Introduction
When working with computer graphics, understanding how images are rendered on screens is very crucial. Two primary methods used in this process are raster scan and random scan. Both of them have unique ways of drawing images, each with its own advantages and use cases.
Raster scan and random scan are two techniques used to display images on screens. The raster scan method fills the screen line by line, similar to how a TV screen works. On the other hand, the random scan method draws images based on specific coordinates, making it suitable for different applications. Understanding these methods will help you choose the right technique for your graphics projects.
Raster Scan
What is Raster Scan?
Raster scan is a method where the screen is divided into a grid of pixels. The image is drawn by scanning each line of pixels from top to bottom. This is the most common method used in monitors and TVs.
How Raster Scan Works
In raster scan, the display hardware continuously scans from the top-left corner to the bottom-right corner of the screen. The image is painted line by line. This process repeats at a high speed, creating the illusion of a complete image.
Key Features of Raster Scan
- Pixel-Based: Images are created by manipulating individual pixels.
- Refresh Rate: The screen updates at a constant rate, usually measured in Hertz (Hz).
- Common Use: Most monitors and TVs use raster scan.
Example of Raster Scan
Consider an image of a simple rectangle. The raster scan process would look like this:
- Start at the top-left corner.
- Draw the first line of pixels.
- Move to the next line and repeat until the bottom of the screen.
Here is a basic representation:
|####|
|####|
|####|
|####|
In the example above, # represents a filled pixel, and | represents the edges of the screen.
Advantages of Raster Scan
- Versatility: Suitable for displaying complex images and videos.
- Compatibility: Works with most display devices.
- Cost-Effective: Easier to implement in hardware.
Disadvantages of Raster Scan
- Resolution Dependent: Image quality depends on the resolution.
- Performance: May be slower for drawing high-resolution images.
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