用位图生成一个区域

贴一个能精确裁减的算法(NiceCrop)，还有一个能满足动画要求的算法(FastCrop)。想要的朋友联系wwwsheng@sian.com function NiceCropRgn(bitmap: TBitmap; clMask: TColor): HRGN;
var
hrgn, hrgn1 : integer;
x, y : integer;
begin
hrgn := CreateRectRgn(0, 0, bitmap.Width, bitmap.Height);
for x := 1 to bitmap.Width do
for y := 1 to bitmap.Height do
if bitmap.Canvas.Pixels[x - 1, y - 1] = clMask then begin
hrgn1 := CreateRectRgn(x - 1, y - 1, x, y);
CombineRgn(hrgn, hrgn, hrgn1, RGN_DIFF);
DeleteObject(hrgn1);
end;
Result := hrgn;
end;
***************
TBitmaps to Windows Regions
---------------------------------------------------------------------
function BitmapToRegion(bmp: TBitmap; TransparentColor: TColor=clBlack;
RedTol: Byte=1; GreenTol: Byte=1; BlueTol: Byte=1): HRGN;
const
AllocUnit = 100;
type
PRectArray = ^TRectArray;
TRectArray = Array[0..(MaxInt div SizeOf(TRect))-1] of TRect;
var
pr: PRectArray;
h: HRGN;
RgnData: PRgnData;
lr, lg, lb, hr, hg, hb: Byte;
x,y, x0: Integer;
b: PByteArray;
ScanLinePtr: Pointer;
ScanLineInc: Integer;
maxRects: Cardinal;
begin
Result := 0;
{ Keep on hand lowest and highest values for the "transparent" pixels }
lr := GetRValue(TransparentColor);
lg := GetGValue(TransparentColor);
lb := GetBValue(TransparentColor);
hr := Min($ff, lr + RedTol);
hg := Min($ff, lg + GreenTol);
hb := Min($ff, lb + BlueTol);
　
bmp.PixelFormat := pf32bit;
　
maxRects := AllocUnit;
GetMem(RgnData,SizeOf(RGNDATAHEADER) + (SizeOf(TRect) * maxRects));
try
with RgnData^.rdh do
begin
dwSize := SizeOf(RGNDATAHEADER);
iType := RDH_RECTANGLES;
nCount := 0;
nRgnSize := 0;
SetRect(rcBound, MAXLONG, MAXLONG, 0, 0);
end;
　
ScanLinePtr := bmp.ScanLine[0];
ScanLineInc := Integer(bmp.ScanLine[1]) - Integer(ScanLinePtr);
for y := 0 to bmp.Height - 1 do
begin
x := 0;
while x < bmp.Width do
begin
x0 := x;
while x < bmp.Width do
begin
b := @PByteArray(ScanLinePtr)[x*SizeOf(TRGBQuad)];
// BGR-RGB: Windows 32bpp BMPs are made of BGRa quads (not RGBa)
if (b[2] >= lr) and (b[2] <= hr) and
(b[1] >= lg) and (b[1] <= hg) and
(b[0] >= lb) and (b[0] <= hb) then
Break; // pixel is transparent
Inc(x);
end;
{ test to see if we have a non-transparent area in the image }
if x > x0 then
begin
{ increase RgnData by AllocUnit rects if we exceeds maxRects }
if RgnData^.rdh.nCount >= maxRects then
begin
Inc(maxRects,AllocUnit);
ReallocMem(RgnData,SizeOf(RGNDATAHEADER) + (SizeOf(TRect) * MaxRects));
end;
{ Add the rect (x0, y)-(x, y+1) as a new visible area in the region }
pr := @RgnData^.Buffer; // Buffer is an array of rects
with RgnData^.rdh do
begin
SetRect(pr[nCount], x0, y, x, y+1);
{ adjust the bound rectangle of the region if we are "out-of-bounds" }
if x0 < rcBound.Left then rcBound.Left := x0;
if y < rcBound.Top then rcBound.Top := y;
if x > rcBound.Right then rcBound.Right := x;
if y+1 > rcBound.Bottom then rcBound.Bottom := y+1;
Inc(nCount);
end;
end; // if x > x0
　
　
if RgnData^.rdh.nCount = 2000 then
begin
h := ExtCreateRegion(nil, SizeOf(RGNDATAHEADER) + (SizeOf(TRect) * maxRects), RgnData^);
if Result > 0 then
begin // Expand the current region
CombineRgn(Result, Result, h, RGN_OR);
DeleteObject(h);
end
else // First region, assign it to Result
Result := h;
RgnData^.rdh.nCount := 0;
SetRect(RgnData^.rdh.rcBound, MAXLONG, MAXLONG, 0, 0);
end;
Inc(x);
end; // scan every sample byte of the image
Inc(Integer(ScanLinePtr), ScanLineInc);
end;
{ need to call ExCreateRegion one more time because we could have left }
{ a RgnData with less than 2000 rects, so it wasn't yet created/combined }
h := ExtCreateRegion(nil, SizeOf(RGNDATAHEADER) + (SizeOf(TRect) * MaxRects), RgnData^);
if Result > 0 then
begin
CombineRgn(Result, Result, h, RGN_OR);
DeleteObject(h);
end
else
Result := h;
finally
FreeMem(RgnData,SizeOf(RGNDATAHEADER) + (SizeOf(TRect) * MaxRects));
end;