Merge pull request #1684 from lvgl/pete-pjb-cpicker

Tidy up the edges of the colour picker widget.

CHANGELOG.md

@@ -14,6 +14,7 @@
 ### Bugfixes
 - Do not print warning for missing glyph if its height OR width is zero.
 - Prevent duplicated sending of `LV_EVENT_INSERT` from text area
+- Tidy outer edges of cpicker widget.
 - Remove duplicated lines from `lv_tabview_add_tab`
 
 ## v7.2.0 (21.07.2020)

src/lv_widgets/lv_cpicker.c

@@ -48,6 +48,13 @@
 
 #define TRI_OFFSET 2
 
+/* The OUTER_MASK_WIDTH define is required to assist with the placing of a mask over the outer ring of the widget as when the
+ * multicoloured radial lines are calculated for the outer ring of the widget their lengths are jittering because of the
+ * integer based arithmetic. From tests the maximum delta was found to be 2 so the current value is set to 3 to achieve
+ * appropriate masking.
+ */
+#define OUTER_MASK_WIDTH 3
+
 /**********************
  *      TYPEDEFS
  **********************/
@@ -483,6 +490,17 @@ static void draw_disc_grad(lv_obj_t * cpicker, const lv_area_t * mask)
     uint16_t i;
     lv_coord_t cir_w = lv_obj_get_style_scale_width(cpicker, LV_CPICKER_PART_MAIN);
 
+    /* Mask outer ring of widget to tidy up ragged edges of lines while drawing outer ring */
+    lv_area_t mask_area_out;
+    lv_area_copy( &mask_area_out, &cpicker->coords);
+    mask_area_out.x1 += OUTER_MASK_WIDTH;
+    mask_area_out.x2 -= OUTER_MASK_WIDTH;
+    mask_area_out.y1 += OUTER_MASK_WIDTH;
+    mask_area_out.y2 -= OUTER_MASK_WIDTH;
+    lv_draw_mask_radius_param_t mask_out_param;
+    lv_draw_mask_radius_init(&mask_out_param, &mask_area_out, LV_RADIUS_CIRCLE, false);
+    int16_t mask_out_id = lv_draw_mask_add(&mask_out_param, 0);
+
     /* The inner line ends will be masked out.
      * So make lines a little bit longer because the masking makes a more even result */
     lv_coord_t cir_w_extra = cir_w + line_dsc.width;
@@ -498,7 +516,8 @@ static void draw_disc_grad(lv_obj_t * cpicker, const lv_area_t * mask)
 
         lv_draw_line(&p[0], &p[1], mask, &line_dsc);
     }
-
+    /* Now remove mask to continue with inner part */
+    lv_draw_mask_remove_id(mask_out_id);
 
     /*Mask out the inner area*/
     lv_draw_rect_dsc_t bg_dsc;