Autotek autocad raster design 2010 用户手册

Changing the pixel depth is useful because it allows you to manipulate file
size or add colors to the palette. Decreasing pixel depth decreases the number
of colors that can be displayed, and decreases the file size of the image.
Likewise, increasing pixel depth increases the number of colors that can be
displayed and increases the file size.

The following table shows the depth conversions supported by the idepth
command:

Yes

Yes

Yes

N/A

Bitonal

Yes

Yes

N/A

Yes

Indexed Color

Yes

N/A

N/A

Yes

Grayscale

Yes

True Color

N/A

Yes

True Color

In most cases, when you convert an image for which you have already specified
a transparency color, the transparency color is maintained. However, there
are two exceptions:

■

When converting to a bitonal image, transparent pixels are OFF if
transparency is enabled. If transparency is disabled, transparent pixels are
treated the same as other pixels.

■

When converting to grayscale, a transparent color is mapped to its
corresponding gray value, whether transparency is ON or OFF.

1 Click Image menu  ➤  Image Processing  ➤  Change Color Depth.

2 Select the image or images you want to change, and then press Enter.

NOTE You can also select your image or images before you select the Change
Color Depth command.

3 Choose a color depth and press Enter.

NOTE You can adjust the pixel depth of multiple images if all selected images
have the same pixel depth.

Convolving an Image | 117