'' 完毕：
Imports System.IO
Imports System.Drawing
Imports GrapeCity.Documents.Pdf
Imports GrapeCity.Documents.Text
Imports GCTEXT = GrapeCity.Documents.Text
Imports GCDRAW = GrapeCity.Documents.Drawing

'' GcDocs.Pdf 支持连字（将两个或多个字母连接成一个字形），
'' 前提是所选字体支持它们，并且相应的字体功能已打开。
'' 有关字体功能的完整列表，请参阅
Public Class Ligatures
    Function CreatePDF(ByVal stream As Stream) As Integer
        '' 常见拉丁连字列表：
        Const latinLigatures = "fi, fj, fl, ff, ffi, ffl."
        '' 设置与连字相关的字体功能：
        '' 全部开启：
        Dim allOn As FontFeature() = {
                New FontFeature(FeatureTag.clig, True), '' Contextual Ligatures
                New FontFeature(FeatureTag.dlig, True), '' Discretionary Ligatures
                New FontFeature(FeatureTag.hlig, True), '' Historical Ligatures
                New FontFeature(FeatureTag.liga, True), '' Standard Ligatures
                New FontFeature(FeatureTag.rlig, True)  '' Required Ligatures
            }
        '' 全部关闭：
        Dim allOff As FontFeature() = {
                New FontFeature(FeatureTag.clig, False),
                New FontFeature(FeatureTag.dlig, False),
                New FontFeature(FeatureTag.hlig, False),
                New FontFeature(FeatureTag.liga, False),
                New FontFeature(FeatureTag.rlig, False)
            }
        Dim doc = New GcPdfDocument()
        Dim g = doc.NewPage().Graphics
        '' 文本插入点：
        Dim ip = New PointF(72, 72)
        Dim tf = New TextFormat()
        tf.Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "times.ttf"))
        tf.FontSize = 20
        g.DrawString($"Common Latin ligatures, font {tf.Font.FontFamilyName}", tf, ip)
        ip.Y += 36
        '' 关闭所有连字功能：
        tf.FontFeatures = allOff
        g.DrawString($"All ligature features OFF: {latinLigatures}", tf, ip)
        ip.Y += 36
        '' 打开所有连字功能：
        tf.FontFeatures = allOn
        g.DrawString($"All ligature features ON: {latinLigatures}", tf, ip)
        ip.Y += 72
        '' 使用不同的字体重复：
        tf.Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "Gabriola.ttf"))
        g.DrawString($"Common Latin ligatures, font {tf.Font.FontFamilyName}", tf, ip)
        ip.Y += 36
        '' 关闭所有连字功能：
        tf.FontFeatures = allOff
        g.DrawString($"All ligature features OFF: {latinLigatures}", tf, ip)
        ip.Y += 36
        '' 打开所有连字功能：
        tf.FontFeatures = allOn
        g.DrawString($"All ligature features ON: {latinLigatures}", tf, ip)
        ''
        '' Done:
        doc.Save(stream)
        Return doc.Pages.Count
    End Function
End Class