Change X by ()
change x by ()
Category Motion
Type Stack

The Change X by () block is a Motion block and a Stack block. The block moves its sprite costume center's X position by the specified amount. The x axis ranges from -240 to 240.

Example Uses

  • Often in games, the player controls a sprite and moves it around — the Change X by () block (and the Change Y by () block) are very common in this event.
when gf clicked
forever
    if <key (left arrow v) pressed?> then
        change x by (-5)
    end
    if <key (right arrow v) pressed?> then
        change x by (5)
  • This block can also be used to move a sprite which creates a sine wave (see Trigonometry) along the x axis. An example script of this situation is:
when gf clicked
go to x (-240) y (([sin v] of (-240)) * (100)) //240 is the leftmost position of the stage
erase all //clears a previously drawn wave if it exists
pen down //draws the first point of the wave
repeat (480) //the width of the stage is 480 x coordinates
    pen up //so the movement to the next position is not interfered with an unintended, out-of-place line
    change x by (1) //the use of the block
    set y to (([sin v] of (x position)) * (100)) //the result is multiplied by "100" to expand the amplitude for visual preference
    pen down //creates the mark

Workaround

Main article: List of Block Workarounds

This block can be replicated with either of the following codes:

set x to ((x position) + (change))
go to x: ((x position) + (change)) y: (y position)

See Also