Second Year Diploma Courses in Computer Science & Engineering / Computer
Engineering / Computer Technology / Information Technology Branch.
Computer Graphics
As per MSBTE ‘I’ Scheme Syllabus
CGR-22318
Unit-I
Basics of Computer Graphics
Total Marks- 08
Contents:
1.1 Image and Objects, pixel and resolution, Text mode. Graphics mode. Basic Graphics
Pipeline, Bitmap and vector based Graphics, Application of Computer Graphics.
1.2 Display Devices: Raster scan Display, random scan display, Flat Panel Display, LED,
LCD Display, Plasma, Touch screen.
1.3 Output primitives: line, polygon, marker, text.
1.4 Graphics functions and standards
1.5 Latest trends in Computer Graphics: Virtual reality, Augmented reality.
, Unit-I Basics of Computer Graphics
Unit-I Basics of Computer Graphics
1. Introduction to Computer Graphics
Computer graphics displays information in the form of graphics objects as windows,
graphs, diagrams etc. Thus, computer graphics express data in pictorial form.
In computer graphics objects are represented as collection of pixels, where pixel is
smallest addressable point which can be displayed on screen. Pixel can be displayed
on screen by setting its intensity and color.
A broad classification of major subfields in computer graphics might be:
1. Geometry: Studies ways to represent and process surfaces.
2. Animation: Studies with ways to represent and manipulate motion.
3. Rendering: Studies algorithms to reproduce light transport.
4. Imaging: Studies image acquisition or image editing.
2. Image and Object
An image is basically representation of a real world object on a computer. It can be
an actual picture display, a stored page in a video memory, or a source code
generated by a program.
Mathematically, an image is a two dimensional array of data with intensity or a color
value at each element of the array. In simple term, an image is defined by pixels.
Object are real world entities defined in three dimensional world co-ordinates.
3. Pixel and Resolution
3.1. Pixel
Pixel stands for picture element. A pixel is the smallest piece of information in an
image.
In computer graphics objects are represented as collection of pixels, where pixel is
smallest addressable point which can be displayed on screen.
Pixel can be displayed on screen by setting its intensity and color.
3.2. Resolution
It is expressed in terms of the number of pixels on the horizontal axis and the number
on the vertical axis.
In pixel resolution, the term resolution refers to the total no. of count of pixels in an
digital image.
CGR-22318 www.freestudyroom.xyz Page 2
, Unit-I Basics of Computer Graphics
For example, if an has M rows and N columns, then its resolution can be defined as
M X N.
4. Text mode and Graphics Mode
There are basically two types of graphics modes namely, Text mode, and Graphics
mode.
There are different graphics functions available in these two modes useful for
drawing different effective texts and different types of geometric shapes.
4.1. Text Mode
In text mode, a display screen is divided into rows and columns of boxes. Each can
contain one character. Text mode is also called character mode.
All video standards support a text mode that divides the screen into 25 rows and 80
columns.
Text mode is also known as Character mode or Alphanumeric mode.
4.2 Graphics mode
Graphics mode is a computer display mode that displays image-using pixels.
In graphics mode, the display screen is treated as an array of pixels. Programs that
run in graphics mode can display an unlimited variety of shapes and fonts.
4.1.1. Text mode graphics function
1) Window( ):- This function specifies a window on screen. The four integer co-
ordinates of the window are passed as parameters to this function.
Syntax- window(left, top, right, bottom);
2) putch( ): It displays a single character at cursor position.
Syntax – putch( char);
Example- putch(‘A’);
Displays character A at specified cursor position.
3) clrscr( ): It clears the entire screen and locates the cursor in top left corner of
screen i.e(1,1).
Syntax – clrscr( );
4) gotoxy( ): It positions the cursor to the specified location on screen, where location
is specified by x, y co-ordinates of the point.
Syntax – gotoxy(x, y);
CGR-22318 www.freestudyroom.xyz Page 3
Engineering / Computer Technology / Information Technology Branch.
Computer Graphics
As per MSBTE ‘I’ Scheme Syllabus
CGR-22318
Unit-I
Basics of Computer Graphics
Total Marks- 08
Contents:
1.1 Image and Objects, pixel and resolution, Text mode. Graphics mode. Basic Graphics
Pipeline, Bitmap and vector based Graphics, Application of Computer Graphics.
1.2 Display Devices: Raster scan Display, random scan display, Flat Panel Display, LED,
LCD Display, Plasma, Touch screen.
1.3 Output primitives: line, polygon, marker, text.
1.4 Graphics functions and standards
1.5 Latest trends in Computer Graphics: Virtual reality, Augmented reality.
, Unit-I Basics of Computer Graphics
Unit-I Basics of Computer Graphics
1. Introduction to Computer Graphics
Computer graphics displays information in the form of graphics objects as windows,
graphs, diagrams etc. Thus, computer graphics express data in pictorial form.
In computer graphics objects are represented as collection of pixels, where pixel is
smallest addressable point which can be displayed on screen. Pixel can be displayed
on screen by setting its intensity and color.
A broad classification of major subfields in computer graphics might be:
1. Geometry: Studies ways to represent and process surfaces.
2. Animation: Studies with ways to represent and manipulate motion.
3. Rendering: Studies algorithms to reproduce light transport.
4. Imaging: Studies image acquisition or image editing.
2. Image and Object
An image is basically representation of a real world object on a computer. It can be
an actual picture display, a stored page in a video memory, or a source code
generated by a program.
Mathematically, an image is a two dimensional array of data with intensity or a color
value at each element of the array. In simple term, an image is defined by pixels.
Object are real world entities defined in three dimensional world co-ordinates.
3. Pixel and Resolution
3.1. Pixel
Pixel stands for picture element. A pixel is the smallest piece of information in an
image.
In computer graphics objects are represented as collection of pixels, where pixel is
smallest addressable point which can be displayed on screen.
Pixel can be displayed on screen by setting its intensity and color.
3.2. Resolution
It is expressed in terms of the number of pixels on the horizontal axis and the number
on the vertical axis.
In pixel resolution, the term resolution refers to the total no. of count of pixels in an
digital image.
CGR-22318 www.freestudyroom.xyz Page 2
, Unit-I Basics of Computer Graphics
For example, if an has M rows and N columns, then its resolution can be defined as
M X N.
4. Text mode and Graphics Mode
There are basically two types of graphics modes namely, Text mode, and Graphics
mode.
There are different graphics functions available in these two modes useful for
drawing different effective texts and different types of geometric shapes.
4.1. Text Mode
In text mode, a display screen is divided into rows and columns of boxes. Each can
contain one character. Text mode is also called character mode.
All video standards support a text mode that divides the screen into 25 rows and 80
columns.
Text mode is also known as Character mode or Alphanumeric mode.
4.2 Graphics mode
Graphics mode is a computer display mode that displays image-using pixels.
In graphics mode, the display screen is treated as an array of pixels. Programs that
run in graphics mode can display an unlimited variety of shapes and fonts.
4.1.1. Text mode graphics function
1) Window( ):- This function specifies a window on screen. The four integer co-
ordinates of the window are passed as parameters to this function.
Syntax- window(left, top, right, bottom);
2) putch( ): It displays a single character at cursor position.
Syntax – putch( char);
Example- putch(‘A’);
Displays character A at specified cursor position.
3) clrscr( ): It clears the entire screen and locates the cursor in top left corner of
screen i.e(1,1).
Syntax – clrscr( );
4) gotoxy( ): It positions the cursor to the specified location on screen, where location
is specified by x, y co-ordinates of the point.
Syntax – gotoxy(x, y);
CGR-22318 www.freestudyroom.xyz Page 3
