Solved

timage rotation

Posted on 1998-04-09
1
415 Views
Last Modified: 2010-04-06
question
how can a timage be rotated in a fix angle say 90 degress
can any body help me..
this is an easy point.
may the force be with you.....
0
Comment
Question by:SABOG7
1 Comment
 
LVL 2

Accepted Solution

by:
Waldek earned 20 total points
ID: 1361363
Maybe this : from UDDF :}
From: Dave Shapiro <daves@cyber-fx.com>

Counterclockwise, that is. This rotates a 640x480 24-bit bitmap 90 degrees
in about 2/10 of sec on my P133 (4MB video card, 128MB RAM). It works
for Delphi 2, and should work for 1 and 3, too.

One thing: This does not work for bitmaps that aren't an integral number of
colors per pixel. If that's the case, you'll have to do some bit twiddling. I'm
working on that part right now (I need it too), but it'll be a few days. Anyways,
suggestions, comments, etc., always welcome.

Special thanks to David Ullrich (ooh, I hope I spelled that correctly) for
pointing out the non-published-but-public-anyway SaveToStream method for
the TBitmap class.

Advance apologies for any formatting problems. Netscape's editor is so
ridiculously crippled that I can't accomplish anything (give me rtin and vim
any day).



procedure RotateBitmap90Degrees(ABitmap: TBitmap);

const
  BITMAP_HEADER_SIZE = SizeOf(TBitmapFileHeader) +
SizeOf(TBitmapInfoHeader);

var
  { Things that end in R are for the rotated image. }
  PbmpInfoR: PBitmapInfoHeader;
  bmpBuffer, bmpBufferR: PByte;
  MemoryStream, MemoryStreamR: TMemoryStream;
  PbmpBuffer, PbmpBufferR: PByte;
  PbmpBufferRFirstScanLine, PbmpBufferColumnZero: PByte;
  BytesPerPixel, BytesPerScanLine, BytesPerScanLineR: Integer;
  X, Y, T: Integer;

begin
  {
    Don't *ever* call GetDIBSizes! It screws up your bitmap.
    I'll be posting about that shortly.
  }

  MemoryStream := TMemoryStream.Create;

  {
   To do: Put in a SetSize, which will eliminate any reallocation
   overhead.
  }

  ABitmap.SaveToStream(MemoryStream);

  {
   Don't need you anymore. We'll make a new one when the time comes.
  }
  ABitmap.Free;

  bmpBuffer := MemoryStream.Memory;

  { Set PbmpInfoR to point to the source bitmap's info header. }
  { Boy, these headers are getting annoying. }
  Inc( bmpBuffer, SizeOf(TBitmapFileHeader) );
  PbmpInfoR := PBitmapInfoHeader(bmpBuffer);

  { Set bmpBuffer to point to the original bitmap bits. }
  Inc(bmpBuffer, SizeOf(PbmpInfoR^));
  { Set the ColumnZero pointer to point to, uh, column zero. }
  PbmpBufferColumnZero := bmpBuffer;

  with PbmpInfoR^ do
  begin
    BytesPerPixel := biBitCount shr 3;
    { ScanLines are DWORD aligned. }
    BytesPerScanLine := ((((biWidth * biBitCount) + 31) div 32) * SizeOf(DWORD));
    BytesPerScanLineR := ((((biHeight * biBitCount) + 31) div 32) * SizeOf(DWORD));

    { The TMemoryStream that will hold the rotated bits. }
    MemoryStreamR := TMemoryStream.Create;
    {
     Set size for rotated bitmap. Might be different from source size
     due to DWORD aligning.
    }
    MemoryStreamR.SetSize(BITMAP_HEADER_SIZE  + BytesPerScanLineR * biWidth);
  end;

  { Copy the headers from the source bitmap. }
  MemoryStream.Seek(0, soFromBeginning);
  MemoryStreamR.CopyFrom(MemoryStream, BITMAP_HEADER_SIZE);

  { Here's the buffer we're going to rotate. }
  bmpBufferR := MemoryStreamR.Memory;
  { Skip the headers, yadda yadda yadda... }
  Inc(bmpBufferR, BITMAP_HEADER_SIZE);

  {
   Set up PbmpBufferRFirstScanLine and advance it to end of the first scan
   line of bmpBufferR.
  }
  PbmpBufferRFirstScanLine := bmpBufferR;
  Inc(PbmpBufferRFirstScanLine, (PbmpInfoR^.biHeight - 1) * BytesPerPixel);

  { Here's the meat. Loop through the pixels and rotate appropriately. }

  { Remember that DIBs have their origins opposite from DDBs. }
  for Y := 1 to PbmpInfoR^.biHeight do
  begin
    PbmpBuffer := PbmpBufferColumnZero;
    PbmpBufferR := PbmpBufferRFirstScanLine;

    for X := 1 to PbmpInfoR^.biWidth do
    begin
      for T := 1 to BytesPerPixel do
      begin
        PbmpBufferR^ := PbmpBuffer^;
        Inc(PbmpBufferR);
        Inc(PbmpBuffer);
      end;
      Dec(PbmpBufferR, BytesPerPixel);
      Inc(PbmpBufferR, BytesPerScanLineR);
    end;

    Inc(PbmpBufferColumnZero, BytesPerScanLine);
    Dec(PbmpBufferRFirstScanLine, BytesPerPixel);
  end;

  { Done with the source bits. }
  MemoryStream.Free;

  { Now set PbmpInfoR to point to the rotated bitmap's info header. }
  PbmpBufferR := MemoryStreamR.Memory;
  Inc( PbmpBufferR, SizeOf(TBitmapFileHeader) );
  PbmpInfoR := PBitmapInfoHeader(PbmpBufferR);

  { Swap the width and height of the rotated bitmap's info header. }
  with PbmpInfoR^ do
  begin
    T := biHeight;
    biHeight := biWidth;
    biWidth := T;
  end;

  ABitmap := TBitmap.Create;

  { Spin back to the very beginning. }
  MemoryStreamR.Seek(0, soFromBeginning);
  ABitmap.LoadFromStream(MemoryStreamR);

  MemoryStreamR.Free;
end;
0

Featured Post

Active Directory Webinar

We all know we need to protect and secure our privileges, but where to start? Join Experts Exchange and ManageEngine on Tuesday, April 11, 2017 10:00 AM PDT to learn how to track and secure privileged users in Active Directory.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Delphi Yen format 3 45
Need Help Delphi 2010 CheckBox1 Stored value in memo 13 73
Delphi...Split view - idea? 1 90
migrate this code to wprk on android 1 4
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
In my programming career I have only very rarely run into situations where operator overloading would be of any use in my work.  Normally those situations involved math with either overly large numbers (hundreds of thousands of digits or accuracy re…
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…

821 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question