# lv_refr.h (/api/core/lv_refr_h)
Functions [#functions]
lv_refr_now [#lv_refr_now]
Redraw the invalidated areas now. Normally the redrawing is periodically executed in `lv_timer_handler` but a long blocking process can prevent the call of `lv_timer_handler`. In this case if the GUI is updated in the process (e.g. progress bar) this function can be called when the screen should be updated.
```c title=" " lineNumbers=1
void lv_refr_now(lv_display_t *disp)
```
Parameters
| Name | Type | Description |
| ------ | -------------------------------------------------------- | ------------------------------------------------------------ |
| `disp` | | pointer to display to refresh. NULL to refresh all displays. |
lv_obj_redraw [#lv_obj_redraw]
Redrawn on object and all its children using the passed draw context
```c title=" " lineNumbers=1
void lv_obj_redraw(lv_layer_t *layer, lv_obj_t *obj)
```
Parameters
| Name | Type | Description |
| ------- | ---------------------------------------------------- | --------------------------------------------- |
| `layer` | | pointer to a layer where to draw. |
| `obj` | | the start object from the redraw should start |
lv_display_refr_timer [#lv_display_refr_timer]
Called periodically to handle the refreshing
```c title=" " lineNumbers=1
void lv_display_refr_timer(lv_timer_t *timer)
```
Parameters
| Name | Type | Description |
| ------- | ---------------------------------------------------- | -------------------------------------- |
| `timer` | | pointer to the timer itself, or `NULL` |
Dependencies [#dependencies]