# Overview (/main-modules/display/overview)



What is a Display? [#what-is-a-display]

In LVGL, an *lv\_display\_t* (not to be confused with a [Screen](/common-widget-features/screens)) is a
data type that represents a single display panel --- the hardware that displays
LVGL-rendered pixels on your device.

How Many Displays Can LVGL Use? [#how-many-displays-can-lvgl-use]

LVGL can use any number of displays.  It is only limited by available RAM and MCU time.

Why would you want multi-display support? Here are some examples:

* Have a "normal" TFT display with local UI and create "virtual" screens on VNC
  on demand. (You need to add your VNC driver.)
* Have a large TFT display and a small monochrome display.
* Have some smaller and simple displays in a large instrument or technology.
* Have two large TFT displays: one for a customer and one for the shop assistant.

If you set up LVGL to use more than one display, be aware that some functions use the
[Default Display](/main-modules/display/setup) during their execution, such as creating [Screens](/common-widget-features/screens).

Attributes [#attributes]

Once created, a Display object remembers the characteristics of the display hardware
it is representing, as well as other things relevant to its lifetime:

* Resolution (width and height in pixels)
* Color Depth (bits per pixel)
* Color Format (how colors in pixels are laid out)
* DPI (default is configured <ApiLink name="LV_DPI_DEF" /> in `lv_conf.h`, but can be
  modified with <ApiLink name="lv_display_set_dpi" display="lv_display_set_dpi(disp, new_dpi)" />).
* 4 [Screen Layers](/main-modules/display/screen_layers) automatically created with each display
* All [Screens](/common-widget-features/screens) created in association with this display (and not yet deleted---only
  one is displayed at any given time)
* The [Draw Buffer(s)](/main-modules/display/setup) assigned to it
* The [Flush Callback](/main-modules/display/setup) function that moves pixels from [Draw Buffer(s)](/main-modules/display/setup) to Display hardware
* What areas of the display have been updated (made "dirty") so rendering logic can
  compute what to render during a display refresh
* Optional custom pointer as [User Data](/main-modules/display/overview)

User Data [#user-data]

With <ApiLink name="lv_display_set_user_data" display="lv_display_set_user_data(display1, p)" /> a custom pointer can be stored
with `lv_display_t` object.  This pointer can be used later, e.g. in
[Display Events](/main-modules/display/display_events).   See code example for how to do this in [Display Events](/main-modules/display/display_events).

API [#api]