bidi: add LV_LABEL_ALIGN_AUTO, LV_BIDI_DIR_AOUT/INHERIT, LV_SIGNAL_BASE_DIR_CHG

lv_conf_template.h

@@ -297,6 +297,19 @@ typedef void * lv_font_user_data_t;
  /*Can break (wrap) texts on these chars*/
 #define LV_TXT_BREAK_CHARS                  " ,.;:-_"
 
+/* Support bidirectional texts.
+ * Allows mixing Left-to-Right and Right-to-Left texts.
+ * The direction will be processed according to the Unicode Bidirectioanl Algorithm:
+ * https://www.w3.org/International/articles/inline-bidi-markup/uba-basics*/
+#define LV_USE_BIDI     1
+#if LV_USE_BIDI
+/* Set the default direction. Supported values:
+ * `LV_BIDI_DIR_LTR` Left-to-Right
+ * `LV_BIDI_DIR_RTL` Right-to-Left
+ * `LV_BIDI_DIR_AUTO` detect texts base direction */
+#define LV_BIDI_BASE_DIR_DEF  LV_BIDI_DIR_AUTO
+#endif
+
 /*===================
  *  LV_OBJ SETTINGS
  *==================*/

lvgl.h

@@ -33,6 +33,7 @@ extern "C" {
 
 #include "src/lv_font/lv_font.h"
 #include "src/lv_font/lv_font_fmt_txt.h"
+#include "src/lv_misc/lv_bidi.h"
 
 #include "src/lv_objx/lv_btn.h"
 #include "src/lv_objx/lv_imgbtn.h"

src/lv_conf_checker.h

@@ -412,6 +412,23 @@
 #define LV_TXT_BREAK_CHARS                  " ,.;:-_"
 #endif
 
+/* Support bidirectional texts.
+ * Allows mixing Left-to-Right and Right-to-Left texts.
+ * The direction will be processed according to the Unicode Bidirectioanl Algorithm:
+ * https://www.w3.org/International/articles/inline-bidi-markup/uba-basics*/
+#ifndef LV_USE_BIDI
+#define LV_USE_BIDI     1
+#endif
+#if LV_USE_BIDI
+/* Set the default direction. Supported values:
+ * `LV_BIDI_DIR_LTR` Left-to-Right
+ * `LV_BIDI_DIR_RTL` Right-to-Left
+ * `LV_BIDI_DIR_AUTO` detect texts base direction */
+#ifndef LV_BIDI_BASE_DIR_DEF
+#define LV_BIDI_BASE_DIR_DEF  LV_BIDI_DIR_AUTO
+#endif
+#endif
+
 /*===================
  *  LV_OBJ SETTINGS
  *==================*/

src/lv_core/lv_obj.c

@@ -49,6 +49,7 @@ static void refresh_children_position(lv_obj_t * obj, lv_coord_t x_diff, lv_coor
 static void report_style_mod_core(void * style_p, lv_obj_t * obj);
 static void refresh_children_style(lv_obj_t * obj);
 static void delete_children(lv_obj_t * obj);
+static void base_dir_refr_children(lv_obj_t * obj);
 static void lv_event_mark_deleted(lv_obj_t * obj);
 static void lv_obj_del_async_cb(void * obj);
 static bool lv_obj_design(lv_obj_t * obj, const lv_area_t * mask_p, lv_design_mode_t mode);
@@ -204,6 +205,16 @@ lv_obj_t * lv_obj_create(lv_obj_t * parent, const lv_obj_t * copy)
         new_obj->opa_scale_en = 0;
         new_obj->opa_scale    = LV_OPA_COVER;
         new_obj->parent_event = 0;
+#if LV_USE_BIDI
+#if LV_BIDI_BASE_DIR_DEF == LV_BIDI_DIR_LTR || LV_BIDI_BASE_DIR_DEF == LV_BIDI_DIR_RTL || LV_BIDI_BASE_DIR_DEF == LV_BIDI_DIR_AUTO
+        new_obj->base_dir     = LV_BIDI_BASE_DIR_DEF;
+#else
+#error "`LV_BIDI_BASE_DIR_DEF` should be `LV_BASE_DIR_LTR` or `LV_BASE_DIR_RTL` (See lv_conf.h)"
+#endif
+#else
+        new_obj->base_dir     = LV_BIDI_DIR_LTR;
+#endif
+
         new_obj->reserved     = 0;
 
