paint* paint, float cx, float cy, float rx, float ry)
* \brief The function appends circle with center in (cx, cy) point, x radius (rx) and y radius (ry)
* \param[in] paint Tvg_Paint pointer
* \param[in] cx circle x center
* \param[in] cy circle y center
* \param[in] rx circle x radius
* \param[in] ry circle y radius
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_append_circle(Tvg_Paint* paint, float cx, float cy, float rx, float ry);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_append_arc(Tvg_Paint* paint, float cx, float cy, float radius, float startAngle, float sweep, uint8_t pie)
* \brief The function append an arc to the shape with center in (cx, cy) position. Arc radius is set by radius parameter. Start position of an
* arcus is defined by startAngle variable. Arcus lenght is set by sweep parameter. To draw closed arcus pie parameter should be set to true.
* \param[in] paint Tvg_Paint pointer
* \param[in] cx arcus x center
* \param[in] cy arcus y center
* \param[in] radius radius of an arc
* \param[in] startAngle start angle of an arc in degrees
* \param[in] sweep lenght of an arc in degrees
* \param[in] pie arcus close parameter
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_append_arc(Tvg_Paint* paint, float cx, float cy, float radius, float startAngle, float sweep, uint8_t pie);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_append_path(Tvg_Paint* paint, const Tvg_Path_Command* cmds, uint32_t cmdCnt, const Tvg_Point* pts, uint32_t ptsCnt)
* \brief The function append path specified by path commands and path points
* \param[in] paint Tvg_Paint pointer
* \param[in] cmds array of path commands
* \param[in] cmdCnt lenght of commands array
* \param[in] pts array of command points
* \param[in] ptsCnt lenght of command points array
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_append_path(Tvg_Paint* paint, const Tvg_Path_Command* cmds, uint32_t cmdCnt, const Tvg_Point* pts, uint32_t ptsCnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_path_coords(const Tvg_Paint* paint, const Tvg_Point** pts, uint32_t* cnt)
* \brief The function get path coordinates to the Tvg_Point array. Array length is specified by cnt output parameter.
* The function does not allocate any data, it operates on internal memory. There is no need to free pts array.
* \code
* Tvg_Shape *shape = tvg_shape_new();
* Tvg_Point *coords = NULL;
* uint32_t len = 0;
*
* tvg_shape_append_circle(shape, 10, 10, 50, 50);
* tvg_shape_get_path_coords(shape, (const Tvg_Point**)&coords, &coords_len);
* //thorvg aproximates circle by four Bezier lines. In example above cmds array will store their coordinates
* \endcode
* \param[in] paint Tvg_Paint pointer
* \param[out] pts points output array
* \param[out] cnt points array length
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_path_coords(const Tvg_Paint* paint, const Tvg_Point** pts, uint32_t* cnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_path_commands(const Tvg_Paint* paint, const Tvg_Path_Command** cmds, uint32_t* cnt)
* \brief The function gets path commands to commands array. Array length is specified by cnt output parameter.
* The function does not allocate any data. There is no need to cmds array.
* \code
* Tvg_Shape *shape = tvg_shape_new();
* Tvg_Point *coords = NULL;
* uint32_t len = 0;
*
* tvg_shape_append_circle(shape, 10, 10, 50, 50);
* tvg_shape_get_path_commands(shape, (const Tvg_Path_Command**)&cmds, &len);
* //thorvg aproximates circle by four Bezier lines. In example above cmds array will store their coordinates
* \endcode
* \param[in] paint Tvg_Paint pointer
* \param[out] cmds commands output array
* \param[out] cnt commands array length
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_path_commands(const Tvg_Paint* paint, const Tvg_Path_Command** cmds, uint32_t* cnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_width(Tvg_Paint* paint, float width)
* \brief The function sets shape's stroke width.
* \param[in] paint Tvg_Paint pointer
* \param[in] width stroke width parameter
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_width(Tvg_Paint* paint, float width);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_stroke_width(const Tvg_Paint* paint, float* width)
* \brief The function gets shape's stroke width
* \param[in] paint Tvg_Paint pointer
* \param[out] width stroke width
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_stroke_width(const Tvg_Paint* paint, float* width);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_color(Tvg_Paint* paint, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
* \brief The function sets shape's stroke color.
* \param[in] paint Tvg_Paint pointer
* \param[in] r red value
* \param[in] g green value
* \param[in] b blue value
* \param[in] a opacity value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_color(Tvg_Paint* paint, uint8_t r, uint8_t g, uint8_t b, uint8_t a);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_stroke_color(const Tvg_Paint* paint, uint8_t* r, uint8_t* g, uint8_t* b, uint8_t* a)
* \brief The function gets shape's stroke color
* \param[in] paint Tvg_Paint pointer
* \param[out] r red value
* \param[out] g green value
* \param[out] b blue value
* \param[out] a opacity value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_stroke_color(const Tvg_Paint* paint, uint8_t* r, uint8_t* g, uint8_t* b, uint8_t* a);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_linear_gradient(Tvg_Paint* paint, Tvg_Gradient* grad)
* \brief The function inserts linear gradient object as an shape stroke.
* \param[in] paint Tvg_Paint pointer
* \param[in] grad Tvg_Gradient pointer (linear)
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_linear_gradient(Tvg_Paint* paint, Tvg_Gradient* grad);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_radial_gradient(Tvg_Paint* paint, Tvg_Gradient* grad)
* \brief The function inserts radial gradient object as an shape stroke.
* \param[in] paint Tvg_Paint pointer
* \param[in] grad Tvg_Gradient pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_radial_gradient(Tvg_Paint* paint, Tvg_Gradient* grad);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_stroke_gradient(const Tvg_Paint* paint, Tvg_Gradient** grad)
* \brief The function returns gradient previously inserted to given shape stroke. Function deos not
* allocate any data.
