"

 COPYRIGHT (c) 1991 by Claus Gittinger

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

ImageReader subclass:#TIFFReader

!

TIFFReader comment:'

COPYRIGHT (c) 1991 by Claus Gittinger

'!

!TIFFReader class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1991 by Claus Gittinger

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

version

"

"

!

documentation

"

    This class knows how to read TIFF files and how to

    write uncompressed TIFF files.

    Only single image files are supported.

    Currently, not all formats are implemented, and of those that are not 

    all are tested.

    It should work with most rgb, mono and 2-plane greyscale

    images, since this is what I have as test material on

    the NeXT.

    It supports reading of uncompressed, LZW and G3 compressed 

    images; JPEG and packbits are currently not implemented.

    Only writing of uncompressed images is currently implemented.

    More formats will come ...

"

! !

!TIFFReader class methodsFor:'testing'!

isValidImageFile:aFileName

    "return true, if aFileName contains a GIF image"

    |inStream char1 char2 version|

    inStream := self streamReadingFile:aFileName.

    inStream isNil ifTrue:[^ false].

    char1 := inStream next.

    char2 := inStream next.

    ((char1 ~~ char2) or:[(char1 ~~ $I) and:[char1 ~~ $M]]) ifTrue:[

    ].

    inStream binary.

    version := inStream nextShortMSB:(char1 == $M).

    inStream close.

    (version ~~ 42) ifTrue:[^ false].

    ^ true

! !

!TIFFReader methodsFor:'reading from file'!

fromFile:aFileName

    "read an image from aFileName"

    |char1 char2 version 

     numberOfTags "{ Class: SmallInteger }"

     tagType      "{ Class: SmallInteger }"

     numberType   "{ Class: SmallInteger }"

     length       "{ Class: SmallInteger }"

     result offset ok|

    inStream := self class streamReadingFile:aFileName.

    inStream isNil ifTrue:[^ nil].

    char1 := inStream next.

    char2 := inStream next.

    (char1 ~~ char2) ifTrue:[

    ].

    (char1 == $I) ifTrue:[

    ] ifFalse:[

    ].

    inStream binary.

    version := self readShort.

    (version ~~ 42) ifTrue:[

    ].

    "setup default values"

    compression := 1. "none"

    fillOrder := #msb.

    planarConfiguration := 1.

    photometric := nil.

    bitsPerSample := 1.

    samplesPerPixel := 1.

    width := nil.

    height := nil.

    stripOffsets := nil.

    rowsPerStrip := nil.

    "resolutionUnit := 2."

    predictor := 1.

    offset := self readLong + 1.

    inStream position:offset.

    numberOfTags := self readShort.

    1 to:numberOfTags do:[:index |

    ].

    offset := self readLong.

    (offset ~~ 0) ifTrue:[

    ].

    "check for required tags"

    ok := true.

    width isNil ifTrue:[

    ].

    height isNil ifTrue:[

    ].

    photometric isNil ifTrue:[

    ].

    stripOffsets isNil ifTrue:[

    ].

    ok ifFalse:[

    ].

    "given all the information, read the bits"

    rowsPerStrip isNil ifTrue:[

    ].

    (compression == 1) ifTrue:[

      result := self readUncompressedTiffImageData

    ] ifFalse:[

      (compression == 5) ifTrue:[

      ] ifFalse:[

      ] 

    ].

    inStream close.

    ^ result

! !

!TIFFReader methodsFor:'writing to file'!

save:image onFile:aFileName

    "save image as (uncompressed) TIFF file on aFileName"

    |pos1 pos|

    outStream := FileStream newFileNamed:aFileName.

    outStream isNil ifTrue:[

    ].

    "save as msb"

    byteOrder := #msb.

"

    byteOrder := #lsb.

"

    fillOrder := #msb.

    width := image width.

    height := image height.

    photometric := image photometric.

    samplesPerPixel := image samplesPerPixel.

    bitsPerSample := image bitsPerSample.

    colorMap := image colorMap.

    planarConfiguration := 1.

    compression := 1.   "none"

    data := image bits.

    currentOffset := 0.

    (byteOrder == #msb) ifTrue:[

    ] ifFalse:[

    ].

    currentOffset := currentOffset + 2.

    outStream binary.

    self writeShort:42.

    currentOffset := currentOffset + 2.

    pos1 := outStream position.

    self writeLong:0.           "start of tags - filled in later"

    currentOffset := currentOffset + 4.

    "output strips"

    self writeUncompressedBits. "this outputs bits as strips, sets stripOffsets and stripByteCounts"

    self writeStripOffsets.     "this outputs strip offsets, sets stripOffsetsPos"

    self writeStripByteCounts.  "this outputs strip bytecounts, sets stripByteCountPos"

    self writeBitsPerSample.    "this outputs bitsPerSample, sets bitsPerSamplePos"

    photometric == #palette ifTrue:[

    ].

    pos := outStream position.                  "backpatch tag offset"

    outStream position:pos1.

    self writeLong:(pos - 1).                   "fill in tag offset"

    outStream position:pos.

"

('patch tag offset at: ', (pos1 printStringRadix:16) , ' to ',

"

    "output tag data"

    photometric == #palette ifTrue:[

    ] ifFalse:[

    ].

    self writeTag:256.               "image width"

    self writeTag:257.               "image height"

    self writeTag:258.               "bits per sample"

    self writeTag:259.               "compression"

    self writeTag:262.               "photometric"

    self writeTag:273.               "strip offsets"

    self writeTag:279.               "strip byte counts"

    self writeTag:284.               "planarconfig"

    photometric == #palette ifTrue:[

    ].

    self writeLong:0.                "end of tags mark"

    outStream close

! !

!TIFFReader methodsFor:'private'!

readLongs:n

    |oldPos offset values|

    values := Array new:n.

    (n == 1) ifTrue:[

    ] ifFalse:[

    ].

    ^ values

!

writeLongs:longs

    1 to:longs size do:[:l |

    ]

!

readShorts:n

    |oldPos offset values|

    values := Array new:n.

    (n <= 2) ifTrue:[

    ] ifFalse:[

    ].

    ^ values

!

readChars:n

    |oldPos offset string|

    string := String new:(n - 1).

    (n <= 4) ifTrue:[

    ] ifFalse:[

    ].

    ^ string

!

readFracts:cnt

    |oldPos offset values n d|

    values := Array new:cnt.

    offset := self readLong.

    oldPos := inStream position.

    inStream position:(offset + 1).

    1 to:cnt do:[:index |

    ].

    inStream position:oldPos.

    ^ values

!

decodeTiffTag:tagType numberType:numberType length:length

    |offset value valueArray 

     n "{ Class: SmallInteger }" |

    (numberType == 3) ifTrue:[

    ] ifFalse:[

    ].

    (tagType == 254) ifTrue:[

"

"

    ].

    (tagType == 255) ifTrue:[

"

"

    ].

    (tagType == 256) ifTrue:[

"

"

    ].

    (tagType == 257) ifTrue:[

"

"

    ].

    (tagType == 258) ifTrue:[

"

"

    ].

    (tagType == 259) ifTrue:[

"

"