lvgl_cpp/lvgl/draw/sw/lv_draw_sw_gradient.h

98 lines
3.5 KiB
C

/**
* @file lv_draw_sw_gradient.h
*
*/
#ifndef LV_DRAW_SW_GRADIENT_H
#define LV_DRAW_SW_GRADIENT_H
#ifdef __cplusplus
extern "C" {
#endif
/*********************
* INCLUDES
*********************/
#include "../../misc/lv_color.h"
#include "../../misc/lv_style.h"
#include "lv_draw_sw_dither.h"
/*********************
* DEFINES
*********************/
#if LV_GRADIENT_MAX_STOPS < 2
#error LVGL needs at least 2 stops for gradients. Please increase the LV_GRADIENT_MAX_STOPS
#endif
/**********************
* TYPEDEFS
**********************/
#if _DITHER_GRADIENT
typedef lv_color32_t lv_grad_color_t;
#else
typedef lv_color_t lv_grad_color_t;
#endif
/** To avoid recomputing gradient for each draw operation,
* it's possible to cache the computation in this structure instance.
* Whenever possible, this structure is reused instead of recomputing the gradient map */
typedef struct _lv_gradient_cache_t {
uint32_t key; /**< A discriminating key that's built from the drawing operation.
* If the key does not match, the cache item is not used */
uint32_t life : 30; /**< A life counter that's incremented on usage. Higher counter is
* less likely to be evicted from the cache */
uint32_t filled : 1; /**< Used to skip dithering in it if already done */
uint32_t not_cached: 1; /**< The cache was too small so this item is not managed by the cache*/
lv_color_t * map; /**< The computed gradient low bitdepth color map, points into the
* cache's buffer, no free needed */
lv_coord_t alloc_size; /**< The map allocated size in colors */
lv_coord_t size; /**< The computed gradient color map size, in colors */
#if _DITHER_GRADIENT
lv_color32_t * hmap; /**< If dithering, we need to store the current, high bitdepth gradient
* map too, points to the cache's buffer, no free needed */
#if LV_DITHER_ERROR_DIFFUSION == 1
lv_scolor24_t * error_acc; /**< Error diffusion dithering algorithm requires storing the last error
* drawn, points to the cache's buffer, no free needed */
lv_coord_t w; /**< The error array width in pixels */
#endif
#endif
} lv_grad_t;
/**********************
* PROTOTYPES
**********************/
/** Compute the color in the given gradient and fraction
* Gradient are specified in a virtual [0-255] range, so this function scales the virtual range to the given range
* @param dsc The gradient descriptor to use
* @param range The range to use in computation.
* @param frac The current part used in the range. frac is in [0; range]
*/
LV_ATTRIBUTE_FAST_MEM lv_grad_color_t lv_gradient_calculate(const lv_grad_dsc_t * dsc, lv_coord_t range,
lv_coord_t frac);
/**
* Set the gradient cache size
* @param max_bytes Max cahce size
*/
void lv_gradient_set_cache_size(size_t max_bytes);
/** Free the gradient cache */
void lv_gradient_free_cache(void);
/** Get a gradient cache from the given parameters */
lv_grad_t * lv_gradient_get(const lv_grad_dsc_t * gradient, lv_coord_t w, lv_coord_t h);
/**
* Clean up the gradient item after it was get with `lv_grad_get_from_cache`.
* @param grad pointer to a gradient
*/
void lv_gradient_cleanup(lv_grad_t * grad);
#ifdef __cplusplus
} /*extern "C"*/
#endif
#endif /*LV_DRAW_GRADIENT_H*/