"

 COPYRIGHT (c) 1993 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.

"

Image subclass:#Depth1Image

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Images'

!

!Depth1Image class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1993 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 represents bilevel (1 bit / pixel) images.

    It mainly consists of methods which are already implemented in Image,

    but reimplemented here for more performance. If you plan to do heavy

    image processing on bilevel images, you may want to add more

    specialized methods here.

    #blackIs0 / #whiteIs0 and #palette formats are supported here.

    [author:]

        Claus Gittinger

    [see also:]

        Depth2Image Depth4Image Depth8Image Depth16Image Depth24Image

        ImageReader

"

! !

!Depth1Image class methodsFor:'queries'!

imageDepth

    "return the depth of images represented by instances of

     this class - here we return 1"

    ^ 1

    "Modified: 20.4.1996 / 23:40:06 / cg"

! !

!Depth1Image methodsFor:'accessing - pixels'!

colorAtX:x y:y

    "retrieve a pixel at x/y; return a color.

     Pixels start at x=0 , y=0 for upper left pixel, end at

     x = width-1, y=height-1 for lower right pixel"

    |lineIndex "{ Class: SmallInteger }"

     byte      "{ Class: SmallInteger }"

     shift     "{ Class: SmallInteger }"

     value     "{ Class: SmallInteger }"

     p|

    lineIndex := (self bytesPerRow * y) + 1.

    "left pixel is in high bit"

    byte := bytes at:(lineIndex + (x // 8)).

    shift := #(-7 -6 -5 -4 -3 -2 -1 0) at:((x \\ 8) + 1).

    value := (byte bitShift:shift) bitAnd:1.

    (p := photometric) == #whiteIs0 ifTrue:[

        value := 1-value.

        p := #blackIs0

    ].

    p == #blackIs0 ifTrue:[

        (value == 0) ifTrue:[

            ^ Color black

        ].

        ^ Color white

    ].

    p ~~ #palette ifTrue:[

        ^ self colorFromValue:value

    ].

    value := value + 1.

    ^ colorMap at:value

    "Modified: 8.6.1996 / 10:52:15 / cg"

    "Created: 24.4.1997 / 17:33:17 / cg"

!

colorAtX:x y:y put:aColor

    "set the pixel at x/y to aColor.

     Pixels start at x=0 , y=0 for upper left pixel, end at

     x = width-1, y=height-1 for lower right pixel.

     This method checks, if it is possible to store the color

     in the image; i.e. for b/w images, the color MUST be black

     or white; for palette images it must be present in the palette."

    |clr0 clr1|

    photometric == #whiteIs0 ifTrue:[

        clr0 := Color white.

        clr1 := Color black.

    ] ifFalse:[

        photometric == #blackIs0 ifTrue:[

            clr0 := Color black.

            clr1 := Color white.

        ] ifFalse:[

            photometric ~~ #palette ifTrue:[

                self error:'format not supported'.

                ^ nil

            ].

            clr0 := colorMap at:1.

            clr1 := colorMap at:2.

        ]

    ].

    aColor = clr0 ifTrue:[

        self pixelAtX:x y:y put:0.

        ^ self

    ].

    aColor = clr1 ifTrue:[

        self pixelAtX:x y:y put:1.

        ^ self

    ].

    "

     the color to be stored is not in the images colormap

    "

    self error:'invalid color - not in colorMap'

    "Modified: 24.4.1997 / 17:16:38 / cg"

    "Created: 24.4.1997 / 17:33:23 / cg"

!

pixelAtX:x y:y

    "retrieve a pixelValue at x/y; return a number.

     The interpretation of the returned value depends on the photometric

     and the colormap. See also Image>>atX:y:)

     Pixels start at 0@0 for upper left pixel, end at

     (width-1)@(height-1) for lower right pixel"

    |bytesPerRow "{Class: SmallInteger}"

     index       "{Class: SmallInteger}"

     byte        "{Class: SmallInteger}"

     mask        "{Class: SmallInteger}"|

%{  /* NOCONTEXT */

    OBJ b = _INST(bytes);

    OBJ w = _INST(width);

    if (__isByteArray(b) && __bothSmallInteger(x, y) && __isSmallInteger(w) ) {

        int _w = __intVal(w);

        int _y = __intVal(y);

        int _x = __intVal(x);

        unsigned _byte;

        int _idx;

        _idx = ((_w + 7) >> 3) * _y + (_x >> 3);

        if ((unsigned)_idx < __byteArraySize(b)) {

            _byte = __ByteArrayInstPtr(b)->ba_element[_idx];

            RETURN( (_byte & (0x80 >> (_x & 7))) ? __MKSMALLINT(1) : __MKSMALLINT(0) );

        }

    }

%}.