         new_obj->ext_attr = NULL;
@@ -288,6 +299,12 @@ lv_obj_t * lv_obj_create(lv_obj_t * parent, const lv_obj_t * copy)
         new_obj->opa_scale    = LV_OPA_COVER;
         new_obj->opa_scale_en = 0;
         new_obj->parent_event = 0;
+#if LV_USE_BIDI
+        new_obj->base_dir     = LV_BIDI_DIR_INHERIT;
+#else
+        new_obj->base_dir     = LV_BIDI_DIR_LTR;
+#endif
+        new_obj->reserved     = 0;
 
         new_obj->ext_attr = NULL;
     }
@@ -1266,6 +1283,23 @@ void lv_obj_set_parent_event(lv_obj_t * obj, bool en)
     obj->parent_event = (en == true ? 1 : 0);
 }
 
+void lv_obj_set_base_dir(lv_obj_t * obj, lv_bidi_dir_t dir)
+{
+    if(dir != LV_BIDI_DIR_LTR && dir != LV_BIDI_DIR_RTL &&
+       dir != LV_BIDI_DIR_AUTO && dir != LV_BIDI_DIR_INHERIT) {
+
+        LV_LOG_WARN("lv_obj_set_base_dir: invalid base dir");
+        return;
+    }
+
+    obj->base_dir = dir;
+    lv_signal_send(obj, LV_SIGNAL_BASE_DIR_CHG, NULL);
+
+    /* Notify the children about the parent base dir has changed.
+     * (The children might have `LV_BIDI_DIR_INHERIT`)*/
+    base_dir_refr_children(obj);
+}
+
 /**
  * Set the opa scale enable parameter (required to set opa_scale with `lv_obj_set_opa_scale()`)
  * @param obj pointer to an object
@@ -1931,6 +1965,25 @@ bool lv_obj_get_parent_event(const lv_obj_t * obj)
     return obj->parent_event == 0 ? false : true;
 }
 
+
+lv_bidi_dir_t lv_obj_get_base_dir(const lv_obj_t * obj)
+{
+#if LV_USE_BIDI
+    const lv_obj_t * parent = obj;
+
+    while(parent) {
+        if(parent->base_dir != LV_BIDI_DIR_INHERIT) return parent->base_dir;
+
+        parent = lv_obj_get_parent(parent);
+    }
+
+    return LV_BIDI_BASE_DIR_DEF;
+#else
+    return LV_BIDI_DIR_LTR;
+#endif
+}
+
+
 /**
  * Get the opa scale enable parameter
  * @param obj pointer to an object
@@ -2326,6 +2379,22 @@ static void delete_children(lv_obj_t * obj)
     lv_mem_free(obj); /*Free the object itself*/
 }
 
+static void base_dir_refr_children(lv_obj_t * obj)
+{
+    lv_obj_t * child;
+    child = lv_obj_get_child(obj, NULL);
+
+    while(child) {
+        if(child->base_dir == LV_BIDI_DIR_INHERIT) {
+            lv_signal_send(child, LV_SIGNAL_BASE_DIR_CHG, NULL);
+            base_dir_refr_children(child);
+        }
+
+        child = lv_obj_get_child(obj, child);
+    }
+}
+
+
 static void lv_event_mark_deleted(lv_obj_t * obj)
 {
     lv_event_temp_data_t * t = event_temp_data_head;

src/lv_core/lv_obj.h

@@ -28,6 +28,7 @@ extern "C" {
 #include "../lv_misc/lv_ll.h"
 #include "../lv_misc/lv_color.h"
 #include "../lv_misc/lv_log.h"
+#include "../lv_misc/lv_bidi.h"
 #include "../lv_hal/lv_hal.h"
 
