Screen

Introduction

The VEX AIR Drone Controller’s screen provides blocks for displaying text, managing the cursor, drawing shapes, and handling touch interactions.

Note: If the VEX AIR Drone is paired with a controller, a timer will be displayed at the top of the print screen indicating the current project’s elapsed time. Any text or drawings will appear behind the timer.

Below is a list of all available blocks, grouped by functionality:

Cursor Print - Manage text display using a row-and-column cursor system.

• print — Displays text on the screen at the current cursor position.

• set cursor to row column — Moves the cursor to a specific row and column.

• set cursor to next row — Moves the cursor to column 1 of the next row.

• clear row — Clears a specified row of text.

• screen cursor column — Returns the column number where text will be printed.

• screen cursor row — Returns the row number where text will be printed.

XY Print - Print text at pixel-based coordinates.

• print at — Displays text at a specified x and y coordinate.

• set screen origin — Changes the origin (0, 0) used for drawing and printing.

Settings - Customize text formatting and screen display.

• clear screen — Erases all text and drawings from the screen.

• wait for screen to render — Prevents any printing or drawing from displaying until the block is used again.

• fill screen — Erases all text and drawings from the screen, then sets the screen’s background color.

• set font — Changes the font type and size for text display.

• set print precision — Adjusts the amount of decimal places for printed numbers.

• set pen width — Adjusts the thickness of drawn lines.

• set pen / font color — Changes the color for text and drawings.

• set fill color — Defines the fill color for shapes.

Draw - Create graphics and visual elements.

• show image file — Displays a user-uploaded image on the screen.

• draw pixel — Draws a single pixel at a specified coordinate.

• draw line — Draws a line between two points.

• draw rectangle — Draws a rectangle with specified dimensions.

• draw circle — Draws a circle with a given radius.

Touch - Detect screen interactions.

• screen pressed? — Returns whether the screen is currently being pressed.

• screen position — Retrieves the x and y coordinates where the screen was last touched.

• when screen event — Triggers when the screen is pressed or released.

Cursor Print

print

The print block displays text on the controller’s screen at the current cursor position and font.

print stack block

    print [VEXcode] on screen ▶

Parameters	Description
value	The text, number, or variable value to display on the screen.
expanding arrow	Expand the block to read and set cursor to next row and make the cursor move to the next row after this block.

Example

When started, displays the message ‘Hello, drone!’ at the starting cursor position on the screen.

    when started :: hat events
    [Display a message at the starting cursor position.]
    print [Time to fly!] on screen ▶

set cursor to row column

When using the set cursor to row column block, the cursor is placed at a specific row and column on the screen. The amount of characters that can fit on a screen depends on the selected font. The font size can be changed using the set font block. With the default monospaced medium font, up to 18 rows and 53 columns can be displayed clearly. Text placed beyond this range may be cut off or become difficult to read.

Set cursor stack block

    set cursor to row [1] column [1] on screen

Parameters	Description
row	The row of the cursor.
column	The column of the cursor.

Examples

When started, moves the cursor to row 7, column 25 on the screen and prints ‘Row 7, Column 25’.

    when started :: hat events
    [Display text starting at Row 7 Column 25.]
    set cursor to row [7] column [25] on screen
    print [Row 7, Column 25] on screen ▶

set cursor to next row

The set cursor to next row block moves the cursor to column 1 on the next row on the controller’s screen.

set cursor to next row stack block

    set cursor to next row on screen

Parameters	Description
	This block has no parameters.

Example

When started, prints ‘Line 1’ on the screen, moves the cursor to the next row, and then prints ‘Line 2’.

    when started :: hat events
    [Display two lines of text.]
    print [Line 1] on screen ▶
    set cursor to next row on screen
    print [Line 2] on screen ▶

clear row

The clear row block clears a row of text on the controller’s screen.

Clear row stack block

    clear row [1] on screen

Parameters	Description
row	The row number to clear.

