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Lecture 2

Main components of graphical systems

Graphical devices

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Graphical system: main components

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Graphical Models. Vector Graphics

Vector: a straight line is drawn between the two end-points

Monitors, plotters

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Graphical Models. Vector Graphics

Vector: a straight line is drawn between the two end-points

Monitors, plotters

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Graphical Models. Raster Graphics

Raster: the images are represented as matrices of colored points (pixels).

Modern monitors, printers

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Graphical Models. Raster Graphics

Raster: the images are represented as matrices of colored points (pixels).

Modern monitors, printers

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Vector Model

Vector Model

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Raster Model

Raster Model

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Vector vs. Raster

Raster Insensitive to

scene complexity

Large, but constant

Textured, colored interiors

Very limited

Vector Sensitive to scene

complexity

Variable. Depends on the scene

No. Boundary only

Based on continuous (Euclidean) geometry

Parameters Rendering

Performance Memory and

processing

Filled areas, interior

Transformations

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Vector vs. Raster

Conclusions about Raster Model:

It is supported by the modern displays and laser and ink-jet printers

It provides a better graphical appearance (filled areas)

It is difficult to use raster graphics for precise work (design, medical applications)

Difficulties in performing geometrical transformations The main geometrical primitives such as lines, circles,

polygons, etc. need approximation (scan-conversion)

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Graphical Model. Mixed Model.

Mixed Model: the images contain straight lines and curves which are rasterized eventually, as well as textures and filled areas.

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Input Devices

Mouse and trackball

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Input Devices

Joystick

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Input Devices

Tablet and pen

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Input Devices

Light pen and touch screen

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Input Devices

Space ball and data glove (3D data)

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Input Devices

Scanner, digital camera, camcorder

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Input Devices

3D scanner

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Output Devices

Plotter

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Output Devices

Plotter

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Output Devices

CRT (cathode Ray Tube)

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Output Devices

CRT

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Output Devices

Raster Scan Refresh at least 24 frames/s

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Output Devices

Color CRT

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Output Devices

Color CRT

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Output Devices

Color CRT

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Output Devices

LCD (Liquid Crystal Display)

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Output Devices

Plasma panels

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Output Devices

Ink-jet and laser printers

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Output Devices

Calligraphic (vector) screens