 /*********************
@@ -111,7 +112,8 @@ enum {
     LV_SIGNAL_CHILD_CHG, /**< Child was removed/added */
     LV_SIGNAL_CORD_CHG, /**< Object coordinates/size have changed */
     LV_SIGNAL_PARENT_SIZE_CHG, /**< Parent's size has changed */
-    LV_SIGNAL_STYLE_CHG, /**< Object's style has changed */
+    LV_SIGNAL_STYLE_CHG,    /**< Object's style has changed */
+    LV_SIGNAL_BASE_DIR_CHG, /**<The base dir has changed*/
     LV_SIGNAL_REFR_EXT_DRAW_PAD, /**< Object's extra padding has changed */
     LV_SIGNAL_GET_TYPE, /**< LittlevGL needs to retrieve the object's type */
 
@@ -123,7 +125,8 @@ enum {
     LV_SIGNAL_LONG_PRESS,        /**< Object has been pressed for at least `LV_INDEV_LONG_PRESS_TIME`.  Not called if dragged.*/
     LV_SIGNAL_LONG_PRESS_REP,    /**< Called after `LV_INDEV_LONG_PRESS_TIME` in every `LV_INDEV_LONG_PRESS_REP_TIME` ms.  Not called if dragged.*/
     LV_SIGNAL_DRAG_BEGIN,	
-    LV_SIGNAL_DRAG_END,                                   
+    LV_SIGNAL_DRAG_END,
+
     /*Group related*/
     LV_SIGNAL_FOCUS,
     LV_SIGNAL_DEFOCUS,
@@ -218,7 +221,8 @@ typedef struct _lv_obj_t
     uint8_t opa_scale_en : 1;   /**< 1: opa_scale is set*/
     uint8_t parent_event : 1;   /**< 1: Send the object's events to the parent too. */
     lv_drag_dir_t drag_dir : 2; /**<  Which directions the object can be dragged in */
-    uint8_t reserved : 6;       /**<  Reserved for future use*/
+    lv_bidi_dir_t base_dir : 2; /**< Base direction of texts related to this object */
+    uint8_t reserved : 3;       /**<  Reserved for future use*/
     uint8_t protect;            /**< Automatically happening actions can be prevented. 'OR'ed values from
                                    `lv_protect_t`*/
     lv_opa_t opa_scale;         /**< Scale down the opacity by this factor. Effects all children as well*/
@@ -510,6 +514,7 @@ void lv_obj_set_drag_parent(lv_obj_t * obj, bool en);
  */
 void lv_obj_set_parent_event(lv_obj_t * obj, bool en);
 
+void lv_obj_set_base_dir(lv_obj_t * obj, lv_bidi_dir_t dir);
 /**
  * Set the opa scale enable parameter (required to set opa_scale with `lv_obj_set_opa_scale()`)
  * @param obj pointer to an object
@@ -849,6 +854,9 @@ bool lv_obj_get_drag_parent(const lv_obj_t * obj);
  */
 bool lv_obj_get_parent_event(const lv_obj_t * obj);
 
+
+lv_bidi_dir_t lv_obj_get_base_dir(const lv_obj_t * obj);
+
 /**
  * Get the opa scale enable parameter
  * @param obj pointer to an object

src/lv_core/lv_style.c

@@ -89,11 +89,11 @@ void lv_style_init(void)
     lv_style_scr.body.shadow.color = LV_COLOR_GRAY;
     lv_style_scr.body.shadow.type  = LV_SHADOW_FULL;
     lv_style_scr.body.shadow.width = 0;
-
+    LV_FONT_DECLARE(lv_font_heb_16);
     lv_style_scr.text.opa          = LV_OPA_COVER;
     lv_style_scr.text.color        = lv_color_make(0x30, 0x30, 0x30);
     lv_style_scr.text.sel_color    = lv_color_make(0x55, 0x96, 0xd8);
-    lv_style_scr.text.font         = LV_FONT_DEFAULT;
+    lv_style_scr.text.font         = &lv_font_heb_16;//LV_FONT_DEFAULT;
     lv_style_scr.text.letter_space = 0;
     lv_style_scr.text.line_space   = 2;
 

src/lv_misc/lv_bidi.c

@@ -10,6 +10,8 @@
 #include <stddef.h>
 #include "lv_txt.h"
 
