VB的gdi+相关声明

模块：

Option Explicit

Public Declare Function GdiplusStartup Lib "gdiplus" (token As Long, inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As GpStatus
Public Declare Function GdiplusShutdown Lib "gdiplus" (ByVal token As Long) As GpStatus

Public Declare Function GdipCreateFromHDC Lib "gdiplus" (ByVal hDC As Long, graphics As Long) As GpStatus
Public Declare Function GdipDeleteGraphics Lib "gdiplus" (ByVal graphics As Long) As GpStatus
Public Declare Function GdipSetSmoothingMode Lib "gdiplus" (ByVal graphics As Long, ByVal SmoothingMd As SmoothingMode) As GpStatus
Public Declare Function GdipSetInterpolationMode Lib "gdiplus" (ByVal graphics As Long, ByVal interpolation As InterpolationMode) As GpStatus
Public Declare Function GdipSetCompositingQuality Lib "gdiplus" (ByVal graphics As Long, ByVal CompositingQlty As CompositingQuality) As GpStatus

Public Declare Function GdipRotateWorldTransform Lib "gdiplus" (ByVal graphics As Long, ByVal angle As Single, ByVal order As MatrixOrder) As GpStatus
Public Declare Function GdipTranslateWorldTransform Lib "gdiplus" (ByVal graphics As Long, ByVal dx As Single, ByVal dy As Single, ByVal order As MatrixOrder) As GpStatus

Public Declare Function GdipLoadImageFromFile Lib "gdiplus" (ByVal filename As Long, Image As Long) As GpStatus
Public Declare Function GdipDisposeImage Lib "gdiplus" (ByVal Image As Long) As GpStatus
Public Declare Function GdipGetImageWidth Lib "gdiplus" (ByVal Image As Long, Width As Long) As GpStatus
Public Declare Function GdipGetImageHeight Lib "gdiplus" (ByVal Image As Long, Height As Long) As GpStatus
Public Declare Function GdipDrawImageRect Lib "gdiplus" (ByVal graphics As Long, ByVal Image As Long, ByVal x As Single, ByVal y As Single, ByVal Width As Single, ByVal Height As Single) As GpStatus

Public Enum MatrixOrder
   MatrixOrderPrepend = 0
   MatrixOrderAppend = 1
End Enum

Public Enum QualityMode
   QualityModeInvalid = -1
   QualityModeDefault = 0
   QualityModeLow = 1
   QualityModeHigh = 2
End Enum

Public Enum SmoothingMode
   SmoothingModeInvalid = QualityModeInvalid
   SmoothingModeDefault = QualityModeDefault
   SmoothingModeHighSpeed = QualityModeLow
   SmoothingModeHighQuality = QualityModeHigh
   SmoothingModeNone
   SmoothingModeAntiAlias
End Enum

Public Enum InterpolationMode
   InterpolationModeInvalid = QualityModeInvalid
   InterpolationModeDefault = QualityModeDefault
   InterpolationModeLowQuality = QualityModeLow
   InterpolationModeHighQuality = QualityModeHigh
   InterpolationModeBilinear
   InterpolationModeBicubic
   InterpolationModeNearestNeighbor
   InterpolationModeHighQualityBilinear
   InterpolationModeHighQualityBicubic
End Enum

Public Enum CompositingQuality
   CompositingQualityInvalid = QualityModeInvalid
   CompositingQualityDefault = QualityModeDefault
   CompositingQualityHighSpeed = QualityModeLow
   CompositingQualityHighQuality = QualityModeHigh
   CompositingQualityGammaCorrected
   CompositingQualityAssumeLinear
End Enum

Public Type GdiplusStartupInput
   GdiplusVersion As Long
   DebugEventCallback As Long
   SuppressBackgroundThread As Long
   SuppressExternalCodecs As Long
End Type

Public Enum GpStatus
   Ok = 0
   GenericError = 1
   InvalidParameter = 2
   OutOfMemory = 3
   ObjectBusy = 4
   InsufficientBuffer = 5
   NotImplemented = 6
   Win32Error = 7
   WrongState = 8
   Aborted = 9
   FileNotFound = 10
   ValueOverflow = 11
   AccessDenied = 12
   UnknownImageFormat = 13
   FontFamilyNotFound = 14
   FontStyleNotFound = 15
   NotTrueTypeFont = 16
   UnsupportedGdiplusVersion = 17
   GdiplusNotInitialized = 18
   PropertyNotFound = 19
   PropertyNotSupported = 20
End Enum

窗体（AutoRedraw=True）
Option Explicit

Dim token As Long
Dim graphics As Long

Dim img As Long, w As Long, h As Long

Private Sub InitGDIPlus()
    Dim uInput As GdiplusStartupInput
    
    uInput.GdiplusVersion = 1
    If GdiplusStartup(token, uInput) <> Ok Then
        MsgBox "GDI+ 初始化错误。程序即将关闭。", vbCritical, "InitError"
        End
    End If
End Sub
 
Private Sub TerminateGDIPlus()
    GdipDisposeImage img
    GdipDeleteGraphics graphics
    
    GdiplusShutdown token
End Sub
    
Private Sub Form_Load()
    InitGDIPlus
    
    GdipCreateFromHDC Me.hDC, graphics
    'GdipSetSmoothingMode graphics, SmoothingModeAntiAlias
    'GdipSetInterpolationMode graphics, InterpolationModeHighQuality
    'GdipSetCompositingQuality graphics, CompositingQualityHighQuality

    GdipLoadImageFromFile StrPtr(App.Path & "1.png"), img
    GdipGetImageWidth img, w
    GdipGetImageHeight img, h
    
    Rotate 15, graphics, 200, 200
End Sub

Sub Rotate(angle As Single, g As Long, x As Single, y As Integer)
    GdipRotateWorldTransform g, angle, MatrixOrderAppend
    GdipTranslateWorldTransform g, x, y, MatrixOrderAppend
    GdipDrawImageRect g, img, -w, -h / 2, w, h
End Sub
 
Private Sub Form_Unload(Cancel As Integer)
    TerminateGDIPlus
End Sub