by Dinesh Thakur Category: Graphics Devices

The dot pitch of a color monitor measures the size of the tiny individual dots of phosphorescent material that coat the back side of the picture tube's face. The dot pitch helps determine how sharp the image looks, independent of the resolution (which is measured in pixels). A smaller dot pitch is better.

 
by Dinesh Thakur Category: Graphics Devices

CGA stands for color graphics adapter, the first IBM video card to permit graphics on the screen. We're lucky they've come out with better models, because CGA graphics are gawdawful crude. With a CGA, your screen can show up to 640 dots across by 200 dots up and down, with only one color. Even at that maximum resolution, pictures look really blocky and out of proportion. Pictures will look even more blocky if you want 4 colors on the screen at once, since you're then limited to 320 dots across and 200 down. If you can tolerate a totally chunky display of 160 by 200 dots, you can get a maximum of 16 colors on a CGA. Wow!

 
by Dinesh Thakur Category: Graphics Devices

LCD stands for liquid crystal display. Your digital watch uses an LCD to show you the time, and most portable computers use an LCD to display the screen. There is actually a liquid compound, liquid crystals, sandwiched between two grids of electrodes. The electrodes can selectively turn on the different cells or pixels in the grid to create the image you see.

 
by Dinesh Thakur Category: Graphics Devices

One of the basic and commonly used display devices is Cathode Ray Tube (CRT). A cathode ray tube is based on the simple concept that an electronic beam, when hits a phosphorescent surface, produces a beam of light (momentarily - though we later describe surfaces that produce light intensities lashing over a period of time).

 
by Dinesh Thakur Category: Graphics Devices

Factors in determining refresh rates

A refresh rate is dependent upon a monitor's horizontal scanning frequency and the number of horizontal lines displayed.The horizontal scanning frequency is the number of times the electron beam sweeps one line and returns to the beginning of the next in one second. Horizontal scanning frequency is measured in kilohertz (kHz).

 
by Dinesh Thakur Category: Graphics Devices

Raster Scan methods have increasingly become the dominant technology since about 1975. These methods use the TV type raster scan. The growth in the use of such methods has been dependent on rapidly decreasing memory prices and on the availability of cheap scan generating hardware from the TV industry.

 
by Dinesh Thakur Category: Graphics Devices

There are used for erasable disks. MO system includes basic principles of both magnetic & optical storage systems. MO systems write magnetically & read optically. It has two standard forms : 5.25 inches & 3.5 inches.

 
by Dinesh Thakur Category: Graphics Devices

Plasma displays are bright, have a wide color gamut, and can be produced in fairly large sizes, up to 262 cm (103 inches) diagonally. They have a very low-luminance "dark-room" black level, creating a black some find more desirable for watching movies. The display panel is only about 6 cm (2½ inches) thick, while the total thickness, including electronics, is less than 10 cm (4 inches).

 
by Dinesh Thakur Category: Graphics Devices

In Shadow Mask CRT tiny holes in a metal plate separate the colored phosphors in the layer behind the front glass of the screen. The holes are placed in a manner ensuring that electrons from each of the tube's three cathode guns reach only the appropriately-colored phosphors on the display. All three beams pass through the same holes in the mask, but the angle of approach is different for each gun.

 
by Dinesh Thakur Category: Graphics Devices

This was one the earlier CRTs to produce color displays. Coating phosphors of different compounds can produce different colored pictures. But the basic problem of graphics is not to produce a picture of a predetermined color, but to produce color pictures, with the color characteristics chosen at run time.

 
by Dinesh Thakur Category: Graphics Devices

Conceptually the Direct View Storage Tube (DVST) behaves like a CRT with highly persistent phosphor. Pictures drawn on there will be seen for several minutes (40-50 minutes) before fading. It is similar to CRT as far as the electronic gun and phosphor-coated mechanisms are concerned. But instead of the electron beam directly writing the pictures on the phosphor coated CRT screen, the writing is done with the help of a fine-mesh wire grid.

 
by Dinesh Thakur Category: Line Drawing Method

On the Macintosh, some programs let you edit bitmapped graphics as FatBits. In FatBits mode, the individual dots, or pixels, making up the image are blown up so you can work with them easily, one at a time. If you see stray dots in an image you've scanned, or if a line in a picture is just slightly too thick or too skinny, it's almost impossible to make precise changes working at normal size.

 
by Dinesh Thakur Category: Line Drawing Method

A typical black-and-white photograph uses only one color. In a duotone, though, the black-and-white photograph (or other artwork) is reproduced using two colors. Perhaps it's black and brown, or black and grey, or dark grey and a rusty color. Halftone images are generated for the photograph, one slightly underexposed and one slightly overexposed, and the two are printed one on top of the other. The result can be an incredibly rich, powerful image-much richer and more interesting than the image with one color. The artist/designer has control over the values and percentages of the two different colors. It is also possible to make "tritones" using three different colors, and "quadtones," using four different colors.

 
by Dinesh Thakur Category: Line Drawing Method

Whenever a photograph, painting or drawing containing many colors or gray tones is printed, the colors and tones must be simulated with tiny dots. Dot gain refers to an increase in the size of these dots when they are actually printed on the paper by the printing press. The dots can increase in size rather dramatically once the ink hits the paper, depending on the characteristics of the press, the absorbency of the paper, and the nature of the ink that is used.

 
by Dinesh Thakur Category: Line Drawing Method

When text or a graphic image is displayed on amonitor,or screen, the smoothness of the edges is limited by the resolution of the screen, which means the edges tend to be a little jagged. This jaggedness is also called aliasing.

 
by Dinesh Thakur Category: Line Drawing Method

A mathematical point (x, y) where x and y are real numbers within an image area, needs to be scan converted to a pixel at location (x’, y’). This may be done by making x’ to be the integer part of x, and y’ to be the integer part of y. In other words, x’ = floor(x) and y’ = floor(y),

 
by Dinesh Thakur Category: Line Drawing Method

You know that a line in computer graphics typically refers to a line segment, which is a portion of a straight line that extends indefinitely in opposite directions. You can define a line by its two end points and by the line equation y = mx + c, where m is called the slope and c the y intercept of the line. Let the two end points of a line be P1(x1, y1) and P2(x2, y2). The line equation describes the coordinates of all the points that lie between the two endpoints.



 
by Dinesh Thakur Category: Line Drawing Method

DDA algorithm is an incremental scan conversion method. Here we perform calculations at each step using the results from the preceding step. The characteristic of the DDA algorithm is to take unit steps along one coordinate and compute the corresponding values along the other coordinate. The unit steps are always along the coordinate of greatest change, e.g. if dx = 10 and dy = 5, then we would take unit steps along x and compute the steps along y.

 
by Dinesh Thakur Category: Line Drawing Method

You know that DDA algorithm is an incremental scan conversion method which performs calculations at each step using the results from the preceding step. Here we are going to discover an accurate and efficient raster line generating algorithm, the Bresenham's line-drawing algorithm.

 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.