Example

When started, prints text on two rows. The first row remains, while the second row disappears after 3 seconds.

    when started :: hat events
    [Display text on two rows.]
    print [This text stays] on screen ▶
    set cursor to next row on screen
    print [This text disappears] on screen ▶
    wait [3] seconds
    clear row [2] on screen

screen cursor column

The screen cursor column returns the cursor’s current column position.

screen cursor column reporter block

    (screen cursor column)

Parameters	Description
	This block has no parameters.

Example

When started, moves the cursor to row 7, column 25 on the screen and prints the current cursor column number.

    when started :: hat events
    [Display the cursor's current column.]
    set cursor to row [7] column [25] on screen
    print (screen cursor column) on screen ▶

screen cursor row

The screen cursor row block returns the cursor’s current row position.

screen cursor row reporter block

    (screen cursor row)

Parameters	Description
	This block has no parameters.

Example

When started, moves the cursor to row 7, column 25 on the screen and prints the current cursor row number.

    when started :: hat events
    [Display the cursor's current row.]
    set cursor to row [7] column [25] on screen
    print (screen cursor row) on screen ▶

XY Print

print at

The print at block displays text on the controller’s screen at a specific (x, y) position in pixels, using the currently set font. x sets how far from the left side the text begins, and y sets where the bottom of the letters sit. This method disregards the current cursor position.

print at stack block

    print [VEXcode] at x:[80] y:[120] on screen

Parameters	Description
value	The text, number, or variable value to display on the screen.
x	The x-coordinate in pixels (0 to 640, where 0 is left and 640 is right).
y	The y-coordinate in pixels (0 to 480, where 0 is top and 480 is bottom).

Example

When started, displays the message ‘Hello, drone!’ in the center of the screen.

    when started :: hat events
    [Display a message starting in the middle of the screen.]
    print [Hello, drone!] at x:[320] y:[240] on screen

set screen origin

The set screen origin sets the origin (0, 0) used for drawing or printing on the controller’s screen. By default, drawing or printing blocks consider the top left corner of the screen as the origin. This block can reset the origin to an alternate (x, y) screen coordinate location.

set screen origin stack block

    set screen origin x:[0] y:[0]

Parameters	Description
x	The x-coordinate in pixels to set the new origin to.
y	The y-coordinate in pixels to set the new origin to.

Example

When started, sets the screen origin to (320, 240) and draws a rectangle at the new origin with top-left corner at (0,0), width 80 pixels, and height 40 pixels.

    when started :: hat events
    [Set the origin to the center of the screen.]
    set screen origin x:[320] y:[240]
    [Draw a rectangle at the new origin.]
    draw rectangle [0] [0] [80] [40] on screen

Settings

clear screen

The clear screen block clears the controller’s screen of all drawings, text, and images.

clear screen block

    clear screen

Parameters	Description
	This block has no parameters.

Example

When started, draws a circle with center (120,120) and radius 40 pixels. After 2 seconds, the screen is cleared.

    when started :: hat events
    [Draw a circle, and clear it after 2 seconds.]
    draw circle [320] [240] [80] on screen
    wait [2] seconds
    clear screen

wait for screen to render

The wait for screen to render block prevents any following screen blocks from displaying and then shows all of their output at once when it is used again.

Note: Using this block changes the project so that all subsequent screen blocks will remain hidden until the wait for screen to render block is used again.

    wait for screen to render

Parameters	Description
	This block has no parameters.

Example

When started, draws a circle with center (120,120) and radius 40 pixels. After 2 seconds, the screen is cleared.

    when started :: hat events
    [Display text and images when button 7 is pressed.]
    wait for screen to render
    print [Screen rendered!] on screen ▶
    draw circle [320] [240] [80] on screen
    wait until <controller button [7 v] pressed?>
    wait for screen to render

fill screen

The fill screen block clears the controller’s screen of all drawings and text, then changes the background to a specified color.

