docs(isp_awb): add isp awb programming guide

components/esp_driver_isp/include/driver/isp_af.h

@@ -178,7 +178,7 @@ typedef struct {
 /**
  * @brief Prototype of ISP AF Env detector event callback
  *
- * @param[in] af_ctrlr  ISP AF controller handle
+ * @param[in] af_ctrlr   ISP AF controller handle
  * @param[in] edata     ISP AF Env detector event data
  * @param[in] user_data User registered context, registered when in `esp_isp_af_env_detector_register_event_callbacks()`
  *

components/esp_driver_isp/include/driver/isp_types.h

@@ -30,6 +30,14 @@ typedef struct {
     float max;          ///< Maximum float value
 } isp_float_range_t;
 
+/**
+ * @brief ISP AF result
+ */
+typedef struct {
+    int definition[ISP_AF_WINDOW_NUM];    ///< Definition, it refers how clear and sharp an image is
+    int luminance[ISP_AF_WINDOW_NUM];     ///< Luminance, it refers how luminant an image is
+} isp_af_result_t;
+
 /**
  * @brief ISP AWB result
  */