c语言图形编程(六、绘图程序设计-01)（C programming language graphics (six, drawing program design -01)）.docVIP

c语言图形编程(六、绘图程序设计-01)（C programming language graphics (six, drawing program design -01)） Examples: draw a graphical parts There is a drawing as follows: In Figure 3-1 the parts of the graph, according to its dimensions, in accordance with the appropriate order step to draw the graphics, the first analysis of the relationship between the geometric shapes, understand nature of the graphics of each line, to draw the graph. Line (line or circle) in parts graph is divided into three categories, namely, the middle line and known line connecting line segment. By use of the circle as an example, according to the geometric principle, the position of the two dimension and radius of known center will be able to draw the circle. Therefore, the graph, the three dimensions of the arc known known arc, the drawing should first draw. All the two dimensions of the said arc known as the middle arc. Where the only known one size (usually called the circular arc radius) connecting arc. The position and the size of the middle circular arc are connected and the default center, it is based on the geometric position of tangent condition to determine. So in an arc order: first known painting arc, and then draw the middle arc, finally draw connecting arc. The parts are symmetric figures, three small uniform distribution in the circle center line, Phi 10, Phi 25, Phi 50 and R10 are known as arc, R8 arc, Phi 50 is known endpoint endpoint of arc and R10 arc known in connection with the arc tangent, which constitute the entire graph. Write algorithm: Know the geometry graphics, is how to use drawing formula or formula will show the geometric relationship, drawing algorithm which is to be written, including a description of the equation or relation of variables and parameters. Now discuss this part graph drawing algorithm. 1. coordinate system The benchmark for the axis, in the center of origin. 2. sure he radius relation Because the program of graphics to draw parts (which is actually a parametric