Graphics Functions Using msimg32.dll (Windows 98/2000 only)

Category:

Screen/Graphics

Type:

Snippets

Difficulty:

Intermediate

Author:

Arkadiy Olovyannikov

Version Compatibility:

More information:

Some graphics functions are very simple if you use msimg32.dll. They are - GradientFill and TransparentBlt. If you have W95 or NT, you don't find this dll, it's shipped with W98 only.

Another demo of these functions within msimg32 is available at http://www.freevbcode.com/ShowCode.ASP?ID=1501.

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:
'Start new project, add to form picture box (Picture1) and 'four buttons - cmdClear,cmdTransparent, cmdTriangle and 'cmdRect.Add any picture to picture box. Paste the following 'declarations and code into the form. Option Explicit Private Type TRIVERTEX x As Long y As Long Red As Integer Green As Integer Blue As Integer Alpha As Integer End Type Private Type GRADIENT_RECT UpperLeft As Long LowerRight As Long End Type Private Type BLENDFUNCTION BlendOp As Byte BlendFlags As Byte SourceConstantAlpha As Byte AlphaFormat As Byte End Type Private Type GRADIENT_TRIANGLE Vertex1 As Long Vertex2 As Long Vertex3 As Long End Type Const GRADIENT_FILL_RECT_H As Long = &H0 Const GRADIENT_FILL_RECT_V As Long = &H1 Const GRADIENT_FILL_TRIANGLE As Long = &H2 Const GRADIENT_FILL_OP_FLAG As Long = &HFF Const AC_SRC_OVER = &H0 Private Declare Function TransparentBlt Lib "msimg32.dll" _ (ByVal hdcDest As Long, ByVal nXOriginDest As Long, ByVal _ nYOriginDest As Long, ByVal nWidthDest As Long, ByVal _ nHeightDest As Long, ByVal hdcSrc As Long, ByVal nXOriginSrc _ As Long, ByVal nYOriginSrc As Long, ByVal nWidthSrc As Long, _ ByVal nHeightSrc As Long, ByVal crTransparent As Long) As Long Private Declare Function GradientFillRect Lib "msimg32" _ Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, _ ByVal dwNumVertex As Long, pMesh As GRADIENT_RECT, ByVal _ dwNumMesh As Long, ByVal dwMode As Long) As Long Private Declare Function GradientFillTri Lib "msimg32" _ Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, _ ByVal dwNumVertex As Long, pMesh As GRADIENT_TRIANGLE, ByVal _ dwNumMesh As Long, ByVal dwMode As Long) As Long

Code:

Private Sub Form_Load()
   Me.ScaleMode = vbPixels
   Picture1.ScaleMode = vbPixels
   Picture1.AutoRedraw = True
   Picture1.Visible = False
End Sub

Private Function LongToUShort(ULong As Long) As Integer
   LongToUShort = CInt(ULong - &H10000)
End Function

Private Function UShortToLong(Ushort As Integer) As Long
   UShortToLong = (CLng(Ushort) And &HFFFF&)
End Function

Private Sub cmdClear_Click()
   Cls
End Sub

Private Sub cmdRect_Click()
Dim vert(1) As TRIVERTEX
Dim gRect As GRADIENT_RECT
With vert(0)
    .x = 0
    .y = 0
    .Red = 0&
    .Green = &HFF&
    .Blue = 0&
    .Alpha = 0&
End With
With vert(1)
    .x = Me.ScaleWidth
    .y = Me.ScaleHeight
    .Red = 0&
    .Green = LongToUShort(&HFF00&)
    .Blue = LongToUShort(&HFF00&)
    .Alpha = 0&
End With
gRect.UpperLeft = 1
gRect.LowerRight = 0
GradientFillRect Me.hdc, vert(0), 2, gRect, 1, GRADIENT_FILL_RECT_H
Me.Refresh
End Sub

Private Sub cmdTriangle_Click()
Dim vert(3) As TRIVERTEX
Dim gTri(1) As GRADIENT_TRIANGLE
With vert(0)
    .x = 0
    .y = 0
    .Red = 0&
    .Green = 0&
    .Blue = 0&
    .Alpha = 0&
End With
With vert(1)
    .x = Me.ScaleWidth
    .y = 0
    .Red = LongToUShort(&HFF00&)
    .Green = 0&
    .Blue = LongToUShort(&HFF00&)
    .Alpha = 0&
End With
With vert(2)
    .x = Me.ScaleWidth
    .y = Me.ScaleHeight
    .Red = LongToUShort(&HFF00&)
    .Green = 0&
    .Blue = LongToUShort(&HFF00&)
    .Alpha = 0&
End With
With vert(3)
    .x = 0
    .y = Me.ScaleHeight
    .Red = LongToUShort(&HFF00&)
    .Green = LongToUShort(&HFF00&)
    .Blue = LongToUShort(&HFF00&)
    .Alpha = 0&
End With
gTri(0).Vertex1 = 0
gTri(0).Vertex2 = 1
gTri(0).Vertex3 = 2

gTri(1).Vertex1 = 0
gTri(1).Vertex2 = 2
gTri(1).Vertex3 = 3

GradientFillTri Me.hdc, vert(0), 4, gTri(0), 1, GRADIENT_FILL_TRIANGLE
Me.Refresh
End Sub

Private Sub cmdTransparent_Click()
  Dim clr As Long, w As Long, h As Long
  w = Picture1.ScaleWidth
  h = Picture1.ScaleHeight
  clr = Picture1.Point(0, 0)
  Call TransparentBlt(Me.hdc, 0, 0, w, h, Picture1.hdc, 0, 0, _
     w, h, clr)
  Me.Refresh
End Sub