The fill screen block

    fill screen with [red v]

Parameters	Description
color	The color to change the background to: red green blue black white yellow orange purple cyan

Example

    when started :: hat events
    [Say "Hello" then turn screen green.]
    print [Hello] on screen ▶
    wait [2] seconds
    fill screen with [green v]

set font

The set font block sets the font and size used for displaying text on the controller’s screen. This font will apply to all subsequently printed text.

set font stack block

    set font to [monospaced v] [medium v] on screen

Parameters	Description
type	The font type: monospaced proportional
size	The font size (shown below): super small extra small small medium large extra large super large

monospaced super small	monospaced extra small	monospaced small
monospaced medium	monospaced large	monospaced extra large
monospaced super large	proportional small	proportional medium
proportional large	proportional extra large	proportional super large

Example

When started, sets the font to ‘monospaced extra large’ and prints ‘VEX’ on the screen.

    when started :: hat events
    [Display text using a larger font.]
    set font to [monospaced v] [extra large v] on screen
    print [VEX] on screen ▶

set print precision

The set print precision block sets the precision formatting used for displaying numbers on the controller’s screen. This print precision will apply to all subsequently printed numbers.

set print precision stack block

    set print precision to [0.1 v] on screen

Parameters	Description
precision	Sets the print precision to: 1 0.1 0.01 0.001 All Digits

Example

When started, sets print precision to two decimal places and prints 1/3 as 0.33 on the screen.

    when started :: hat events
    [Print 1/3 as 0.33.]
    set print precision to [0.01 v] on screen
    print ([1] [math_division v] [3]) on screen ▶

set pen width

The set pen width block sets the pen width used for drawing lines and shapes.

set pen width block

    set pen width to [10] on screen

Parameters	Description
width	The pen width in pixels.

Example

When started, sets the pen width to 10 pixels and draws a rectangle with the top-left corner at (50,50), width 130 pixels, and height 60 pixels.

    when started :: hat events
    [Draw a rectangle with a pen width of 10.]
    set pen width to [10] on screen
    draw rectangle [200] [200] [200] [80] on screen

set pen / font color

The set pen / font color block sets the pen color used for drawing lines, shapes, and text on the controller’s screen. The default color is white.

set pen font color

    set pen / font color to [red v] on screen

Example

Parameters	Description
color	Sets the pen color to: red green blue black white yellow orange purple cyan transparent

When started, sets the pen color to red and draws a rectangle with the top-left corner at (50, 50), width 130 pixels, and height 60 pixels.

    when started :: hat events
    [Draw a rectangle with an orange outline.]
    set pen / font color to [orange v] on screen
    draw rectangle [200] [150] [240] [150] on screen
    set pen / font color to [white v] on screen
    print [VEXcode AIR] at x: [250] y: [220] on screen

set fill color

The set fill color block sets the color used to fill shapes when they are drawn. The default fill color is black.

set fill color stack block

    set fill color to [red v] on screen

Parameters	Description
color	Sets the fill color to: red green blue black white yellow orange purple cyan transparent

Examples

When started, sets the fill color to orange and draws two rectangles. The first is at (50, 50), and the second is at (50, 130), both with a width of 100 pixels and a height of 60 pixels.

    when started :: hat events
    [Draw an orange-filled rectangle with text on top.]
    set fill color to [orange v] on screen
    draw rectangle [200] [150] [240] [150] on screen
    print [VEXcode AIR] at x: [250] y: [220] on screen

Draw

show image file

The show image file block draws a custom user-uploaded image on the controller’s screen at the set origin.

show user image stack block

    show image file [IMAGE1 v]

Parameters	Description
image number	The user-uploaded image to use. Options will change if image names are edited in the Control Panel.

Example

todo

    when started :: hat events
    [Display custom image on screen.]
    show image file [IMAGE1 v]

draw pixel

The draw pixel block draws a pixel at the specified (x, y) screen coordinate in the current pen color.

draw pixel stack block

    draw pixel [0] [0] on screen

Parameters	Description
x	The x coordinate to draw the pixel, ranging from 0 to 640.
y	The y coordinate to draw the pixel, ranging from 0 to 480.

