专栏首页一心无二用,本人只专注于基础图像算法的实现与优化。VB6.0用GDI+保存图像为BMP\JPG\PNG\GIF格式终结版。

VB6.0用GDI+保存图像为BMP\JPG\PNG\GIF格式终结版。

鉴于之前在http://blog.csdn.net/laviewpbt/article/details/756547发布的代码很匆忙,也存在不少错误,现发布比较完美版的解决方案。

Option Explicit

Private Const UnitPixel                  As Long = 2
Private Const EncoderQuality             As String = "{1D5BE4B5-FA4A-452D-9CDD-5DB35105E7EB}"

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

Private Enum EncoderParameterValueType
    EncoderParameterValueTypeByte = 1
    EncoderParameterValueTypeASCII = 2
    EncoderParameterValueTypeShort = 3
    EncoderParameterValueTypeLong = 4
    EncoderParameterValueTypeRational = 5
    EncoderParameterValueTypeLongRange = 6
    EncoderParameterValueTypeUndefined = 7
    EncoderParameterValueTypeRationalRange = 8
End Enum

Private Type EncoderParameter
    GUID(0 To 3)        As Long
    NumberOfValues      As Long
    Type                As EncoderParameterValueType
    Value               As Long
End Type

Private Type EncoderParameters
    Count               As Long
    Parameter           As EncoderParameter
End Type

Private Type ImageCodecInfo
    ClassID(0 To 3)     As Long
    FormatID(0 To 3)    As Long
    CodecName           As Long
    DllName             As Long
    FormatDescription   As Long
    FilenameExtension   As Long
    MimeType            As Long
    Flags               As Long
    Version             As Long
    SigCount            As Long
    SigSize             As Long
    SigPattern          As Long
    SigMask             As Long
End Type

Private Declare Function GdiplusStartup Lib "gdiplus" (Token As Long, inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As Long
Private Declare Sub GdiplusShutdown Lib "gdiplus" (ByVal Token As Long)
Private Declare Function GdipSaveImageToFile Lib "gdiplus" (ByVal hImage As Long, ByVal sFilename As Long, clsidEncoder As Any, encoderParams As Any) As Long
Private Declare Function GdipDisposeImage Lib "gdiplus" (ByVal Image As Long) As Long
Private Declare Function GdipCreateBitmapFromHBITMAP Lib "gdiplus" (ByVal hbm As Long, ByVal hPal As Long, Bitmap As Long) As Long
Private Declare Function GdipGetImageEncodersSize Lib "gdiplus" (numEncoders As Long, Size As Long) As Long
Private Declare Function GdipGetImageEncoders Lib "gdiplus" (ByVal numEncoders As Long, ByVal Size As Long, Encoders As Any) As Long

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Declare Function lstrlenW Lib "kernel32" (ByVal psString As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32" (ByVal lpszProgID As Long, pCLSID As Any) As Long
Private Declare Function GdipBitmapSetResolution Lib "gdiplus" (ByVal Bitmap As Long, ByVal xdpi As Single, ByVal ydpi As Single) As Long


Public Enum ImageFileFormat
    Bmp = 1
    Jpg = 2
    Png = 3
    Gif = 4
End Enum

Public Function SaveStdPicToFile(Stdpic As StdPicture, ByVal FileName As String, _
                              Optional ByVal FileFormat As ImageFileFormat = Jpg, _
                              Optional ByVal JpgQuality As Long = 80, _
                              Optional Resolution As Single) As Boolean
                              
    Dim CLSID(3)        As Long
    Dim Bitmap          As Long
    Dim Token           As Long
    Dim Gsp             As GdiplusStartupInput

