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| // The FlipReverseRotate Library provides three functions to flip and/or
// reverse a bitmap. You can choose which approach you'd like to use from the
// three methods to flip or reverse a bitmap: ScanLine, CopyRect, StretchBlt.
//
// A "Flip" operation takes the top of an image to the bottom and the bottom of
// the image to the top. It is a reflection along a horizontal line in the
// middle of an image.
//
// A "Reverse" operation takes the left of an image to the right and the right
// of the image to the left. It is a reflection along a vertical line in the
// middle of an image.
//
// Any Flip/Reverse operation is commutative, i.e., the flip and reverse can
// be performed in any order to get the same result. A flip followed by a
// reverse is the same as a reverse followed by a flip.
//
// A "rotate" operation spins an image 0, 90, 180 or 270 degrees around an
// axis in the center of the image.
//
// A flip/reverse operation along with a rotation is not commutative in general.
// A flip followed by a rotation will not always result in the same image as a
// rotation followed by a flip. The rotation here ALWAYS follows any flip and/or
// reversal.
//
// The examples here are intended for use with bitmaps that have 24 bits/pixel.
// Palettes may be lost on 256-color bitmaps.
//
// Copyright (C) 1998, Earl F. Glynn. All Rights Reserved.
// May be used freely for non-comercial use.
UNIT FlipReverseRotateLibrary;
{.$MODE Delphi}
{$mode objfpc}{$H+}
INTERFACE
USES
Dialogs,
LCLIntf, LCLType,// LMessages, // TRGBTriple (put here to avoid TBitmap conflict in Implementation)
Graphics; // TBitmap
// Flip/Reverse functions by Method
FUNCTION FlipReverseScanLine(CONST Flip, Reverse: BOOLEAN;
CONST Bitmap: TBitmap): TBitmap;
FUNCTION FlipReverseCopyRect(CONST Flip, Reverse: BOOLEAN;
CONST Bitmap: TBitmap): TBitmap;
FUNCTION FlipReverseStretchBlt(CONST Flip, Reverse: BOOLEAN;
CONST Bitmap: TBitmap): TBitmap;
// The Rotation function is only for the Scanline Method.
// Note: Windows NT supports a "plgblt" API call that can be used to rotate
// images.
FUNCTION RotateScanline90(CONST angle: INTEGER;
CONST Bitmap: TBitmap): TBitmap;
IMPLEMENTATION
USES
Classes, // Rect
SysUtils; // Exception
CONST
MaxPixelCount = 65536; // or some other arbitrarily large value
// ouais, parce que ça fait un peu petit, ça : 256 x 256 seulement...
TYPE
EBitmapError = CLASS(Exception);
// TRGBArray = ARRAY[0..MaxPixelCount-1] OF TRGBTriple;
// pRGBArray = ^TRGBArray;
TRGBArray = ARRAY[0..MaxPixelCount-1] OF TRGBQuad;
pRGBArray = ^TRGBArray;
//////////////////////////////////////////////////////////////////////////////
FUNCTION FlipReverseScanLine(CONST Flip, Reverse: BOOLEAN;
CONST Bitmap: TBitmap): TBitmap;
VAR
i : INTEGER;
j : INTEGER;
//RowIn : pRGBArray;
//RowOut: pRGBArray;
RowIn : pRGBTriple;
RowOut: pRGBTriple;
BEGIN
IF Bitmap.PixelFormat <> pf24bit
THEN RAISE EBitmapError.Create('Can Flip/Reverse only 24-bit bitmap');
RESULT := TBitmap.Create;
RESULT.PixelFormat := Bitmap.PixelFormat;
RESULT.Width := Bitmap.Width;
RESULT.Height := Bitmap.Height;
RESULT.BeginUpdate();
FOR j := 0 TO Bitmap.Height-1 DO BEGIN
RowIn := pRGBTriple(Bitmap.RawImage.GetLineStart(j));
IF Flip
// THEN RowOut := RESULT.Scanline[Bitmap.Height - 1 - j]
// ELSE RowOut := RESULT.Scanline[j];
THEN RowOut := pRGBTriple(RESULT.RawImage.GetLineStart(Bitmap.Height - 1 - j))
ELSE RowOut := pRGBTriple(RESULT.RawImage.GetLineStart(j));
// Optimization technique: Use two FOR loops so IF is outside of inner loop
IF Reverse
THEN BEGIN
FOR i := 0 TO Bitmap.Width-1 DO begin
RowOut[i] := RowIn[Bitmap.Width-1-i] // 2 chapeaux si pas mode Delphi ! !
