lv_theme: add live update feature

lv_conf_templ.h

@@ -24,11 +24,6 @@
 #define LV_MEM_CUSTOM_ALLOC   malloc       /*Wrapper to malloc*/
 #define LV_MEM_CUSTOM_FREE    free         /*Wrapper to free*/
 #endif     /*LV_MEM_CUSTOM*/
-#define LV_TICK_CUSTOM     0               /*1: use a custom tick source (removing the need to manually update the tick with `lv_tick_inc`) */
-#if LV_TICK_CUSTOM == 1
-#define LV_TICK_CUSTOM_INCLUDE  "Arduino.h"  /*Header for the sys time function*/
-#define LV_TICK_CUSTOM_SYS_TIME_EXPR (millis())   /*Expression evaluating to current systime in ms*/
-#endif     /*LV_TICK_CUSTOM*/
 
 /*===================
    Graphical settings
@@ -95,6 +90,14 @@
 #define LV_COMPILER_NON_CONST_INIT_SUPPORTED 0	/* 1: Initialization with non constant values are supported (In Visual studio it is not supported)*/
 //#define _CRT_SECURE_NO_WARNINGS			    /* Visual Studio needs it to use `strcpy`, `sprintf` etc*/
 
+/*HAL settings*/
+#define LV_TICK_CUSTOM     0                        /*1: use a custom tick source (removing the need to manually update the tick with `lv_tick_inc`) */
+#if LV_TICK_CUSTOM == 1
+#define LV_TICK_CUSTOM_INCLUDE  "Arduino.h"         /*Header for the sys time function*/
+#define LV_TICK_CUSTOM_SYS_TIME_EXPR (millis())     /*Expression evaluating to current systime in ms*/
+#endif     /*LV_TICK_CUSTOM*/
+
+
 /*Log settings*/
 #define USE_LV_LOG		1	/*Enable/disable the log module*/
 #if USE_LV_LOG
@@ -113,6 +116,8 @@
 /*================
  *  THEME USAGE
  *================*/
+#define LV_THEME_LIVE_UPDATE    0       /*Enable to change the theme in run time. Requires 8..10 kB extra RAM*/
+
 #define USE_LV_THEME_TEMPL      0       /*Just for test*/
 #define USE_LV_THEME_DEFAULT    0       /*Built mainly from the built-in styles. Consumes very few RAM*/
 #define USE_LV_THEME_ALIEN      0       /*Dark futuristic theme*/

lv_themes/lv_theme.c

@@ -7,6 +7,7 @@
  *      INCLUDES
  *********************/
 #include "lv_theme.h"
+#include "../lv_core/lv_obj.h"
 
 /*********************
  *      DEFINES
@@ -23,7 +24,23 @@
 /**********************
  *  STATIC VARIABLES
  **********************/
+
+#if LV_THEME_LIVE_UPDATE == 0
 static lv_theme_t * current_theme;
+#else
+/* If live update is used then a big `lv_style_t` array is used to store the real styles of the theme not only pointers.
+ * On `lv_theme_set_current` the styles of the theme are copied to this array.
+ * The pointers in `current_theme` are initialized to point to the styles in the array.
+ * This way the theme styles will always point to the same memory address even after theme is change.
+ * (The pointers in the theme points to the styles declared by the theme itself) */
+
+/* Store the styles in this array.
+ * Can't determine the size in compile time because sizeof is not evaluated (should be `sizeof(lv_theme_t) / sizeof(lv_style_t*)`).
+ * Error will be generated in run time if too small.*/
+static lv_style_t th_styles[100];
+static bool inited = false;
+static lv_theme_t current_theme;
+#endif
 
 /**********************
  *      MACROS
@@ -38,9 +55,42 @@ static lv_theme_t * current_theme;
  * From now, all the created objects will use styles from this theme by default
  * @param th pointer to theme (return value of: 'lv_theme_init_xxx()')
  */
-void lv_theme_set_current(lv_theme_t * th)
+void lv_theme_set_current(lv_theme_t *th)
 {
+#if LV_THEME_LIVE_UPDATE == 0
     current_theme = th;
+#else
+    uint32_t style_num = sizeof(lv_theme_t) / sizeof(lv_style_t*);      /*Number of styles in a theme*/
+
+    if(!inited) {
+        /*It's not sure `th_styles` is big enough. Check it now!*/
+        if(style_num > sizeof(th_styles) / sizeof(lv_style_t)) {
+            LV_LOG_ERROR("Themes: th_styles array is too small. Increase it's size!");
+            while(1);
+        }
+
+        /*Initialize the style pointers `current_theme` to point to the `th_styles` style array */
+        uint16_t i;
+        lv_style_t ** cur_th_style_p = (lv_style_t **) &current_theme;
+        for(i = 0; i < style_num; i++) {
+            uint64_t adr = (uint64_t)&th_styles[i];
+            memcpy(&cur_th_style_p[i], &adr, sizeof(lv_style_t*));
+        }
+        inited = true;
+    }
+
+
+    /*Copy the styles pointed by the new theme to the `th_styles` style array*/
+    uint16_t i;
+    lv_style_t ** th_style = (lv_style_t **) th;
+    for(i = 0; i < style_num; i++) {
+        uint64_t s = (uint64_t)th_style[i];
+        if(s) memcpy(&th_styles[i], (void*)s, sizeof(lv_style_t));
+    }
+
+    /*Let the object know their style might change*/
+    lv_obj_report_style_mod(NULL);
+#endif
 }
 
 /**
@@ -49,7 +99,12 @@ void lv_theme_set_current(lv_theme_t * th)
  */
 lv_theme_t * lv_theme_get_current(void)
 {
+#if LV_THEME_LIVE_UPDATE == 0
     return current_theme;
+#else
+    if(!inited) return NULL;
+    else return &current_theme;
+#endif
 }
 
 /**********************