在WPF应用程序中从字体符号创建光标

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介绍 我必须为我正在工作的应用程序创建一个大的光标，因为我已经使用了符号字体，所以决定使用字体中的符号来表示光标。 请注意 自初始版本以来，代码已经进行了相当程度的更新，以修复游标的问题。光标中的图像没有正确居中，因此光标的实际大小不接近调用中指定的值。沙漏现在也有三张沙子向下的图像，然后旋转90度。 的代码 我开始尝试使用代码来从按钮等的字体生成图像，这包括在代码中，以及用于在示例中生成图像的代码。但这并没有起作用，我不得不在互联网上搜索，并且玩了很多。不幸的是，似乎有几个微软的绘图库，我想没有太多的思想投入到创建不同的。下面的代码最终是有效的。 GlyphRun的创建 这段代码与用于为示例中显示的按钮创建图像的代码类似，但略有不同，因为我需要的对象与WPF中的图像所需的对象略有不同。它的作用是将字体字符转换为位图: 隐藏,复制Code

public static GlyphRun GetGlyphRun(double size, FontFamily fontFamily, string text)
{
 Typeface typeface = new Typeface(fontFamily, FontStyles.Normal,
  FontWeights.Normal, FontStretches.Normal);
 GlyphTypeface glyphTypeface;
 if (!typeface.TryGetGlyphTypeface(out glyphTypeface))
  throw new InvalidOperationException("No glyphtypeface found");
 ushort[] glyphIndexes = new ushort[text.Length];
 double[] advanceWidths = new double[text.Length];

 for (int n = 0; n < text.Length; n++)
 {
  advanceWidths[n] = glyphTypeface.AdvanceWidths[glyphIndexes[n]
   = GetGlyph(text[n], glyphTypeface)];
 }
 var centerX = (1 - advanceWidths[0]) * size / 2;
 Point origin = new Point(centerX, size * .85);

 GlyphRun glyphRun = new GlyphRun(glyphTypeface, 0, false, size,
   glyphIndexes, origin, advanceWidths, null, null, null, null,
   null, null);

 return glyphRun;
}

该方法使用另一种方法获取字符，并处理当字体没有与位置关联的字符时抛出的异常，用空格符号替换字符: 隐藏,复制Code

private static ushort GetGlyph(char text, GlyphTypeface glyphTypeface)
{
 try { return glyphTypeface.CharacterToGlyphMap[text]; }
 catch { return 42; }
}

在创建GlyphRun时，GetGlyphRun方法使用默认的FontSyle、FontWeight和FontStretch。它会获取一个字符串并创建一个包含所有字符的GlyphRun。 创建内存流对象 下一个方法用于创建游标对象。游标需要一种特定的二进制格式，因此使用一个MemoryStream来创建二进制对象(结构参见https://en.wikipedia.org/wiki/ICO_(file_format))。这也可以用不安全的代码完成，但是MemoryStream方法不需要不安全关键字就可以工作。 隐藏,收缩,复制Code

private static Cursor CreateCursorObject(int size, double xHotPointRatio, double yHotPointRatio,
    BitmapSource rtb)
{
 using (var ms1 = new MemoryStream())
 {
  var penc = new PngBitmapEncoder();
  penc.Frames.Add(BitmapFrame.Create(rtb));
  penc.Save(ms1);

  var pngBytes = ms1.ToArray();
  var byteCount = pngBytes.GetLength(0);

  //.cur format spec <a href="http://en.wikipedia.org/wiki/ICO_(file_format"><font color="#0066cc">http://en.wikipedia.org/wiki/ICO_(file_format</font></a>)
  using (var stream = new MemoryStream())
  {
   //ICONDIR Structure
   stream.Write(BitConverter.GetBytes((Int16) 0), 0, 2); //Reserved must be zero; 2 bytes
   stream.Write(BitConverter.GetBytes((Int16) 2), 0, 2); //image type 1 = ico 2 = cur; 2 bytes
   stream.Write(BitConverter.GetBytes((Int16) 1), 0, 2); //number of images; 2 bytes
   //ICONDIRENTRY structure
   stream.WriteByte(32); //image width in pixels
   stream.WriteByte(32); //image height in pixels

   stream.WriteByte(0); //Number of Colors. Should be 0 if the image doesn't use a color palette
   stream.WriteByte(0); //reserved must be 0

   stream.Write(BitConverter.GetBytes((Int16) (size*xHotPointRatio)), 0, 2);
   //2 bytes. In CUR format: Specifies the number of pixels from the left.
   stream.Write(BitConverter.GetBytes((Int16) (size*yHotPointRatio)), 0, 2);
   //2 bytes. In CUR format: Specifies the number of pixels from the top.