{ RowOut[i].rgbtBlue := RowIn[Bitmap.Width-1-i].rgbtBlue;
RowOut[i].rgbtGreen := RowIn[Bitmap.Width-1-i].rgbtGreen;
RowOut[i].rgbtRed := RowIn[Bitmap.Width-1-i].rgbtRed; }
// RowOut[i].rgbReserved := 255;
end;
END
ELSE BEGIN
FOR i := 0 TO Bitmap.Width-1 DO begin
RowOut[i] := RowIn[i] // 2 chapeaux si pas mode Delphi ! !
{ RowOut[i].rgbtBlue := RowIn[i].rgbtBlue;
RowOut[i].rgbtGreen := RowIn[i].rgbtGreen;
RowOut[i].rgbtRed := RowIn[i].rgbtRed; }
// RowOut[i].rgbReserved := 255;
end;
END;
END;
RESULT.EndUpdate();
END {FlipReverseScanLine};
//////////////////////////////////////////////////////////////////////////////
// This function implements a suggestion by David Ullrich in a July 25, 1997
// post to comp.lang.pascal.delphi.misc.
//
// The Graphics.PAS unit shows that CopyRect calls the Windows StretchBlt API
// function.
FUNCTION FlipReverseCopyRect(CONST Flip, Reverse: BOOLEAN;
CONST Bitmap: TBitmap): TBitmap;
VAR
Bottom: INTEGER;
Left : INTEGER;
Right : INTEGER;
Top : INTEGER;
BEGIN
RESULT := TBitmap.Create;
RESULT.PixelFormat := Bitmap.PixelFormat;
RESULT.Width := Bitmap.Width;
RESULT.Height := Bitmap.Height;
// Flip Top to Bottom
IF Flip
THEN BEGIN
// Unclear why extra "-1" is needed here.
Top := Bitmap.Height-1;
Bottom := -1
END
ELSE BEGIN
Top := 0;
Bottom := Bitmap.Height
END;
// Reverse Left to Right
IF Reverse
THEN BEGIN
// Unclear why extra "-1" is needed here.
Left := Bitmap.Width-1;
Right := -1;
END
ELSE BEGIN
Left := 0;
Right := Bitmap.Width;
END;
RESULT.Canvas.CopyRect(Rect(Left,Top, Right,Bottom),
Bitmap.Canvas,
Rect(0,0, Bitmap.Width,Bitmap.Height));
END {FlipReverseCopyRect};
//////////////////////////////////////////////////////////////////////////////
FUNCTION FlipReverseStretchBlt(CONST Flip, Reverse: BOOLEAN;
CONST Bitmap: TBitmap): TBitmap;
VAR
Bottom: INTEGER;
Left : INTEGER;
Right : INTEGER;
Top : INTEGER;
BEGIN
RESULT := TBitmap.Create;
RESULT.PixelFormat := Bitmap.PixelFormat;
RESULT.Width := Bitmap.Width;
RESULT.Height := Bitmap.Height;
// Flip Top to Bottom
IF Flip
THEN BEGIN
// Unclear why extra "-1" is needed here.
Top := Bitmap.Height-1;
Bottom := -1
END
ELSE BEGIN
Top := 0;
Bottom := Bitmap.Height
END;
// Reverse Left to Right
IF Reverse
THEN BEGIN
// Unclear why extra "-1" is needed here.
