"

 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:#Depth2Image

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Images'

!

!Depth2Image 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 four-color (2 bit / pixel) images 

    (as used mainly on the NeXT).

    It mainly consists of methods already implemented in Image,

    reimplemented here for more performance.

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

    [author:]

        Claus Gittinger

    [see also:]

        Depth1Image Depth4Image Depth8Image Depth16Image Depth24Image 

        ImageReader

"

! !

!Depth2Image class methodsFor:'queries'!

imageDepth

    "return the depth of images represented by instances of

     this class - here we return 2"

    ^ 2

    "Modified: 20.4.1996 / 23:40:12 / cg"

! !

!Depth2Image 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 grey|

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

    "left pixel in high bits"

    byte := bytes at:(lineIndex + (x // 4)).

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

    value := (byte bitShift:shift) bitAnd:3.

    p := photometric.

    p == #whiteIs0 ifTrue:[

        value := 3 - value.

        p := #blackIs0

    ].

    p == #blackIs0 ifTrue:[

        (value == 0) ifTrue:[

            ^ Color black

        ].

        (value == 3) ifTrue:[

            ^ Color white

        ].

        (value == 1) ifTrue:[

            grey := 33

        ] ifFalse:[

            grey := 67

        ].

        ^ Color gray:grey

    ].

    photometric ~~ #palette ifTrue:[

        ^ self colorFromValue:value

    ].

    ^ colorMap at:(value+1).

    "Modified: 8.6.1996 / 10:52:38 / cg"

    "Created: 24.4.1997 / 17:33:41 / cg"

!

pixelAtX:x y:y

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

     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 }" |

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

    "left pixel in high bits"

    byte := bytes at:(lineIndex + (x // 4)).

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

    ^ (byte bitShift:shift) bitAnd:3.

    "Created: 24.4.1997 / 16:06:39 / cg"

!

pixelAtX:x y:y put:aPixelValue

    "set the pixel 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"

    |lineIndex "{ Class: SmallInteger }"

     index     "{ Class: SmallInteger }"

     byte      "{ Class: SmallInteger }"

     shift     "{ Class: SmallInteger }" |

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

    "left pixel is in high bits"

    index := lineIndex + (x // 4).

    byte := bytes at:index.

    shift := #(6 4 2 0) at:((x \\ 4) + 1).

    byte := (byte bitAnd:(3 bitShift:shift) bitInvert) bitOr:(aPixelValue bitShift:shift).

    bytes at:index put:byte

    "Created: 24.4.1997 / 17:06:36 / cg"

! !

anyImageAsTrueColorFormOn:aDevice

    "return a true-color device-form for the receiver.

     Supports true color devices with depths: 8, 16, 24 and 32"

    |depth 

     colorValues 

     form imageBits bestFormat usedDeviceDepth usedDeviceBitsPerPixel 

     usedDevicePadding usedDeviceBytesPerRow padd n|

    depth := aDevice depth.

    "/ gather r/g/b values for all colors in the map ...

    colorValues := self rgbColormapFor:aDevice.

    bestFormat := self bestSupportedImageFormatFor:aDevice.

    usedDeviceDepth := bestFormat at:#depth.

    usedDeviceDepth == 1 ifTrue:[

        ^ self asMonochromeFormOn:aDevice

    ].

    usedDeviceBitsPerPixel := bestFormat at:#bitsPerPixel.

    usedDevicePadding := bestFormat at:#padding.

    usedDeviceBytesPerRow := self class bytesPerRowForWidth:width depth:usedDeviceBitsPerPixel padding:usedDevicePadding.

    padd := usedDeviceBytesPerRow -( self class bytesPerRowForWidth:width depth:usedDeviceBitsPerPixel padding:8).

    imageBits := ByteArray uninitializedNew:(usedDeviceBytesPerRow * height).

