"

 COPYRIGHT (c) 1997 by eXept Software AG / Claus Gittinger

              All Rights Reserved

 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:#IrisRGBReader

	instanceVariableNames:'bytesPerPixel'

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Images-Support'

!

!IrisRGBReader class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1997 by eXept Software AG / Claus Gittinger

              All Rights Reserved

 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.

"

!

documentation

"

    this class provides methods for loading Iris RGB format images. 

    Only 3-byte/pixel format is supported.

    Writing is not (yet) supported.

    [author:]

        Claus Gittinger

    [See also:]

        Image Form Icon

        BlitImageReader FaceReader GIFReader JPEGReader PCXReader 

        ST80FormReader SunRasterReader TargaReader TIFFReader WindowsIconReader 

        XBMReader XPMReader XWDReader 

"

! !

!IrisRGBReader class methodsFor:'initialization'!

initialize

    "install myself in the Image classes fileFormat table

     for the `.rgb' extension."

    MIMETypes defineImageType:'image/x-rgb' suffix:'rgb' reader:self.

    "Modified: 14.4.1997 / 15:49:19 / cg"

! !

!IrisRGBReader class methodsFor:'testing'!

isValidImageFile:aFileName

    "return true, if aFileName contains an IRIS_RGB image"

    |inStream magic type bpp dim w h bytesPerPixel|

    inStream := self streamReadingFile:aFileName.

    inStream isNil ifTrue:[^ false].

    inStream binary.

    magic := inStream nextShortMSB:true.

    type := inStream nextShortMSB:true.

    dim := inStream nextShortMSB:true.

    w := inStream nextShortMSB:true.

    h := inStream nextShortMSB:true.

    bytesPerPixel := inStream nextShortMSB:true.

    inStream close.

    magic ~~ 8r0732 ifTrue:[^ false].

    bpp := type bitAnd:16r00FF.

    bpp ~~ 1 ifTrue:[^ false].

    bytesPerPixel ~~ 3 ifTrue:[^ false].

    ^ true

    "

     IrisRGBReader isValidImageFile:'/home2/cg/capture.rgb'

    "

    "Modified: 14.4.1997 / 16:51:58 / cg"

! !

!IrisRGBReader methodsFor:'reading from file'!

fromStream:aStream

    "read a Portable bitmap file format as of Jeff Poskanzers Portable Bitmap Package.

     supported are IRIS_RGB, PGB and PNM files." 

    | magic type dim isRLE bpp|

    inStream := aStream.

    inStream binary.

    magic := inStream nextShortMSB:true.

    magic ~~ 8r0732 ifTrue:[

        ^ self fileFormatError:'bad magic number'.

    ].

    type := inStream nextShortMSB:true.

    dim := inStream nextShortMSB:true.

    width := inStream nextShortMSB:true.

    height := inStream nextShortMSB:true.

    bytesPerPixel := inStream nextShortMSB:true.

    isRLE := (type bitAnd:16rFF00) == 16r0100.

    bpp := type bitAnd:16r00FF.

    bpp ~~ 1 ifTrue:[

        ^ self fileFormatError:'only 1byte/pixel channel supported'.

    ].

    bytesPerPixel ~~ 3 ifTrue:[

        ^ self fileFormatError:'can only read 3-channel images'.

    ].

    isRLE ifTrue:[

        self readRLEData

    ] ifFalse:[

        ^ self fileFormatError:'currently, only RLE encoding supported'.

        "/ self readVerbatimData

    ].

    photometric := #rgb.

    samplesPerPixel := 3.

    bitsPerSample := #(8 8 8).

    "

     IrisRGBReader fromFile:'/home2/cg/capture.rgb'

    "

    "Created: / 14.4.1997 / 15:38:51 / cg"

    "Modified: / 1.4.1998 / 14:28:51 / cg"

!

readRLEData 

    "read RLE compressed data"

    |rleBufferLen tableLen startTable lengthTable rleData

    rleBufferLen := width * 2 + 10.

    tableLen := height * bytesPerPixel.

    startTable := Array new:tableLen.

    lengthTable := Array new:tableLen.

    rleData := ByteArray uninitializedNew:rleBufferLen.

    "/ read rowStart & length table

    inStream position:512+1.

    1 to:tableLen do:[:i |

        startTable at:i put:(inStream nextLongMSB:true).

    ].

    1 to:tableLen do:[:i |

        lengthTable at:i put:(inStream nextLongMSB:true).

    ].

    data := ByteArray uninitializedNew:(width*height*3).

    dstIdx := width * (height-1) * 3 + 1.

    0 to:(height-1) do:[:y |

        0 to:(bytesPerPixel-1) do:[:z |

            |start length|

            tblIdx := y + (z*height) + 1.

            start := startTable at:tblIdx.

            length := lengthTable at:tblIdx.

            inStream position:(start + 1).

            (inStream nextBytes:length into:rleData startingAt:1) ~~ length ifTrue:[

                self halt:'short read'

            ].

            (rleData at:length) ~~ 0 ifTrue:[

                self halt.

            ].

            self class

                decompressRLEFrom:rleData at:1 

                into:data at:dstIdx+z increment:3.

"/            self expandRow:rleData to:dstIdx+z. "/ (3-z).

        ].

        dstIdx := dstIdx - (width * 3).

    ].

    "

     IrisRGBReader fromFile:'/home2/cg/capture.rgb'

    "

    "Modified: 23.4.1997 / 18:59:11 / cg"

! !

!IrisRGBReader methodsFor:'testing '!

canRepresent:anImage

    "return true, if anImage can be represented in my file format.

     Currently only B&W and Depth8 images are supported."

"/    anImage photometric == #rgb ifTrue:[

"/        ^ false  "/ not yet implemented

"/    ].

"/    (depth := anImage depth) == 1 ifTrue:[^ true].

"/    depth == 8 ifTrue:[^ true].

    ^ false

    "Created: 14.4.1997 / 15:38:51 / cg"

    "Modified: 14.4.1997 / 15:58:20 / cg"

! !

!IrisRGBReader class methodsFor:'documentation'!

version

! !

IrisRGBReader initialize!