screenshot.ahk

#SingleInstance, Force
SendMode Input
SetWorkingDir, %A_ScriptDir%

F12::
  CaptureScreen(0, 0, A_Desktop . "\" . A_Now ".bmp", 100)
return

/* CaptureScreen(aRect, bCursor, sFileTo, nQuality)
1) If the optional parameter bCursor is True, captures the cursor too.
2) If the optional parameter sFileTo is 0, set the image to Clipboard.
   If it is omitted or "", saves to screen.bmp in the script folder,
   otherwise to sFileTo which can be BMP/JPG/PNG/GIF/TIF.
3) The optional parameter nQuality is applicable only when sFileTo is JPG. Set it to the desired quality level of the resulting JPG, an integer between 0 - 100.
4) If aRect is 0/1/2/3, captures the entire desktop/active window/active client area/active monitor.
5) aRect can be comma delimited sequence of coordinates, e.g., "Left, Top, Right, Bottom" or "Left, Top, Right, Bottom, Width_Zoomed, Height_Zoomed".
   In this case, only that portion of the rectangle will be captured. Additionally, in the latter case, zoomed to the new width/height, Width_Zoomed/Height_Zoomed.

Example:
CaptureScreen(0)
CaptureScreen(1)
CaptureScreen(2)
CaptureScreen(3)
CaptureScreen("100, 100, 200, 200")
CaptureScreen("100, 100, 200, 200, 400, 400")   ; Zoomed
*/

/* Convert(sFileFr, sFileTo, nQuality)
Convert("C:\image.bmp", "C:\image.jpg")
Convert("C:\image.bmp", "C:\image.jpg", 95)
Convert(0, "C:\clip.png")   ; Save the bitmap in the clipboard to sFileTo if sFileFr is "" or 0.
*/


CaptureScreen(aRect = 0, bCursor = False, sFile = "", nQuality = "")
{
	If !aRect
	{
		SysGet, nL, 76  ; virtual screen left & top
		SysGet, nT, 77
		SysGet, nW, 78	; virtual screen width and height
		SysGet, nH, 79
	}
	Else If aRect = 1
		WinGetPos, nL, nT, nW, nH, A
	Else If aRect = 2
	{
		WinGet, hWnd, ID, A
		VarSetCapacity(rt, 16, 0)
		DllCall("GetClientRect" , "ptr", hWnd, "ptr", &rt)
		DllCall("ClientToScreen", "ptr", hWnd, "ptr", &rt)
		nL := NumGet(rt, 0, "int")
		nT := NumGet(rt, 4, "int")
		nW := NumGet(rt, 8)
		nH := NumGet(rt,12)
	}
	Else If aRect = 3
	{
		VarSetCapacity(mi, 40, 0)
		DllCall("GetCursorPos", "int64P", pt), NumPut(40,mi,0,"uint")
		DllCall("GetMonitorInfo", "ptr", DllCall("MonitorFromPoint", "int64", pt, "Uint", 2, "ptr"), "ptr", &mi)
		nL := NumGet(mi, 4, "int")
		nT := NumGet(mi, 8, "int")
		nW := NumGet(mi,12, "int") - nL
		nH := NumGet(mi,16, "int") - nT
	}
	Else
	{
		StringSplit, rt, aRect, `,, %A_Space%%A_Tab%
		nL := rt1	; convert the Left,top, right, bottom into left, top, width, height
		nT := rt2
		nW := rt3 - rt1
		nH := rt4 - rt2
		znW := rt5
		znH := rt6
	}

	mDC := DllCall("CreateCompatibleDC", "ptr", 0, "ptr")
	hBM := CreateDIBSection(mDC, nW, nH)
	oBM := DllCall("SelectObject", "ptr", mDC, "ptr", hBM, "ptr")
	hDC := DllCall("GetDC", "ptr", 0, "ptr")
	DllCall("BitBlt", "ptr", mDC, "int", 0, "int", 0, "int", nW, "int", nH, "ptr", hDC, "int", nL, "int", nT, "Uint", 0x40CC0020)
	DllCall("ReleaseDC", "ptr", 0, "ptr", hDC)
	If bCursor
		CaptureCursor(mDC, nL, nT)
	DllCall("SelectObject", "ptr", mDC, "ptr", oBM)
	DllCall("DeleteDC", "ptr", mDC)
	If znW && znH
		hBM := Zoomer(hBM, nW, nH, znW, znH)
	If sFile = 0
		SetClipboardData(hBM)
	Else Convert(hBM, sFile, nQuality), DllCall("DeleteObject", "ptr", hBM)
}

