A simple curve line drawing system that uses Bezier and B-spline.
0.655556 0.93 x, y position for the control points in world coordinates (0 to 1) 0.782222 0.925556 0.805556 0.718889 0.591111 0.764444 0.596667 0.86 0.733333 0.736667
My program reads this file and draw the curves from this file and allows users to modify these curves as well as add a new curve or delete a selected curve. After the user makes all changes to the curves, and press esc to exit and save the scene, my program will output to the same file (test.txt) with the new curves information.
All controls points are drew as a square for better mouse clicking. Control points for Bezier curve is labled blue color, curve is red color. Control points for Bspline curve is labled pink color, curve is green color.
To perform add points for a curve, the user need to select the curve to add points first. To select a curve, simply use your mouse to left-click one of the control points of the curve you want to add. Once you select the curve, the user can simply left-click anywhere in the window to add a new control point for the curve (it always adds the point as the last point of the control points). Also, when the user selects a Bspline curve, the k value for that curve will be showed on the bottom right corner of the window. Then the user can press K to increase k by 1 or press L to decrease k by 1. (Notice: k must be in range in (1, n + 1), so if the user trys to increase or decrease more than this range, it won't work and an error message will be printed out on the cosole.)
To move a control points of any curve, just hold the left-click down of the mouse on the point and drag to somewhere you want it to be. To delete a control point of any curve, just right-click the point you want to delete. (Notice: the number of control points can not be lower than 1 for Bezier curve and not be lower than k for Bspline curve).
To add a new curve, press 1 to add a new Bezier curve, press 2 to add new Bspline curve. Then the user needs to left-click on the window to choose the control point for the curve. (After the user left-click somewhere, the control point will show up.) After the user is finished with choosing the points for the curve, just press f to finish the process and draw out the new curve. (Notice: for Bspline curve, the user also needs to enter the k value for the curve after finishing choosing the points. While constructing a new curve try not to press any other keys.)
To delete a curve, just select a curve by left-click one of the control points of the curve (same as before for selecting a curve), and press d to delete the curve.
To change the resolution for Bezier curve, press A to enter a new resolution for Bezier curve using console. To change the resolution for Bspline curve, press S to enter a new resolution for Bspline curve using console.
Lines for implementing algorithms:
de Casteljau: bezier_c.cpp: line 12 - 35
de Boor: bspline_c.cpp: line 11 - 37
add points: bezier_c.cpp: line 38 - 42 bspline_c.cpp: line 68 - 72 main.cpp: 242 - 258
move points: bezier_c.cpp: line 74 - 78 bspline_c.cpp: line 120 - 124 main.cpp: 373 - 404 delete points: bezier_c.cpp: line 45 - 54 bspline_c.cpp: line 75 - 83 main.cpp: 289 - 334