feat(draw/sw): make I1 luminance threshold configurable (#7616)

Kconfig

@@ -269,6 +269,12 @@ menu "LVGL configuration"
 			default y
 			depends on LV_USE_DRAW_SW
 
+		config LV_DRAW_SW_I1_LUM_THRESHOLD
+			int "Luminance threshold for a pixel to be active"
+			default 127
+			range 0 254
+			depends on LV_DRAW_SW_SUPPORT_I1
+
 		config LV_DRAW_SW_DRAW_UNIT_CNT
 			int "Number of draw units"
 			default 1

lv_conf_template.h

@@ -174,6 +174,10 @@
     #define LV_DRAW_SW_SUPPORT_A8           1
     #define LV_DRAW_SW_SUPPORT_I1           1
 
+    /* The threshold of the luminance to consider a pixel as
+     * active in indexed color format */
+    #define LV_DRAW_SW_I1_LUM_THRESHOLD 127
+
     /** Set number of draw units.
      *  - > 1 requires operating system to be enabled in `LV_USE_OS`.
      *  - > 1 means multiple threads will render the screen in parallel. */

src/draw/sw/blend/lv_draw_sw_blend_to_i1.c

@@ -82,7 +82,7 @@ static inline void * /* LV_ATTRIBUTE_FAST_MEM */ drawbuf_next_row(const void * b
  *      MACROS
  **********************/
 
-#define I1_LUM_THRESHOLD 127
+#define I1_LUM_THRESHOLD LV_DRAW_SW_I1_LUM_THRESHOLD
 
 #ifndef LV_DRAW_SW_I1_BLEND_NORMAL_TO_I1
     #define LV_DRAW_SW_I1_BLEND_NORMAL_TO_I1(...)                    LV_RESULT_INVALID

src/lv_conf_internal.h

@@ -500,6 +500,16 @@
         #endif
     #endif
 
+    /* The threshold of the luminance to consider a pixel as
+     * active in indexed color format */
+    #ifndef LV_DRAW_SW_I1_LUM_THRESHOLD
+        #ifdef CONFIG_LV_DRAW_SW_I1_LUM_THRESHOLD
+            #define LV_DRAW_SW_I1_LUM_THRESHOLD CONFIG_LV_DRAW_SW_I1_LUM_THRESHOLD
+        #else
+            #define LV_DRAW_SW_I1_LUM_THRESHOLD 127
+        #endif
+    #endif
+
     /** Set number of draw units.
      *  - > 1 requires operating system to be enabled in `LV_USE_OS`.
      *  - > 1 means multiple threads will render the screen in parallel. */