Hi,
I have read in several images as INTEGER*2 matrices, am doing pixel manipulations with them and writing the result to an output matrix.  How do I convert this output matrix into a bitmap image file?
Thanks for any help.
Mvpr

MVPR:

I have the same question on storing integer*2 matrices as bmp files.

I see the file format info described ad nauseum on the web, but wondered if you found a bit of code to do this file creation/image storage.

DoctorDoug

I know how to create a bmp file in C/C++ but I can't figure out how to do it with the compiler I have.  I've got all the structures in but I can't read/write the files.  There are lots of integer(len=2) and character(len=1) in the format specification.  Looks like my Fortran compiler, which is the Lahey-Fujitsu elf90 (when it was free) doesn't support input/output of binary files.

Just wondering whether it is worth trying it in F77 or is everything F90/F95 based nowadays?

I've written a noddy one in F77 but it is too big to post in this forum (appx 300 lines, including comments).  It will handle a 32x32 bitmap.  You will have to modify the code for a bigger map.  I haven't got a website and I can't be bothered to set one up.  If you email me at

tech@cup.btinternet.co.uk
subject Fortran BMP

I'll email the source to you.

I don't mind if you decide to put it on your website.  Just post it here to let everyone know.

Just looked at one of the other messages.  Maybe 300 lines isn't so big after all.  There are 2 files below.  If your version of F77 does not accept includes, then you will need to replicate the header file wherever the common block is required

Header File
-----------
!     BmpMap.h
!
!     Bitmap file header
***********************************************************************
      common /BitMap/
     &    bfSize,
     &    bfReserved,
     &    bfOffBits,
     &    biSize,
     &    biWidth,
     &    biHeight,
     &    biPlanes,
     &    biBitCount,
     &    biCompression,
     &    biSizeImage,
     &    biXPelsPerMeter,
     &    biYPelsPerMeter,
     &    biClrUsed,
     &    biClrImportant,
     &    bcColours,
     &    bcIxPerByte,
     &    bcBitsPerIx,
     &    bmpPosn,
     &    bfType     ! Smallest so it must appear last

!     type:: BmpFileHeader
          character*2 bfType
          integer*4 bfSize
          integer*4 bfReserved ! actually Reserved1 & 2
          integer*4 bfOffBits
!     end type BmpFileHeader

!     type:: BmpInfoHeader
          integer*4 biSize
          integer*4 biWidth
          integer*4 biHeight
          integer*2 biPlanes
          integer*2 biBitCount
          integer*4 biCompression
          integer*4 biSizeImage
          integer*4 biXPelsPerMeter
          integer*4 biYPelsPerMeter
          integer*4 biClrUsed
          integer*4 biClrImportant
!     end type BmpInfoHeader
!
!     Some variables for colours
      integer bcColours    ! number of colours
      integer bcIxPerByte  ! colour indices per byte
      integer bcBitsPerIx  ! bits per colour index
      integer bmpPosn

Source File
-----------
!     WriteBmp
!
!     Create a bmp file.
!     This code assumes integer*2 takes up 2 bytes: not the space
!     taken by 2 integers.  If the implementation is such that it
!     takes up the space of 2 integers, lots of declarations will
!     have to be changed
!
!     Many of the numbers are hard coded: no excuse except laziness
!
!     Maximum image size is 32x32.  If it is
!     Any bigger, change all arrays preceded by !!!!!!CHANGE
!**********************************************************************
      program main
!     Common Blocks
!     Locals
!!!!!!CHANGE
      integer image(32,32)
      integer imageHeight, imageWidth
      
      call CreateImage (image, imageHeight, imageWidth)
      call CreateBmp ('criss.bmp', image, imageHeight, imageWidth)
      stop
      end
!**********************************************************************
!     Create a dummy image
!**********************************************************************
      subroutine CreateImage (oImage, oHeight, oWidth)
      implicit none
!     Parameters
!!!!!!CHANGE
      integer oImage(32,32)
      integer oHeight
      integer oWidth
!     Common Blocks
!     Locals
      integer x, y

!     Clear the image
      oHeight = 16
      oWidth = 16
      do 20 x = 1, oWidth, 1
          do 10 y = 1, oHeight, 1
              oImage(x,y) = 0
10        continue
20    continue
!     Draw a cross
      do 30 x = 1, oWidth, 1
          oImage(x,x) = 1
          oImage(oWidth - x + 1, x) = 1
30    continue
!     Put a line at the top
      do 40 x = 1, oWidth, 1
          oImage(x,3) = 1
40    continue
!     Put a line at the side
      do 50 y = 1, oHeight, 1
          oImage(5,y) = 1
50    continue
      return
      end
!**********************************************************************
!     Create a bitmap
!**********************************************************************
      subroutine CreateBmp (iFilename, iImage, iWidth, iHeight)
      implicit none
!     Parameters
      character*(*) iFilename
!!!!!!CHANGE
      integer iImage(32,32)
      integer iHeight
      integer iWidth
!     Common Blocks
!     Locals
      integer fhand
      
