'================================================================
'= 画像透過転送(�V)
'=    (AlphaBlend3.bas)
'================================================================
#include "Windows.bi"

#define AC_SRC_ALPHA &H1                '
#define AC_SRC_OVER &H0                 '

Type BLENDFUNCTION
    BlendOp             As Byte         'ブレンド操作(AC_SRC_OVER)
    BlendFlags          As Byte         '常に0
    SourceConstantAlpha As Byte         'コピー元のビットマップ全体に適用するアルファ値
    AlphaFormat         As Byte         'コピー元のビットマップがアルファ値を持つとき(AC_SRC_ALPHA)
End Type

' 透過ピクセルと半透過ピクセルを持つビットマップを表示
Declare Function Api_AlphaBlend& Lib "msimg32" Alias "AlphaBlend" (ByVal hdcDest&, ByVal nXDest&, ByVal nYDest&, ByVal nWidthDest&, ByVal nHeightDest&, ByVal hdcSrc&, ByVal nXSrc&, ByVal nYSrc&, ByVal nWidthSrc&, ByVal nHeightSrc&, ByVal nBlendFunc&)

' メモリの指定領域をコピー
Declare Sub MoveMemory Lib "Kernel32" Alias "RtlMoveMemory" (Dest As Any, Source As Any, ByVal Length&)

' 指定されたウィンドウのデバイスコンテキストのハンドルを取得
Declare Function Api_GetDC& Lib "user32" Alias "GetDC" (ByVal hWnd&)

' デバイスコンテキストを解放
Declare Function Api_ReleaseDC& Lib "user32" Alias "ReleaseDC" (ByVal hWnd&, ByVal hDC&)

Var Shared Picture1 As Object
Var Shared Picture2 As Object
Var Shared Button1 As Object
Var Shared Bitmap As Object

Picture1.Attach GetDlgItem("Picture1")
Picture2.Attach GetDlgItem("Picture2")
Button1.Attach GetDlgItem("Button1") : Button1.SetFontSize 14
BitmapObject Bitmap

'================================================================
'=
'================================================================
Declare Sub MainForm_Start edecl ()
Sub MainForm_Start()
    Bitmap.LoadFile "Flower.bmp"
    Picture1.DrawBitmap Bitmap, 0, 0
    Bitmap.DeleteObject

    Bitmap.LoadFile "Bike1.bmp"
    Picture2.DrawBitmap Bitmap, 0, 0
    Bitmap.DeleteObject
End Sub

'================================================================
'=
'================================================================
Declare Sub Button1_on edecl ()
Sub Button1_on()
    Var phDC1 As Long
    Var phDC2 As Long
    Var bf As BLENDFUNCTION
    Var lBF As Long
    Var Alpha As Byte
    Var Ret As Long

    phDC1 = Api_GetDC(Picture1.GethWnd)
    phDC2 = Api_GetDC(Picture2.GethWnd)

    Alpha = 180

    bf.BlendOp = AC_SRC_OVER
    bf.BlendFlags = 0
    bf.SourceConstantAlpha = Alpha
    bf.AlphaFormat = 0

    MoveMemory lBF, BF, 4

    Ret = Api_AlphaBlend(phDC1, 10, 10, 50, 50, phDC2, 0, 0, Picture2.GetWidth, Picture2.GetHeight, lBF)

    Ret = Api_ReleaseDC(Picture1.GethWnd, phDC1)
    Ret = Api_ReleaseDC(Picture2.GethWnd, phDC1)
End Sub

'================================================================
'=
'================================================================
While 1
    WaitEvent
Wend
Stop
End