Type Default Read Only Description
[C#]
IDictionary<char, int>

[Visual Basic]
IDictionary<char, int>
n/a Yes The widths of the characters in the font.

 

   

Notes
 

The character widths for all the characters in the font.

The array is indexable by Unicode value. For example to find the width of a space (ASCII 32) you would simply reference item 32 in the collection. The values are measured in in 1000ths of a PDF unit.

Font subsetting can result in characters being partially or completely removed from a font. ABCpdf will attempt to ensure that the Widths collection only contains entries for valid characters. However sometimes it is difficult to tell and as such you cannot rely on a character being present simply because it has a width.

 

   

Example
 

The example below shows how to add text on a curve and text flowing round a circle.

[C#]
void Example() {
  string theFont = "Comic Sans MS";
  string theText = "Gallia est omnis divisa in partes tres, quarum unam incolunt Belgae...";
  string theTitle = "Commentarii de Bello Gallico";
  using (Doc doc = new Doc()) {
    doc.FontSize = 36;
    doc.TextStyle.Kerning = XTextStyle.KerningType.None;
    doc.Font = doc.EmbedFont(theFont, LanguageType.Latin, false, true, false);
    // add some radial text in the top middle of the page
    double cx = doc.MediaBox.Width * 0.5;
    double cy = doc.MediaBox.Height * 0.6;
    double r = doc.MediaBox.Width * 0.3;
    CurvedText.AddRadial(doc, theText, cx, cy, r, 225, true, false);
    // add some curved text to a rectangle
    double width = doc.MeasureText(theTitle);
    doc.Rect.SetRect(100, 100, width, doc.FontSize * 1.5);
    doc.FrameRect();
    CurvedText.AddCurved(doc, theTitle);
    // save
    doc.Save("ExampleCurvedText.pdf");
  }
}

class CurvedText {
  public static void AddCurved(Doc doc, string text) {
    double halfWidth = doc.Rect.Width / 2;
    double height = doc.Rect.Height - doc.TextStyle.Size;
    double radius = ((halfWidth * halfWidth) + (height * height)) / (2 * height);
    double centerX = doc.Rect.Left + halfWidth;
    double centerY = doc.Rect.Bottom + radius + doc.TextStyle.Size;
    double alpha = Math.Asin(halfWidth / radius) - Math.PI;
    AddRadial(doc, text, centerX, centerY, radius, RadiansToDegrees(alpha), true, false);
  }

  public static void AddRadial(Doc doc, string text, double centerX, double centerY, double radius, double startAngleDegrees, bool inside, bool clockwise) {
    FontObject font = doc.ObjectSoup[doc.Font] as FontObject;
    IDictionary<char, int> widths = font.Widths;
    int n = text.Length;
    double a = DegreesToRadians(startAngleDegrees);
    double fontWidthToRadians = doc.TextStyle.Size / (radius * 1000);
    doc.Rect.String = doc.MediaBox.String;
    for (int i = 0; i < n; i++) {
      // work out position
      double x = centerX + (Math.Sin(a) * radius);
      double y = centerY + (Math.Cos(a) * radius);
      // add a character
      doc.Pos.X = x;
      doc.Pos.Y = y;
      doc.Transform.Reset();
      double charRotation = inside ? RadiansToDegrees(-a) + 180 : RadiansToDegrees(-a);
      doc.Transform.Rotate(charRotation, x, y);
      doc.AddText(text[i].ToString());
      // increment angle
      double da = Convert.ToDouble(widths[text[i]]) * fontWidthToRadians;
      a += clockwise ? da : -da;
    }
    doc.Transform.Reset();
  }

  private static double DegreesToRadians(double degrees) {
    return degrees * Math.PI / 180;
  }

  private static double RadiansToDegrees(double radians) {
    return radians * 180 / Math.PI;
  }
}

[Visual Basic]
Sub ...
  Dim theFont As String = "Comic Sans MS"
  Dim theText As String = "Gallia est omnis divisa in partes tres, quarum unam incolunt Belgae..."
  Dim theTitle As String = "Commentarii de Bello Gallico"
  Using doc As New Doc()
    doc.FontSize = 36
    doc.TextStyle.Kerning = XTextStyle.KerningType.None
    doc.Font = doc.EmbedFont(theFont, LanguageType.Latin, False, True, False)
    ' add some radial text in the top middle of the page
    Dim cx As Double = doc.MediaBox.Width * 0.5
    Dim cy As Double = doc.MediaBox.Height * 0.6
    Dim r As Double = doc.MediaBox.Width * 0.3
    CurvedText.AddRadial(doc, theText, cx, cy, r, 225, _
      True, False)
    ' add some curved text to a rectangle
    Dim width As Double = doc.MeasureText(theTitle)
    doc.Rect.SetRect(100, 100, width, doc.FontSize * 1.5)
    doc.FrameRect()
    CurvedText.AddCurved(doc, theTitle)
    ' save
    doc.Save("ExampleCurvedText.pdf")
  End Using
End Sub

Private Class CurvedText
  Public Shared Sub AddCurved(doc As Doc, text As String)
    Dim halfWidth As Double = doc.Rect.Width / 2
    Dim height As Double = doc.Rect.Height - doc.TextStyle.Size
    Dim radius As Double = ((halfWidth * halfWidth) + (height * height)) / (2 * height)
    Dim centerX As Double = doc.Rect.Left + halfWidth
    Dim centerY As Double = doc.Rect.Bottom + radius + doc.TextStyle.Size
    Dim alpha As Double = Math.Asin(halfWidth / radius) - Math.PI
    AddRadial(doc, text, centerX, centerY, radius, RadiansToDegrees(alpha), _
      True, False)
  End Sub

  Public Shared Sub AddRadial(doc As Doc, text As String, centerX As Double, centerY As Double, radius As Double, startAngleDegrees As Double, _
    inside As Boolean, clockwise As Boolean)
    Dim font As FontObject = TryCast(doc.ObjectSoup(doc.Font), FontObject)
    Dim widths As IDictionary(Of Char, Integer) = font.Widths
    Dim n As Integer = text.Length
    Dim a As Double = DegreesToRadians(startAngleDegrees)
    Dim fontWidthToRadians As Double = doc.TextStyle.Size / (radius * 1000)
    doc.Rect.[String] = doc.MediaBox.[String]
    For i As Integer = 0 To n - 1
      ' work out position
      Dim x As Double = centerX + (Math.Sin(a) * radius)
      Dim y As Double = centerY + (Math.Cos(a) * radius)
      ' add a character
      doc.Pos.X = x
      doc.Pos.Y = y
      doc.Transform.Reset()
      Dim charRotation As Double = If(inside, RadiansToDegrees(-a) + 180, RadiansToDegrees(-a))
      doc.Transform.Rotate(charRotation, x, y)
      doc.AddText(text(i).ToString())
      ' increment angle
      Dim da As Double = Convert.ToDouble(widths(text(i))) * fontWidthToRadians
      a += If(clockwise, da, -da)
    Next
    doc.Transform.Reset()
  End Sub

  Private Shared Function DegreesToRadians(degrees As Double) As Double
    Return degrees * Math.PI / 180
  End Function

  Private Shared Function RadiansToDegrees(radians As Double) As Double
    Return radians * 180 / Math.PI
  End Function
End Class


ExampleCurvedText.pdf