    "/ for now, only support some depths

    usedDeviceBitsPerPixel == 16 ifTrue:[

        "/ 16 bits/pixel

        "/ now, walk over the image and replace

        "/ colorMap indices by color values in the bits array

%{  

        if (__bothSmallInteger(_INST(height), _INST(width))

         && __isArray(colorValues)

         && __isByteArray(_INST(bytes))

         && __isByteArray(imageBits)) {

            int r,p;

            int x, y, w, h, nPix;

            int byte, shift;

            unsigned char *srcPtr = __ByteArrayInstPtr(_INST(bytes))->ba_element;

            unsigned char *dstPtr = __ByteArrayInstPtr(imageBits)->ba_element;

            OBJ *ap = __ArrayInstPtr(colorValues)->a_element;

            w = __intVal(_INST(width));

            h = __intVal(_INST(height));

            r = 0;

            p = __intVal(padd);

            nPix = w * h;

            shift = -2;

            while (nPix-- > 0) {

                unsigned idx, v;

                OBJ clr;

                if (shift < 0) {

                    byte = *srcPtr++;

                    shift = 6;

                }

                idx = (byte >> shift) & 3;

                shift -= 2;

                clr = ap[idx];

                v = __intVal(clr);

#ifdef __MSBFIRST

                ((short *)dstPtr)[0] = v;

#else

# ifdef xxSWAP_BYTES

                SWAP_BYTES(v);

                ((short *)dstPtr)[0] = v;

# else

                dstPtr[0] = (v>>8) & 0xFF;

                dstPtr[1] = (v) & 0xFF;

# endif

#endif

                dstPtr += 2;

                if (++r == w) {

                    dstPtr += p;

                    r = 0;

                    shift = -2;

                }

            }

        }

%}.

    ] ifFalse:[

        usedDeviceBitsPerPixel == 32 ifTrue:[

            "/ 32 bits/pixel

            "/ now, walk over the image and replace

            "/ colorMap indices by color values in the bits array

%{       

            if (__bothSmallInteger(_INST(height), _INST(width))

             && __isArray(colorValues)

             && __isByteArray(_INST(bytes))

             && __isByteArray(imageBits)) {

                int x, y, w, h, nPix;

                int r,p;

                int byte, shift;

                unsigned char *srcPtr = __ByteArrayInstPtr(_INST(bytes))->ba_element;

                unsigned char *dstPtr = __ByteArrayInstPtr(imageBits)->ba_element;

                OBJ *ap = __ArrayInstPtr(colorValues)->a_element;

                w = __intVal(_INST(width));

                h = __intVal(_INST(height));

                r = 0;

                p = __intVal(padd);

                nPix = w * h;

                shift = -2;

                while (nPix > 0) {

                    unsigned idx, v;

                    OBJ clr;

                    if (shift < 0) {

                        byte = *srcPtr++;

                        shift = 6;

                    }

                    idx = (byte >> shift) & 3;

                    shift -= 2;

                    clr = ap[idx];

                    v = __intVal(clr);

#ifdef __MSBFIRST

                    ((long *)dstPtr)[0] = v;

#else

                    dstPtr[0] = (v>>24) & 0xFF;

                    dstPtr[1] = (v>>16) & 0xFF;

                    dstPtr[2] = (v>>8) & 0xFF;

                    dstPtr[3] = (v) & 0xFF;

#endif

                    dstPtr += 4;

                    nPix--;

                    if (++r == w) {

                        dstPtr += p;

                        r = 0;

                        shift = -2;

                    }

                }

            }

%}.

        ] ifFalse:[

            usedDeviceBitsPerPixel == 8 ifTrue:[

                "/ 8 bits/pixel

                "/ now, walk over the image and replace

                "/ colorMap indices by color values in the bits array

%{       

                if (__bothSmallInteger(_INST(height), _INST(width))

                 && __isArray(colorValues)

                 && __isByteArray(_INST(bytes))

                 && __isByteArray(imageBits)) {

                    int x, y, w, h, nPix;

                    int r,p, byte, shift;

                    unsigned char *srcPtr = __ByteArrayInstPtr(_INST(bytes))->ba_element;

                    unsigned char *dstPtr = __ByteArrayInstPtr(imageBits)->ba_element;

                    OBJ *ap = __ArrayInstPtr(colorValues)->a_element;

                    w = __intVal(_INST(width));

                    h = __intVal(_INST(height));

                    r = 0;

                    p = __intVal(padd);

                    nPix = w * h;

                    shift = -2;

                    while (nPix > 0) {

                        unsigned idx, v;

                        OBJ clr;

                        if (shift < 0) {

                            byte = *srcPtr++;

                            shift = 6;

                        }

                        idx = (byte >> shift) & 3;

                        shift -= 2;

                        clr = ap[idx];

                        v = __intVal(clr);

                        dstPtr[0] = v;

                        dstPtr += 1;

                        nPix--;

                        if (++r == w) {

                            dstPtr += p;

                            r = 0;

                            shift = -2;

                        }

                    }

                }

%}.

