//这里将顺序调整和R和B值的交换的代码进行了合并
end;
end;{end of RT_FORMAT_RGB}
else
RasError(''''不支持的文件格式！'''');
end;{end of 32Bit}
end;
else
begin
FreeImage;
RasError(''''不支持的文件格式！'''');
end;
end;
end
else
RasError(''''不支持的文件格式！'''');
end;{end with}
end;
{上面的代码中多次出现如下代码：
if (Width mod 2)=1 then
begin
Position := Position + 1;
end;
这是因为每行的数据都要按字对齐，既每行的数据都要用偶数的字节记录。当每个像素的颜色信息用1字节(8位)或3字节(24位)记录且每行像素数为奇数时，要补齐一个字节。所以这里跳过一个字节。
后面代码中的
if (Width mod 2) = 1 then
begin
FillByte:=0;
Stream.Write(FillByte,1);
end;
也是基于同一道理。}
procedure TRASGraphic.SaveToStream(Stream: TStream);
var
Header: TRASHeader;
Row8: PByte;
Row24: PRGBTriple;
Row32: PRGBQuad;
FillByte: Byte;
Y: Integer;
I: Integer;
Pal: TMaxLogPalette;
R,G,B:array[0..255] of Byte;
begin
Header.Magic := $956AA659;
Header.Width := SwapLong(Width);
Header.Height := SwapLong(Height);
Header.RasType := SwapLong(RT_STANDARD);
if (PixelFormat = pf1bit) or (PixelFormat = pf4bit) then
PixelFormat:=pf8bit
else if (PixelFormat <> pf8bit) and (PixelFormat <> pf24bit) and (PixelFormat <> pf32bit) then
PixelFormat:=pf24bit;
case PixelFormat of
pf8bit:
begin
Header.Length := SwapLong(Height*(Width+(Width mod 2)));
Header.Depth := SwapLong(8);
Header.MapType := SwapLong(RMT_EQUAL_RGB);
Header.MapLength := SwapLong(3*256);
Stream.WriteBuffer(Header,SizeOf(Header));
GetPaletteEntries(Palette, 0, 256, Pal.palPalEntry);
for I := 0 to 255 do
begin
R[I]:=Pal.palPalEntry[I].peRed;
G[I]:=Pal.palPalEntry[I].peGreen;
B[I]:=Pal.palPalEntry[I].peBlue;
end;
//相关调色板操作的API请查询MSDN
Stream.WriteBuffer(R,256);
Stream.WriteBuffer(G,256);
Stream.WriteBuffer(B,256);
for Y := 0 to Height-1 do
begin
Row8 := ScanLine[Y];
Stream.WriteBuffer(Row8^,Width);
if (Width mod 2) = 1 then
begin
FillByte:=0;
Stream.Write(FillByte,1);
end;
end;
end;
pf32bit:
begin
Header.Length := SwapLong(Height*Width*4);
Header.Depth := SwapLong(32);
Header.MapType := SwapLong(RMT_NONE);
Header.MapLength := 0;
Stream.WriteBuffer(Header,SizeOf(Header));
for Y := 0 to Height-1 do
begin
Row32 := ScanLine[Y];
for I := 0 to Width-1 do
begin
Stream.WriteBuffer(Row32.rgbReserved,1);
Stream.WriteBuffer(Row32^,3);
Inc(Row32);
end;
end;
end;
else
begin
Header.Length := SwapLong(Height*Width*3);
Header.Depth := SwapLong(24);
Header.MapType := SwapLong(RMT_NONE);
Header.MapLength := 0;
Stream.WriteBuffer(Header,SizeOf(Header));
for Y := 0 to Height-1 do
begin
Row24 := ScanLine[Y];
Stream.WriteBuffer(Row24^,Width*3);
if (Width mod 2) = 1 then
begin
FillByte:=0;
Stream.Write(FillByte,1);
end;
end;
end;
end;
//SaveToStream基本上就是LoadFromStream的逆过程。
end;
initialization
TPicture.RegisterFileFormat(''''RAS'''', ''''Sun RAS'''', TRASGraphic);
finalization
TPicture.UnregisterGraphicClass(TRASGraphic);
加上这几句代码，一个完整的图像解析组件就完成了。
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