CISC 110Day 3

Introduction to Computer Graphics

Outline

• Raster and Vector Graphics

• RGB Color Model

• Geometric Transformations

• Animation

• Tweening

• Masks

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Vector Graphics

Vector graphics is the use of geometrical primitives, such as points, lines, curves, and shapes or polygons, which are all based upon mathematical equations, to represent images in computer graphics.

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Vector Graphics

To draw a circle, a program needs to know the radius, the location of the center point, the line style and color, and fill style and color.

More complex shapes can be created with Bézier curves. 4

Raster Graphics

In computer graphics, a raster graphics image, or bitmap, is a generally rectangular grid of pixels, or points of color.

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Vector vs. Raster Graphics

Raster images are based on pixels and thus scale with loss of clarity, while vector-based images can be scaled indefinitely without degrading.

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RGB Color Model

The RGB color model is an additive color model in which red, green, and blue light are added together to produce a wide range of colors.

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RGB Color Model

An RGB image, along with its separate R, G and B components

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Numerical Representation

A color in the RGB color model is described by indicating how much of each of the red, green, and blue is included. The color is expressed as an RGB triplet (r,g,b), each component of which can vary from zero (no light) to a defined maximum value (usually 255). 9

Geometric Transformations

A translation moves every point of a figure or a space by the same amount in a given direction.

A rotation is a progressive radial orientation to a common point. That common point lay within the axis of that motion.

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Animation

Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement.

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Traditional Cell Animation

Transparent cels, each with a different character drawn on them, and an opaque background are photographed together to form the composite image.

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Tweening

Inbetweening or tweening is the process of generating intermediate frames between two images (key frames) to give the appearance that the first image evolves smoothly into the second image.

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Motion, Shape & Color Tweening

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Masks

A mask provides a hole through which underlying layers show, so that you can limit the area of the layers that is visible.

CISC 110 Week 1 Flash 15