In computer graphics, a drop shadow is a visual effect consisting of drawing that looks like the shadow of an object, giving the impression that the object is raised above the objects behind it. The drop shadow is often used for elements of a graphical user interface such as windows or menus, and for simple text. The text label for icons on desktops in many desktop environments has a drop shadow, as this effect effectively distinguishes the text from any colored background it may be in front of.
A simple way of drawing a drop shadow of a rectangular object is to draw a gray or black area underneath and offset from the object. In general, a drop shadow is a copy in black or gray of the object, drawn in a slightly different position. Realism may be increased by:
- Darkening the colors of the pixels where the shadow casts instead of making them gray. This can be done with alpha blending the shadow with the area it is cast on.
- Softening the edges of the shadow. This can be done by adding Gaussian blur to the shadow's alpha channel before blending.
Famous quotes containing the words drop and/or shadow:
“The pipe, with solemn interposing puff,
Makes half a sentence at a time enough;
The dozing sages drop the drowsy strain,
Then pause, and puff—and speak, and pause again.”
—William Cowper (1731–1800)
“It is the same for all men. None of us can escape this shadow of the father, even if that shadow fills us with fear, even if it has no name or face. To be worthy of that man, to prove something to that man, to exorcise the memory of that man from every corner of our life—however it affects us, the shadow of that man cannot be denied.”
—Kent Nerburn (20th century)