ES 101. Module 14 Other Graphics File Formats

Last Lecture(s)

• Color Pallettes• Graphics Interchange Format - GIF• Joint Photographic Experts Group – JPEG• Tagged Image File Format – TIFF

This Lecture

• More Graphical Image Formats– Bitmapped Images – BMP

– Portable Network Graphics – PNG

– Windows Icon – ICO

– Photo CD – PCD

– Paintbrush – PCX

– and other miscellaneous formats

• Graphics viewers– Web browsers

– OLE applications

– Windows accessories

This Lecture (cont’d)

• Graphics editors– Paint Shop Pro vs. Adobe Photoshop

• Image Capture– Scanning

Bit Mapped Image - BMP

• BMP is the native Microsoft Windows’ format• It can be used for wallpapers, backgrounds, and

other graphics• BMP files describe an image at the bit, or pixel,

level and are generally not compressed– As a result, BMP files tend to be large

• This makes them unsuitable for web pages

Why aren’t BMP Images Compressed?

• They weren’t designed for transmission via a network

• They were designed to be used by the OS to refresh a video display– Transmission time was not a consideration

– In general the back plane of the PC and the video graphics circuitry provide very high performance

BMP Internals

• As in all other graphics formats, a BMP file contains a header which describes the file, containing:– Dimensions in pixels– Color depth– Compression type– Number of colors actually used in the bit map– Number of colors considered important in the bit map

• The last sub-bullet deals with the problem of using a monitor that can’t display the full color palette

• The video card knows which colors can be “thrown away”– This is different for each image

BMP Color Depth

• BMPs can have 1, 4, 8, or 24 bit color depth• For every level except the 24-bit, the information

header defines the color palette– The main file consists of a string of indexes to the

palette

• For 24-bit color depth, no palette is required– Full color information is provided for each pixel

So, for a 1024 X 768 BMP, and 24-bit depth, howbig would the image file be?

18.9 Megabits!

BMP Compression

• Only 4 and 8 bit images can be compressed• BMP uses a lossless compression technique called

Run Length Encoding (RLE), which is quite different from GIF and JPEG– It replaces strings of identical bytes with a token

indicating how many bytes of what color were replaced

– This is a lossless technique

• To decompress the data, you expand the tokens

Device Independent Bit Maps - DIB

• Sometimes BMPs are referred to as a “Device Independent Bitmap”

• All BMPs are device independent, since they are stored in such a way that they can be displayed on any monitor

Creating BMPs

• MS Paint can create simple BMPs• Most other graphics editors can as well, but MS

Paint is included with your OS

Other BMP Information

• There are many sources of BMPs on the web, since they are most times used for wallpapers– Google “BMP” and cruise around

• You can also find a lot of specs and more detailed descriptions on the web

Portable Network Graphics - PNG

• As mentioned previously, the PNG format is now appearing on the web

– Replacing GIF due to legal problems with the compression algorithm licensing

• PNG is pronounced “ping”• It offers much greater color depth, and an improved

grayscale– 48 bit color depth

• Slightly better data compression than GIF, although not as good as JPEG

• Better interlacing and transparency

Windows Icon - ICO

• If you want to fool around with the icons and title bars of your desktop, you can develop your own icons

• An icon is a 4-bit, 32 X 32 pixel image stored in ICO format

• ICOs can have a transparent color that adapts to the color selected for your screen

• To create ICOs, you have to have an icon editor

Photo CD - PCD

• If you go to a film processor, you have the option of receiving a CD of your photos– These are not JPEGs, but PCDs

• The PCD format was invented by Kodak, and yields the highest possible image quality– Much higher than ordinary desktop scanners

– PCDs are scanned directly from film

• One CD-ROM can hold about 100 photographs

• You normally don’t need this quality for a web site– The image would take forever to load

PCD Internals

• When a photo is scanned, each image is digitized at six resolution levels– 128 X 192 pixels, up to– 4096 X 6144 pixels

• The highest resolution image contains so much detail that it is nearly indistinguishable from the original photo

• Each PCD file contains the entire range of resolution levels for a single picture

• Most fully featured graphics viewers and editors can handle the PCD format, but it can go slowly– Paint Shop Pro

Other File Formats

Format Source

ART PFS First PublisherCDR CorelDrawCGM Computer Graphics metafileCLP Windwos ClipboardCPT Corel PhotopaintCUT Dr. HaloDXF AutodeskEPS Adobe PostscriptHPGL Hewlett PackardIMG GemPaint, Ventura PublisherLBM Deluxe PaintMAC MacpaintMSP Microsoft PaintPSD PhotoshopRAS Sun MicrosystemsTGA TrueVision TargaWMF Windows MetagraphicsWPG WordPerfect

Compression and Encoding

• Sometimes you download an image file from email or the Internet, and it has been either encoded and/or compressed for transmission

• It this case, you must decode/expand the file before you can access the image file itself– Most times the file has been “zipped” and must

therefore be “unzipped”

• Be aware that these compression techniques achieve very little reduction in file size if you have already used a compression technique

Unknown File Format

• What do you do if you receive a graphic from a source, but do not know the file format– First, look at the file extension

• Example: .pps is the format for Paint Shop Pro

• Open the file with a text editor like Notepad– It will look like gibberish

– However, the beginning of the file may have some revealing information

• GIF Files contain “GIF89a”

• JFIF Files contain “JFIF”

• BMP Files contain “BM”

Graphics Viewers

• Web browsers– All will open GIFs and JPEGs– You can open local files on your hard drive

• Office applications– Object Linking and Embedding (OLE) compatible– OLE is a feature of many MS Windows applications that allow

insertion of “foreign files”– This is done by the “Inserf: Object” command

• Windows accessories– Paint – BMP and PCX files– WordPad – OLE client

Graphics Editors

• Graphics editors allow you to view, crop, resize, convert, and add text and other effects to an image

• There are two workhorse applications that are widely used– JASC Paint Shop Pro - $105

– Adobe PhotoShop - $650

• As can be seen, PSP is the least expensive– However, you get a very sophisticated editor for the money

• So, let’s take a look at Paint Shop Pro

What can PPS do?

• Create new graphics from scratch

• View and edit existing graphics formats

• Retouch photos

• Capture graphics from your computer screen– Screen “scrape”

– Useful for importing graphics from Adobe “pdf” documents into MS Office applications

• Convert between graphical file formats

• Create animated GIFs, using JASC Animation Pro– All for only $105!!

Basic PPS Editing Tools

• Resizing• Cropping• Flipping• Rotating• Adjusting colors• Increasing and decreasing color depth

Web Sites

• By now, you should have created your web site, and gotten it hosted on the “webdev” server

• The requirements are as previously stated– Frames page with 3 frames– 10 subpages– Content of your choice

• However, you must be willing to publish this work on the web• No improper content

• Those of you who are working on existing web sites must rehost your web on the server in order to receive a grade– These web sites will be archived in the VSC-IT library at the end

of the semester as examples of your work

Web Sites (cont’d)

• If you don’t rehost your existing web site, or fail to create a web site on the “webdev” server, I will not be able to give you a grade, since this is the only work that you will do this semester– You will receive a grade of “incomplete” or “I”– At the point in time that you meet the requirements of the class, I

will fill out a grade card to change your grade

• It is my intention to have a design jury for these web sites and rank the web sites accordingly– “Best in Show”– Most creative theme– etc.

Next Lecture(s)

• Paint Shop Pro• Animated GIFs• Semester wrapup