+#if LV_USE_BIDI
+
 /*********************
  *      DEFINES
  *********************/
@@ -62,7 +64,6 @@ void lv_bidi_process(const char * str_in, char * str_out, lv_bidi_dir_t base_dir
         if(dir != LV_BIDI_DIR_NEUTRAL) break;
     }
 
-    /*if there were neutrals in the beginning apply `base_dir` on them */
     if(rd && str_in[rd] != '\0') lv_txt_encoded_prev(str_in, &rd);
 
     if(rd) {
@@ -110,6 +111,21 @@ void lv_bidi_process(const char * str_in, char * str_out, lv_bidi_dir_t base_dir
 
 }
 
+lv_bidi_dir_t lv_bidi_detect_base_dir(const char * txt)
+{
+    uint32_t i = 0;
+    uint32_t letter;
+    while(txt[i] != '\0') {
+        letter = lv_txt_encoded_next(txt, &i);
+
+        lv_bidi_dir_t dir;
+        dir = lv_bidi_get_letter_dir(letter);
+        if(dir == LV_BIDI_DIR_RTL || dir == LV_BIDI_DIR_LTR) return dir;
+    }
+
+    /*If there were no strong char earlier return with the default base dir */
+    return LV_BIDI_BASE_DIR_DEF;
+}
 
 lv_bidi_dir_t lv_bidi_get_letter_dir(uint32_t letter)
 {
@@ -279,7 +295,6 @@ static uint32_t char_change_to_pair(uint32_t letter)
     }
 
     return letter;
-
-
 }
 
+#endif /*LV_USE_BIDI*/

src/lv_misc/lv_bidi.h

@@ -23,19 +23,27 @@ extern "C" {
 /**********************
  *      TYPEDEFS
  **********************/
-typedef enum
+enum
 {
-    LV_BIDI_DIR_LTR,
+    /*The first 4 values are stored in `lv_obj_t` on 2 bits*/
-    LV_BIDI_DIR_RTL,
+    LV_BIDI_DIR_LTR      = 0x00,
-    LV_BIDI_DIR_NEUTRAL,
+    LV_BIDI_DIR_RTL      = 0x01,
-    LV_BIDI_DIR_WEAK,
+    LV_BIDI_DIR_AUTO     = 0x02,
-}lv_bidi_dir_t;
+    LV_BIDI_DIR_INHERIT  = 0x03,
+
+    LV_BIDI_DIR_NEUTRAL  = 0x20,
+    LV_BIDI_DIR_WEAK     = 0x21,
+};
+
+typedef uint8_t lv_bidi_dir_t;
 
 /**********************
  * GLOBAL PROTOTYPES
  **********************/
-void lv_bidi_process(const char * str_in, char * str_out, lv_bidi_dir_t base_dir);
+#if LV_USE_BIDI
 
+void lv_bidi_process(const char * str_in, char * str_out, lv_bidi_dir_t base_dir);
+lv_bidi_dir_t lv_bidi_detect_base_dir(const char * txt);
 lv_bidi_dir_t lv_bidi_get_letter_dir(uint32_t letter);
 bool lv_bidi_letter_is_weak(uint32_t letter);
 bool lv_bidi_letter_is_rtl(uint32_t letter);
@@ -45,6 +53,8 @@ bool lv_bidi_letter_is_neutral(uint32_t letter);
  *      MACROS
  **********************/
 
+#endif /*LV_USE_BIDI*/
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif

src/lv_objx/lv_ddlist.c

@@ -180,7 +180,8 @@ void lv_ddlist_set_options(lv_obj_t * ddlist, const char * options)
 
     lv_ddlist_refr_width(ddlist);
 
