image_alpha

This variable is used to get or to set the alpha value for the sprite. Alpha is always calculated as a value between 0 and 1 where 0 is completely transparent and 1 is completely opaque. Please note that for changes in this variable to be visible, the instance should have either no draw event (and so GameMaker will default draw the sprite) or be drawn using one of the extended drawing functions like draw_self or draw_sprite_ext.

Syntax:

image_alpha

Returns:

Real

Example:

image_alpha = clamp(image_alpha - 0.01, 0, 1);

The above code will slowly reduce the image_alpha until it reaches 0.