* \param[in] paint Tvg_Paint pointer
* \param[out] grad Tvg_Gradient pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_stroke_gradient(const Tvg_Paint* paint, Tvg_Gradient** grad);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_dash(Tvg_Paint* paint, const float* dashPattern, uint32_t cnt)
* \brief The function sets shape's stroke dash mode. Dash pattern is an array of floats with size which have to be
* divisible by 2. Position with index not divisible by 2 defines length of line. Positions divisible by 2 defines
* length of gap
* \code
* //dash pattern examples
* float dashPattern[2] = {20, 10};  // -- - -- - -- -
* float dashPattern[2] = {40, 20};  // ----  ----  ----
* float dashPattern[4] = {10, 20, 30, 40} // -  ---
* \endcode
* \param[in] paint Tvg_Paint pointer
* \param[in] dashPattern array of floats descibing pattern [(line, gap)]
* \param[in] cnt size of an array
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_dash(Tvg_Paint* paint, const float* dashPattern, uint32_t cnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_stroke_dash(const Tvg_Paint* paint, const float** dashPattern, uint32_t* cnt)
* \brief The function returns shape's stroke dash pattern and its size.
* \see tvg_shape_set_stroke_dash
* \param[in] paint Tvg_Paint pointer
* \param[out] dashPattern array of floats describing pattern
* \param[out] cnt size of an array
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_stroke_dash(const Tvg_Paint* paint, const float** dashPattern, uint32_t* cnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_cap(Tvg_Paint* paint, Tvg_Stroke_Cap cap)
* \brief The function sets the stroke capabilities style to be used for stroking the path.
* \see Tvg_Stroke_Cap
* \see tvg_shape_get_stroke_cap
* \param[in] paint Tvg_Paint pointer
* \param[in] cap stroke capabilities
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_cap(Tvg_Paint* paint, Tvg_Stroke_Cap cap);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_stroke_cap(const Tvg_Paint* paint, Tvg_Stroke_Cap* cap)
* \brief The function gets the stroke capabilities.
* \see Tvg_Stroke_Cap
* \see tvg_shape_set_stroke_cap
* \param[in] paint Tvg_Paint pointer
* \param[out] cap stroke capabilities
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_stroke_cap(const Tvg_Paint* paint, Tvg_Stroke_Cap* cap);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_stroke_join(Tvg_Paint* paint, Tvg_Stroke_Join join)
* \brief The function sets the stroke join method.
* \see Tvg_Stroke_Join
* \see tvg_shape_set_stroke_cap
* \param[in] paint Tvg_Paint pointer
* \param[in] join join method
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_stroke_join(Tvg_Paint* paint, Tvg_Stroke_Join join);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_stroke_join(const Tvg_Paint* paint, Tvg_Stroke_Join* join)
* \brief The function gets the stroke join method
* \param[in] paint Tvg_Paint pointer
* \param[out] join join method
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_stroke_join(const Tvg_Paint* paint, Tvg_Stroke_Join* join);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_fill_color(Tvg_Paint* paint, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
* \brief The function sets shape's fill color.
* \see tvg_shape_get_fill_color
* \param[in] paint Tvg_Paint pointer
* \param[in] r red value
* \param[in] g green value
* \param[in] b blue value
* \param[in] a alpha value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_fill_color(Tvg_Paint* paint, uint8_t r, uint8_t g, uint8_t b, uint8_t a);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_fill_color(const Tvg_Paint* paint, uint8_t* r, uint8_t* g, uint8_t* b, uint8_t* a)
* \brief The function gets shape's fill color
* \see tvg_shape_set_fill_color
* \param[in] paint Tvg_Paint pointer
* \param[out] r red value
* \param[out] g green value
* \param[out] b blue value
* \param[out] a alpha value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_fill_color(const Tvg_Paint* paint, uint8_t* r, uint8_t* g, uint8_t* b, uint8_t* a);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_fill_rule(Tvg_Paint* paint, Tvg_Fill_Rule rule)
* \brief The function sets shape's fill rule.  TVG_FILL_RULE_WINDING is used as default fill rule
* \see \link Wiki https://en.wikipedia.org/wiki/Nonzero-rule \endlink
* \param[in] paint Tvg_Paint pointer
* \param[in] rule fill rule
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_fill_rule(Tvg_Paint* paint, Tvg_Fill_Rule rule);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_fill_rule(const Tvg_Paint* paint, Tvg_Fill_Rule* rule)
* \brief The function gets shape's fill rule.
* \see tvg_shape_get_fill_rule
* \param[in] paint Tvg_Paint pointer
* \param[out] rule shape's fill rule
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_fill_rule(const Tvg_Paint* paint, Tvg_Fill_Rule* rule);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_linear_gradient(Tvg_Paint* paint, Tvg_Gradient* grad)
* \brief The function inserts linear gradient object as an shape fill.
* \code
* Tvg_Gradient* grad = tvg_linear_gradient_new();
* tvg_linear_gradient_set(grad, 700, 700, 800, 800);
* tvg_shape_set_linear_gradient(shape, grad);
* \endcode
* \param[in] paint Tvg_Paint pointer
* \param[in] grad Tvg_Gradient pointer (linear)
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_linear_gradient(Tvg_Paint* paint, Tvg_Gradient* grad);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_set_radial_gradient(Tvg_Paint* paint, Tvg_Gradient* grad)
* \brief The function inserts radial gradient object as an shape fill.
* \code
* Tvg_Gradient* grad = tvg_radial_gradient_new();
* tvg_radial_gradient_set(grad, 550, 550, 50));
* tvg_shape_set_radial_gradient(shape, grad);
* \endcode
* \param[in] paint Tvg_Paint pointer
* \param[in] grad Tvg_Gradient pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_set_radial_gradient(Tvg_Paint* paint, Tvg_Gradient* grad);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_shape_get_gradient(const Tvg_Paint* paint, Tvg_Gradient** grad)
* \brief The function returns gradient previously inserted to given shape. Function deos not
* allocate any data.
* \param[in] paint Tvg_Paint pointer
* \param[out] grad Tvg_Gradient pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_shape_get_gradient(const Tvg_Paint* paint, Tvg_Gradient** grad);