-    switch(lv_label_get_align(ext->label)) {
+    lv_label_align_t align = lv_label_get_align(ext->label);
+    switch(align) {
         case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
         case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
         case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
@@ -621,6 +622,15 @@ static lv_res_t lv_ddlist_signal(lv_obj_t * ddlist, lv_signal_t sign, void * par
     lv_ddlist_ext_t * ext = lv_obj_get_ext_attr(ddlist);
 
     if(sign == LV_SIGNAL_STYLE_CHG) {
+        lv_ddlist_refr_size(ddlist, 0);
+    } else if(sign == LV_SIGNAL_BASE_DIR_CHG) {
+        lv_label_align_t align = lv_label_get_align(ext->label);
+        switch(align) {
+            case LV_LABEL_ALIGN_LEFT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_LEFT_MID, 0, 0); break;
+            case LV_LABEL_ALIGN_CENTER: lv_obj_align(ext->label, NULL, LV_ALIGN_CENTER, 0, 0); break;
+            case LV_LABEL_ALIGN_RIGHT: lv_obj_align(ext->label, NULL, LV_ALIGN_IN_RIGHT_MID, 0, 0); break;
+        }
+
         lv_ddlist_refr_size(ddlist, 0);
     } else if(sign == LV_SIGNAL_CLEANUP) {
         ext->label = NULL;

src/lv_objx/lv_label.c

@@ -13,6 +13,7 @@
 #include "../lv_core/lv_group.h"
 #include "../lv_misc/lv_color.h"
 #include "../lv_misc/lv_math.h"
+#include "../lv_misc/lv_bidi.h"
 
 /*********************
  *      DEFINES
@@ -88,7 +89,7 @@ lv_obj_t * lv_label_create(lv_obj_t * par, const lv_obj_t * copy)
     ext->static_txt = 0;
     ext->recolor    = 0;
     ext->body_draw  = 0;
-    ext->align      = LV_LABEL_ALIGN_LEFT;
+    ext->align      = LV_LABEL_ALIGN_AUTO;
     ext->dot_end    = LV_LABEL_DOT_END_INV;
     ext->long_mode  = LV_LABEL_LONG_EXPAND;
 #if LV_USE_ANIMATION
@@ -190,14 +191,33 @@ void lv_label_set_text(lv_obj_t * label, const char * text)
         if(ext->text != NULL && ext->static_txt == 0) {
             lv_mem_free(ext->text);
             ext->text = NULL;
+
+#if LV_USE_BIDI
+            lv_mem_free(ext->text_ori);
+            ext->text_ori = NULL;
+#endif
         }
 
         ext->text = lv_mem_alloc(len);
         lv_mem_assert(ext->text);
         if(ext->text == NULL) return;
 
+#if LV_USE_BIDI == 0
         strcpy(ext->text, text);
-        ext->static_txt = 0; /*Now the text is dynamically allocated*/
+#else
+        ext->text_ori = lv_mem_alloc(len);
+        lv_mem_assert(ext->text_ori);
+        if(ext->text_ori == NULL) return;
+
+        strcpy(ext->text_ori, text);
+
+        lv_bidi_dir_t base_dir = lv_obj_get_base_dir(label);
+        if(base_dir == LV_BIDI_DIR_AUTO) base_dir = lv_bidi_detect_base_dir(text);
+
+        lv_bidi_process(ext->text_ori, ext->text, base_dir);
+#endif
+        /*Now the text is dynamically allocated*/
+        ext->static_txt = 0;
     }
 
     lv_label_refr_text(label);
@@ -425,7 +445,22 @@ lv_label_long_mode_t lv_label_get_long_mode(const lv_obj_t * label)
 lv_label_align_t lv_label_get_align(const lv_obj_t * label)
 {
     lv_label_ext_t * ext = lv_obj_get_ext_attr(label);
-    return ext->align;
+
+    lv_label_align_t align = ext->align;
+
+    if(align == LV_LABEL_ALIGN_AUTO) {
+#if LV_USE_BIDI
+        lv_bidi_dir_t base_dir = lv_obj_get_base_dir(label);
+        if(base_dir == LV_BIDI_DIR_AUTO) base_dir = lv_bidi_detect_base_dir(ext->text);
+
+        if(base_dir == LV_BIDI_DIR_LTR) align = LV_LABEL_ALIGN_LEFT;
+        else if (base_dir == LV_BIDI_DIR_RTL) align = LV_LABEL_ALIGN_RIGHT;
+#else
+        align = LV_LABEL_ALIGN_LEFT;
+#endif
+    }
+
+    return align;
 }
 