"/ the above is equivalent to:

"/   (notice that the code below is evaluated if the bytes-collection is

"/   not a byteArray, or the arguments are not integers)

"/    bytesPerRow := width // 8.

"/    ((width \\ 8) ~~ 0) ifTrue:[

"/        bytesPerRow := bytesPerRow + 1

"/    ].

"/    index := (bytesPerRow * y) + 1 + (x // 8).

"/

"/    "left pixel is in high bit"

"/    byte := bytes at:index.

"/    mask := #(16r80 16r40 16r20 16r10 16r08 16r04 16r02 16r01) at:((x \\ 8) + 1).

"/    (byte bitAnd:mask) == 0 ifTrue:[^ 0].

"/    ^ 1

"/ since that cannot happen, we faile here

    self primitiveFailed.

    ^ 0

!

pixelAtX:x y:y put:aPixelValue

    "set a pixels value at x/y to aPixelValue.

     Pixels start at x=0 , y=0 for upper left pixel, end at

     x = width-1, y=height-1 for lower right pixel"

    |bytesPerRow "{Class: SmallInteger}"

     index       "{Class: SmallInteger}"

     byte        "{Class: SmallInteger}"

     mask        "{Class: SmallInteger}"|

%{  /* NOCONTEXT */

    OBJ b = _INST(bytes);

    OBJ w = _INST(width);

    if (__isByteArray(b) && __bothSmallInteger(x, y) && __isSmallInteger(w) ) {

        int _w = __intVal(w);

        int _y = __intVal(y);

        int _x = __intVal(x);

        int _idx;

        _idx = ((_w + 7) >> 3) * _y + (_x >> 3);

        if ((unsigned)_idx < __byteArraySize(b)) {

            if (aPixelValue == __MKSMALLINT(0)) {

                __ByteArrayInstPtr(b)->ba_element[_idx] &= ~(0x80 >> (_x & 7));

            } else {

                __ByteArrayInstPtr(b)->ba_element[_idx] |= (0x80 >> (_x & 7));

            }

            RETURN( self );

        }

    }

%}.

    "fall back code for nonByteArray or nonInteger arguments"

    bytesPerRow := width // 8.

    ((width \\ 8) ~~ 0) ifTrue:[

        bytesPerRow := bytesPerRow + 1

    ].

    index := (bytesPerRow * y) + 1 + (x // 8).

    "left pixel is in high bit"

    byte := bytes at:index.

    mask := #(16r80 16r40 16r20 16r10 16r08 16r04 16r02 16r01) at:((x \\ 8) + 1).

    aPixelValue == 0 ifTrue:[

        byte := byte bitAnd:(mask bitInvert)

    ] ifFalse:[

        byte := byte bitOr:mask

    ].

    bytes at:index put:byte

! !

!Depth1Image methodsFor:'converting greyscale images'!

asFormOn:aDevice

    "convert a monochrome image to a device form"

    |f|

    ((aDevice == device) and:[deviceForm notNil]) ifTrue:[^ deviceForm].

    f := Form width:width height:height fromArray:bytes on:aDevice.

    f notNil ifTrue:[

        f colorMap:(Array with:(self colorFromValue:0)

                          with:(self colorFromValue:1)).

    ].

    ^ f

    "Created: 14.6.1996 / 15:20:00 / cg"

    "Modified: 24.4.1997 / 17:50:43 / cg"

!

greyImageAsFormOn:aDevice

    "convert a greyscale image to a device form"

    ^ self asFormOn:aDevice

    "Modified: 14.6.1996 / 15:21:04 / cg"

!

greyImageAsMonoFormOn:aDevice

    "convert to a monochrome form - thats easy"

    ^ self asFormOn:aDevice

    "Modified: 14.6.1996 / 15:21:09 / cg"

! !

!Depth1Image methodsFor:'converting palette images'!

paletteImageAsMonoFormOn:aDevice

    "convert a palette image to a b&w monochrome device form"

    |f c0 c1|

    f := Form width:width height:height fromArray:bytes on:aDevice.

    c0 := self colorFromValue:0.

    c1 := self colorFromValue:1.

    c0 brightness > 0.5 ifTrue:[

        c0 := Color white

    ] ifFalse:[

        c0 := Color black.

    ].

    c1 brightness > 0.5 ifTrue:[

        c1 := Color white

    ] ifFalse:[

        c1 := Color black.

    ].

    f colorMap:(Array with:c0 with:c1).

    ^ f

    "Modified: 24.4.1997 / 17:51:54 / cg"

!

paletteImageAsPseudoFormOn:aDevice

    "return a pseudo-deviceForm from the palette image."

    ^ self asFormOn:aDevice

    "Modified: 14.6.1996 / 15:21:33 / cg"

!

paletteImageAsTrueColorFormOn:aDevice

    "since all devices must support monochrome images, and

     a 2-entry colormap is implemented by ST/X's drawForm methods,

     we can do this on all color devices as a palette image."

