如何在 Visual Basic 中创建 PNG 文件? [英] How to create a PNG file in Visual Basic?
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问题描述
可能的重复:
VB6 PictureBox SavePicture - 将图片保存为png?
如何在 Visual Basic 6.5 中创建一个高度为 10,宽度为 6 的 PNG 文件?
How do I create a PNG file in Visual Basic 6.5 with a height of 10 and a width of 6?
绘制png文件的头文件是什么?
What is the header file inclusion to draw an png file?
推荐答案
之前看过一个模块,是用GDI+把BMP转PNG
I've seen a module before that uses GDI+ to convert BMP to PNG
这是一个 .bas 文件的模块:
Here's that module as a .bas file:
Option Explicit
Private Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(0 To 7) As Byte
End Type
Private Type GdiplusStartupInput
GdiplusVersion As Long
DebugEventCallback As Long
SuppressBackgroundThread As Long
SuppressExternalCodecs As Long
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 As EncoderParameter
End Type
Private Declare Function GdiplusStartup Lib "GDIPlus" (token As Long, inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As Long
Private Declare Function GdiplusShutdown Lib "GDIPlus" (ByVal token 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 GdipDisposeImage Lib "GDIPlus" (ByVal Image As Long) As Long
Private Declare Function GdipSaveImageToFile Lib "GDIPlus" (ByVal Image As Long, ByVal FileName As Long, clsidEncoder As GUID, encoderParams As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32" (ByVal Str As Long, id As GUID) As Long
Private Declare Function CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Dest As Any, Src As Any, ByVal cb As Long) As Long
Public Sub SavePic(ByVal pict As StdPicture, ByVal FileName As String, PicType As String, _
Optional ByVal Quality As Byte = 80, _
Optional ByVal TIFF_ColorDepth As Long = 24, _
Optional ByVal TIFF_Compression As Long = 6)
Screen.MousePointer = vbHourglass
Dim tSI As GdiplusStartupInput
Dim lRes As Long
Dim lGDIP As Long
Dim lBitmap As Long
Dim aEncParams() As Byte
On Error GoTo ErrHandle:
tSI.GdiplusVersion = 1
lRes = GdiplusStartup(lGDIP, tSI)
If lRes = 0 Then
lRes = GdipCreateBitmapFromHBITMAP(pict.Handle, 0, lBitmap)
If lRes = 0 Then
Dim tJpgEncoder As GUID
Dim tParams As EncoderParameters
Select Case PicType
Case ".jpg"
CLSIDFromString StrPtr("{557CF401-1A04-11D3-9A73-0000F81EF32E}"), tJpgEncoder
tParams.count = 1
With tParams.Parameter
CLSIDFromString StrPtr("{1D5BE4B5-FA4A-452D-9CDD-5DB35105E7EB}"), .GUID
.NumberOfValues = 1
.type = 4
.Value = VarPtr(Quality)
End With
ReDim aEncParams(1 To Len(tParams))
Call CopyMemory(aEncParams(1), tParams, Len(tParams))
Case ".png"
CLSIDFromString StrPtr("{557CF406-1A04-11D3-9A73-0000F81EF32E}"), tJpgEncoder
ReDim aEncParams(1 To Len(tParams))
Case ".gif"
CLSIDFromString StrPtr("{557CF402-1A04-11D3-9A73-0000F81EF32E}"), tJpgEncoder
ReDim aEncParams(1 To Len(tParams))
Case ".tiff"
CLSIDFromString StrPtr("{557CF405-1A04-11D3-9A73-0000F81EF32E}"), tJpgEncoder
tParams.count = 2
ReDim aEncParams(1 To Len(tParams) + Len(tParams.Parameter))
With tParams.Parameter
.NumberOfValues = 1
.type = 4
CLSIDFromString StrPtr("{E09D739D-CCD4-44EE-8EBA-3FBF8BE4FC58}"), .GUID
.Value = VarPtr(TIFF_Compression)
End With
Call CopyMemory(aEncParams(1), tParams, Len(tParams))
With tParams.Parameter
.NumberOfValues = 1
.type = 4
CLSIDFromString StrPtr("{66087055-AD66-4C7C-9A18-38A2310B8337}"), .GUID
.Value = VarPtr(TIFF_ColorDepth)
End With
Call CopyMemory(aEncParams(Len(tParams) + 1), tParams.Parameter, Len(tParams.Parameter))
Case ".bmp"
SavePicture pict, FileName
Screen.MousePointer = vbDefault
Exit Sub
End Select
lRes = GdipSaveImageToFile(lBitmap, StrPtr(FileName), tJpgEncoder, aEncParams(1))
GdipDisposeImage lBitmap
End If
GdiplusShutdown lGDIP
End If
Screen.MousePointer = vbDefault
Erase aEncParams
Exit Sub
ErrHandle:
Screen.MousePointer = vbDefault
MsgBox "Error" & vbCrLf & vbCrLf & "Error No. " & Err.Number & vbCrLf & " Error .Description: " & Err.Description, vbInformation Or vbOKOnly
End Sub
如何调用:
SavePic(ByVal pict As StdPicture, ByVal FileName As String, PicType As String, _
Optional ByVal Quality As Byte = 80, _
Optional ByVal TIFF_ColorDepth As Long = 24, _
Optional ByVal TIFF_Compression As Long = 6)
StdPicture - A picture handle, or a picture box
FileName - The file name to save
PicType - File format to save, available formats: .jpg, .png, .gif, .tiff, .bmp
Quality - Picture quality, default is 80%
示例:
SavePic Picture1.Image, "C:\Test.png", ".png"
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