Multimedia in Web Images. A Picture Tells A Thousand Words Forms of Images Photograph Painting...
-
Upload
aleesha-young -
Category
Documents
-
view
214 -
download
1
Transcript of Multimedia in Web Images. A Picture Tells A Thousand Words Forms of Images Photograph Painting...
Multimedia in Web
Images
A Picture Tells A Thousand Words
Forms of ImagesPhotographPaintingSymbolLogoFlagMapDiagram
FunctionsProvide factsExplain a processSet a moodEvoke an ideaPinpoint location Illustrate
relationships
Digitalization & Pixel
Numeric Representation & RGB
16 digits instead of 1009 & AFBase 16 can represent 0 to 255 color
scalesTwo digits of hexadecimal numbers
00 in Hex. 0 in decimalFF in Hex. 255 in decimal
RBG Colors
Color Red Green Blue Hexadecimal ColorBlack 0 0 0 # 00 00 00Red 255 0 0 # ff 00 00
Green 0 255 0 # 00 ff 00Blue 0 0 255 # 00 00 ffWhite 255 255 255 # ff ff ff
Blue-green 0 153 153 # 00 99 99
Color Chart: http://quasar.unl.edu/tutorials/rgb.html
Sample Colors
Color Depth
16-bit vs. 8-bit30,000 colors vs. 256 colorsWeb-safe colors (No longer a concern?)
Compression
PurposeReduce file size for transmissionFast download
JPEG
Photographs From 255 levels of color and brightness to
lower levels Group pixels into blocks. Adjacent and similar
color and brightness block or average Example: The next slide
Example
9 values with 3 different colors for 9 pixels 1 value for the average and 2 values for difference from the average for other colors
A string of values such as #FF3399, #FF3399, #FF3399, #CC3399 … for all 9 pixels #FF3399 as the average, 2 values for other colors differentiating from the average
GIF
For line drawings Reduce color depth of every pixel to 8 bits or
less Repeated colors across a row of pixels are
reduce to the color value, the value of the repetition, other instructions.
Vector Graphics
Web images use bitmapped format or pixel-by-pixel
Collection of lines & shapes defined by mathematical formula (e.g. Flash)
Source of Image
Scanned imageDigital cameraOriginal artworkWeb siteCD-ROMClip artStock photograph
Photoshop
Explore editing, compressing, & saving for Web
Image & HTML
IMG tagLinking with imageImage map