fix(textarea): fill letter space with selection bg color. (lvgl#8238)

Author: liujp-arch

src/draw/lv_draw_label.c

@@ -461,9 +461,9 @@ void lv_draw_label_iterate_characters(lv_draw_task_t * t, const lv_draw_label_ds
             letter_w = lv_text_is_marker(letter) ? 0 : glyph_dsc.adv_w;
 
             /*Always set the bg_coordinates for placeholder drawing*/
-            bg_coords.x1 = pos.x;
+            bg_coords.x1 = pos.x - dsc->letter_space / 2;
             bg_coords.y1 = pos.y;
-            bg_coords.x2 = pos.x + letter_w - 1;
+            bg_coords.x2 = pos.x + letter_w - 1 + (dsc->letter_space + 1) / 2;
             bg_coords.y2 = pos.y + line_height - 1;
 
             if(next_char_offset >= line_end - line_start) {

src/widgets/textarea/lv_textarea.c

@@ -1198,11 +1198,12 @@ static void refr_cursor_area(lv_obj_t * obj)
     int32_t bottom = lv_obj_get_style_pad_bottom(obj, LV_PART_CURSOR) + border_width;
     int32_t left = lv_obj_get_style_pad_left(obj, LV_PART_CURSOR) + border_width;
     int32_t right = lv_obj_get_style_pad_right(obj, LV_PART_CURSOR) + border_width;
+    int32_t letter_space_w = lv_obj_get_style_text_letter_space(ta->label, LV_PART_MAIN);
 
     lv_area_t cur_area;
-    cur_area.x1 = letter_pos.x - left;
+    cur_area.x1 = letter_pos.x - left - letter_space_w / 2;
     cur_area.y1 = letter_pos.y - top;
-    cur_area.x2 = letter_pos.x + right + letter_w - 1;
+    cur_area.x2 = letter_pos.x + right + letter_w - 1 + (letter_space_w + 1) / 2;
     cur_area.y2 = letter_pos.y + bottom + letter_h - 1;
 
     /*Save the new area*/

tests/ref_imgs/draw/label_selection_letter_space.png

@@ -145,4 +145,24 @@ void test_label_selection_and_recolor(void)
     TEST_ASSERT_EQUAL_SCREENSHOT("draw/label_selection_and_recolor.png");
 }
 
+void test_label_selection_with_letter_space(void)
+{
+    lv_color_t color = lv_palette_main(LV_PALETTE_BLUE);
+    lv_color_t sel_bg_color = lv_palette_lighten(LV_PALETTE_RED, 4);
+    lv_color_t sel_color = lv_palette_darken(LV_PALETTE_RED, 4);
+
+    lv_obj_t * label = lv_label_create(lv_screen_active());
+    lv_label_set_text(label, "Testing selection with letter space label.");
+    lv_obj_set_style_text_color(label, color, 0);
+    lv_obj_set_style_text_opa(label, LV_OPA_COVER, 0);
+    lv_obj_set_style_text_align(label, LV_TEXT_ALIGN_LEFT, 0);
+    lv_obj_set_style_bg_color(label, sel_bg_color, LV_PART_SELECTED);
+    lv_obj_set_style_text_color(label, sel_color, LV_PART_SELECTED);
+    lv_obj_set_style_text_letter_space(label, 10, 0);
+    lv_label_set_text_selection_start(label, 10);
+    lv_label_set_text_selection_end(label, 25);
+
+    TEST_ASSERT_EQUAL_SCREENSHOT("draw/label_selection_letter_space.png");
+}
+
 #endif