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Shadows

A shadow is an image painted underneath, and offset from, a graphics object such that the shadow mimics the effect of a light source cast on the graphics object, as shown in Figure 7-1. Text can also be shadowed. Shadows can make an image appear three dimensional or as if it’s floating.

Shadows have three characteristics:

• An x-offset, which specifies how far in the horizontal direction the shadow is offset from the image. Positive values indicate rightward displacement, and negative values indicate leftward displacement.

• A y-offset, which specifies how far in the vertical direction the shadow is offset from the image. Positive values indicate upward displacement, and negative values indicate downward displacement.

• A blur value, which specifies whether the image has a hard edge, as seen in the left side of Figure 7-2, or a diffuse edge, as seen in the right side of the figure.

This chapter describes how shadows work and shows how to use the Quartz 2D API to create them.

Contents:

How Shadows Work
Painting With Shadows

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