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:
“How shall a man escape from his ancestors, or draw off from his veins the black drop which he drew from his father’s or mother’s life?”
—Ralph Waldo Emerson (1803–1882)
“We saw one schoolhouse in our walk, and listened to the sounds which issued from it; but it appeared like a place where the process, not of enlightening, but of obfuscating the mind was going on, and the pupils received only so much light as could penetrate the shadow of the Catholic Church.”
—Henry David Thoreau (1817–1862)