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C#利用GDI+繪制旋轉(zhuǎn)文字等效果實(shí)例

更新時(shí)間：2014年09月20日 10:43:03 投稿：shichen2014

這篇文章主要介紹了C#利用GDI+繪制旋轉(zhuǎn)文字等效果實(shí)例,是非常實(shí)用的重要技巧,需要的朋友可以參考下

本文實(shí)例講述了C#利用GDI+繪制旋轉(zhuǎn)文字等效果的方法，是非常實(shí)用的技巧。分享給大家供大家參考之用。具體如下：

C#中利用GDI+繪制旋轉(zhuǎn)文本的文字，網(wǎng)上有很多資料，基本都使用矩陣旋轉(zhuǎn)的方式實(shí)現(xiàn)。但基本都只提及按點(diǎn)旋轉(zhuǎn)，若要實(shí)現(xiàn)在矩形范圍內(nèi)旋轉(zhuǎn)文本，資料較少。經(jīng)過(guò)琢磨，可以將矩形內(nèi)旋轉(zhuǎn)轉(zhuǎn)化為按點(diǎn)旋轉(zhuǎn)，不過(guò)需要經(jīng)過(guò)不少的計(jì)算過(guò)程。利用下面的類(lèi)可以實(shí)現(xiàn)該功能。

具體實(shí)現(xiàn)代碼如下：

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> 
    /// 繪制根據(jù)矩形旋轉(zhuǎn)文本 
    /// </summary> 
    /// <param name="s">文本</param> 
    /// <param name="font">字體</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); 
 
      // 根據(jù)旋轉(zhuǎn)角度，求取旋轉(zhuǎn)后字符串大小 
      SizeF sizeRotate = ConvertSize(size, angle); 
 
      // 根據(jù)旋轉(zhuǎn)后尺寸、布局矩形、布局方式計(jì)算文本旋轉(zhuǎn)點(diǎn) 
      PointF rotatePt = GetRotatePoint(sizeRotate, layoutRectangle, format); 
 
      // 重設(shè)布局方式都為Center 
      StringFormat newFormat = new StringFormat(format); 
      newFormat.Alignment = StringAlignment.Center; 
      newFormat.LineAlignment = StringAlignment.Center; 
 
      // 繪制旋轉(zhuǎn)后文本 
      DrawString(s, font, brush, rotatePt, newFormat, angle); 
    } 
    /// <summary> 
    /// 繪制根據(jù)點(diǎn)旋轉(zhuǎn)文本，一般旋轉(zhuǎn)點(diǎn)給定位文本包圍盒中心點(diǎn) 
    /// </summary> 
    /// <param name="s">文本</param> 
    /// <param name="font">字體</param> 
    /// <param name="brush">填充</param> 
    /// <param name="point">旋轉(zhuǎn)點(diǎn)</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); 
      // 旋轉(zhuǎn)矩形四個(gè)頂點(diǎn) 
      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); 
      // 求取四個(gè)頂點(diǎn)的包圍盒 
      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; 
    } 
  } 
}

測(cè)試代碼如下：

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; 
 
      // 繪制圍繞點(diǎn)旋轉(zhuǎn)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); 
 
      // 繪制矩形內(nèi)旋轉(zhuǎn)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); 
    } 
  } 
}

效果如下圖：