LVGL源码解析之 lv_draw_sw_img_decoded

lv_draw_sw_img_decoded

img_decoded 是用于解码图片并且将图片绘制到指定buffer区域。

LV_ATTRIBUTE_FAST_MEM 
void lv_draw_sw_img_decoded
(
struct _lv_draw_ctx_t * draw_ctx,
const lv_draw_img_dsc_t * draw_dsc,
const lv_area_t * coords, 
const uint8_t * src_buf, 
lv_img_cf_t cf
)

/**
    struct _lv_draw_ctx_t * draw_ctx        // 绘制上下文
    const lv_draw_img_dsc_t * draw_dsc      // 图像素材绘制描述
    const lv_area_t * coords                // 绘制区(图像在output buffer上的绝对定位)
    const uint8_t * src_buf                  // 图像buffer
    lv_img_cf_t cf                          // 图像色彩格式
**/

绘制上下文中，与当前绘制图像相关的属性：

typedef struct _lv_draw_ctx_t  {
    /**
     *  Pointer to a buffer to draw into
     */
    void * buf;

    /**
     * The position and size of `buf` (absolute coordinates)
     */
    lv_area_t * buf_area;

    /**
     * The current clip area with absolute coordinates, always the same or smaller than `buf_area`
     */
    const lv_area_t * clip_area;

} lv_draw_ctx_t;

与图像本身的绘制效果相关的：

typedef struct {

    int16_t angle;
    uint16_t zoom;
    lv_point_t pivot;

    lv_color_t recolor;
    lv_opa_t recolor_opa;

    lv_opa_t opa;
    lv_blend_mode_t blend_mode : 4;

    int32_t frame_id;
    uint8_t antialias       : 1;
} lv_draw_img_dsc_t;