Leandro Ascierto

Modulo Clase para dibujar texto utilizando GDI+ tiene funciones básicas como poder asignar la fuente, color, alineación, alineación vertical, Flags del formato, Trimming, Opacity. Para los que ya utilizaron alguna vez el api DrawText de «User32» no les resultara muy difícil de implementar.

Option Explicit
'--------------------------------------------
'Autor: Leandro Ascierto
'Web:   www.leandroascierto.com.ar
'Date:  27/12/2009
'--------------------------------------------
Private Declare Function GdipCreateFont Lib "gdiplus" (ByVal fontFamily As Long, ByVal emSize As Single, ByVal Style As GDIPLUS_FONTSTYLE, ByVal UNIT As Long, createdfont As Long) As Long
Private Declare Function GdipCreateFontFamilyFromName Lib "gdiplus" (ByVal name As String, ByVal fontCollection As Long, fontFamily As Long) As Long
Private Declare Function GdipCreateSolidFill Lib "gdiplus" (ByVal argb As Long, brush As Long) As Long
Private Declare Function GdipCreateStringFormat Lib "gdiplus" (ByVal formatAttributes As Long, ByVal language As Integer, StringFormat As Long) As Long
Private Declare Function GdipDeleteBrush Lib "gdiplus" (ByVal brush As Long) As Long
Private Declare Function GdipDeleteFont Lib "gdiplus" (ByVal curFont As Long) As Long
Private Declare Function GdipDeleteFontFamily Lib "gdiplus" (ByVal fontFamily As Long) As Long
Private Declare Function GdipDeleteStringFormat Lib "gdiplus" (ByVal StringFormat As Long) As Long
Private Declare Function GdipDrawString Lib "gdiplus" (ByVal graphics As Long, ByVal str As String, ByVal Length As Long, ByVal thefont As Long, layoutRect As RECTF, ByVal StringFormat As Long, ByVal brush As Long) As Long
Private Declare Function GdipSetStringFormatAlign Lib "gdiplus" (ByVal StringFormat As Long, ByVal Align As StringAlignment) As Long
Private Declare Function GdipSetStringFormatLineAlign Lib "gdiplus" (ByVal StringFormat As Long, ByVal Align As StringAlignment) As Long
Private Declare Function GdipSetStringFormatFlags Lib "GdiPlus.dll" (ByVal mFormat As Long, ByVal mFlags As StringFormatFlags) As Long
Private Declare Function GdipSetStringFormatTrimming Lib "GdiPlus.dll" (ByVal mFormat As Long, ByVal mTrimming As StringTrimming) As Long
Private Declare Function GdiplusStartup Lib "gdiplus" (Token As Long, inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As Long
Private Declare Function GdipCreateFromHDC Lib "gdiplus" (ByVal Hdc As Long, hGraphics As Long) As Long
Private Declare Function GdipDeleteGraphics Lib "gdiplus" (ByVal hGraphics As Long) As Long
Private Declare Sub GdiplusShutdown Lib "gdiplus" (ByVal Token As Long)
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Declare Function GetDeviceCaps Lib "gdi32" (ByVal Hdc As Long, ByVal nIndex As Long) As Long
Private Declare Function MulDiv Lib "kernel32.dll" (ByVal nNumber As Long, ByVal nNumerator As Long, ByVal nDenominator As Long) As Long
 
Private Type GdiplusStartupInput
    GdiplusVersion           As Long
    DebugEventCallback       As Long
    SuppressBackgroundThread As Long
    SuppressExternalCodecs   As Long
End Type
 
Private Type RECTF
    Left    As Single
    Top     As Single
    Width   As Single
    Height  As Single
End Type
 
Public Enum GDIPLUS_FONTSTYLE
    FontStyleRegular = 0
    FontStyleBold = 1
    FontStyleItalic = 2
    FontStyleBoldItalic = 3
    FontStyleUnderline = 4
    FontStyleStrikeout = 8
End Enum
 
Public Enum StringAlignment
    StringAlignmentNear = &H0
    StringAlignmentCenter = &H1
    StringAlignmentFar = &H2
End Enum
 
Public Enum StringTrimming
    StringTrimmingNone = &H0
    StringTrimmingCharacter = &H1
    StringTrimmingWord = &H2
    StringTrimmingEllipsisCharacter = &H3
    StringTrimmingEllipsisWord = &H4
    StringTrimmingEllipsisPath = &H5
End Enum
 
