//Advanced Delphi Systems Code: ads_Bitmap
{Copyright(c)2000 Advanced Delphi Systems
Richard Maley
Advanced Delphi Systems
12613 Maidens Bower Drive
Potomac, MD 20854 USA
phone 301-840-1554
maley@advdelphisys.com
The code herein can be used or modified by anyone. Please retain references
to Richard Maley at Advanced Delphi Systems. If you make improvements to the
code please send your improvements to maley@advdelphisys.com so that the
entire Delphi community can benefit. All comments are welcome.
Please note if you are viewing this Delphi unit as a web page all you have to
do to turn it into a Delphi unit is save it with a ".pas" extension. The
html in the unit should not affect its performance.
}
unit ads_Bitmap;
(*UnitIndex Master Index Implementation Section Download Units
Description: ads_Bitmap.pas
This unit contains the following routines.
RotateBitmap_ads
*)
interface
Uses Windows,Graphics;
(* RotateBitmap_ads
Example:
procedure TForm1.Button1Click(Sender: TObject);
Var
Center : TPoint;
Bitmap : TBitmap;
begin
Bitmap := TBitmap.Create;
Try
Center.y := (Image.Height div 2)+20;
Center.x := (Image.Width div 2)+0;
RotateBitmap_ads(
Image.Picture.Bitmap, //SourceBitmap : TBitmap;
Bitmap , //DestBitmap : TBitmap;
Center , //Center : TPoint;
Angle );//Angle : Extended): TBitmap;
Angle := Angle + 15;
Image2.Picture.Bitmap.Assign(Bitmap);
Finally
Bitmap.Free;
End;
end;
*)
Procedure RotateBitmap_ads(
SourceBitmap : TBitmap;
out DestBitmap : TBitmap;
Center : TPoint;
Angle : Double);
implementation
Const PixelMax = 32768;
Type
pPixelArray = ^TPixelArray;
TPixelArray = Array[0..PixelMax-1] Of TRGBTriple;
//Unit Description UnitIndex Master Index
Procedure RotateBitmap_ads(
SourceBitmap : TBitmap;
out DestBitmap : TBitmap;
Center : TPoint;
Angle : Double);
Var
cosRadians : Double;
inX : Integer;
inXOriginal : Integer;
inXPrime : Integer;
inXPrimeRotated : Integer;
inY : Integer;
inYOriginal : Integer;
inYPrime : Integer;
inYPrimeRotated : Integer;
OriginalRow : pPixelArray;
Radians : Double;
RotatedRow : pPixelArray;
sinRadians : Double;
begin
DestBitmap.Width := SourceBitmap.Width;
DestBitmap.Height := SourceBitmap.Height;
DestBitmap.PixelFormat := pf24bit;
Radians := -(Angle) * PI / 180;
sinRadians := Sin(Radians);
cosRadians := Cos(Radians);
For inX := DestBitmap.Height-1 Downto 0 Do
Begin
RotatedRow := DestBitmap.Scanline[inX];
inXPrime := 2*(inX - Center.y) + 1;
For inY := DestBitmap.Width-1 Downto 0 Do
Begin
inYPrime := 2*(inY - Center.x) + 1;
inYPrimeRotated := Round(inYPrime * CosRadians - inXPrime * sinRadians);
inXPrimeRotated := Round(inYPrime * sinRadians + inXPrime * cosRadians);
inYOriginal := (inYPrimeRotated - 1) Div 2 + Center.x;
inXOriginal := (inXPrimeRotated - 1) Div 2 + Center.y;
If
(inYOriginal >= 0) And
(inYOriginal <= SourceBitmap.Width-1) And
(inXOriginal >= 0) And
(inXOriginal <= SourceBitmap.Height-1)
Then
Begin
OriginalRow := SourceBitmap.Scanline[inXOriginal];
RotatedRow[inY] := OriginalRow[inYOriginal]
End
Else
Begin
RotatedRow[inY].rgbtBlue := 255;
RotatedRow[inY].rgbtGreen := 0;
RotatedRow[inY].rgbtRed := 0
End;
End;
End;
End;
end.
//