The formats you can save to depend on the format
(pixel or vector) in which the image was originally saved. Regarding
images stored in a
temporary folder, note that you can save them only in BMP
format on Windows and UNIX. |
For
pixel images, the formats are:
- Adobe Photoshop Format (*.psd)
- Apple Macintosh File Format (*.pic)
- Amiga IFF (*.iff)
- CALS Group 4 (*.cals)
- HP/RTL (UNIX only)
- JPEG Fair Quality (*.jpg)
- JPEG Medium Quality (*.jpg)
- JPEG High Quality (*.jpg)
- PNG (Portable Network Graphics) (*.png)
- Silicon Graphics File (*.rgb)
- Sun Raster File (*.ras)
- TIFF CCITT Group 4 (*.tif)
- TIFF True Color (*.tif)
- TIFF Indexed Packbit (*.tif)
- TIFF True Color Packbit (*.tif)
- TIFF Indexed (*.tif)
- TIFF Grey Scale Packbit (*.tif)
- TIFF BW Packbit (*.tif)
- Truevision Targa (*.tga)
- RGB (SGI Format) Not Compressed (*.rgb)
- ZSoft Paintbrush (*.pcx)
- Windows Bitmap (*.bmp)
- X-Window Pixmap (*.xpm)
- X-Window Dump (*.xwd).
For detailed information about JPG and TIFF format, browse the
following Internet sites:
http://www.jpeg.org
and http://www.ijg.org
http://partners.adobe.com/asn/developer/pdfs/tn/TIFFphotoshop.pdf
|
A bitmap is a
set of pixels arranged in lines and columns and is fully described
by its width and height, its color depth (bits per pixel) and its
compression scheme. The common format is true color (24 bits
per pixel). An additional color component, called Alpha component,
may be used to define the transparency of each pixel. The bitmap
format generally supports compression (either lossless or lossy).
Some of these bitmaps are coded on 8 bits and the pixels are
indexed on a color table, called the palette. The advantage of
bitmap files is that they can reproduce complex scenes (for
instance photographic or photo-realistic images) that could not be
reproduced using basic geometrical shapes. |
The following table summarizes information about
bitmap files and the various formats you can use to save your
images in the album: |
|
Bit depth |
Compression |
Max. size
in pixels |
Comments |
1 |
8 |
16 |
24 |
32 |
None |
RLE |
JPEG |
ZLIB |
CCITT |
BMP |
X |
X |
X |
X |
X |
X |
X |
|
|
|
2G*2G |
Standard bitmap storage on
MS-Windows |
JPEG |
X |
X |
X |
X |
|
|
|
X |
|
|
64K*64K |
Very few applications support the
lossless JPEG mode |
PNG |
X |
X |
X |
X |
X |
|
|
|
X |
|
2G*2G |
Successor of the GIF format |
RGB |
X |
X |
X |
X |
X |
X |
X |
|
|
|
64K*64K |
Supported by very few applications |
TIFF |
X |
X |
X |
X |
X |
X |
X |
|
|
X |
2G*2G |
Very popular and general format
recognized by most imaging applications |
|
For
vector images, the formats are:
- Windows Metafile (Windows only)
|
The following CGM vector formats
are supported:
- CGM
- CGM CALS
- CGM ATA
- CGM Graphic Software.
CGM (Computer Graphics Metafile) is an ANSI/ISO standardized
platform-independent format used for the interchange of vector and
bitmap data.
Version 5 supports the CGM Version 1 and Version 3 standards. CGM
Version 3 adds vector primitives such as Bezier and Nurbs, improved
font and text support as well as bitmap compression.
The CGM-ATA and CGM-CALS profiles which are specific subsets of the
Version 3 standard are also supported.
For detailed information about CGM formats, browse the following
Internet site:
http://www.cgmopen.org
|
Vector files contain geometrical descriptions of
the image elements.These elements may be lines, dots, rectangles,
circles, polygons, splines, text with font information or bitmaps
(only in metafiles) and are used to reconstruct the final image.
Each element has its own attributes specifying its size, its
relative position in the whole image, its color and filling type.
The advantage of vector files over bitmap files is that image
scaling does not affect image appearance. When zooming bitmap
files, pixels become visible as shown in the example below: |
Vector image |
Bitmap image |
|
|
|
The table below summarizes the purposes of the
above mentioned formats: |
Purpose |
Printing/Plotting |
Data Exchange |
Format |
HPGL/2-RTL |
X |
|
PS |
X |
|
EPS |
|
X |
PDF |
|
X |
CGM |
|
X |
|
Note that high quality images require longer
computation time. |