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COS 125

COS 125. Day 13. Agenda. Assignment 3 Due Assignment 4 Posted Due March 25 Left to do 6 Assignments (9 total) About one per week 2 Quizzes Capstone projects Exam #3 will first week of April Castro Chaps 1-10? Today we will look at creating and using images Examples

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COS 125

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  1. COS 125 Day 13

  2. Agenda • Assignment 3 Due • Assignment 4 Posted • Due March 25 • Left to do • 6 Assignments (9 total) • About one per week • 2 Quizzes • Capstone projects • Exam #3 will first week of April • Castro Chaps 1-10? • Today we will look at creating and using images • Examples • http://perleybrook.umfk.maine.edu/samples/imagesplay.htm • http://perleybrook.umfk.maine.edu/samples/bk.htm

  3. Factors to Consider for Web Image • Format • Color • Size/resolution • Speed • Transparency • Animation

  4. Formats • 3 Possibilities • GIF • Version 87a • Older • Version 89a • Transparency and animations • Interlaced or non-interlaced • JPEG • Compressed (variable) • PNG • Optimized or non-optimized palette • Interlaced or non-interlaced

  5. Color • Depth • 24 bit • 16,777,216 possible colors • “true color” • Photo quality • 16 bit • 65,536 colors • 8 bit • 256 colors

  6. Browser Colors • Most Browser cheat! • Lock palette to 256 specifics colors • Because of difference in O/S only 216 colors are Web Safe • http://www.cookwood.com/html/colors/websafecolors.html • Non web safe colors may be dithered or shifted

  7. Size and Resolution • Pixels • Monitors are 70-90 pixels per inch • Printers are >200 ppi • 800 X 600 image • 10X7.5 inches on monitor • 4X3 inches (or less) on printer • The more pixels on a printer means greater detail • The more pixels on a monitor means larger size • Standard SVGA monitors are 800X600 16 bit • XGA monitors are 1024X768 24 bit or better

  8. Speed • How fast can the picture be displayed? • Factors • Size of graphic file • Size of graphic • Color depth • Compression • Interlacing • Sneak peek

  9. How to make graphic load faster • Use the right image format • For Photo realistic use jpeg • Lossy compression • Use Gaussian blur and re-compress • < 256 colors (logos, text, cartoons) • Gif using LZW compression • PNG • Only covert images to web format after all editing is done

  10. Transparency • Only for GIF and PNG • “remove” one color from image • Remove Background to make image non-rectangular • Remove color in image to create special effects

  11. Animations • Animated Gifs • Flash • Both work with frames • Like cartoons • Series of images with slight changes between each image

  12. Where to get images • Buy or download • Scan existing images • Blake library • Digital camera • Blake library • Create using image editing program • Goggle image search

  13. Paint Shop Pro • File >New • Set image size • Set depth • Set background • transparent

  14. Paint Shop Pro • Resizing Images • Image >> resize • Don’t make larger! • Lose detail • If image is twice as big • File is 4 times larger • 4 time slower • Better to use image resizing in XHTML

  15. Creating Transparent GIFS • Save image as GIF • Colors>> Set palette transparency • Set dialog as shown • Select color • Save

  16. Paint Shop Pro • Reduce Color Depth • Colors>>decrease color depth • Make image file smaller • Show images Progressively • Save as • options

  17. Playing with photos • Compressing Images • Image>>blur>>Gaussian blur • Save as jpeg • Select options • Set compression as desired

  18. Creating animated Gifs • Create frames • Slight change between each image • Save as series of images • Image1.gif, image2.gif etc • File>>run animation shop • File>>animation wizard • Add images in order

  19. Gee Whiz Tip of the Day • Creating “Tile”able images for backgrounds • Images must blend on top edge to bottom edge • Images must blend left edge to right • Gradient effects • Use long narrow stripes • Textures • Create squares (100x100) • Cut into four (50X50) • Swap corners • Blend middle

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