1. Vector-drawn images versus bitmaps (continued) -Vector images cannot be used for photorealistic images. -Vector images require a plug-in for web-based display. -Bitmaps are not easily scalable and resizable. -Bitmaps can be converted to vector images using autotracing.
2. Colors and Palettes in Multimedia
2.1. -Additive color In the additive color method, a color is created by combining colored light sources in three primary colors - red, green, and blue (RGB). TV and computer monitors use this method. -Subtractive color In the subtractive color method, color is created by combining colored media such as paints or ink. The colored media absorb (or subtract) some parts of the color spectrum of light and reflect the others back to the eye.
2.2. Color palettes -Palettes are mathematical tables that define the color of pixels displayed on the screen. Palettes are called “color lookup tables,” or CLUTs, on the Macintosh. The most common palettes are 1-, 4-, 8-, 16-, and 24-bits deep.
3. Image File Types Used in Multimedia -Macintosh formats -Windows formats -Cross-platform formats
3.1. Macintosh formats -On the Macintosh, the most commonly used format is PICT. -PICT is a complicated and versatile format developed by Apple. -Almost every image application on the Macintosh can import or export PICT files. -In a PICT file, both vector-drawn objects and bitmaps can reside side by side.
3.2. Windows formats -The most commonly used image file format on Windows is DIB, also known as BMP.
3.3. Cross-platform formats JPEG, GIF, and PNG – Most commonly used format on the Web Adobe Portable Document Format (PDF) – Manages multimedia content PSD, AI, CDR, DXF – Proprietary formats used by applications Initial Graphics Exchange Standard (IGS or IGES) – Standard for transferring CAD drawings
4. Making Still Images -Still images may be the most important element of a multimedia project -Still images may be small or large, or even full screen. They may be colored, placed at random on the screen, evenly geometric, or oddly shaped. -Still images are generated in two ways: *Bitmaps (raster) *Vector-drawn graphics -Bitmaps editors are called painting program, vector editors are called drawing program. -Bitmaps -Capturing and editing images -Image editing programs enable the user to:Enhance and make composite images
5. Vector Drawing *Vector-drawn graphics -Applications of vector-drawn object -How vector-drawn images work -Vector-drawn images versus bitmaps
6. Vector-drawn images are used in the following areas: -Computer-aided design (CAD) programs needed by architects and engineers -Graphic artists designing for the print media -3-D animation programs – changes of position, rotation, and shading of light -Applications requiring drawing of graphic shapes