/** \}*/

/**
* \defgroup ThorVGCapi_Gradient Gradient
* \brief Functions representing the gradient fill of the Shape object.
*
* It contains the information about the gradient colors and their arrangement
* inside the gradient bounds. The gradients bounds are defined in the LinearGradient
* or RadialGradient class, depending on the type of the gradient to be used.
* It specifies the gradient behavior in case the area defined by the gradient bounds
* is smaller than the area to be filled.
*
* \{
*/

/*!
* \struct Tvg_Color_Stop
* \brief A data structure storing the information about the color and its relative position inside the gradient bounds.
*/
typedef struct
{
    float offset; /**< The relative position of the color. */
    uint8_t r;    /**< The red color channel value in the range [0 ~ 255]. */
    uint8_t g;    /**< The green color channel value in the range [0 ~ 255]. */
    uint8_t b;    /**< The blue color channel value in the range [0 ~ 255]. */
    uint8_t a;    /**< The alpha channel value in the range [0 ~ 255], where 0 is completely transparent and 255 is opaque. */
} Tvg_Color_Stop;


/************************************************************************/
/* Gradient API                                                         */
/************************************************************************/
/*!
* \fn TVG_EXPORT Tvg_Gradient* tvg_linear_gradient_new()
* \brief The function creates new linear gradient object.
* \code
* Tvg_Paint shape = tvg_shape_new();
* tvg_shape_append_rect(shape, 700, 700, 100, 100, 20, 20);
* Tvg_Gradient* grad = tvg_linear_gradient_new();
* tvg_linear_gradient_set(grad, 700, 700, 800, 800);
* Tvg_Color_Stop color_stops[2] =
* {
*   {.offset=0, .r=0, .g=0, .b=0,   .a=255},
*   {.offset=1, .r=0, .g=255, .b=0, .a=255},
* };
* tvg_gradient_set_color_stops(grad, color_stops, 2);
* tvg_shape_set_linear_gradient(shape, grad);
* \endcode
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Gradient* tvg_linear_gradient_new();


