Computer Computer Graphics Graphics

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ComputerComputer GraphicsGraphics BasicsBasics• Computer graphic is the image generated

by a computer and shown on a display. (such as monitor, television, etc.)

Computer Graphics - PixelsComputer Graphics - Pixels• The image in the computer is made up of a

number of tiny ‘dots’ or picture elements called ‘pixels’.

• The computer has special hardware for creating images, commonly known as a graphics card.

• The graphics card generates an image which is displayed on a screen.

• The image is drawn by the monitor a certain number of times every second, referred to as ‘refresh rate’.

• An image consists of an arbitrary number of picture elements, ‘pixels’.

Computer Graphics Computer Graphics

Binary CodeBinary Code• The binary system uses only 2 digits, 1 and 0.• The easiest way to be sure that a computer

recognizes a signal is to only have two options, ‘Signal’ and ‘No Signal’.

• ‘0’ represents ‘No Signal’, and ‘1’ represents ‘Signal’.

• The computer records and processes each pixel in binary code.

Computer Graphics Computer Graphics Color DepthColor Depth

• It takes about 16 million colors to display a picture with all the colors the human eye can see. This number of colors is the value a group of people decided would be enough to display pictures with photographic quality.

• The actual value is 16,777,216 colors, or about 16.8 million colors, which is also called 24-bit graphics. It is also called ‘True color’ or ‘Real color’.

• The color on a computer is a combination of the 3 light components, RGB (Red, Green, and Blue), which each component has 256 nuances and can be combined into about 16.8 colors in use of 24-bit graphics.

Computer Graphics Computer Graphics Color DepthColor Depth

Computer Graphics Computer Graphics Screen Resolution & Color DepthScreen Resolution & Color Depth• Different screen resolutions and color depth

can be adjusted on your computer, but how you do it depends on what computer you use.

• There is a simple relationship between the amount of graphics memory and the maximum resolution/color depth you can use.

Computer GraphicsComputer Graphics Screen Resolution & Color Depth Screen Resolution & Color Depth

Resolution Color Depth Required Memory

640x480 8-Bit 300 KB

640x480 16-Bit 600 KB

640x480 24-Bit 900 KB

640x480 32-Bit 1200 KB

Resolution Color Depth Required Memory

800x600 8-Bit 469 KB

800x600 16-Bit 937 KB

800x600 24-Bit 1.37 MB

800x600 32-Bit 1.83 MB

Computer Graphics Computer Graphics Screen Resolution & Color DepthScreen Resolution & Color Depth

Resolution Color Depth Required Memory

1024x768 8-Bit 768 KB

1024x768 16-Bit 1.5 MB

1024x768 24-Bit 2.25 MB

1024x768 32-Bit 3 MB

Resolution Color Depth Required Memory

1280x1024 8-Bit 1.25 MB

1280x1024 16-Bit 2.5 MB

1280x1024 24-Bit 3.75 MB

1280x1024 32-Bit 5 MB

Computer Graphics Computer Graphics Screen Resolution & Color DepthScreen Resolution & Color Depth

Resolution Color Depth Required Memory

1600x1200 8-Bit 1.83 MB

1600x1200 16-Bit 3.66 MB

1600x1200 24-Bit 5.49 MB

1600x1200 32-Bit 7.32 MB

Resolution Color Depth Required Memory

2048x1536 8-Bit 3.07 MB

2048x1536 16-Bit 6.14 MB

2048x1536 24-Bit 9.21 MB

2048x1536 32-Bit 12.28 MB

Difference Between Difference Between Vector & Raster GraphicsVector & Raster Graphics

Vector Graphics Raster Graphics (Bitmap)• A kind of graphic that is

a drawing picture.• The computer will

remember as geometric formulae.

• Small in-sized and can make it bigger without broken.

• Needs specific programs to open (such as Acrobat, Adobe Flash, etc.)

• Collects in a form of pixels.

• Larger sized.

• No need special programs to open.

Difference Between Difference Between Vector & Raster GraphicsVector & Raster Graphics

PhotoshopPhotoshop• Photoshop is the industry-standard image

rendering software. You can use Photoshop tocreate customized graphics, edit photographs and make flyers and images for print as well as

for the web. This handout provides a simple how-to guide to familiarizing yourself with the Photoshop environment.

Photoshop EnvironmentPhotoshop Environment• Menu Bar- Contains all the commands necessary

to use the program • Toolbox- displays the common tools (or

commands) that you need in creating /editing your images.

• Toolbar- this one changes when you select a tool from the toolbox. It provides additional options for each tool, if any.

• Canvass- This is where you create/edit your image • Layers - Using layers makes photoshop a very

powerful tool in editing images. Soon in this tutorial we will discover the power of layers.

Photoshop EnvironmentPhotoshop Environment

Photoshop – Important ToolsPhotoshop – Important Tools• Airbrush – Used for drawing smooth lines and coloring.• Paintbrush – Used for drawing lines and coloring.• Eraser – Used for erasing picture or coloring

background.• Line – Used for making lines.• Blur – Used for blurring parts of the picture.• Dodge – Used for making parts of the picture brighter.• Text – Used for adding text to the picture.• Gradient – Used for coloring with shadings.• Eyedropper – Used for choosing colors that are in the

picture.

Photoshop –Important ToolsPhotoshop –Important Tools

Photoshop Photoshop Important CommandsImportant Commands

• X (Switch Colors) - Swap your foreground and background colors.

• D (Default Colors) - Reset your foreground and background colors to black and white, respectively.

• Ctrl + ‘+’/'-’ (Zoom In/Out) - Quickly zoom in or out without changing your current tool.

• Alt + Mouse Scroll (Zoom In/Out) - Fastest way to zoom.• Ctrl + Alt + Z (Step Back) - Ctrl + Z is OK if you catch a

mistake immediately after it happens, same as the command ‘undo’.

• Ctrl + S - (Save)• Ctrl + Alt + Shift + N (New Layer No Dialog) - Quickly insert a

new empty layer on top of the active layer. Get rid of the Alt key to bring up the new layer dialog for more options.

QuestionQuestion• 1.What is the difference between raster and

vector graphic?• 2. What are 1 and 0 mean in binary system?• 3. What is pixel mean?