Autodesk 057B1-41A111-1001 - AutoCAD LT 2010, Руководство пользователя

Страница: 512 / 574

images with vector files, including scanning documents, faxes, or microfilm
drawings; using aerial and satellite photographs; using digital photographs;
creating effects such as watermarks and logos; and adding computer-rendered
images.
Overview of Raster Images
Raster images consist of a rectangular grid of small squares or dots known as
pixels. For example, a photograph of a house is made up of a series of pixels
colorized to represent the appearance of a house. A raster image references
the pixels in a specific grid.
Raster images, like many other drawing objects, can be copied, moved, or
clipped. You can modify an image with grip modes, adjust an image for
contrast, clip the image with a rectangle or polygon, or use an image as a
cutting edge for a trim.
The image file formats supported by the program include the most common
formats used in major technical imaging application areas: computer graphics,
document management, engineering, mapping, and geographic information
systems (GIS). Images can be bitonal, 8-bit gray, 8-bit color, or 24-bit color.
Images with 16-bit color depth are not supported.
Several image file formats support images with transparent pixels. When image
transparency is set to on, the program recognizes those transparent pixels and
allows graphics in the drawing area to “show through” those pixels. (In bitonal
images, background pixels are treated as transparent.) Transparent images can
be gray-scale or color.
492 | Chapter 11 Share Data Between Files