/*!
* \fn TVG_EXPORT Tvg_Gradient* tvg_radial_gradient_new()
* \brief The function creates new gradient object.
* \code
* Tvg_Paint shape = tvg_shape_new();
* tvg_shape_append_rect(shape, 700, 700, 100, 100, 20, 20);
* Tvg_Gradient* grad = tvg_radial_gradient_new();
* tvg_linear_gradient_set(grad, 550, 550, 50);
* Tvg_Color_Stop color_stops[2] =
* {
*   {.offset=0, .r=0, .g=0, .b=0,   .a=255},
*   {.offset=1, .r=0, .g=255, .b=0, .a=255},
* };
* tvg_gradient_set_color_stops(grad, color_stops, 2);
* tvg_shape_set_radial_gradient(shape, grad);
* \endcode
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Gradient* tvg_radial_gradient_new();


/*!
* \fn TVG_EXPORT Tvg_Result tvg_linear_gradient_set(Tvg_Gradient* grad, float x1, float y1, float x2, float y2)
* \brief The function sets start (x1, y1) and end point (x2, y2) of the gradient.
* \param[in] grad Tvg_Gradient pointer
* \param[in] x1 start point x coordinate
* \param[in] y1 start point y coordinate
* \param[in] x2 end point x coordinate
* \param[in] y2 end point y coordinate
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_linear_gradient_set(Tvg_Gradient* grad, float x1, float y1, float x2, float y2);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_linear_gradient_get(Tvg_Gradient* grad, float* x1, float* y1, float* x2, float* y2)
* \brief The function gets linear gradient start and end postion.
* \param[in] grad Tvg_Gradient pointer
* \param[out] x1 start point x coordinate
* \param[out] y1 start point y coordinate
* \param[out] x2 end point x coordinate
* \param[out] y2 end point y coordinate
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_linear_gradient_get(Tvg_Gradient* grad, float* x1, float* y1, float* x2, float* y2);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_radial_gradient_set(Tvg_Gradient* grad, float cx, float cy, float radius)
* \brief The function sets radial gradient center and radius
* \param[in] grad Tvg_Gradient pointer
* \param[in] cx radial gradient center x coordinate
* \param[in] cy radial gradient center y coordinate
* \param[in] radius radial gradient radius value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_radial_gradient_set(Tvg_Gradient* grad, float cx, float cy, float radius);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_radial_gradient_get(Tvg_Gradient* grad, float* cx, float* cy, float* radius)
* \brief The function gets radial gradient center point ant radius
* \param[in] grad Tvg_Gradient pointer
* \param[out] cx gradient center x coordinate
* \param[out] cy gradient center y coordinate
* \param[out] radius gradient radius value
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_radial_gradient_get(Tvg_Gradient* grad, float* cx, float* cy, float* radius);

/*!
* \fn TVG_EXPORT Tvg_Result tvg_gradient_set_color_stops(Tvg_Gradient* grad, const Tvg_Color_Stop* color_stop, uint32_t cnt)
* \brief The function sets lists of color stops for the given gradient
* \see tvg_linear_gradient_new
* \param[in] grad Tvg_Gradient pointer
* \param[in] color_stop color stops list
* \param[in] cnt color stops size
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_gradient_set_color_stops(Tvg_Gradient* grad, const Tvg_Color_Stop* color_stop, uint32_t cnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_gradient_get_color_stops(Tvg_Gradient* grad, const Tvg_Color_Stop** color_stop, uint32_t* cnt)
* \brief The function gets lists of color stops for the given gradient
* \param[in] grad Tvg_Gradient pointer
* \param[out] color_stop color stops list
* \param[out] cnt color stops list size
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_gradient_get_color_stops(Tvg_Gradient* grad, const Tvg_Color_Stop** color_stop, uint32_t* cnt);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_gradient_set_spread(Tvg_Gradient* grad, const Tvg_Stroke_Fill spread)
* \brief The function sets spread fill method for given gradient
* \param[in] grad Tvg_Gradient pointer
* \param[in] spread spread method
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_gradient_set_spread(Tvg_Gradient* grad, const Tvg_Stroke_Fill spread);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_gradient_get_spread(Tvg_Gradient* grad, Tvg_Stroke_Fill* spread)
* \brief The function gets spread fill method for given gradient
* \param[in] grad Tvg_Gradient pointer
* \param[out] spread spread method
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_gradient_get_spread(Tvg_Gradient* grad, Tvg_Stroke_Fill* spread);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_gradient_del(Tvg_Gradient* grad)
* \brief The function deletes given gradient object
* \param[in] grad Tvg_Gradient pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_gradient_del(Tvg_Gradient* grad);

