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* Optimized StretchMaskBlt. Default to Blitting when no aplhachannel is present

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git-svn-id: trunk@12366 -
This commit is contained in:
marc 2007-10-07 22:03:18 +00:00
parent 43bfcae67b
commit 1e1d30f9a2
1 changed files with 42 additions and 17 deletions
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45
lcl/interfaces/win32/win32winapi.inc
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@ -3264,28 +3264,51 @@ End;
------------------------------------------------------------------------------}
function TWin32WidgetSet.StretchMaskBlt(DestDC: HDC; X, Y, Width, Height: Integer; SrcDC: HDC; XSrc, YSrc, SrcWidth, SrcHeight: Integer; Mask: HBITMAP; XMask, YMask: Integer; Rop: DWORD): Boolean;
function CreatePremultipliedBitmap(AWinBmp: Windows.TBitmap; ABitmap: HBITMAP): HBITMAP;
function CreatePremultipliedBitmap(AWinBmp: Windows.TBitmap; ABitmap: HBITMAP; out AAlphaBmp: HBITMAP): Boolean;
var
Data: Pointer;
Pixel: PRGBAQuad;
ByteCount: PtrUInt;
Header: Windows.TBitmapInfoHeader;
HasAlpha0, HasAlphaN, HasAlpha255: Boolean;
begin
// todo, process only requested rectangle
Result := False;
if not GetBitmapBytes(AWinBmp, ABitmap, Rect(0, 0, AWinBmp.bmWidth, AWinBmp.bmHeight), rileDWordBoundary, riloTopToBottom, Data, ByteCount)
then Exit(0);
then Exit;
HasAlpha0 := False;
HasAlphaN := False;
HasAlpha255 := False;
Pixel := Data;
ByteCount := ByteCount shr 2;
while ByteCount > 0 do
begin
Pixel^.Red := (Pixel^.Red * Pixel^.Alpha) shr 8;
Pixel^.Green := (Pixel^.Green * Pixel^.Alpha) shr 8;
Pixel^.Blue := (Pixel^.Blue * Pixel^.Alpha) shr 8;
case Pixel^.Alpha of
0: begin
Pixel^.Red := 0;
Pixel^.Green := 0;
Pixel^.Blue := 0;
HasAlpha0 := True;
end;
255: begin
HasAlpha255 := True;
end;
else
Pixel^.Red := (Pixel^.Red * Pixel^.Alpha) div 255;
Pixel^.Green := (Pixel^.Green * Pixel^.Alpha) div 255;
Pixel^.Blue := (Pixel^.Blue * Pixel^.Alpha) div 255;
HasAlphaN := True;
end;
Inc(Pixel);
Dec(ByteCount);
end;
// only create bitmap when not opaque or not fully transparent
// (all zero alpha is unlikly for alpha bitmap, so it is probably a bitmap without alpha channel)
Result := HasAlphaN or (HasAlpha0 and HasAlpha255);
if Result
then begin
FillChar(Header, SizeOf(Header), 0);
Header.biSize := SizeOf(Header);
Header.biWidth := AWinBmp.bmWidth;
@ -3294,7 +3317,8 @@ function TWin32WidgetSet.StretchMaskBlt(DestDC: HDC; X, Y, Width, Height: Intege
Header.biBitCount := 32;
Header.biCompression := BI_RGB;
Result := Windows.CreateDIBitmap(SrcDC, Header, CBM_INIT, Data, Windows.TBitmapInfo((@Header)^), DIB_RGB_COLORS);
AAlphaBmp := Windows.CreateDIBitmap(SrcDC, Header, CBM_INIT, Data, Windows.TBitmapInfo((@Header)^), DIB_RGB_COLORS);
end;
Freemem(Data);
end;
var
@ -3312,11 +3336,11 @@ begin
bmp := Windows.GetCurrentObject(SrcDC, OBJ_BITMAP);
// get info
HasAlpha := (Windows.GetObject(bmp, SizeOf(WinBmp), @WinBmp) <> 0)
and (WinBmp.bmBitsPixel = 32);
and (WinBmp.bmBitsPixel = 32)
and CreatePremultipliedBitmap(WinBmp, Bmp, AlphaBmp);
if HasAlpha
then begin
// premultiply pixels
AlphaBmp := CreatePremultipliedBitmap(WinBmp, Bmp);
AlphaDC := Windows.CreateCompatibleDC(SrcDC);
AlphaObj := Windows.SelectObject(AlphaDC, AlphaBmp);
@ -3344,7 +3368,8 @@ begin
Result := Windows.StretchBlt(DestDC, X, Y, Width, Height, SrcDC, XSrc, YSrc, SrcWidth, SrcHeight, SRCCOPY);
end;
end;
end else begin
end
else begin
MaskDC := Windows.CreateCompatibleDC(DestDC);
MaskObj := Windows.SelectObject(MaskDC, Mask);