   //Specifies the size of the image's data in bytes
   stream.Write(BitConverter.GetBytes(byteCount), 0, 4);
   stream.Write(BitConverter.GetBytes((Int32) 22), 0, 4);
   //Specifies the offset of BMP or PNG data from the beginning of the ICO/CUR file
   stream.Write(pngBytes, 0, byteCount); //write the png data.
   stream.Seek(0, SeekOrigin.Begin);
   return new System.Windows.Input.Cursor(stream);
  }
 }
}

用于翻转和旋转的变换 当发生水平或垂直翻转或旋转时，将调用TransformImage。 隐藏,复制Code

private static void TransformImage(DrawingGroup drawingGroup, double angle, FlipValues flip)
{
 if (flip == FlipValues.None && Math.Abs(angle) < .1) return;
 if (flip == FlipValues.None)
  drawingGroup.Transform = new RotateTransform(angle);
 if (Math.Abs(angle) < .1)
  drawingGroup.Transform = new ScaleTransform(flip == FlipValues.Vertical ? -1 : 1, flip == FlipValues.Horizontal ? -1 : 1);
 else
 {
  var transformGroup = new TransformGroup();
  transformGroup.Children.Add(new ScaleTransform(flip == FlipValues.Vertical ? -1 : 1, flip == FlipValues.Horizontal ? -1 : 1));
  transformGroup.Children.Add(new RotateTransform(angle));
  drawingGroup.Transform = transformGroup;
 }
}

基本公共方法调用 CreateCursor使用这两个方法返回使用FontFamily中指定符号的游标对象。这是创建游标对象时调用的公共方法: 隐藏,复制Code

public static System.Windows.Input.Cursor CreateCursor(int size, double xHotPointRatio,
 double yHotPointRatio, FontFamily fontFamily, string symbol, Brush brush, double rotationAngle = 0)
{
 var vis = new DrawingVisual();
 using (var dc = vis.RenderOpen())
 {
  dc.DrawGlyphRun(brush, GetGlyphRun(size, fontFamily, symbol));
  dc.Close();
 }/*CreateGlyphRun(symbol, fontFamily, FontStyles.Normal, FontWeights.Normal, FontStretches.Normal)*/
 if (Math.Abs(rotationAngle) > .1)
   vis.Transform = new RotateTransform(rotationAngle, size / 2, size / 2);
 var renderTargetBitmap = new RenderTargetBitmap(size, size, 96, 96, PixelFormats.Pbgra32);
 renderTargetBitmap.Render(vis);

 return CreateCursorObject(size, xHotPointRatio, yHotPointRatio, renderTargetBitmap);
}

使用的代码 在WPF中，你可能想要在窗口初始化时设置光标: 隐藏,复制Code

public MainWindow()
{
 InitializeComponent();
 Mouse.OverrideCursor = FontSymbolCursor.CreateCursor(100, .5, .03, "arial",
  'A'.ToString, System.Windows.Media.Brushes.Black);
}

BaseWindow类 在示例中，MainWindow继承了BaseWindow类。 隐藏,复制Code

<fontAwesomeImageSample:BaseWindow x:Class="FontAwesomeImageSample.MainWindow"
        xmlns="<a href="http://schemas.microsoft.com/winfx/2006/xaml/presentation">http://schemas.microsoft.com/winfx/2006/xaml/presentation</a>"
        xmlns:x="<a href="http://schemas.microsoft.com/winfx/2006/xaml">http://schemas.microsoft.com/winfx/2006/xaml</a>"
        xmlns:d="<a href="http://schemas.microsoft.com/expression/blend/2008">http://schemas.microsoft.com/expression/blend/2008</a>"
        xmlns:fontAwesomeImageSample="clr-namespace:FontAwesomeImageSample"
        xmlns:mc="<a href="http://schemas.openxmlformats.org/markup-compatibility/2006">http://schemas.openxmlformats.org/markup-compatibility/2006</a>"
        Title="Font Awesome Icon Image &amp; Cursor"
        Width="525"
        Height="350"
        mc:Ignorable="d">
 <Grid>
  <Button Margin="50"
          HorizontalAlignment="Center"
          VerticalAlignment="Center"
          Click="ButtonBase_OnClick">
   <fontAwesomeImageSample:FontSymbolImage Foreground="HotPink"
                                           FontFamily="{StaticResource FontAwesomeTtf}"
                       Flip="Horizontal"
                       Rotation="10"
                                           FontAwesomeSymbol="fa_bar_chart_o" />
  </Button>
 </Grid>
</fontAwesomeImageSample:BaseWindow>