/** \}*/

/**
* \defgroup ThorVGCapi_Picture Picture
* \brief Functions class representing an image read in one of the supported formats: svg, png and raw.
* Besides the methods inherited from the Paint, it provides methods to load the image,
* to change its size and to get the basic information.
*
* \{
*/


/************************************************************************/
/* Picture API                                                          */
/************************************************************************/
/*!
* \fn TVG_EXPORT Tvg_Paint* tvg_picture_new()
* \brief The function creates new picture object.
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Paint* tvg_picture_new();


/*!
* \fn TVG_EXPORT Tvg_Result tvg_picture_load(Tvg_Paint* paint, const char* path)
* \brief The function loads image into given paint object
* \param[in] paint Tvg_Paint pointer
* \param[in] path absolute path to the image file
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_picture_load(Tvg_Paint* paint, const char* path);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_picture_load_raw(Tvg_Paint* paint, uint32_t *data, uint32_t w, uint32_t h, bool copy)
* \brief The function loads raw image data into given paint object.
* \param[in] paint Tvg_Paint pointer
* \param[in] data raw data pointer
* \param[in] w picture width
* \param[in] h picture height
* \param[in] copy if copy is set to true function copies data into the paint
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_picture_load_raw(Tvg_Paint* paint, uint32_t *data, uint32_t w, uint32_t h, bool copy);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_picture_get_viewbox(const Tvg_Paint* paint, float* x, float* y, float* w, float* h)
* \brief The function returns viewbox coordinates and size for given paint
* \param[in] paint Tvg_Paint pointer
* \param[out] x left top corner x coordinate
* \param[out] y left top corner y coordinate
* \param[out] w viewbox width
* \param[out] h viewbox height
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_picture_get_viewbox(const Tvg_Paint* paint, float* x, float* y, float* w, float* h);

/** \}*/

/**
* \defgroup ThorVGCapi_Scene Scene
* \brief Functions enabling to hold many Paint objects.
*
* As a whole they can be transformed, their transparency can be changed, or the composition
* methods may be used to all of them at once.
*
* \{
*/

/************************************************************************/
/* Scene API                                                            */
/************************************************************************/
/*!
* \fn TVG_EXPORT Tvg_Paint* tvg_scene_new()
* \brief The function creates new scene object. Scene object is used to group paints
* into one object which can be manipulated using Tvg_Paint API.
* \return Tvg_Paint pointer to newly allocated scene or NULL if something went wrong
*/
TVG_EXPORT Tvg_Paint* tvg_scene_new();


/*!
* \fn TVG_EXPORT Tvg_Result tvg_scene_reserve(Tvg_Paint* scene, uint32_t size)
* \brief The function reserves a space in given space for specific number of paints
* \see tvg_canvas_reserve
* \param[in] scene Tvg_Paint pointer
* \param[in] size size to allocate
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_scene_reserve(Tvg_Paint* scene, uint32_t size);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_scene_push(Tvg_Paint* scene, Tvg_Paint* paint)
* \brief The function inserts given paint in the specified scene.
* \see tvg_canvas_push
* \param[in] scene Tvg_Paint pointer (scene)
* \param[in] paint Tvg_Paint pointer (paint)
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint or scene is invalid
*/
TVG_EXPORT Tvg_Result tvg_scene_push(Tvg_Paint* scene, Tvg_Paint* paint);


/*!
* \fn TVG_EXPORT Tvg_Result tvg_scene_clear(Tvg_Paint* scene)
* \brief The function claers paints inserted in scene
* \see tvg_canvas_clear
* \param scene Tvg_Paint pointer
* \return Tvg_Result return value
* - TVG_RESULT_SUCCESS: if ok.
* - TVG_RESULT_INVALID_PARAMETERS: if paint is invalid
*/
TVG_EXPORT Tvg_Result tvg_scene_clear(Tvg_Paint* scene);
/** \}*/

/** \}*/

#ifdef __cplusplus
}
#endif

#endif //_THORVG_CAPI_H_