Add option to align title text in window (#1953)

* Add option to align title text in window 

I found that i really needed a basic way to align the title text in a window, and therefore i did a bit of tinkering and came up with this solution. Mind you that I'm very new to this so it might not be the most optimal way. I have tested a bit and it pretty looked promising,
I have of course written the alignments as I felt was most suitable, but I shouldn't be the judge of that.
Current alignment:

LV_TXT_FLAG_CENTER makes the text align in the center of the header but ensures it can’t overextend into to header button area;

LV_TXT_FLAG_RIGHT makes the text align at the right side, but takes the right side header buttons into account

LV_TXT_FLAG_FIT & LV_TXT_FLAG_EXPAND I wasn’t too sure about what to do so as of now it just aligns them as normal

LV_TXT_FLAG_NONE Is equal to no flag set by the user and therefore I have just set it to the default coords, like normal. The text then align at the left side.

* Update lv_win.h

* Added functions

Added function to set and get alignment of the header title as requested

* Added functions

Added setter and getter functions for the header title alignment as requested

src/lv_widgets/lv_win.c

@@ -92,6 +92,7 @@ lv_obj_t * lv_win_create(lv_obj_t * par, const lv_obj_t * copy)
     ext->page          = NULL;
     ext->header        = NULL;
     ext->title_txt    = lv_mem_alloc(strlen(DEF_TITLE) + 1);
+    ext->title_txt_align = LV_TXT_FLAG_NONE;
     strcpy(ext->title_txt, DEF_TITLE);
 
     /*Init the new window object*/
@@ -363,6 +364,14 @@ void lv_win_set_drag(lv_obj_t * win, bool en)
     lv_obj_set_drag(win, en);
 }
 
+void lv_win_title_set_alignment(lv_obj_t * win, uint8_t alignment)
+{
+    lv_win_ext_t * ext = lv_obj_get_ext_attr(win);
+
+    ext->title_txt_align = alignment;
+
+}
+
 /*=====================
  * Getter functions
  *====================*/
@@ -491,6 +500,14 @@ lv_coord_t lv_win_get_width(lv_obj_t * win)
     return lv_obj_get_width_fit(scrl) - left - right;
 }
 
+uint8_t lv_win_title_get_alignment(lv_obj_t * win)
+{
+    lv_win_ext_t * ext = lv_obj_get_ext_attr(win);
+
+    return ext->title_txt_align;
+}
+
+
 /*=====================
  * Other functions
  *====================*/
@@ -538,11 +555,13 @@ static lv_design_res_t lv_win_header_design(lv_obj_t * header, const lv_area_t *
         lv_win_ext_t * ext = lv_obj_get_ext_attr(win);
 
         lv_style_int_t header_left = lv_obj_get_style_pad_left(win, LV_WIN_PART_HEADER);
+        lv_style_int_t header_right = lv_obj_get_style_pad_right(win, LV_WIN_PART_HEADER);
         lv_style_int_t header_inner = lv_obj_get_style_pad_inner(win, LV_WIN_PART_HEADER);
 
         lv_draw_label_dsc_t label_dsc;
         lv_draw_label_dsc_init(&label_dsc);
         lv_obj_init_draw_label_dsc(header, LV_OBJ_PART_MAIN, &label_dsc);
+        label_dsc.flag = ext->title_txt_align;
 
         lv_area_t txt_area;
         lv_point_t txt_size;
@@ -557,21 +576,41 @@ static lv_design_res_t lv_win_header_design(lv_obj_t * header, const lv_area_t *
 
         /*Get x position of the title (should be on the right of the buttons on the left)*/
 
-        lv_coord_t left_btn_offset = 0;
+        lv_coord_t btn_offset = 0;
         btn = lv_obj_get_child_back(ext->header, NULL);
         while(btn != NULL) {
             if(LV_WIN_BTN_ALIGN_LEFT == lv_win_btn_get_alignment(btn)) {
-                left_btn_offset += btn_w + header_inner;
+                btn_offset += btn_w + header_inner;
             }
 
             btn = lv_obj_get_child_back(header, btn);
         }
-
+        switch(label_dsc.flag) {
-        txt_area.x1 = header->coords.x1 + header_left + left_btn_offset;
+            case LV_TXT_FLAG_CENTER:
-        txt_area.y1 = header->coords.y1 + (lv_obj_get_height(header) - txt_size.y) / 2;
+                txt_area.x1 = header->coords.x1 + header_left + btn_offset;
-        txt_area.x2 = txt_area.x1 + txt_size.x  + left_btn_offset;
+                txt_area.x2 = header->coords.x2 - header_right - btn_offset;
-        txt_area.y2 = txt_area.y1 + txt_size.y;
+                txt_area.y1 = header->coords.y1 + (lv_obj_get_height(header) - txt_size.y) / 2;                                                 
-
+                txt_area.y2 = txt_area.y1 + txt_size.y;         
+                break;
+            case LV_TXT_FLAG_RIGHT:
+                txt_area.x1 = header->coords.x1;
+                txt_area.x2 = header->coords.x2 - header_right - btn_offset;
+                txt_area.y1 = header->coords.y1 + (lv_obj_get_height(header) - txt_size.y) / 2; 
+                txt_area.y2 = txt_area.y1 + txt_size.y;
+                break;                                         
+            case LV_TXT_FLAG_FIT || LV_TXT_FLAG_EXPAND:
+                txt_area.x1 = header->coords.x1;
+                txt_area.x2 = header->coords.x2;
+                txt_area.y1 = header->coords.y1 + (lv_obj_get_height(header) - txt_size.y) / 2; 
+                txt_area.y2 = txt_area.y1 + txt_size.y;
+                break;                                         
+            default:
+                txt_area.x1 = header->coords.x1 + header_left + btn_offset;
+                txt_area.x2 = txt_area.x1 + txt_size.x  + btn_offset;
+                txt_area.y1 = header->coords.y1 + (lv_obj_get_height(header) - txt_size.y) / 2;
+                txt_area.y2 = txt_area.y1 + txt_size.y;
+                break;
+        }
         lv_draw_label(&txt_area, clip_area, &label_dsc, ext->title_txt, NULL);
     }
     else if(mode == LV_DESIGN_DRAW_POST) {

src/lv_widgets/lv_win.h

@@ -57,6 +57,7 @@ typedef struct {
     lv_obj_t * header;                /*Pointer to the header container of the window*/
     char * title_txt;                 /*Pointer to the title label of the window*/
     lv_coord_t btn_w;                 /*Width of the control buttons*/
+    uint8_t title_txt_align;          /*Control the alignment of the header text*/
 } lv_win_ext_t;
 
 /** Window parts. */
@@ -175,6 +176,13 @@ void lv_win_set_anim_time(lv_obj_t * win, uint16_t anim_time);
  */
 void lv_win_set_drag(lv_obj_t * win, bool en);
 
+/**
+ * Set alignment of title text in window header. 
+ * @param win pointer to a window object
+ * @param alignment set the type of alignment with LV_TXT_FLAGS
+ */
+void lv_win_title_set_alignment(lv_obj_t * win, uint8_t alignment);
+
 /*=====================
  * Getter functions
  *====================*/
@@ -254,6 +262,12 @@ static inline bool lv_win_get_drag(const lv_obj_t * win)
     return lv_obj_get_drag(win);
 }
 
+/**
+ * Get the current alignment of title text in window header. 
+ * @param win pointer to a window object
+ */
+uint8_t lv_win_title_get_alignment(lv_obj_t * win);
+
 /*=====================
  * Other functions
  *====================*/