C#中利用GDI+绘制旋转文本的文字,网上有很多资料,基本都使用矩阵旋转的方式实现。但基本都只提及按点旋转,若要实现在矩形范围内旋转文本,资料较少。经过琢磨,可以将矩形内旋转转化为按点旋转,不过需要经过不少的计算过程。利用下面的类可以实现该功能。
- using System;
- using System.Collections.Generic;
- using System.Drawing;
- using System.Drawing.Drawing2D;
- namespace RotateText
- {
- public class GraphicsText
- {
- private Graphics _graphics;
- public GraphicsText()
- {
- }
- public Graphics Graphics
- {
- get { return _graphics; }
- set { _graphics = value; }
- }
- /// <summary>
- /// 绘制根据矩形旋转文本
- /// </summary>
- /// <param name="s">文本</param>
- /// <param name="font">字体</param>
- /// <param name="brush">填充</param>
- /// <param name="layoutRectangle">局部矩形</param>
- /// <param name="format">布局方式</param>
- /// <param name="angle">角度</param>
- public void DrawString(string s, Font font, Brush brush, RectangleF layoutRectangle, StringFormat format, float angle)
- {
- // 求取字符串大小
- SizeF size = _graphics.MeasureString(s, font);
- // 根据旋转角度,求取旋转后字符串大小
- SizeF sizeRotate = ConvertSize(size, angle);
- // 根据旋转后尺寸、布局矩形、布局方式计算文本旋转点
- PointF rotatePt = GetRotatePoint(sizeRotate, layoutRectangle, format);
- // 重设布局方式都为Center
- StringFormat newFormat = new StringFormat(format);
- newFormat.Alignment = StringAlignment.Center;
- newFormat.LineAlignment = StringAlignment.Center;
- // 绘制旋转后文本
- DrawString(s, font, brush, rotatePt, newFormat, angle);
- }
- /// <summary>
- /// 绘制根据点旋转文本,一般旋转点给定位文本包围盒中心点
- /// </summary>
- /// <param name="s">文本</param>
- /// <param name="font">字体</param>
- /// <param name="brush">填充</param>
- /// <param name="point">旋转点</param>
- /// <param name="format">布局方式</param>
- /// <param name="angle">角度</param>
- public void DrawString(string s, Font font, Brush brush, PointF point, StringFormat format, float angle)
- {
- // Save the matrix
- Matrix mtxSave = _graphics.Transform;
- Matrix mtxRotate = _graphics.Transform;
- mtxRotate.RotateAt(angle, point);
- _graphics.Transform = mtxRotate;
- _graphics.DrawString(s, font, brush, point, format);
- // Reset the matrix
- _graphics.Transform = mtxSave;
- }
- private SizeF ConvertSize(SizeF size, float angle)
- {
- Matrix matrix = new Matrix();
- matrix.Rotate(angle);
- // 旋转矩形四个顶点
- PointF[] pts = new PointF[4];
- pts[0].X = -size.Width / 2f;
- pts[0].Y = -size.Height / 2f;
- pts[1].X = -size.Width / 2f;
- pts[1].Y = size.Height / 2f;
- pts[2].X = size.Width / 2f;
- pts[2].Y = size.Height / 2f;
- pts[3].X = size.Width / 2f;
- pts[3].Y = -size.Height / 2f;
- matrix.TransformPoints(pts);
- // 求取四个顶点的包围盒
- float left = float.MaxValue;
- float right = float.MinValue;
- float top = float.MaxValue;
- float bottom = float.MinValue;
- foreach(PointF pt in pts)
- {
- // 求取并集
- if(pt.X < left)
- left = pt.X;
- if(pt.X > right)
- right = pt.X;
- if(pt.Y < top)
- top = pt.Y;
- if(pt.Y > bottom)
- bottom = pt.Y;
- }
- SizeF result = new SizeF(right - left, bottom - top);
- return result;
- }
- private PointF GetRotatePoint(SizeF size, RectangleF layoutRectangle, StringFormat format)
- {
- PointF pt = new PointF();
- switch (format.Alignment)
- {
- case StringAlignment.Near:
- pt.X = layoutRectangle.Left + size.Width / 2f;
- break;
- case StringAlignment.Center:
- pt.X = (layoutRectangle.Left + layoutRectangle.Right) / 2f;
- break;
- case StringAlignment.Far:
- pt.X = layoutRectangle.Right - size.Width / 2f;
- break;
- default:
- break;
- }
- switch (format.LineAlignment)
- {
- case StringAlignment.Near:
- pt.Y = layoutRectangle.Top + size.Height / 2f;
- break;
- case StringAlignment.Center:
- pt.Y = (layoutRectangle.Top + layoutRectangle.Bottom) / 2f;
- break;
- case StringAlignment.Far:
- pt.Y = layoutRectangle.Bottom - size.Height / 2f;
- break;
- default:
- break;
- }
- return pt;
- }
- }
- }
测试代码如下:
- using System;
- using System.Collections.Generic;
- using System.ComponentModel;
- using System.Data;
- using System.Drawing;
- using System.Windows.Forms;
- namespace RotateText
- {
- public partial class FormMain : Form
- {
- private Font _font = new Font("Arial", 12);
- private Brush _brush = new SolidBrush(Color.Black);
- private Pen _pen = new Pen(Color.Black, 1f);
- private string _text = "Crow Soft";
- public FormMain()
- {
- InitializeComponent();
- }
- protected override void OnPaint(PaintEventArgs e)
- {
- base.OnPaint(e);
- GraphicsText graphicsText = new GraphicsText();
- graphicsText.Graphics = e.Graphics;
- // 绘制围绕点旋转的文本
- StringFormat format = new StringFormat();
- format.Alignment = StringAlignment.Center;
- format.LineAlignment = StringAlignment.Center;
- graphicsText.DrawString(_text, _font, _brush, new PointF(100, 80), format, 45f);
- graphicsText.DrawString(_text, _font, _brush, new PointF(200, 80), format, -45f);
- graphicsText.DrawString(_text, _font, _brush, new PointF(300, 80), format, 90f);
- graphicsText.DrawString(_text, _font, _brush, new PointF(400, 80), format, -60f);
- // 绘制矩形内旋转的文本
- // First line
- RectangleF rc = RectangleF.FromLTRB(50, 150, 200, 230);
- RectangleF rect = rc;
- format.Alignment = StringAlignment.Near;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 30);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Near;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, -30);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Center;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, -90);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Far;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 70);
- // Second line
- rect = rc;
- rect.Location += new SizeF(0, 100);
- format.Alignment = StringAlignment.Center;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 40);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Near;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 30);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Center;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, -70);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Far;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 60);
- // Third line
- rect = rc;
- rect.Location += new SizeF(0, 200);
- format.Alignment = StringAlignment.Far;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, -30);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Near;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, -30);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Center;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 90);
- rect.Location += new SizeF(180, 0);
- format.LineAlignment = StringAlignment.Far;
- e.Graphics.DrawRectangle(_pen, rect.Left, rect.Top, rect.Width, rect.Height);
- graphicsText.DrawString(_text, _font, _brush, rect, format, 45);
- }
- }
- }
效果如下图:
资源地址:http://download.csdn.net/detail/alicehyxx/6626473