BaseWindow类具有IsBusy DependencyProperty并创建一个箭头光标和几个Busy光标。当IsBusy从true变为false时，光标将从它的普通箭头变为沙漏，沙漏将清空并旋转。要完成动画，需要使用DispatchTimer。当IsBusy DependencyProperty设置为true时启动，当设置为false时停止: 隐藏,收缩,复制Code

 public class BaseWindow : Window
 {
  private const int CursorSize = 32;
  private readonly DispatcherTimer _updateTimer;
  private readonly System.Windows.Input.Cursor _normalCursor;
  private readonly System.Windows.Input.Cursor _busyCursor;
  private readonly System.Windows.Input.Cursor[] _busyCursors;
  private int _busyCursorNumber;  public BaseWindow()
  {
   _updateTimer = new DispatcherTimer { Interval = new TimeSpan(0, 0, 1) };
   _updateTimer.Tick += UpdateBusyCursor;
   System.Windows.Input.Mouse.OverrideCursor = _normalCursor 
        = FontSymbolCursor.CreateCursor(CursorSize, .2, 0, "FontAwesome",
          FontSymbolImage.FontAwesomeSymbols.fa_mouse_pointer, System.Windows.Media.Brushes.Black);
   _busyCursors = new[] {
     FontSymbolCursor.CreateCursor(CursorSize, .5, .5, "FontAwesome",
       FontSymbolImage.FontAwesomeSymbols.fa_hourglass_start, System.Windows.Media.Brushes.Black),
     FontSymbolCursor.CreateCursor(CursorSize, .5, .5, "FontAwesome",
       FontSymbolImage.FontAwesomeSymbols.fa_hourglass_half, System.Windows.Media.Brushes.Black),
     FontSymbolCursor.CreateCursor(CursorSize, .5, .5, "FontAwesome",
       FontSymbolImage.FontAwesomeSymbols.fa_hourglass_end, System.Windows.Media.Brushes.Black),
     FontSymbolCursor.CreateCursor(CursorSize, .5, .5, "FontAwesome",
       FontSymbolImage.FontAwesomeSymbols.fa_hourglass_end, System.Windows.Media.Brushes.Black, 90.0)};
  }

  public static readonly DependencyProperty IsBusyProperty =
    DependencyProperty.Register("IsBusy", typeof(bool), typeof(BaseWindow), 
    new PropertyMetadata(false, PropertyChangedCallback));
  public bool IsBusy { 
    get { return (bool)GetValue(IsBusyProperty); } 
    set { SetValue(IsBusyProperty, value); } 
  }

  private static void PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
  {
   var window = (BaseWindow)d;
   if (window.IsBusy)
   {
    window._busyCursorNumber = 0;
    window._updateTimer.Start();
    System.Windows.Input.Mouse.OverrideCursor = window._busyCursors[0];
   }
   else
   {
    window._updateTimer.Stop();
    System.Windows.Input.Mouse.OverrideCursor = window._normalCursor;
   }
  }

  private void UpdateBusyCursor(object sender, EventArgs e)
  {
   _busyCursorNumber = ++_busyCursorNumber % _busyCursors.Length;
   System.Windows.Input.Mouse.OverrideCursor = _busyCursors[_busyCursorNumber];
  }
 }

这个示例是一个简单的表单，只有一个大按钮，其中包含一个非常棒的字体字符。如果单击此按钮，光标将在两秒钟内变为一个旋转的沙漏。 上面光标的实际XAML为: 隐藏,复制Code

<Button Margin="50"
        HorizontalAlignment="Center"
        VerticalAlignment="Center"
        Click="ButtonBase_OnClick">
 <fontAwesomeImageSample:FontSymbolImage Foreground="HotPink"
                                         FontFamily="{StaticResource FontAwesomeTtf}"
                                 Flip="Horizontal"
                                 Rotation="10"
                                         FontAwesomeSymbol="fa_bar_chart_o" />
</Button>

额外的 示例包括从字体符号创建WPF图像的代码。这是在为WPF创建一个从字体符号(字体Awesome)的图像文件 历史 更新05/12/2015:更新样例更改光标时按钮点击05/17/2016:更新代码与改进的等待光标实现05/20/2016:更新代码与新的BaseWindow控件 本文转载于：http://www.diyabc.com/frontweb/news286.html