在這篇論文中，我們開發一套繪圖系統Violet，這套繪圖系統使用到微軟提供的MFC(Microsoft Foundation Classes)函式庫來建立視窗與達到和作業系統的溝通，這套系統中使用了兩層畫布的概念解決刪除重疊圖形的問題，我們的圖形操作並不會失真。我們的繪圖系統目前已經有：選取、群組、刪除、移動、格點、縮放和旋轉七種操作，以及：直線、矩形、圓形和曲線四種基本圖形。

In this thesis, we developed a graphics system called Violet. Our graphics system uses MFC (Microsoft Foundation Classes) library provided by Microsoft to construct the window of the program and the communication capability with the operating system. Our graphics system uses a concept of two canvases to resolve the overlapping of figures. The figures which are enlarged or shrunk by our system are not distorted. Our graphics system now has seven operations: selection, grouping, deletion, moving, grid, enlargement and rotation, and four basic figures: straight line, rectangle, circle and curve.

Chapter 1 Introduction to the Violet System 12
1.1 Overview 12
1.2 Tools and Operations 13
Chapter 2 The MFC (Microsoft Foundation Class) background in our Graphic System 35
2.1The Process to Create an MFC Project 35
2.2 Subroutines Related to Operations of the Mouse 45
2.3 The Handling of Icons Produced by Our Program 49
2-4 Storing and Loading file by the MFC 58
Chapter 3 The Basic Principle of Drawing Figures 60
3.1 The Drawing of a Line 62
3.2 The Drawing of a Circle 63
3.3 The Drawing of the Curve 65
3.4 The Drawing of a Rectangle 68
3.5 The Progressive Figure Drawing Method 70
3.6 The Process of Deletion, Rotation, Enlargement and Moving of Figures. 74
3.7 The Parameters of Figures 76
3.8 Modifications of Figures 77
3.9 The Grouping of a Set of Figures 83
Chapter 4 The Operations of the Button 88
Chapter 5 Concluding Remarks and Future Work 97
Reference 99
Appendix A The program code 100

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[HB91] Hearn, D., Baker, M. P., Computer Graphics, 2nd ed, Prentice Hall, 1991, ch.3, p. 186~p.188.

[J2003] Joy, K. I., Cubic Uniform B-Spline Curve Refinement, On-Line Geometric Modeling Notes, Visualization and Graphics Research Group, Department of Computer Science, University of California, Davis., California, 2003.

[M99]Mortenson, M. E., Mathematics for Computer Graphics Applications, 2nd ed, Industrial Press, 1999, ch.3.

[MJ2010] Mukherjee, D. P., Jana, D., Computer graphics, PHI Learning, 2010, ch.2.