Left := Bitmap.Width-1;
Right := -1;
END
ELSE BEGIN
Left := 0;
Right := Bitmap.Width;
END;
StretchBlt(RESULT.Canvas.Handle, Left, Top, Right-Left, Bottom-Top,
Bitmap.Canvas.Handle,
0,0, Bitmap.Width, Bitmap.Height, cmSrcCopy);
END {FlipReverseStretchBlt};
//////////////////////////////////////////////////////////////////////////////
// Rotate 24-bits/pixel Bitmap any multiple of 90 degrees.
FUNCTION RotateScanLine90(CONST angle: INTEGER;
CONST Bitmap: TBitmap): TBitmap;
// These four internal functions parallel the four cases in rotating a
// bitmap using the Pixels property. See the RotatePixels example on
// the Image Processing page of efg's Computer Lab for an example of the
// use of the Pixels property (which is very slow).
// A Bitmap.Assign could be used for a simple copy. A complete example
// using ScanLine is included here to help explain the other three cases.
FUNCTION SimpleCopy: TBitmap;
VAR
//i : INTEGER;
//j : INTEGER;
//rowIn : pRGBQuad;//pRGBArray;
//rowOut: pRGBQuad;//pRGBArray;
h,w: Integer;
//cnt: single;
//idx: Integer;
//pbS,pbD: pByte;
pbS: pRGBTriple;
pbD: pRGBQuad;
BEGIN
RESULT := TBitmap.Create;
RESULT.PixelFormat := Bitmap.PixelFormat; // only pf24bit for now
RESULT.Width := Bitmap.Width;
RESULT.Height := Bitmap.Height;
RESULT.BeginUpdate();
// Out[i, j] = In[i, j]
{ FOR j := 0 TO Bitmap.Height - 1 DO BEGIN
rowIn := pRGBQuad(Bitmap.RawImage.GetLineStart(j));
rowOut := pRGBQuad(RESULT.RawImage.GetLineStart(j));
// Could optimize the following by using a function like CopyMemory
// from the Windows unit.
FOR i := 0 TO Bitmap.Width - 1 DO BEGIN
// RowOut[i] := RowIn[i];
// Why does this crash with RowOut[i] := RowIn[i]? Alignment?
// Use this longer form as workaround.
WITH rowOut[i] DO BEGIN
// rgbtRed := rowIn[i].rgbtRed;
// rgbtGreen := rowIn[i].rgbtGreen;
// rgbtBlue := rowIn[i].rgbtBlue;
rgbRed := rowIn[i].rgbRed;
rgbGreen := rowIn[i].rgbGreen;
rgbBlue := rowIn[i].rgbBlue;
rgbReserved := rowIn[i].rgbReserved;
END
END
END; }
{ for h := 0 to Bitmap.Height-1 do begin
pbS := Bitmap.RawImage.GetLineStart(h);
pbD := RESULT.RawImage.GetLineStart(h);
cnt := 0; idx := 0;
for w := 0 to (Bitmap.Width * 3)-1 do begin
pbD[idx] := pbS[w];
cnt := w+1; // pour chercher le 4e byte de la destination
if ( Frac(cnt / 3) = 0 ) then begin
// "bourrer" le 4e byte, le "Reserved", qui a l'air inclus par le widgetset gtk2
inc(idx);
pbD[idx]:=255;
end;
inc(idx);
end;
end; }
for h := 0 to Bitmap.Height-1 do begin
pbS := pRGBTriple(Bitmap.RawImage.GetLineStart(h));
pbD := pRGBQuad(RESULT.RawImage.GetLineStart(h));
for w := 0 to Bitmap.Width-1 do begin
pbD[w].rgbBlue := pbS[w].rgbtBlue;
pbD[w].rgbGreen := pbS[w].rgbtGreen;
pbD[w].rgbRed := pbS[w].rgbtRed;
pbD[w].rgbReserved := 255;
end;
end;
RESULT.EndUpdate();
END {SimpleCopy};
FUNCTION Rotate90DegreesCounterClockwise: TBitmap;
VAR
i : INTEGER;