CaptureCursor(hDC, nL, nT)
{
	VarSetCapacity(mi, 32, 0), Numput(16+A_PtrSize, mi, 0, "uint")
	DllCall("GetCursorInfo", "ptr", &mi)
	bShow   := NumGet(mi, 4, "uint")
	hCursor := NumGet(mi, 8)
	xCursor := NumGet(mi,8+A_PtrSize, "int")
	yCursor := NumGet(mi,12+A_PtrSize, "int")

	DllCall("GetIconInfo", "ptr", hCursor, "ptr", &mi)
	xHotspot := NumGet(mi, 4, "uint")
	yHotspot := NumGet(mi, 8, "uint")
	hBMMask  := NumGet(mi,8+A_PtrSize)
	hBMColor := NumGet(mi,16+A_PtrSize)

	If bShow
		DllCall("DrawIcon", "ptr", hDC, "int", xCursor - xHotspot - nL, "int", yCursor - yHotspot - nT, "ptr", hCursor)
	If hBMMask
		DllCall("DeleteObject", "ptr", hBMMask)
	If hBMColor
		DllCall("DeleteObject", "ptr", hBMColor)
}

Zoomer(hBM, nW, nH, znW, znH)
{
	mDC1 := DllCall("CreateCompatibleDC", "ptr", 0, "ptr")
	mDC2 := DllCall("CreateCompatibleDC", "ptr", 0, "ptr")
	zhBM := CreateDIBSection(mDC2, znW, znH)
	oBM1 := DllCall("SelectObject", "ptr", mDC1, "ptr",  hBM, "ptr")
	oBM2 := DllCall("SelectObject", "ptr", mDC2, "ptr", zhBM, "ptr")
	DllCall("SetStretchBltMode", "ptr", mDC2, "int", 4)
	DllCall("StretchBlt", "ptr", mDC2, "int", 0, "int", 0, "int", znW, "int", znH, "ptr", mDC1, "int", 0, "int", 0, "int", nW, "int", nH, "Uint", 0x00CC0020)
	DllCall("SelectObject", "ptr", mDC1, "ptr", oBM1)
	DllCall("SelectObject", "ptr", mDC2, "ptr", oBM2)
	DllCall("DeleteDC", "ptr", mDC1)
	DllCall("DeleteDC", "ptr", mDC2)
	DllCall("DeleteObject", "ptr", hBM)
	Return zhBM
}

Convert(sFileFr = "", sFileTo = "", nQuality = "")
{
	If (sFileTo = "")
		sFileTo := A_ScriptDir . "\screen.bmp"
	SplitPath, sFileTo, , sDirTo, sExtTo, sNameTo

	If Not hGdiPlus := DllCall("LoadLibrary", "str", "gdiplus.dll", "ptr")
		Return	sFileFr+0 ? SaveHBITMAPToFile(sFileFr, sDirTo (sDirTo = "" ? "" : "\") sNameTo ".bmp") : ""
	VarSetCapacity(si, 16, 0), si := Chr(1)
	DllCall("gdiplus\GdiplusStartup", "UintP", pToken, "ptr", &si, "ptr", 0)

	If !sFileFr
	{
		DllCall("OpenClipboard", "ptr", 0)
		If	(DllCall("IsClipboardFormatAvailable", "Uint", 2) && (hBM:=DllCall("GetClipboardData", "Uint", 2, "ptr")))
			DllCall("gdiplus\GdipCreateBitmapFromHBITMAP", "ptr", hBM, "ptr", 0, "ptr*", pImage)
		DllCall("CloseClipboard")
	}
	Else If	sFileFr Is Integer
		DllCall("gdiplus\GdipCreateBitmapFromHBITMAP", "ptr", sFileFr, "ptr", 0, "ptr*", pImage)
	Else	DllCall("gdiplus\GdipLoadImageFromFile", "wstr", sFileFr, "ptr*", pImage)
	DllCall("gdiplus\GdipGetImageEncodersSize", "UintP", nCount, "UintP", nSize)
	VarSetCapacity(ci,nSize,0)
	DllCall("gdiplus\GdipGetImageEncoders", "Uint", nCount, "Uint", nSize, "ptr", &ci)
	struct_size := 48+7*A_PtrSize, offset := 32 + 3*A_PtrSize, pCodec := &ci - struct_size
	Loop, %	nCount
		If InStr(StrGet(Numget(offset + (pCodec+=struct_size)), "utf-16") , "." . sExtTo)
			break