Public Enum StringFormatFlags
    StringFormatFlagsNone = &H0
    StringFormatFlagsDirectionRightToLeft = &H1
    StringFormatFlagsDirectionVertical = &H2
    StringFormatFlagsNoFitBlackBox = &H4
    StringFormatFlagsDisplayFormatControl = &H20
    StringFormatFlagsNoFontFallback = &H400
    StringFormatFlagsMeasureTrailingSpaces = &H800
    StringFormatFlagsNoWrap = &H1000
    StringFormatFlagsLineLimit = &H2000
    StringFormatFlagsNoClip = &H4000
End Enum
 
Private Const LOGPIXELSY         As Long = 90
 
Private m_Font                  As StdFont
Private m_Color                 As OLE_COLOR
Private m_Alignment             As StringAlignment
Private m_VerticalAlignment     As StringAlignment
Private m_FormatFlags           As StringFormatFlags
Private m_Trimming              As StringTrimming
Private m_Opacity               As Long
 
Private Sub Class_Initialize()
    Set m_Font = New StdFont
    m_Font.name = "Tahoma"
    m_Color = vbWindowText
    m_Opacity = 100
End Sub
 
Private Sub Class_Terminate()
    Set m_Font = Nothing
End Sub
 
Public Property Get Font() As StdFont
    Set Font = m_Font
End Property
 
Public Property Let Font(ByVal NewFont As StdFont)
    Set m_Font = NewFont
End Property
 
Public Property Get Color() As OLE_COLOR
    Color = m_Color
End Property
 
Public Property Let Color(ByVal NewColor As OLE_COLOR)
    m_Color = NewColor
End Property
 
Public Property Get Alignment() As StringAlignment
    Alignment = m_Alignment
End Property
 
Public Property Let Alignment(ByVal NewAlignment As StringAlignment)
    m_Alignment = NewAlignment
End Property
 
Public Property Get VerticalAlignment() As StringAlignment
    VerticalAlignment = m_VerticalAlignment
End Property
 
Public Property Let VerticalAlignment(ByVal NewVerticalAlignment As StringAlignment)
    m_VerticalAlignment = NewVerticalAlignment
End Property
 
Public Property Get FormatFlags() As StringFormatFlags
    FormatFlags = m_FormatFlags
End Property
 
Public Property Let FormatFlags(ByVal NewFormatFlags As StringFormatFlags)
    m_FormatFlags = NewFormatFlags
End Property
 
Public Property Get Trimming() As StringTrimming
    Trimming = m_Trimming
End Property
 
Public Property Let Trimming(ByVal NewTrimming As StringTrimming)
    m_Trimming = NewTrimming
End Property
 
Public Property Get Opacity() As Long
    Opacity = m_Opacity
End Property
 
Public Property Let Opacity(ByVal NewOpacity As Long) 
    m_Opacity = NewOpacity 
    If m_Opacity < 0 Then
        Opacity = 0
    ElseIf m_Opacity > 100 Then
        m_Opacity = 100
    End If 
End Property
  
Public Function DrawString(ByVal Hdc As Long, _
                        ByVal Text As String, _
                        ByVal X As Single, _
                        ByVal Y As Single, _
                        Optional ByVal Width As Single, _
                        Optional ByVal Height As Single) As Boolean
 
    On Error Resume Next
 
    Dim hGraphic As Long
    Dim lBrush As Long
    Dim lFontFamily As Long
    Dim lCurrentFont As Long
    Dim lFontSize As Long
    Dim lFontStyle As GDIPLUS_FONTSTYLE
    Dim lFormat As Long
    Dim RctText As RECTF
    Dim GdiToken As Long
    Dim GDIsi As GdiplusStartupInput
 
    GDIsi.GdiplusVersion = 1&
 
    If GdiplusStartup(GdiToken, GDIsi) = 0 Then 
        Call GdipCreateFromHDC(Hdc, hGraphic) 
        GdipCreateSolidFill ConvertColor(m_Color, m_Opacity), lBrush 
        GdipCreateFontFamilyFromName StrConv(m_Font.name, vbUnicode), 0, lFontFamily
 