    Gsp.GdiplusVersion = 1                      'GDI+ 1.0版本
    GdiplusStartup Token, Gsp                   '初始化GDI+
    GdipCreateBitmapFromHBITMAP Stdpic.Handle, Stdpic.hPal, Bitmap
    If Bitmap <> 0 Then                          '说明我们成功的将StdPic对象转换为GDI+的Bitmap对象了
        GdipBitmapSetResolution Bitmap, Resolution, Resolution
        Select Case FileFormat
        Case ImageFileFormat.Bmp
            If Not GetEncoderClsID("Image/bmp", CLSID) = -1 Then
                SaveStdPicToFile = (GdipSaveImageToFile(Bitmap, StrPtr(FileName), CLSID(0), ByVal 0) = 0)
            End If
        Case ImageFileFormat.Jpg                    'JPG格式可以设置保存的质量
            Dim aEncParams()        As Byte
            Dim uEncParams          As EncoderParameters
            If GetEncoderClsID("Image/jpeg", CLSID) <> -1 Then
                uEncParams.Count = 1                                        ' 设置自定义的编码参数,这里为1个参数
                If JpgQuality < 0 Then
                    JpgQuality = 0
                ElseIf JpgQuality > 100 Then
                    JpgQuality = 100
                End If
                ReDim aEncParams(1 To Len(uEncParams))
                With uEncParams.Parameter
                    .NumberOfValues = 1
                    .Type = EncoderParameterValueTypeLong                   ' 设置参数值的数据类型为长整型
                    Call CLSIDFromString(StrPtr(EncoderQuality), .GUID(0))  ' 设置参数唯一标志的GUID,这里为编码品质
                    .Value = VarPtr(JpgQuality)                                ' 设置参数的值:品质等级,最高为100,图像文件大小与品质成正比
                End With
                CopyMemory aEncParams(1), uEncParams, Len(uEncParams)
                SaveStdPicToFile = (GdipSaveImageToFile(Bitmap, StrPtr(FileName), CLSID(0), aEncParams(1)) = 0)
            End If
        Case ImageFileFormat.Png
            If Not GetEncoderClsID("Image/png", CLSID) = -1 Then
                SaveStdPicToFile = (GdipSaveImageToFile(Bitmap, StrPtr(FileName), CLSID(0), ByVal 0) = 0)
            End If
        Case ImageFileFormat.Gif
            If Not GetEncoderClsID("Image/gif", CLSID) = -1 Then                '如果原始的图像是24位,则这个函数会调用系统的调色板来将图像转换为8位,转换的效果会不尽人意,但也有可能系统不自动转换,保存失败
                SaveStdPicToFile = (GdipSaveImageToFile(Bitmap, StrPtr(FileName), CLSID(0), ByVal 0) = 0)
            End If
        End Select
    End If
    GdipDisposeImage Bitmap      '注意释放资源
    GdiplusShutdown Token       '关闭GDI+。
End Function


Private Function GetEncoderClsID(strMimeType As String, ClassID() As Long) As Long
    Dim Num         As Long
    Dim Size        As Long
    Dim I           As Long
    Dim Info()      As ImageCodecInfo
    Dim Buffer()    As Byte
    GetEncoderClsID = -1
    GdipGetImageEncodersSize Num, Size               '得到解码器数组的大小
    If Size <> 0 Then
       ReDim Info(1 To Num) As ImageCodecInfo       '给数组动态分配内存
       ReDim Buffer(1 To Size) As Byte
       GdipGetImageEncoders Num, Size, Buffer(1)            '得到数组和字符数据
       CopyMemory Info(1), Buffer(1), (Len(Info(1)) * Num)     '复制类头
       For I = 1 To Num             '循环检测所有解码
           If (StrComp(PtrToStrW(Info(I).MimeType), strMimeType, vbTextCompare) = 0) Then         '必须把指针转换成可用的字符
               CopyMemory ClassID(0), Info(I).ClassID(0), 16  '保存类的ID
               GetEncoderClsID = I      '返回成功的索引值
               Exit For
           End If
       Next
    End If
End Function

Private Function PtrToStrW(ByVal lpsz As Long) As String
    Dim Out         As String
    Dim Length      As Long
    Length = lstrlenW(lpsz)
    If Length > 0 Then
        Out = StrConv(String$(Length, vbNullChar), vbUnicode)
        CopyMemory ByVal Out, ByVal lpsz, Length * 2
        PtrToStrW = StrConv(Out, vbFromUnicode)
    End If
End Function

本文参与腾讯云自媒体分享计划,欢迎正在阅读的你也加入,一起分享。

我来说两句

0 条评论
登录 后参与评论

相关文章

  • 24位真彩色图像转换为16位高彩色图像的实现方法及效果改进

     本文是对多年前作者的一篇博文的重新整理和书写。 一、前言        高彩色位图像即我们常说16位图像,每个像素占用两个字节,相比于24位真彩色来说,...

    用户1138785
  • 自己编码使用去色、曲线、色阶算法实现照片怀旧特效。

      天下文章一大抄,看你会抄不会抄,这个算法的初步雏形其实很简单,很多傻瓜级的软件业提供了相应的一键功能,比如美图秀秀。其实这就是个简单的调色功能,实现的方式五...

    用户1138785
  • 【短道速滑四】Halcon的texture_laws算子自我研究

      Halcon里有个texture_laws 算子,最近实现了下,记录下相关细节。

    用户1138785
  • SqlServer 获取数据库全部字段

    用户2657851
  • .NET中的密钥加密

    本教程将演示如何通过System.Security.Cryptography在.NET Framework 1.1中实现对称加密/密钥加密。

    MelodyS
  • vb.net 连接MYSQL数据库,需要MySql.Data.dll连接控件!

    '---------------------------------------------------------------------------...

    巴西_prince
  • VBA实战技巧06: 复制文本到剪贴板

    注意,上述代码运行前需要添加对“Microsoft Forms 2.0 Object Library”库的引用,方法是在VBE中单击菜单“工具——引用”,在“引...

    fanjy
  • 类模块——举例

    前面使用Open 进行的文件操作,使用起来不是很方便,但是FileSystemObject里的TextStream使用起来就比较方便了,知道了类之后,就可以使用...

    xyj
  • vb.net_一个半成品

    landv
  • VB.NET 仿spy++拖拽图标获取窗体句柄

    巴西_prince

扫码关注云+社区

领取腾讯云代金券