http://jhlong12345.blog.163.com/blog/static/1230631292015544450189/#
结合上一篇，继续
矩形大小的调整
还有小bug，思路有了，就行了，就不贴修改正常的代码了，自己动动手，有思路基本都可以很快写出来的
思路：
画一个矩形，然后在mousedown时，判断鼠标是否在区域内，如果在，就在四个角画四个小正方形，然后在mousemove中判断是否在四个方格中，如果在，就出现箭头鼠标，然后做个标记，表示开始调整尺寸
直接看代码吧，有点复杂了
//是否开始画了 bool bDrawStart = false; //矩形的起始点 Point pointStart = Point.Empty; //矩形的起始点的对角点，鼠标移动点 Point pointContinue = Point.Empty; //是否要修改矩形，以鼠标点击点在矩形内部为准，修改时自动在4个端点创建4个小方框，不能创建其他的矩形 bool bChange = false; //修改矩形时移动点的X、Y记录，好根据它在dicPoints找到对应的矩形，或dicPointsChange找到对应小方框 Point pMove1 = Point.Empty; Point pMove2 = Point.Empty; //修改矩形时鼠标点击进4个小方框内，确认要根据鼠标移动修改 bool bChangeMove = false; //当前全部创建的矩形的记录 Dictionary<Point, Point> dicPoints = new Dictionary<Point, Point>(); //矩形要修改大小时4个端点创建4个小方框的记录 Dictionary<Point, Point> dicPointsChange = new Dictionary<Point, Point>(); private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { if (bDrawStart) { bDrawStart = false; } else { bDrawStart = true; pointStart = e.Location; } if (bChange) { bDrawStart = false; foreach (var item in dicPointsChange) { Point p1 = item.Key; Point p2 = item.Value; //如果在4个小框里 if ((e.Location.X > p1.X && e.Location.X < p2.X && e.Location.Y > p1.Y && e.Location.Y < p2.Y) || (e.Location.X > p2.X && e.Location.X < p1.X && e.Location.Y > p2.Y && e.Location.Y < p1.Y) || (e.Location.X > p2.X && e.Location.X < p1.X && e.Location.Y > p1.Y && e.Location.Y < p2.Y) || (e.Location.X > p1.X && e.Location.X < p2.X && e.Location.Y > p2.Y && e.Location.Y < p1.Y)) { bChangeMove = true; //p1、p2为小方框的对角点，中心点为矩形的端点,首先获取端点， //然后根据pMove1，pMove2确定小方框在的端点是矩形的哪个端点 //最后确定起始点，起始点pointStart为移动点（鼠标点击点、小方框在的端点）的对角点 //pointContinue为移动点（鼠标点击点、小方框在的端点） Point p = Point.Empty; p.X = p1.X > p2.X ? p1.X - 5 : p1.X + 5; p.Y = p1.Y > p2.Y ? p1.Y - 5 : p1.Y + 5; if (p == pMove1) { pointStart = pMove2; } else if (p == pMove2) { pointStart = pMove1; } else if (p == new Point(pMove1.X, pMove2.Y)) { pointStart = new Point(pMove2.X, pMove1.Y); } else if (p == new Point(pMove2.X, pMove1.Y)) { pointStart = new Point(pMove1.X, pMove2.Y); } break; } } //如果没点击4个小方框，则默认放弃修改 if (!bChangeMove) { bDrawStart = true; dicPointsChange.Clear(); bChange = false; } } else { foreach (var item in dicPoints) { Point p1 = item.Key; Point p2 = item.Value; if ((e.Location.X > p1.X && e.Location.X < p2.X && e.Location.Y > p1.Y && e.Location.Y < p2.Y) || (e.Location.X > p2.X && e.Location.X < p1.X && e.Location.Y > p2.Y && e.Location.Y < p1.Y) || (e.Location.X > p2.X && e.Location.X < p1.X && e.Location.Y > p1.Y && e.Location.Y < p2.Y) || (e.Location.X > p1.X && e.Location.X < p2.X && e.Location.Y > p2.Y && e.Location.Y < p1.Y)) { bChange = true; bDrawStart = false; //不能画新矩形了 