"

 COPYRIGHT (c) 1994 by 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:#TargaReader

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Images-Support'

!

!TargaReader class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1994 by 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 targa-file (tga) images.

    Limitations: 

        not fully tested (I only had a few targe files to check things)

        only supports 24 bits/pixel uncompressed format

        Image saving not supported

    I had two tga files to test this code with - it may not work with

    other targa files (it certainly does not work with RLE-encoded or

    1/8 bit images).

    Suggestions: adapt & use the pbmplus library here.

    [See also:]

        Image Form Icon

        BlitImageReader FaceReader GIFReader JPEGReader PBMReader PCXReader 

        ST80FormReader SunRasterReader TIFFReader WindowsIconReader 

        XBMReader XPMReader XWDReader

"

! !

!TargaReader class methodsFor:'initialization'!

initialize

    "tell Image-class, that a new fileReader is present

! !

!TargaReader class methodsFor:'testing'!

isValidImageFile:aFileName

    "return true, if aFileName contains a targa-file image"

    |aStream w h depth flags|

    aStream := self streamReadingFile:aFileName.

    aStream isNil ifTrue:[^ false].

    aStream binary.

    aStream skip:12.   "/ skip 12 bytes

    w := aStream nextShortMSB:false.

    h := aStream nextShortMSB:false.

    depth := aStream next.

    flags := aStream next.

    (#("8" 24) includes:depth) ifFalse:[

	aStream close. ^ false

    ].

    flags ~~ 16r20 ifTrue:[

	aStream close. ^ false

    ].

    aStream close. 

    ^ true

    "

     TargaReader isValidImageFile:'bitmaps/test.tga'    

     TargaReader isValidImageFile:'bitmaps/garfield.gif'  

    " 

! !

!TargaReader methodsFor:'reading from file'!

fromStream:aStream

    "read a targa-image from aFileName. return the receiver (with all

     relevant instance variables set for the image) or nil on error"

    |depth flags nBytes ok lenID hasColorMap imageType 

     cmapOffset cmapLength cmapEntrySize xOrg yOrg

     t

     dSize "{ Class: SmallInteger }" |

    inStream := aStream.

    aStream binary.

    lenID := aStream next.

    hasColorMap := aStream next.

    imageType := aStream next.

    cmapOffset := aStream nextShortMSB:false.

    cmapLength := aStream nextShortMSB:false.

    cmapEntrySize := aStream next.

    xOrg := aStream nextShortMSB:false.

    yOrg := aStream nextShortMSB:false.

    width := aStream nextShortMSB:false.

    height := aStream nextShortMSB:false.

    depth := aStream next.

    depth ~~ 24 ifTrue:[

        'TARGA: unsupported depth' errorPrintNL.

        ^ nil

    ].

    "/ flags:

    "/    0000 xxxx  attribute-bits-per-pixel

    "/    00xx 0000  origin (0 -> lower-left / 1 -> l-r / 2 -> u-l / 3 -> u-r)

    "/    xx00 0000  interleave (0 -> none / 1 -> odd/even / 2 ->4-fould / 3 reserved)

    "/

    flags := aStream next.

    flags ~~ 16r20 ifTrue:[

        ^ false

    ].

    lenID ~~ 0 ifTrue:[

        aStream skip:lenID

    ].

    data := ByteArray new:(width * height * (depth / 8)).

    aStream nextBytes:(data size) into:data.

    "

     mhmh - pixel-byte order is blue-green-red

     swap blue & red bytes

    "

    nBytes := data size.

    ok := false.

%{  /* OPTIONAL */

    if (__isByteArray(_INST(data))) {

        int __lastIndex = __intVal(nBytes) - 2;

        unsigned char *__cp = __ByteArrayInstPtr(_INST(data))->ba_element;

        int __i;

        unsigned char __t;

        for (__i=0; __i<__lastIndex; __i+=3, __cp+=3) {

            __t = __cp[0];

            __cp[0] = __cp[2];

            __cp[2] = __t;

        }

        ok = true;

    }

%}.

    ok ifFalse:[

        dSize := data size.

        1 to:(dSize - 2) by:3 do:[:i |

            t := data at:i.

            data at:i put:(data at:i+2).

            data at:i+2 put:t

        ]

    ].

    photometric := #rgb.

    samplesPerPixel := 3.

    bitsPerSample := #(8 8 8).

    "

     TargaReader fromFile:'bitmaps/test.tga' 

    " 

! !

!TargaReader class methodsFor:'documentation'!

version

! !

TargaReader initialize!