"

 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.

"

"{ Package: 'stx:libview2' }"

"{ NameSpace: Smalltalk }"

ImageReader subclass:#PCXReader

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Images-Readers'

!

!PCXReader 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 8-plane PCX bitmap files.

    Due to not having too many examples for testing, this could fail

    to read some files. 

    (especially, I have no uncompressed files for testing).

    Only 8-bit (i.e. 256 color) PCX images are supported.

    Image writing is not supported.

    [See also:]

	Image Form Icon

	BlitImageReader FaceReader GIFReader JPEGReader PBMReader 

	ST80FormReader SunRasterReader TargaReader TIFFReader WindowsIconReader 

	XBMReader XPMReader XWDReader 

"

!

examples

"

    Image fromFile:'/usr/share/lilo/suse_640x480.pcx'

"

! !

!PCXReader class methodsFor:'initialization'!

initialize

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

     for the '.pcx' extension."

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

    "Modified: 27.6.1997 / 18:39:23 / cg"

! !

!PCXReader class methodsFor:'testing'!

isValidImageFile:aFilename

    "return true, if aFilename contains a PCX image"

    |count header inStream|

    inStream := self streamReadingFile:aFilename.

    inStream isNil ifTrue:[^ false].

    inStream binary.

    header := ByteArray uninitializedNew:128.

    count := inStream nextBytes:128 into:header.

    inStream close.

    ((count == 128) and:[self isValidPCXHeader:header]) ifFalse:[

	^ false

    ].

    ^ true

    "Modified: 17.9.1995 / 17:32:07 / claus"

!

isValidPCXHeader:aHeader

    "return true, if aHeader looks like a PCX image header"

    "check magic number"

    ((aHeader at:1) ~~ 16r0A) ifTrue:[

	^ false

    ].

    "check version"

    (#(0 2 3 5) includes:(aHeader at:2)) ifFalse:[

	^ false

    ].

    ^ true

    "Modified: 16.4.1997 / 22:24:32 / cg"

! !

!PCXReader methodsFor:'private-reading'!

extractColorMap16

    "extract the 16-entry colormap from the header"

    |rawMap|

    rawMap := header copyFrom:17 to:(17 + (16*3) - 1).

    ^ MappedPalette rgbBytesVector:rawMap 

!

nextByteFromBufferOrStream

    |byte|

    nBuffer ~~ 0 ifTrue:[

        byte := buffer at:bufferIndex.

        bufferIndex := bufferIndex + 1. nBuffer := nBuffer - 1.

    ] ifFalse:[

        byte := inStream next

    ].

    ^ byte

!

readColorMap256

    |rawMap mapSize|

    rawMap := ByteArray uninitializedNew:(256*3).

    nBuffer ~~ 0 ifTrue:[

        mapSize := buffer size - bufferIndex + 1.

        mapSize := mapSize min:(256*3).

        rawMap replaceFrom:1 to:mapSize with:buffer startingAt:bufferIndex.

        nBuffer < (256*3) ifTrue:[

            inStream nextBytes:((256*3)-nBuffer) into:rawMap startingAt:nBuffer+1

        ]

    ] ifFalse:[

        inStream nextBytes:(256*3) into:rawMap.

    ].

    ^ MappedPalette rgbBytesVector:rawMap 

!

readCompressedData

    |bendIndex rowIndex dstIndex endIndex byte nByte value idx2

    buffer := ByteArray uninitializedNew:4096.

    bufferIndex := 1.

    bendIndex := 1.

    rowIndex := 1.

    1 to:height do:[:row |

                bufferIndex == bendIndex ifTrue:[

                    nBuffer := inStream nextBytes:4096 into:buffer.

                    bufferIndex := 1.

                    bendIndex := nBuffer + 1.

                ].

                bufferIndex := bufferIndex + 1.

            ].

        ].

    ].

    nBuffer := endIndex - bufferIndex.

!

readRestAfterHeader

    "read an raw image in pcx format from aStream.