    ^ self asFormOn:aDevice

    "

     |i|

     i := Depth1Image

                width:4

                height:4

                fromArray:#[ 2r00000000

                             2r11110000

                             2r01010000

                             2r10100000 ].

     i photometric:#rgb.

     i samplesPerPixel:3.

     i bitsPerSample:#(1 0 0).

     i := i magnifiedBy:30.

     i inspect.

    "

    "Modified: 14.6.1996 / 15:21:37 / cg"

! !

!Depth1Image methodsFor:'enumerating'!

colorsAtY:y from:xLow to:xHigh do:aBlock

    "perform aBlock for each pixel from x1 to x2 in row y.

     The block is passed the color at each pixel.

     This method allows slighly faster processing of an

     image than using atX:y:, since some processing can be

     avoided when going from pixel to pixel. However, for

     real image processing, specialized methods should be written."

    |srcIndex "{ Class: SmallInteger }"

     byte     "{ Class: SmallInteger }"

     mask     "{ Class: SmallInteger }"

     x1       "{ Class: SmallInteger }"

     x2       "{ Class: SmallInteger }"

     color0 color1|

    x1 := xLow.

    x2 := xHigh.

    srcIndex := (self bytesPerRow * y) + 1.

    "left pixel is in high bit"

    photometric == #whiteIs0 ifTrue:[

        color0 := Color white.

        color1 := Color black

    ] ifFalse:[

        photometric == #blackIs0 ifTrue:[

            color0 := Color black.

            color1 := Color white

        ] ifFalse:[

            photometric == #palette ifTrue:[

                color0 := colorMap at:1.

                color1 := colorMap at:2

            ] ifFalse:[

                color0 := self colorFromValue:0.

                color1 := self colorFromValue:1.

            ]

        ]

    ].

    srcIndex := srcIndex + (x1 // 8).

    mask := #[2r10000000 

              2r01000000

              2r00100000

              2r00010000

              2r00001000

              2r00000100

              2r00000010

              2r00000001] at:((x1 \\ 8) + 1).

    byte := bytes at:srcIndex.

    x1 to:x2 do:[:x |

        (byte bitAnd:mask) == 0 ifTrue:[

            aBlock value:x value:color0

        ] ifFalse:[

            aBlock value:x value:color1

        ].

        mask := mask bitShift:-1.

        mask == 0 ifTrue:[

            mask := 2r10000000.

            srcIndex := srcIndex + 1.

            x < x2 ifTrue:[

                byte := bytes at:srcIndex.

            ]

        ]

    ]

    "Created: 7.6.1996 / 19:12:26 / cg"

    "Modified: 10.6.1996 / 10:33:06 / cg"

!

valuesAtY:y from:xLow to:xHigh do:aBlock

    "perform aBlock for each pixelValue from x1 to x2 in row y.

     The block is passed the color at each pixel.

     This method allows slighly faster processing of an

     image than using atX:y:, since some processing can be

     avoided when going from pixel to pixel. However, for

     real image processing, specialized methods should be written."

    |srcIndex "{ Class: SmallInteger }"

     byte     "{ Class: SmallInteger }"

     mask     "{ Class: SmallInteger }"

     x1       "{ Class: SmallInteger }"

     x2       "{ Class: SmallInteger }"

     pixelValue|

    "this method needs more tuning, if used heavily 

     (fetch 8 bits at once, unroll the loop over these 8 pixels)"

    x1 := xLow.

    x2 := xHigh.

    srcIndex := (self bytesPerRow * y) + 1.

    "left pixel is in high bit"

    srcIndex := srcIndex + (x1 // 8).

    mask := #[2r10000000 

              2r01000000

              2r00100000

              2r00010000

              2r00001000

              2r00000100

              2r00000010

              2r00000001] at:((x1 \\ 8) + 1).

    byte := bytes at:srcIndex.

    x1 to:x2 do:[:x |

        (byte bitAnd:mask) == 0 ifTrue:[

            aBlock value:x value:0

        ] ifFalse:[

            aBlock value:x value:1

        ].

        mask := mask bitShift:-1.

        mask == 0 ifTrue:[

            mask := 2r10000000.

            srcIndex := srcIndex + 1.

            x < x2 ifTrue:[

                byte := bytes at:srcIndex.

            ]

        ]

    ]

    "Created: 7.6.1996 / 19:09:38 / cg"

    "Modified: 8.6.1996 / 13:36:37 / cg"

! !

!Depth1Image methodsFor:'magnification'!

hardMagnifiedBy:scalePoint

    "return a new image magnified by scalePoint, aPoint.

     This is the general magnification method, handling non-integral values.

     It is slower than the integral magnification method."

    |mX