dicPointsChange.Clear(); pMove1 = p1; pMove2 = p2; //画出点击矩形的4个端点的4个小方框，并记录入dicPointsChange Graphics g = pictureBox1.CreateGraphics(); System.Drawing.Pen pen = new System.Drawing.Pen(Color.Red); g.DrawRectangle(pen, p1.X - 5, p1.Y - 5, 10, 10); g.DrawRectangle(pen, p2.X - 5, p2.Y - 5, 10, 10); g.DrawRectangle(pen, p1.X - 5, p2.Y - 5, 10, 10); g.DrawRectangle(pen, p2.X - 5, p1.Y - 5, 10, 10); pen.Dispose(); dicPointsChange.Add(new Point(p1.X - 5, p1.Y - 5), new Point(p1.X + 5, p1.Y + 5)); dicPointsChange.Add(new Point(p2.X - 5, p2.Y - 5), new Point(p2.X + 5, p2.Y + 5)); dicPointsChange.Add(new Point(p2.X - 5, p1.Y - 5), new Point(p2.X + 5, p1.Y + 5)); dicPointsChange.Add(new Point(p1.X - 5, p2.Y - 5), new Point(p1.X + 5, p2.Y + 5)); break; } } } } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (bDrawStart) { pointContinue = e.Location; Refresh(); } if (bChangeMove) { pointContinue = e.Location; Point p = Point.Empty; foreach (var item in dicPoints) { Point p1 = item.Key; Point p2 = item.Value; //找到dicPoints里的原始记录 if (p1 == pointStart || p2 == pointStart || new Point(p1.X, p2.Y) == pointStart || new Point(p2.X, p1.Y) == pointStart) { p = p1; break; } } if (p != Point.Empty) { //先删除dicPoints里的原始记录，再根据新点创建新的记录 dicPoints.Remove(p); dicPoints.Add(pointStart, pointContinue); dicPointsChange.Clear(); Point p1 = pointStart; Point p2 = pointContinue; //移动过程即时创建4个小方框，看起来小方框和矩形一起变大变小的效果 dicPointsChange.Add(new Point(p1.X - 5, p1.Y - 5), new Point(p1.X + 5, p1.Y + 5)); dicPointsChange.Add(new Point(p2.X - 5, p2.Y - 5), new Point(p2.X + 5, p2.Y + 5)); dicPointsChange.Add(new Point(p2.X - 5, p1.Y - 5), new Point(p2.X + 5, p1.Y + 5)); dicPointsChange.Add(new Point(p1.X - 5, p2.Y - 5), new Point(p1.X + 5, p2.Y + 5)); Refresh(); } } } private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { if (bDrawStart) { //此时矩形画完，记录矩形两个对角点，在Paint里画 dicPoints.Add(pointStart, pointContinue); } if (bChangeMove) { bChangeMove = false; bChange = false; } bDrawStart = false; } private void pictureBox1_Paint(object sender, PaintEventArgs e) { System.Drawing.Pen pen = new System.Drawing.Pen(Color.LimeGreen); pen.Width = 2; if (bDrawStart) { //实时的画矩形 Graphics g = e.Graphics; g.DrawRectangle(pen, pointStart.X, pointStart.Y, pointContinue.X - pointStart.X, pointContinue.Y - pointStart.Y); } //实时的画之前已经画好的矩形 foreach (var item in dicPoints) { Point p1 = item.Key; Point p2 = item.Value; e.Graphics.DrawRectangle(pen, p1.X, p1.Y, p2.X - p1.X, p2.Y - p1.Y); } if (bChangeMove) { pen.Color = Color.Red; foreach (var item in dicPointsChange) { Point p1 = item.Key; Point p2 = item.Value; e.Graphics.DrawRectangle(pen, p1.X, p1.Y, p2.X - p1.X, p2.Y - p1.Y); } } pen.Dispose(); }