      fhand = 10
!     try
          open (
     &        unit = fhand,
     &        file = iFilename,
     &        status = 'UNKNOWN',
     &        access = 'DIRECT', ! Otherwise it assumes a record header
     &        form = 'UNFORMATTED',
     &        recl = 1,
     &        err = 100)
          goto 200
!     catch
100       print *, 'Unable to open ', iFilename
          return
!     end catch
200   continue

      call CreateBmpInfo (fhand, iWidth, iHeight)
      call CreateBmpColours (fhand)
      call CreateBmpData (fhand, iImage, iWidth, iHeight)
      call CreateBmpFile (fhand)
      return
      end
!**********************************************************************
!**********************************************************************
      subroutine CreateBmpFile (iHand)
      implicit none
!     Parameters
      integer iHand
!     Common Blocks
      include 'BitMap.h'
!     Locals

      bfType = 'BM'
!     bfSize is set by CreateBmpData
      bfReserved = 0
      bfOffBits = 62
      write (iHand, rec=1) bfType, bfSize, bfReserved, bfOffBits
      return
      end
!**********************************************************************
!     Write Bmp Info Header to the file
!**********************************************************************
      subroutine CreateBmpInfo (iHand, iWidth, iHeight)
      implicit none
!     Parameters
      integer iHand
      integer iWidth
      integer iHeight
!     Common Blocks
      include 'BitMap.h'
!     Locals
      integer scanwidth
      
      biSize = 40            ! Size of BITMAPINFOHEADER
      biWidth = iWidth
      biHeight = iHeight
      biPlanes = 1           ! for a 2 colour bitmap
      biBitCount = 1         ! for a 2 colour bitmap
      biCompression = 0      ! no compression
!     Minimum number of bytes
      scanwidth = ((biWidth - 1) / 8 + 1)
!     Scan width must be a multiple of 4
      scanwidth = ((scanwidth - 1) / 4 + 1) * 4
      biSizeImage = scanwidth * iHeight
      biXPelsPerMeter = 3780 ! Some random figure that MS chooses
      biYPelsPerMeter = 3780
      biClrUsed = 0          ! for a 2 colour bitmap
      biClrImportant = 0     ! for a 2 colour bitmap
      bmpPosn = 55           ! where the colour table starts
      write (iHand, rec = 15)
     &    biSize,
     &    biWidth,
     &    biHeight,
     &    biPlanes,
     &    biBitCount,
     &    biCompression,
     &    biSizeImage,
     &    biXPelsPerMeter,
     &    biYPelsPerMeter,
     &    biClrUsed,
     &    biClrImportant
      return
      end
!**********************************************************************
!     Write the data to the file.  This is written backwards because
!     .bmp format stores everything backwards
!**********************************************************************
      subroutine CreateBmpData (iHand, iImage, iHeight, iWidth)
      implicit none
!     Parameters
      integer iHand
!!!!!!CHANGE
      integer iImage(32,32)
      integer iHeight
      integer iWidth
!     Common Blocks
      include 'BitMap.h'
!     Locals
      integer row, col
!!!!!!CHANGE At least iImage xmax / 32
      character bmp(32)*1
      integer ix, ixmax, posninc, patn
      
      ixmax = ((biWidth - 1) / 8 + 1)
!     Get the nearest number of 32-bit words
      ixmax = ((ixmax - 1) / 4 + 1) * 4

      do 30 row = iHeight, 1, -1
          do 10 ix = 1, ixmax, 1
              bmp(ix) = char (0)
10        continue
          ix = 1
          patn = 0
          do 20 col = 1, iWidth, 1
              patn = iShft (patn, 1)
!             0 = black, 1 = white
              if (iImage(col,row) .eq. 0)
     &            patn = iOr (patn, 1)

              if (mod (col, 8) .eq. 0) then
                  bmp(ix) = char (patn)
                  patn = 0
                  ix = ix + 1
              endif
20        continue
          write (iHand, rec = bmpPosn) (bmp(ix), ix = 1, ixmax, 1)
          bmpPosn = bmpPosn + ixmax
30    continue
      bfSize = bmpPosn - 1
      return
      end
!**********************************************************************
!     Set the colours
!**********************************************************************
      subroutine CreateBmpColours (iHand)
      implicit none
!     Parameters
      integer iHand
!     Common Blocks
      include 'BitMap.h'
!     Locals
      character*1 red, green, blue, reserved

!     bmpPosn is initialized in CreateBmpInfo
!     Set up for B/W bitmap
      bcColours = 2
      bcIxPerByte = 8
      bcBitsPerIx = 1
!     Black
      red = char(0)
      green = char(0)
      blue = char(0)
      reserved = char(0)
      write (iHand, rec = bmpPosn) blue, green, red, reserved
      bmpPosn = bmpPosn + 4
!     White
      red = char(255)
      green = char(255)
      blue = char(255)
      write (iHand, rec = bmpPosn) blue, green, red, reserved
      bmpPosn = bmpPosn + 4
      return
      end

Sources are also available under code samples on http://www.forceproject.hpg.ig.com.br/