1. Graphics Graphics Lab @ Korea University cgvr.korea.ac.kr Raster Graphics 고려대학교 컴퓨터 그래픽스 연구실

2. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Contents Display Hardware How are images display? Raster Graphics Systems How are imaging system organized? Output Primitives How can we describe shapes with primitives? Color Models How can we describe and represent colors?

3. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Display Hardware Video Display Devices Cathode Ray Tube (CRT) Liquid Crystal Display (LCD) Plasma panels Thin-film electroluminescent display Light-emitting diodes (LED) Hard-Copy Devices Ink-jet printer Laser printer Film recorder Electrostatic printer Pen plotter

4. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Cathode Ray Tube (CRT)

5. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Liquid Crystal Display (LCD)

6. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Raster Graphics

7. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Frame Buffer

8. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Frame Buffer Refresh Refresh Rate Usually 30~75 Hz

9. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Color Frame Buffer 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 255150750 Blue channel Green channel Red channel

10. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Color CRT

11. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Contents Display Hardware How are images display? Raster Graphics Systems How are imaging system organized? Output Primitives How can we describe shapes with primitives? Color Models How can we describe and represent colors?

12. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Output Primitives Points Lines DDA Algorithm Bresenham’s Algorithm Polygons Scan-Line Polygon Fill Inside-Outside Tests Boundary-Fill Algorithm Antialiasing

13. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Points Single Coordinate Position Set the bit value(color code) corresponding to a specified screen position within the frame buffer x y setPixel (x, y)

14. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Lines Intermediate Positions between Two Endpoints DDA, Bresenham’s line algorithms Jaggies = Aliasing

15. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr DDA Algorithm Digital Differential Analyzer 0 < Slope <= 1  Unit x interval = 1 x1 y1 x2 y2

16. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr DDA Algorithm Digital Differential Analyzer 0 < Slope <= 1  Unit x interval = 1 Slope > 1  Unit y interval = 1 x1 y1 x2 y2

17. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr DDA Algorithm Digital Differential Analyzer 0 < Slope <= 1  Unit x interval = 1 Slope > 1  Unit y interval = 1 -1 <= Slope < 0  Unit x interval = -1 x1 y2 x2 y1

18. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr DDA Algorithm Digital Differential Analyzer Slope >= 1  Unit x interval = 1 0 < Slope < 1  Unit y interval = 1 -1 <= Slope < 0  Unit x interval = -1 Slope < -1  Unit y interval = -1 x1 y1 x2 y2

19. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Bresenham’s Line Algorithm Midpoint Line Algorithm Decision variable d > 0 : choose NE  : d new = d old +a+b d <= 0 : choose E  : d new = d old +a NE M Q P(x p, y p )E

20. CGVR Graphics Lab @ Korea University cgvr.korea.ac.kr Bresenham’s Algorithm(cont.) Initial Value of d Update d