vb6 - 如何使用 VB6 将 PNG（图像）文件打开为 RGB 数组或 R、G、B 数组

Question

如何使用 VB6 打开 PNG 格式的图像文件？理想情况下，我（即我的客户）希望打开 PNG 文件并将其放入单独的 R(ed)、G(reen) 和 B(lue) 数组中。

VB6 不是我选择的工具（因为缺乏知识），如果有人能为我指出正确的 VB6 解决方案方向，我会很高兴。

Answer 1

感谢您的链接，虽然不是一个流利的 VB 人（更多的 C 和 ASM 风格），但代码似乎非常以 BMP 为中心；不是PNG。

如果是这种情况，我必须相信您建议了该链接，因为使代码PNG'able 是一件简单的事情，但我不知道如何处理。

Answer 2

您可以尝试开源FreeImage 项目。

Answer 3

'1 form with :
'    1 picturebox : name=Picture1
'    1 commandbutton : name=Command1
Option Explicit

Private Type BITMAP
  bmType As Long
  bmWidth As Long
  bmHeight As Long
  bmWidthBytes As Long
  bmPlanes As Integer
  bmBitsPixel As Integer
  bmBits As Long
End Type

Private Declare Function GetObject Lib "gdi32" Alias "GetObjectA" (ByVal hObject As Long, ByVal nCount As Long, ByRef lpObject As Any) As Long
Private Declare Function GetBitmapBits Lib "gdi32" (ByVal hBitmap As Long, ByVal dwCount As Long, ByRef lpBits As Any) As Long
Private Declare Function SetBitmapBits Lib "gdi32" (ByVal hBitmap As Long, ByVal dwCount As Long, ByRef lpBits As Any) As Long

Private mbmpBits() As Byte
Private mudtBmp As BITMAP

Private Sub Command1_Click()
  ShowRed
'  ShowGreen
'  ShowBlue
End Sub

Private Sub Form_Load()
  Picture1.Picture = LoadPicture("c:\temp\pic.bmp")
End Sub

Private Sub Form_Unload(Cancel As Integer)
  Set Form1 = Nothing
End Sub

Private Sub ShowRed()
  Dim lngX As Long, lngY As Long
  ReadBits
  For lngX = 0 To mudtBmp.bmWidth - 1
    For lngY = 0 To mudtBmp.bmHeight - 1
      mbmpBits(0, lngX, lngY) = 0
      mbmpBits(1, lngX, lngY) = 0
    Next lngY
  Next lngX
  ShowBits
End Sub

Private Sub ShowGreen()
  Dim lngX As Long, lngY As Long
  ReadBits
  For lngX = 0 To mudtBmp.bmWidth - 1
    For lngY = 0 To mudtBmp.bmHeight - 1
      mbmpBits(0, lngX, lngY) = 0
      mbmpBits(2, lngX, lngY) = 0
    Next lngY
  Next lngX
  ShowBits
End Sub

Private Sub ShowBlue()
  Dim lngX As Long, lngY As Long
  ReadBits
  For lngX = 0 To mudtBmp.bmWidth - 1
    For lngY = 0 To mudtBmp.bmHeight - 1
      mbmpBits(1, lngX, lngY) = 0
      mbmpBits(2, lngX, lngY) = 0
    Next lngY
  Next lngX
  ShowBits
End Sub

Private Sub ReadBits()
  GetObject Picture1.Picture.Handle, Len(mudtBmp), mudtBmp
  With mudtBmp
    ReDim mbmpBits(0 To (.bmBitsPixel \ 8) - 1, 0 To .bmWidth - 1, 0 To .bmHeight - 1) As Byte
    GetBitmapBits Picture1.Picture.Handle, .bmWidthBytes * .bmHeight, mbmpBits(0, 0, 0)
  End With 'mudtBmp
End Sub

Private Sub ShowBits()
  SetBitmapBits Picture1.Picture.Handle, mudtBmp.bmWidthBytes * mudtBmp.bmHeight, mbmpBits(0, 0, 0)
  Erase mbmpBits
  Picture1.Refresh
End Sub