	If (InStr(".JPG.JPEG.JPE.JFIF", "." . sExtTo) && nQuality<>"" && pImage && pCodec < &ci + nSize)
	{
		DllCall("gdiplus\GdipGetEncoderParameterListSize", "ptr", pImage, "ptr", pCodec, "UintP", nCount)
		VarSetCapacity(pi,nCount,0), struct_size := 24 + A_PtrSize
		DllCall("gdiplus\GdipGetEncoderParameterList", "ptr", pImage, "ptr", pCodec, "Uint", nCount, "ptr", &pi)
		Loop, %	NumGet(pi,0,"uint")
			If (NumGet(pi,struct_size*(A_Index-1)+16+A_PtrSize,"uint")=1 && NumGet(pi,struct_size*(A_Index-1)+20+A_PtrSize,"uint")=6)
			{
				pParam := &pi+struct_size*(A_Index-1)
				NumPut(nQuality,NumGet(NumPut(4,NumPut(1,pParam+0,"uint")+16+A_PtrSize,"uint")),"uint")
				Break
			}
	}

	If pImage
		pCodec < &ci + nSize	? DllCall("gdiplus\GdipSaveImageToFile", "ptr", pImage, "wstr", sFileTo, "ptr", pCodec, "ptr", pParam) : DllCall("gdiplus\GdipCreateHBITMAPFromBitmap", "ptr", pImage, "ptr*", hBitmap, "Uint", 0) . SetClipboardData(hBitmap), DllCall("gdiplus\GdipDisposeImage", "ptr", pImage)

	DllCall("gdiplus\GdiplusShutdown" , "Uint", pToken)
	DllCall("FreeLibrary", "ptr", hGdiPlus)
}


CreateDIBSection(hDC, nW, nH, bpp = 32, ByRef pBits = "")
{
	VarSetCapacity(bi, 40, 0)
	NumPut(40, bi, "uint")
	NumPut(nW, bi, 4, "int")
	NumPut(nH, bi, 8, "int")
	NumPut(bpp, NumPut(1, bi, 12, "UShort"), 0, "Ushort")
	Return DllCall("gdi32\CreateDIBSection", "ptr", hDC, "ptr", &bi, "Uint", 0, "UintP", pBits, "ptr", 0, "Uint", 0, "ptr")
}

SaveHBITMAPToFile(hBitmap, sFile)
{
	VarSetCapacity(oi,104,0)
	DllCall("GetObject", "ptr", hBitmap, "int", 64+5*A_PtrSize, "ptr", &oi)
	fObj := FileOpen(sFile, "w")
	fObj.WriteShort(0x4D42)
	fObj.WriteInt(54+NumGet(oi,36+2*A_PtrSize,"uint"))
	fObj.WriteInt64(54<<32)
	fObj.RawWrite(&oi + 16 + 2*A_PtrSize, 40)
	fObj.RawWrite(NumGet(oi, 16+A_PtrSize), NumGet(oi,36+2*A_PtrSize,"uint"))
	fObj.Close()
}

SetClipboardData(hBitmap)
{
	VarSetCapacity(oi,104,0)
	DllCall("GetObject", "ptr", hBitmap, "int", 64+5*A_PtrSize, "ptr", &oi)
	sz := NumGet(oi,36+2*A_PtrSize,"uint")
	hDIB :=	DllCall("GlobalAlloc", "Uint", 2, "Uptr", 40+sz, "ptr")
	pDIB := DllCall("GlobalLock", "ptr", hDIB, "ptr")
	DllCall("RtlMoveMemory", "ptr", pDIB, "ptr", &oi + 16 + 2*A_PtrSize, "Uptr", 40)
	DllCall("RtlMoveMemory", "ptr", pDIB+40, "ptr", NumGet(oi, 16+A_PtrSize), "Uptr", sz)
	DllCall("GlobalUnlock", "ptr", hDIB)
	DllCall("DeleteObject", "ptr", hBitmap)
	DllCall("OpenClipboard", "ptr", 0)
	DllCall("EmptyClipboard")
	DllCall("SetClipboardData", "Uint", 8, "ptr", hDIB)
	DllCall("CloseClipboard")
}