Web File Formats

1
Web File Formats

• Weinman, chapter 10
• Bitmap vs. Vector,Compression algorithms (lossy,
  lossless), common formats (GIF, JPEG, PNG),
  Digital Watermarks

2
Bitmap vs. Vector
3
Web Formats

• gif and jpeg are bitmap formats, so vector
  graphics (like png) must be rasterized for the
  Web
• When you rasterize, set height and width so you
  dont have to resize on Web page

4
Compression Algorithms
5
GIF vs JPEG
6
Animated GIFs

• Can create them in Fireworks Photoshop
• GIF supported by all browsers
• Plays a series of bitmaps at set speed
• Developer can control the number of repetitions
  speed
• Best for simple animations (use Flash for complex
  animations, interaction, and Web interfaces)

7
PNG

• Cross platform, but not fully supported by Web
  browsers
• Lossless
• Multiple options for bit depth
• Gamma correction based on platform
• Variable transparency (alpha channel
  transparency)

8
Digital watermarks

• Allow artist to mark image

9
SVG

• Vector format
• Shapes are described in XML code, so download is
  quick
• May become the standard for portable wireless
  devices

10
SWF

• Small Web File - Flash format
• Vector - small file size scales nicely
• Supports MP3 audio complex animation
• Allows interactivity through scripting, so can be
  used for interaction and interfaces
• Requires plug-in
• distributed with Browsers
• Most users have plug-in, but may have old version

11
WBMP

• Wireless Bitmap
• 1-bit (black and white)
• Used with Wireless Markup Language (WML) to
  deliver graphics to wireless devices (cell
  phones, PDAs)
• Not compressed
• Limited to less than 90 x 24 pixels