Merge pull request #1341 from littlevgl/improve-hittest

Implement advanced hit-testing for zoomed images

src/lv_core/lv_obj.c

@@ -2412,12 +2412,14 @@ bool lv_obj_is_focused(const lv_obj_t * obj)
  *------------------*/
 
 /**
- * Hit-test an object given a particular point in screen space.
+ * Check if a given screen-space point is on an object's coordinates.
- * @param obj object to hit-test
+ * 
+ * This method is intended to be used mainly by advanced hit testing algorithms to check
+ * whether the point is even within the object (as an optimization).
+ * @param obj object to check
  * @param point screen-space point
- * @return true if the object is considered under the point
  */
-bool lv_obj_hittest(lv_obj_t * obj, lv_point_t * point) {
+bool lv_obj_is_point_on_coords(lv_obj_t * obj, const lv_point_t * point) {
 #if LV_USE_EXT_CLICK_AREA == LV_EXT_CLICK_AREA_TINY
     lv_area_t ext_area;
     ext_area.x1 = obj->coords.x1 - obj->ext_click_pad_hor;
@@ -2439,15 +2441,24 @@ bool lv_obj_hittest(lv_obj_t * obj, lv_point_t * point) {
 #endif
         return false;
     }
+    return true;
+}
+
+/**
+ * Hit-test an object given a particular point in screen space.
+ * @param obj object to hit-test
+ * @param point screen-space point
+ * @return true if the object is considered under the point
+ */
+bool lv_obj_hittest(lv_obj_t * obj, lv_point_t * point) {
     if(obj->adv_hittest) {
         lv_hit_test_info_t hit_info;
         hit_info.point = point;
         hit_info.result = true;
         obj->signal_cb(obj, LV_SIGNAL_HIT_TEST, &hit_info);
-        if(!hit_info.result)
+        return hit_info.result;
-            return false;
+    } else
-    }
+        return lv_obj_is_point_on_coords(obj, point);
-    return true;
 }
 
 /**

src/lv_core/lv_obj.h

@@ -940,6 +940,22 @@ lv_event_cb_t lv_obj_get_event_cb(const lv_obj_t * obj);
  * Other get
  *-----------------*/
 
+/**
+ * Check if a given screen-space point is on an object's coordinates.
+ * 
+ * This method is intended to be used mainly by advanced hit testing algorithms to check
+ * whether the point is even within the object (as an optimization).
+ * @param obj object to check
+ * @param point screen-space point
+ */
+bool lv_obj_is_point_on_coords(lv_obj_t * obj, const lv_point_t * point);
+
+/**
+ * Hit-test an object given a particular point in screen space.
+ * @param obj object to hit-test
+ * @param point screen-space point
+ * @return true if the object is considered under the point
+ */
 bool lv_obj_hittest(lv_obj_t * obj, lv_point_t * point);
 
 /**

src/lv_objx/lv_cpicker.c

@@ -900,9 +900,14 @@ static lv_res_t lv_cpicker_signal(lv_obj_t * cpicker, lv_signal_t sign, void * p
 
 static bool lv_cpicker_hit(lv_obj_t * cpicker, const lv_point_t * p)
 {
+    bool is_point_on_coords = lv_obj_is_point_on_coords(cpicker, p);
+    if(!is_point_on_coords)
+        return false;
+    
     lv_cpicker_ext_t * ext = (lv_cpicker_ext_t *)lv_obj_get_ext_attr(cpicker);
     if(ext->type != LV_CPICKER_TYPE_DISC || ext->preview)
         return true;
+    
     const lv_style_t * style_main = lv_cpicker_get_style(cpicker, LV_CPICKER_STYLE_MAIN);
     lv_area_t area_mid;
     lv_area_copy(&area_mid, &cpicker->coords);

src/lv_objx/lv_img.c

@@ -97,6 +97,7 @@ lv_obj_t * lv_img_create(lv_obj_t * par, const lv_obj_t * copy)
 
     if(copy == NULL) {
         lv_obj_set_click(new_img, false);
+        lv_obj_set_adv_hittest(new_img, true); /*Images have fast hit-testing*/
         /* Enable auto size for non screens
          * because image screens are wallpapers
          * and must be screen sized*/
@@ -590,6 +591,26 @@ static lv_res_t lv_img_signal(lv_obj_t * img, lv_signal_t sign, void * param)
             lv_coord_t d = ds.i / 2;
             img->ext_draw_pad = LV_MATH_MAX(img->ext_draw_pad, d);
         }
+    } else if(sign == LV_SIGNAL_HIT_TEST) {
+        lv_hit_test_info_t *info = param;
+        if(ext->zoom != 256 && ext->angle == 0) {
+            lv_coord_t origin_width = lv_area_get_width(&img->coords);
+            lv_coord_t origin_height = lv_area_get_height(&img->coords);
+            lv_coord_t scaled_width = (origin_width * ext->zoom + 255) / 256;
+            lv_coord_t scaled_height = (origin_height * ext->zoom + 255) / 256;
+
+            lv_coord_t width_offset = (origin_width - scaled_width) / 2;
+            lv_coord_t height_offset = (origin_height - scaled_height) / 2;
+
+            lv_area_t coords;
+            lv_area_copy(&coords, &img->coords);
+            coords.x1 += width_offset;
+            coords.x2 -= width_offset;
+            coords.y1 += height_offset;
+            coords.y2 -= height_offset;
+            info->result = lv_area_is_point_on(&coords, info->point, 0);
+        } else
+            info->result = lv_obj_is_point_on_coords(img, info->point);
     }
 
     return res;