Example

When started, draws a pixel at the center of the screen at coordinates (120, 120).

    when started :: hat events
    [Draw five pixels in a diagonal.]
    draw pixel [360] [200] on screen
    draw pixel [340] [220] on screen
    draw pixel [320] [240] on screen
    draw pixel [300] [260] on screen
    draw pixel [280] [280] on screen

draw line

The draw line block draws a line from the first specified screen coordinate (x1, y1) to the second specified screen coordinate (x2, y2) using the current pen width and pen color.

draw line stack block

    draw line [0] [0] [10] [10] on screen

Parameters	Description
x1	The x coordinate in pixels of the start of the line, ranging from 0 to 640.
y1	The y coordinate in pixels of the start of the line, ranging from 0 to 480.
x2	The x coordinate in pixels of the end of the line, ranging from 0 to 640.
y2	The y coordinate in pixels of the end of the line, ranging from 0 to 480.

Example

When started, draws a diagonal line from the top-left corner (0,0) to the bottom-right corner (240,240) of the screen.

    when started :: hat events
    [Make an X across the screen.]
    draw line [0] [0] [640] [480] on screen
    set pen / font color to [cyan v] on screen
    draw line [0] [480] [640] [0] on screen

draw rectangle

The draw rectangle block draws a rectangle using the current pen width, pen color, and fill color.

draw rectangle block

    draw rectangle [0] [0] [10] [10] on screen

Example

Parameters	Description
x	The x coordinate in pixels of the top-left corner of the rectangle, ranging from 0 to 640.
y	The y coordinate in pixels of the top-left corner of the rectangle, ranging from 0 to 480.
width	The width of the rectangle in pixels.
height	The height of the rectangle in pixels.

When started, draws a rectangle on the screen with the top-left corner at (50,50), width of 130 pixels, and height of 60 pixels.

    when started :: hat events
    [Draw two rectangles on the screen.]
    draw rectangle [0] [0] [620] [460] on screen
    set fill color to [green v] on screen
    draw rectangle [200] [180] [200] [100] on screen

draw circle

The draw circle block draws a circle using the current pen width, pen color, and fill color.

draw circle stack block

    draw circle [0] [0] [10] on screen

Parameters	Description
x	The x coordinate in pixels of the center of the circle, ranging from 0 to 640.
y	The y coordinate in pixels of the center of the circle, ranging from 0 to 480.
radius	The radius of the circle in pixels.

Example

When started, draws a circle on the screen with the center at (120,120) and a radius of 40 pixels.

    when started :: hat events
    [Draw one green circle on the screen.]
    set fill color to [green v] on screen
    draw circle [320] [240] [200] on screen

Touch

screen pressed?

The screen pressed? block reports if the controller’s screen is currently being pressed or not pressed. This block returns a Boolean value:

• True - Screen is currently being pressed

• False - Screen is not being pressed

screen pressed boolean block

    <screen pressed?>

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Play a sound when the screen is pressed.]
    forever
    if <screen pressed?> then
    play note [low v] [C v] [note_eight v] ▶

screen position

The screen position block returns an integer showing the x- and y-coordinate (in pixels) where the screen was pressed. The return value for x is between 0 (left) and 640 (right). The return value for y is between 0 (top) and 480 (bottom).

screen position reporter block

    (screen [x v] position)

Parameters	Description
coordinate	The coordinate of the last screen press in pixels: x - The horizontal position y - The vertical position

Example

When started, continuously checks for screen presses. If pressed, clears the screen and prints the x- and y-coordinates of the touch position.

    when started :: hat events
    [Play high or low note based on where screen is pressed.]
    forever
    if <screen pressed?> then
    if <(screen [x v] position) [math_greater_than v] [320]> then
    play note [high v] [C v] [note_eight v] ▶
    else
    play note [low v] [C v] [note_eight v] ▶

when screen event

The when screen event block is called when the controller’s screen is pressed or released.

When screen event hat block

    when screen [pressed v] :: hat events

Parameters	Description
action	Determines when the attached stack of blocks will run: pressed released

Example

    when screen [pressed v] :: hat events
    [Play a sound when the screen is pressed.]
    play sound [success v] ▶