     The header has already been read into the header argument."

      paletteType 

      byte        "{Class: SmallInteger }" 

      nMaxPad|

    "/ typedef struct {                         /*header for PCX bitmap files*/

    "/    unsigned char       signature;          /*1 PCX file identifier */

    "/    unsigned char       version;            /*2 version compatibility level */

    "/    unsigned char       encoding;           /*3 compression method */

    "/    unsigned char       bitsperpix;         /*4 bits per pixel, or depth */

    "/    unsigned short      Xleft;              /*5 X position of left edge */

    "/    unsigned short      Ytop;               /*7 Y position of top edge */

    "/    unsigned short      Xright;             /*9 X position of right edge */

    "/    unsigned short      Ybottom;            /*11 Y position of bottom edge */

    "/    unsigned short      Xscreensize;        /*13 X screen res of source image */

    "/    unsigned short      Yscreensize;        /*15 Y screen res of source image */

    "/    unsigned char       PCXpalette[16][3];  /*17 PCX color map */

    "/    unsigned char       reserved1;          /*17+48 should be 0, 1 if std res fax */

    "/    unsigned char       planes;             /*66 bit planes in image*/

    "/    unsigned short      linesize;           /*67 byte delta between scanlines */

    "/    unsigned char       paletteinfo;        /*69 paletteType */

    "/                                                /*0 == undef

    "/                                                  1 == color

    "/                                                  2 == grayscale*/

    "/    unsigned char reserved2[58];            /*70 fill to struct size of 128*/

    "/ } PCX_HEADER;

    version := header at:2.

    "/    'version=' print. version printNL.

    compression := header at:3.

    "/    'compression=' print. compression printNL.

    (#(0 1) includes:compression) ifFalse:[

        ^ self fileFormatError:'unknown compression'.

    ].

    depth := header at:4.

    "/    'depth=' print. depth printNL.

    nPlanes := header at:66.

    "/    'planes=' print. nPlanes printNL.

    sourceBytesPerRow := header wordAt:67 MSB:false.

    "/    'srcBytesPerRow=' print. srcBytesPerRow printNL.

    paletteType := header at:69.

    xmin := header wordAt:5 MSB:false. 

    ymin := header wordAt:7 MSB:false.

    xmax := header wordAt:9 MSB:false. 

    ymax := header wordAt:11 MSB:false.

    width := (xmax - xmin + 1).

    height := (ymax - ymin + 1).

    "/    'width=' print. width printNL.

    "/    'height=' print. width printNL.

    self reportDimension.

    compression == 1 ifTrue:[

        self readCompressedData

    ] ifFalse:[

        self readUncompressedData

    ].

    paletteType == 2 ifTrue:[

        photometric := #blackIs0.

    ] ifFalse:[

        depth == 1 ifTrue:[

            photometric := #blackIs0.

        ] ifFalse:[    

            photometric := #palette.

        ].

    ].

                ].

                    'PCXREADER: no valid 256-entry palette (got' errorPrint. 

                    byte errorPrint. '; expected ' errorPrint. 16rC0 errorPrint. ')' errorPrintCR.

                ].

            ].

        ].

    ].

    samplesPerPixel := 1.

    bitsPerSample := { depth }.

    "

     |i f|

     i := Image fromFile:'somefile.pcx'.

     i inspect.

    "

!

readUncompressedData

    |dstIndex|

    "

     actually untested ...

    "

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

    sourceBytesPerRow ~~ width ifTrue:[

        dstIndex := 1.

        1 to:height do:[:row |

            inStream nextBytes:width into:data startingAt:dstIndex.

            dstIndex := dstIndex + width.

            inStream skip:(sourceBytesPerRow - width).

        ]

    ] ifFalse:[

        inStream nextBytes:(height * width) into:data.

    ].

    nBuffer := 0.

! !

!PCXReader methodsFor:'reading'!

readImage

    "read an image in pcx format from inStream"

    inStream binary.

    header := ByteArray uninitializedNew:128.

    (inStream nextBytes:128 into:header) == 128 ifFalse:[

        ^ self fileFormatError:'short file'.

    ].

    (self class isValidPCXHeader:header) ifFalse:[

        ^ self fileFormatError:'wrong header'.

    ].

    self readRestAfterHeader.

! !

!PCXReader class methodsFor:'documentation'!

version

    ^ '$Header$'

! !

PCXReader initialize!