User Guide

Basics48
name implies, progressive format
displays an image in stages—as a
series of scans—while the file
downloads. The first scan is a low
quality image; the following scans
improve in quality. This allows the
user to see the whole image very
quickly.
• The HTML Map Options—
National Center for
Supercomputing Applications
(NCSA) Map File, Conseil
Europeén pour la Recherche
Nucléaire (CERN) Map File, and
Client Side Map File—let you
generate an image map. Use the
NCSA Map File or CERN Map
File option to generate a server-
side image map. Use the Client
Side Map File option to generate a
client-side image map.
Refer to “Image Maps” on
page 406 for more information
about image map types.
It is best not to decompress and
recompress a file multiple times.
Although JPEG can compress and
discard data not visible or obvious, the
degradation of the data can affect the
condition of your file.
When a file has lost a significant
amount of data, block patterns can
appear in areas of the image. If you try
to use the Apply Surface Texture
feature on a JPEG file, you may find it
will accent the block patterns.
Saving GIF Files
Corel Painter allows you to save
documents in GIF file format. GIF is
an 8-bit (or less) file format commonly
used to display graphics on the Web.
When you save a file as a GIF, you can
choose from 4 up to 256 colors. You
can choose how your colors will be
displayed and what part of your image
will be transparent.
You can use the Color Set option to
force all colors to match the colors in
the current color set. This option uses
the colors in the color set for the color
table in the GIF file. This can be
useful when doing Web work,
especially if you want to constrain
colors to a specific color set or control
the number of colors in a Web page,
thus controlling image file size. The
default color set in Corel Painter is a
“Web safe” color set, mapping to the
default Netscape Navigator® color
set.
An Imaging Method determines how
your 24-bit Corel Painter document
will be converted to the limited
number of colors that GIF uses. If you
choose Quantize to Nearest Color,
Corel Painter picks the color nearest to
that of each pixel. If you choose
Dither Colors, Corel Painter will
apply a pattern to the colors chosen to
generate a more accurate, less banded
result.
Corel Painter can also save a frame
stack as a GIF animation file. For
more information, refer to “Creating
Animated GIFs” on page410.
If you want your image to have
transparency, click the checkbox for
Output Transparency. Most programs
that display GIF files support
transparency, but for those that don’t,
you should specify the color of the
“transparent” area. If your image will
be displayed on the World Wide Web,