Progress bar is rendering incorrectly. about lvgl HOT 7 CLOSED

template<typename Derived>
class BaseWidget
{
protected:
    int32_t _w, _h;
    lv_draw_buf_t *_draw_buf;
    lv_obj_t * _canvas;
    lv_layer_t _layer;
    lv_draw_rect_dsc_t _dsc_bg;

public:
    BaseWidget(lv_obj_t *parent, int32_t w, int32_t h)
    {
        _w = w;
        _h = h;

        _draw_buf = lv_draw_buf_create(w, h, LV_COLOR_FORMAT_RGB888, 0);

        _canvas = lv_canvas_create(parent);
        lv_canvas_set_draw_buf(_canvas, _draw_buf);
        
        lv_canvas_init_layer(_canvas, &_layer);
        lv_draw_rect_dsc_init(&_dsc_bg);
        _dsc_bg.radius = 8;
    }

    virtual ~BaseWidget() {}

    inline lv_obj_t *getCanvas()
    {
        return _canvas;
    }
    
    inline Derived& setBgColor(lv_color_t color, lv_opa_t opa)
    {
        _dsc_bg.bg_color = color;
        _dsc_bg.bg_opa = opa;

        return static_cast<Derived&>(*this);
    }

    inline Derived& clearBg()
    {
        lv_area_t coordsbg = {0, 0, _w, _h};
		lv_draw_rect(&_layer, &_dsc_bg, &coordsbg);

        return static_cast<Derived&>(*this);
    }
};


class ProgressBarWidget : public BaseWidget<ProgressBarWidget>
{
private:
    int32_t _min, _max, _range, _value; 
    lv_draw_rect_dsc_t _dsc;

public:
    ProgressBarWidget(lv_obj_t *parent, int32_t w, int32_t h) : BaseWidget(parent, w, h)
    {
        lv_draw_rect_dsc_init(&_dsc);
        _dsc.radius = 8;
    }

    ~ProgressBarWidget() {}

    inline ProgressBarWidget& setIndicatorColor(lv_color_t color, lv_opa_t opa)
    {
        _dsc.bg_color = color;
        _dsc.bg_opa = opa;
        return *this;
    }

    inline ProgressBarWidget& setRange(int min, int max)
    {
        _min = min;
        _max = max;
        _range = _max - _min;
        return *this;
    }

    inline ProgressBarWidget& setValue(int value)
    {
		_value = value;
        if (value < _min) {
            value = _min;
        }
        else if (value > _max) {
            value = _max;
        }
        int px = ((value - _min) / (float)_range) * _w;
        lv_area_t coords = {0, 0, px, 50};
        clearBg();
        lv_draw_rect(&_layer, &_dsc, &coords);

        lv_canvas_finish_layer(_canvas, &_layer);
        lv_obj_invalidate(_canvas);

        return *this;
    }

	inline ProgressBarWidget& setValueAnim(int value, int duration=800)
	{
		lv_anim_t a;
		lv_anim_init(&a);
		lv_anim_set_exec_cb(&a, [](void *obj, int32_t v) {
			ProgressBarWidget *self = static_cast<ProgressBarWidget*>(obj);
			self->setValue(v);
		});
		lv_anim_set_path_cb(&a, lv_anim_path_ease_out);
		lv_anim_set_duration(&a, duration);
		lv_anim_set_var(&a, this);
		lv_anim_set_values(&a, _value, value);
		lv_anim_set_repeat_count(&a, 0);
		lv_anim_start(&a);

		return *this;
	}
};

ProgressBarWidget *pb = new ProgressBarWidget(lv_screen_active(), 200, 20);
    pb->setBgColor(lv_color_make(0x00, 0x00, 0x00), LV_OPA_COVER)
        .setIndicatorColor(lv_color_make(0x00, 0x00, 0xFF), LV_OPA_COVER)
        .setRange(0, 100)
        .setValue(50);

printf("flush: %d %d %d %d\n", area->x1, area->y1, area->x2, area->y2);

refresh: 0 0 200 20