j : INTEGER;
rowIn : pRGBArray;
h,w: Integer;
cnt: single;
idx: Integer;
pbS,pbD: pByte;
BEGIN
RESULT := TBitmap.Create;
RESULT.PixelFormat := Bitmap.PixelFormat; // only pf24bit for now
RESULT.Width := Bitmap.Height;
RESULT.Height := Bitmap.Width;
RESULT.BeginUpdate();
// Out[j, Right - i - 1] = In[i, j]
FOR j := 0 TO Bitmap.Height - 1 DO BEGIN
// rowIn := Bitmap.ScanLine[j];
rowIn := pRGBArray(Bitmap.RawImage.GetLineStart(j));
FOR i := 0 TO Bitmap.Width - 1 DO
pRGBArray(RESULT.ScanLine[Bitmap.Width - i - 1])[j] := rowIn[i]
END;
RESULT.EndUpdate();
END {Rotate90DegreesCounterClockwise};
// Could use Rotate90DegreesCounterClockwise twice to get a
// Rotate180DegreesCounterClockwise. Rotating 180 degrees is the same
// as a Flip and Reverse
FUNCTION Rotate180DegreesCounterClockwise: TBitmap;
VAR
i : INTEGER;
j : INTEGER;
rowIn : pRGBArray;
rowOut: pRGBArray;
BEGIN
RESULT := TBitmap.Create;
RESULT.PixelFormat := Bitmap.PixelFormat; // only pf24bit for now
RESULT.Width := Bitmap.Width;
RESULT.Height := Bitmap.Height;
RESULT.BeginUpdate();
// Out[Right - i - 1, Bottom - j - 1] = In[i, j]
FOR j := 0 TO Bitmap.Height - 1 DO BEGIN
// rowIn := Bitmap.ScanLine[j];
// rowOut := RESULT.ScanLine[Bitmap.Height - j - 1];
rowIn := pRGBArray(Bitmap.RawImage.GetLineStart(j));
rowOut := pRGBArray(RESULT.RawImage.GetLineStart(Bitmap.Height - j - 1));
FOR i := 0 TO Bitmap.Width - 1 DO
rowOut[Bitmap.Width - i - 1] := rowIn[i]
END;
RESULT.EndUpdate();
END {Rotate180DegreesCounterClockwise};
// Could use Rotate90DegreesCounterClockwise three times to get a
// Rotate270DegreesCounterClockwise
FUNCTION Rotate270DegreesCounterClockwise: TBitmap;
VAR
i : INTEGER;
j : INTEGER;
rowIn: pRGBArray;
BEGIN
RESULT := TBitmap.Create;
RESULT.PixelFormat := pf32bit;//Bitmap.PixelFormat; // only pf24bit for now
RESULT.Width := Bitmap.Height;
RESULT.Height := Bitmap.Width;
RESULT.BeginUpdate();
// Out[Bottom - j - 1, i] = In[i, j]
FOR j := 0 TO Bitmap.Height - 1 DO BEGIN
// rowIn := Bitmap.ScanLine[j];
rowIn := pRGBArray(Bitmap.RawImage.GetLineStart(j));
FOR i := 0 TO Bitmap.Width - 1 DO
// pRGBArray(RESULT.Scanline[i])[Bitmap.Height - j - 1] := rowIn[i]
pRGBArray(RESULT.RawImage.GetLineStart(i))[Bitmap.Height - j - 1] := rowIn[i]
END;
RESULT.EndUpdate();
END {Rotate270DegreesCounterClockwise};
BEGIN
// IF Bitmap.PixelFormat <> pf24bit
// THEN RAISE EBitmapError.Create('Can Rotate90 only 24-bit bitmap');
IF (angle >= 0) AND (angle MOD 90 <> 0)
THEN RAISE EBitmapError.Create('Rotate90: Angle not positive multiple of 90 degrees');
CASE (angle DIV 90) MOD 4 OF
0: RESULT := SimpleCopy;
1: RESULT := Rotate90DegreesCounterClockwise; // Anticlockwise for the Brits
2: RESULT := Rotate180DegreesCounterClockwise;
3: RESULT := Rotate270DegreesCounterClockwise
ELSE
RESULT := NIL // avoid compiler warning
END;
END {RotateScanline90};
END. |