        If m_Font.Bold Then lFontStyle = lFontStyle Or FontStyleBold
        If m_Font.Italic Then lFontStyle = lFontStyle Or FontStyleItalic
        If m_Font.Strikethrough Then lFontStyle = lFontStyle Or FontStyleStrikeout
        If m_Font.Underline Then lFontStyle = lFontStyle Or FontStyleUnderline
 
        lFontSize = MulDiv(m_Font.Size, GetDeviceCaps(Hdc, LOGPIXELSY), 72) 
        GdipCreateFont lFontFamily, lFontSize, lFontStyle, 0, lCurrentFont
 
        If GdipCreateStringFormat(0, 0, lFormat) = 0 Then
            If m_FormatFlags Then GdipSetStringFormatFlags lFormat, m_FormatFlags
            If m_Alignment Then GdipSetStringFormatAlign lFormat, m_Alignment
            If m_Trimming Then GdipSetStringFormatTrimming lFormat, m_Trimming
            If m_VerticalAlignment Then GdipSetStringFormatLineAlign lFormat, m_VerticalAlignment
        End If
 
        With RctText
            .Left = X
            .Top = Y
            .Width = Width
            .Height = Height
        End With
 
        DrawString = GdipDrawString(hGraphic, StrConv(Text, vbUnicode), -1, lCurrentFont, RctText, lFormat, lBrush) = 0
 
        GdipDeleteStringFormat lFormat
        GdipDeleteFont lCurrentFont
        GdipDeleteFontFamily lFontFamily
        GdipDeleteBrush lBrush
        GdipDeleteGraphics hGraphic
        GdiplusShutdown GdiToken
    End If
End Function
  
Private Function ConvertColor(Color As Long, Opacity As Long) As Long
    Dim BGRA(0 To 3) As Byte
 
    BGRA(3) = CByte((Abs(Opacity) / 100) * 255)
    BGRA(0) = ((Color \ &H10000) And &HFF)
    BGRA(1) = ((Color \ &H100) And &HFF)
    BGRA(2) = (Color And &HFF)
    CopyMemory ConvertColor, BGRA(0), 4&
End Function

Este es un pequeño módulo para convertir archivos de imágenes de un formato a otro. Es muy sencillo de usar, sólo basta con llamar a la función ConvertFileImage, donde pasamos como primer parámetro el Path de la imágen de origen y como segundo parámetro el Path de destino más el nombre y extensión. El tercer parámetro es opcional y es un valor de 0 a 100 en los caso que la extensión de destino sea .JPG, para elegir la calidad de conversión.
También cuenta con una función llamada IsGdiPlusInstaled que es para averiguar si el PC que ejecute el programa tiene instalado GDI Plus.
No tiene muchas opciones ya que el módulo intenta ser algo pequeño para pocas pretensiones.
Las extensiones de de lectura soportadas son: «BMP, DIB, JPG, JPEG, JPE, JFIF, GIF, PNG, TIF, TIFF, EMF, WMF, ICO, CUR».
y las extensiones de conversión soportadas son: «BMP, DIB, JPG, JPEG, JPE, JFIF, GIF, PNG, TIF, TIFF».

* Edit 06/02/2010, corrección en el código, me confundí en poner PGN, por PGN.

Option Explicit
'--------------------------------------------
'Autor: Leandro Ascierto
'Web: www.leandroascierto.com.ar
'Date: 01/11/2009
'--------------------------------------------
Private Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryA" (ByVal lpLibFileName As String) As Long
Private Declare Function FreeLibrary Lib "kernel32" (ByVal hLibModule As Long) As Long
Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Long, ByVal lpProcName As String) As Long
Private Declare Function GdiplusStartup Lib "gdiplus" (Token As Long, inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As Long
Private Declare Function GdipLoadImageFromFile Lib "GdiPlus.dll" (ByVal mFilename As Long, ByRef mImage As Long) As Long
Private Declare Function GdipDisposeImage Lib "gdiplus" (ByVal image As Long) As Long
Private Declare Sub GdiplusShutdown Lib "gdiplus" (ByVal Token As Long)
Private Declare Function GdipSaveImageToFile Lib "gdiplus" (ByVal image As Long, ByVal FileName As Long, ByRef clsidEncoder As GUID, ByRef encoderParams As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32" (ByVal str As Long, id As GUID) As Long
 
Private Type GUID
    Data1           As Long
    Data2           As Integer
    Data3           As Integer
    Data4(0 To 7)   As Byte
End Type
 