            ] ifFalse:[

                usedDeviceBitsPerPixel == 24 ifTrue:[

                    "/ 24 bits/pixel

                    "/ now, walk over the image and replace

                    "/ colorMap indices by color values in the bits array

%{       

                    if (__bothSmallInteger(_INST(height), _INST(width))

                     && __isArray(colorValues)

                     && __isByteArray(_INST(bytes))

                     && __isByteArray(imageBits)) {

                        int x, y, w, h, nPix;

                        int r, p, byte, shift;

                        unsigned char *srcPtr = __ByteArrayInstPtr(_INST(bytes))->ba_element;

                        unsigned char *dstPtr = __ByteArrayInstPtr(imageBits)->ba_element;

                        OBJ *ap = __ArrayInstPtr(colorValues)->a_element;

                        w = __intVal(_INST(width));

                        h = __intVal(_INST(height));

                        r = 0;

                        p = __intVal(padd);

                        nPix = w * h;

                        shift = -2;

                        while (nPix > 0) {

                            unsigned idx, v;

                            OBJ clr;

                            if (shift < 0) {

                                byte = *srcPtr++;

                                shift = 6;

                            }

                            idx = (byte >> shift) & 3;

                            shift -= 2;

                            clr = ap[idx];

                            v = __intVal(clr);

                            dstPtr[0] = (v>>16) & 0xFF;

                            dstPtr[1] = (v>>8) & 0xFF;

                            dstPtr[2] = (v) & 0xFF;

                            dstPtr += 3;

                            nPix--;

                            if (++r == w) {

                                dstPtr += p;

                                r = 0;

                                shift = -2;

                            }

                        }

                    }

%}.

                ] ifFalse:[

                    'Image [warning]: unimplemented trueColor depth in anyImageAsTrueColorFormOn: ' errorPrint. usedDeviceBitsPerPixel errorPrintCR.

                    ^ nil

                ]

            ]

        ]

    ].

    imageBits isNil ifTrue:[            

        ^ nil

    ].

    form := Form width:width height:height depth:usedDeviceDepth on:aDevice.

    form isNil ifTrue:[^ nil].

    form initGC.

    form

        copyBitsFrom:imageBits

        bitsPerPixel:usedDeviceBitsPerPixel

        depth:usedDeviceDepth

        padding:usedDevicePadding

        width:width height:height 

        x:0 y:0

        toX:0 y:0. 

    ^ form

    "Created: 20.10.1995 / 22:05:10 / cg"

    "Modified: 21.10.1995 / 19:30:26 / cg"

!

greyImageAsTrueColorFormOn:aDevice

    "return a true-color device-form for the grey-image receiver.

     Supports true color devices with depths: 8, 16, 24 and 32"

    |f|

    f := self anyImageAsTrueColorFormOn:aDevice.

    f notNil ifTrue:[^ f].

    ^ super greyImageAsTrueColorFormOn:aDevice

    "Created: / 28.7.1998 / 16:57:32 / cg"

!

paletteImageAsTrueColorFormOn:aDevice

    "return a true-color device-form for the palette-image receiver.

     Supports true color devices with depths: 8, 16, 24 and 32"

    |f|

    f := self anyImageAsTrueColorFormOn:aDevice.

    f notNil ifTrue:[^ f].

    ^ super paletteImageAsTrueColorFormOn:aDevice

    "Created: / 28.7.1998 / 16:57:47 / cg"

!

rgbImageAsTrueColorFormOn:aDevice

    "return a true-color device-form for the rgb-image receiver.

     Supports true color devices with depths: 8, 16, 24 and 32"

    |f|

    f := self anyImageAsTrueColorFormOn:aDevice.

    f notNil ifTrue:[^ f].

    ^ super rgbImageAsTrueColorFormOn:aDevice

    "Created: / 28.7.1998 / 16:58:01 / cg"

! !

!Depth2Image methodsFor:'dither helpers'!

orderedDitheredMonochromeBitsWithDitherMatrix:ditherMatrix ditherWidth:dW

    "return the dithered monochrome bits for the receiver image;

     with a constant ditherMatrix, this can be used for thresholding.

     Redefined to make use of knowing that pixels are 2-bit values."