 /**
@@ -842,14 +877,13 @@ static bool lv_label_design(lv_obj_t * label, const lv_area_t * mask, lv_design_
             lv_draw_rect(&bg, mask, style, lv_obj_get_opa_scale(label));
         }
 
-        /*TEST: draw a background for the label*/
+        lv_label_align_t align = lv_label_get_align(label);
-        // lv_draw_rect(&label->coords, mask, &lv_style_plain_color, LV_OPA_COVER);
 
         lv_txt_flag_t flag = LV_TXT_FLAG_NONE;
         if(ext->recolor != 0) flag |= LV_TXT_FLAG_RECOLOR;
         if(ext->expand != 0) flag |= LV_TXT_FLAG_EXPAND;
-        if(ext->align == LV_LABEL_ALIGN_CENTER) flag |= LV_TXT_FLAG_CENTER;
+        if(align == LV_LABEL_ALIGN_CENTER) flag |= LV_TXT_FLAG_CENTER;
-        if(ext->align == LV_LABEL_ALIGN_RIGHT) flag |= LV_TXT_FLAG_RIGHT;
+        if(align == LV_LABEL_ALIGN_RIGHT) flag |= LV_TXT_FLAG_RIGHT;
 
         /* In ROLL mode the CENTER and RIGHT are pointless so remove them.
          * (In addition they will result mis-alignment is this case)*/
@@ -947,6 +981,9 @@ static lv_res_t lv_label_signal(lv_obj_t * label, lv_signal_t sign, void * param
             label->ext_draw_pad = LV_MATH_MAX(label->ext_draw_pad, style->body.padding.top);
             label->ext_draw_pad = LV_MATH_MAX(label->ext_draw_pad, style->body.padding.bottom);
         }
+    }
+    else if(sign == LV_SIGNAL_BASE_DIR_CHG) {
+        if(ext->static_txt == 0) lv_label_set_text(label, NULL);
     } else if(sign == LV_SIGNAL_GET_TYPE) {
         lv_obj_type_t * buf = param;
         uint8_t i;

src/lv_objx/lv_label.h

@@ -55,6 +55,7 @@ enum {
     LV_LABEL_ALIGN_LEFT, /**< Align text to left */
     LV_LABEL_ALIGN_CENTER, /**< Align text to center */
     LV_LABEL_ALIGN_RIGHT, /**< Align text to right */
+    LV_LABEL_ALIGN_AUTO, /**< Use LEFT or RIGHT depending on the direction of the text (LTR/RTL)*/
 };
 typedef uint8_t lv_label_align_t;
 
@@ -63,12 +64,17 @@ typedef struct
 {
     /*Inherited from 'base_obj' so no inherited ext.*/ /*Ext. of ancestor*/
     /*New data for this type */
-    char * text; /*Text of the label*/
+    char * text;        /*Text of the label*/
+
+#if LV_USE_BIDI
+    char * text_ori;    /*The original text. With BiDi `text` stores the characters in "bidi" ordered text*/
+#endif
+
     union
     {
         char * tmp_ptr; /* Pointer to the allocated memory containing the character which are replaced by dots (Handled
                            by the library)*/
-        char tmp[sizeof(char *)]; /* Directly store the characters if <=4 characters */
+        char tmp[LV_LABEL_DOT_NUM + 1]; /* Directly store the characters if <=4 characters */
     } dot;
     uint16_t dot_end;  /*The text end position in dot mode (Handled by the library)*/
     lv_point_t offset; /*Text draw position offset*/