Private Type EncoderParameter
    GUID            As GUID
    NumberOfValues  As Long
    type            As Long
    Value           As Long
End Type
 
Private Type EncoderParameters
    Count           As Long
    Parameter(15)   As EncoderParameter
End Type
 
Private Type GdiplusStartupInput
    GdiplusVersion           As Long
    DebugEventCallback       As Long
    SuppressBackgroundThread As Long
    SuppressExternalCodecs   As Long
End Type 
 
Const ImageCodecBMP = "{557CF400-1A04-11D3-9A73-0000F81EF32E}"
Const ImageCodecJPG = "{557CF401-1A04-11D3-9A73-0000F81EF32E}"
Const ImageCodecGIF = "{557CF402-1A04-11D3-9A73-0000F81EF32E}"
Const ImageCodecTIF = "{557CF405-1A04-11D3-9A73-0000F81EF32E}"
Const ImageCodecPNG = "{557CF406-1A04-11D3-9A73-0000F81EF32E}"
 
Const EncoderQuality = "{1D5BE4B5-FA4A-452D-9CDD-5DB35105E7EB}"
Const EncoderCompression = "{E09D739D-CCD4-44EE-8EBA-3FBF8BE4FC58}"
 
Const TiffCompressionNone = 6
Const EncoderParameterValueTypeLong = 4
 
Public Function ConvertFileImage(ByVal SrcPath As String, ByVal DestPath As String, Optional ByVal JPG_Quality As Long = 85) As Boolean
 
    On Error Resume Next
    Dim GDIsi As GdiplusStartupInput, gToken As Long, hBitmap As Long
    Dim tEncoder  As GUID
    Dim tParams     As EncoderParameters
    Dim sExt        As String
    Dim lPos        As Long
 
    DestPath = Trim(DestPath)
 
    lPos = InStrRev(DestPath, ".")
    If lPos Then
        sExt = UCase(Right(DestPath, Len(DestPath) - lPos))
    End If
 
    Select Case sExt
        Case "PNG"
            CLSIDFromString StrPtr(ImageCodecPNG), tEncoder 
        Case "TIF", "TIFF"
            CLSIDFromString StrPtr(ImageCodecTIF), tEncoder
 
            With tParams
                .Count = 1
                .Parameter(0).NumberOfValues = 1
                .Parameter(0).type = EncoderParameterValueTypeLong
                .Parameter(0).Value = VarPtr(TiffCompressionNone)
                CLSIDFromString StrPtr(EncoderCompression), .Parameter(0).GUID
            End With
 
        Case "BMP", "DIB"
            CLSIDFromString StrPtr(ImageCodecBMP), tEncoder
 
        Case "GIF"
            CLSIDFromString StrPtr(ImageCodecGIF), tEncoder
 
        Case "JPG", "JPEG", "JPE", "JFIF" 
            If JPG_Quality > 100 Then JPG_Quality = 100
            If JPG_Quality < 0 Then JPG_Quality = 0
 
            CLSIDFromString StrPtr(ImageCodecJPG), tEncoder
 
            With tParams
                .Count = 1
                .Parameter(0).NumberOfValues = 1
                .Parameter(0).type = EncoderParameterValueTypeLong
                .Parameter(0).Value = VarPtr(JPG_Quality)
                CLSIDFromString StrPtr(EncoderQuality), .Parameter(0).GUID
            End With
 
        Case Else
            Exit Function
 
    End Select
 
    GDIsi.GdiplusVersion = 1& 
    GdiplusStartup gToken, GDIsi
 
    If gToken Then
        If GdipLoadImageFromFile(StrPtr(SrcPath), hBitmap) = 0 Then 
            If GdipSaveImageToFile(hBitmap, StrPtr(DestPath), tEncoder,ByVal  tParams) = 0 Then
                ConvertFileImage = True
            End If 
            GdipDisposeImage hBitmap 
        End If 
        GdiplusShutdown gToken
    End If
 
End Function 
 
Public Function IsGdiPlusInstaled() As Boolean
    Dim hLib As Long
 
    hLib = LoadLibrary("gdiplus.dll")
    If hLib Then
        If GetProcAddress(hLib, "GdiplusStartup") Then
            IsGdiPlusInstaled = True
        End If
        FreeLibrary hLib
    End If
 
End Function