Visualization

Several processing units:

☛ Contains a special purpose processor, called video controller or display controller

☛ Video controller: A fixed area of the system memory is reserved for the frame buffer, and the video controller is given access to the framebuffer memory.

Tow registers are used to store the coordinates of the screen pixels.

The value is stored in the frame buffer for this pixel position is then retrieved and used to set the intensity of the CRT beam Initially the x register is set to 0 and the y register is set to ymax.

Then the x register is incremented by 1, and the process repeated for the next pixel on the top scan line.

The emissive display converts electrical energy into light energy. The plasma panels, thin film electro-luminescent displays are the examples.

When a key is pressed on the keyboard, the keyboard controller places a code carry to the key pressed into a part of the memory called as the keyboard buffer. This code is called as the scan code.

Resource Manager now handles access to all localized resources in an application. Any components that extend UIComponent, Formatter, or Validator now have a new resourceManager property, which lets you easily access the singleton instance of this manager. If you?re writing some other kind of class that needs to use the Resource Manager, you can call Resource Manager. get Instance() to get a reference to it.

The salient feature of computer graphics is the creation and manipulation of graphics (artificial images) by computer.

Computer graphics provides a tool called as motion dynamics which allows user to move object.

☼ It is an inexpensive technique.

☼ It has only four colors.

☼ The quality of the picture is not good when it is compared to other techniques.

☼ It can display color scans in monitors.

They are optical effects to convert the sunlight or light from any other source to graphic form. Liquid crystal display is an example.

The production of the 2D display of the 3D scene is called projection. Project points on the object surface along the parallel lines on to the display plane. Different 2D views of objects can be produced by projecting the visible points.

Done by the projecting points to the display plane along the converging points Causes the objects farther from the viewing point should be smaller of the same sized object present here.

Winding number method is used to check whether a given point is inside or out side the polygon. In this method give a direction number to all the edges which cross the scan line. If the edge starts below the line and ends above scan line give direction as -1 . otherwise1. Fr polygons or two dimensional objects, the point is said to be inside when the value of winding number is nonzero.

The frame buffer used in the black and white system is known as bitmap which take one bit per pixel. For systems with multiple bits per pixel, the frame buffer is often referred to as a pixmap.

Some objects do not maintain a fixed shape, but change their surface characteristics in certain motions or when in proximity to other objects. That is known as blobby objects. Example - molecular structures, water droplets.

❁ They are faster than pen plotters and very high quality printers.

❁ Recent electrostatic plotters include a scan-conversion capability.

❁ Color electrostatic plotters are available. They make multiple passes over the paper to plot color pictures.

Both image and object space operations

Perform the basic function

Surface are sorted in order of decreasing depth

Surface are scan converted in order, starting with the surface of greatest depth

Often referred as painters algorithm

Test listed in the order of increasing difficulty

Surface do not overlap

Projections of the two surfaces on to the view plane do not overlap

Pixel phasing is an antialiasing technique, stair steps are smoothed out by moving the electron beam to more nearly approximate positions specified by the object geometry.

Basically, packages designed for graphics programming contain functions for setting primitives, attributes, and parameters for various graphics operations such as viewing and transformations. Packages designed for applications allow a user to create scenes in terms of the particular application, rather than in terms of graphics functions.

☛ Lightening conditions in the screen

☛ Assigned characteristics

☛ Degree of transparency

☛ How rough or smooth the surfaces are to be

☛ Exploded and cutaway views

☛ Three dimensional and stereoscopic views