Pillow/src/libImaging/Point.c

/*
 * The Python Imaging Library
 * $Id$
 *
 * point (pixel) translation
 *
 * history:
 * 1995-11-27 fl   Created
 * 1996-03-31 fl   Fixed colour support
 * 1996-08-13 fl   Support 8-bit to "1" thresholding
 * 1997-05-31 fl   Added floating point transform
 * 1998-07-02 fl   Added integer point transform
 * 1998-07-17 fl   Support L to anything lookup
 * 2004-12-18 fl   Refactored; added I to L lookup
 *
 * Copyright (c) 1997-2004 by Secret Labs AB.
 * Copyright (c) 1995-2004 by Fredrik Lundh.
 *
 * See the README file for information on usage and redistribution.
 */

#include "Imaging.h"

typedef struct {
    const void *table;
} im_point_context;

static void
im_point_8_8(Imaging imOut, Imaging imIn, im_point_context *context) {
    int x, y;
    /* 8-bit source, 8-bit destination */
    UINT8 *table = (UINT8 *)context->table;
    for (y = 0; y < imIn->ysize; y++) {
        UINT8 *in = imIn->image8[y];
        UINT8 *out = imOut->image8[y];
        for (x = 0; x < imIn->xsize; x++) {
            out[x] = table[in[x]];
        }
    }
}

static void
im_point_2x8_2x8(Imaging imOut, Imaging imIn, im_point_context *context) {
    int x, y;
    /* 2x8-bit source, 2x8-bit destination */
    UINT8 *table = (UINT8 *)context->table;
    for (y = 0; y < imIn->ysize; y++) {
        UINT8 *in = (UINT8 *)imIn->image[y];
        UINT8 *out = (UINT8 *)imOut->image[y];
        for (x = 0; x < imIn->xsize; x++) {
            out[0] = table[in[0]];
            out[3] = table[in[3] + 256];
            in += 4;
            out += 4;
        }
    }
}

static void
im_point_3x8_3x8(Imaging imOut, Imaging imIn, im_point_context *context) {
    int x, y;
    /* 3x8-bit source, 3x8-bit destination */
    UINT8 *table = (UINT8 *)context->table;
    for (y = 0; y < imIn->ysize; y++) {
        UINT8 *in = (UINT8 *)imIn->image[y];
        UINT8 *out = (UINT8 *)imOut->image[y];
        for (x = 0; x < imIn->xsize; x++) {
            out[0] = table[in[0]];
            out[1] = table[in[1] + 256];
            out[2] = table[in[2] + 512];
            in += 4;
            out += 4;
        }
    }
}

static void
im_point_4x8_4x8(Imaging imOut, Imaging imIn, im_point_context *context) {
    int x, y;
    /* 4x8-bit source, 4x8-bit destination */
    UINT8 *table = (UINT8 *)context->table;
    for (y = 0; y < imIn->ysize; y++) {
        UINT8 *in = (UINT8 *)imIn->image[y];
        UINT8 *out = (UINT8 *)imOut->image[y];
        for (x = 0; x < imIn->xsize; x++) {
            out[0] = table[in[0]];
            out[1] = table[in[1] + 256];
            out[2] = table[in[2] + 512];
            out[3] = table[in[3] + 768];
            in += 4;
            out += 4;
        }
    }
}

static void
im_point_8_32(Imaging imOut, Imaging imIn, im_point_context *context) {
    int x, y;
    /* 8-bit source, 32-bit destination */
    char *table = (char *)context->table;
    for (y = 0; y < imIn->ysize; y++) {
        UINT8 *in = imIn->image8[y];
        INT32 *out = imOut->image32[y];
        for (x = 0; x < imIn->xsize; x++) {
            memcpy(out + x, table + in[x] * sizeof(INT32), sizeof(INT32));
        }
    }
}

static void
im_point_32_8(Imaging imOut, Imaging imIn, im_point_context *context) {
    int x, y;
    /* 32-bit source, 8-bit destination */
    UINT8 *table = (UINT8 *)context->table;
    for (y = 0; y < imIn->ysize; y++) {
        INT32 *in = imIn->image32[y];
        UINT8 *out = imOut->image8[y];
        for (x = 0; x < imIn->xsize; x++) {
            int v = in[x];
            if (v < 0) {
                v = 0;
            } else if (v > 65535) {
                v = 65535;
            }
            out[x] = table[v];
        }
    }
}

Imaging
ImagingPoint(Imaging imIn, const char *mode, const void *table) {
    /* lookup table transform */

    ImagingSectionCookie cookie;
    Imaging imOut;
    im_point_context context;
    void (*point)(Imaging imIn, Imaging imOut, im_point_context *context);

    if (!imIn) {
        return (Imaging)ImagingError_ModeError();
    }

    if (!mode) {
        mode = imIn->mode;
    }

    if (imIn->type != IMAGING_TYPE_UINT8) {
        if (imIn->type != IMAGING_TYPE_INT32 || strcmp(mode, "L") != 0) {
            goto mode_mismatch;
        }
    } else if (!imIn->image8 && strcmp(imIn->mode, mode) != 0) {
        goto mode_mismatch;
    }

    imOut = ImagingNew(mode, imIn->xsize, imIn->ysize);
    if (!imOut) {
        return NULL;
    }

    /* find appropriate handler */
    if (imIn->type == IMAGING_TYPE_UINT8) {
        if (imIn->bands == imOut->bands && imIn->type == imOut->type) {
            switch (imIn->bands) {
                case 1:
                    point = im_point_8_8;
                    break;
                case 2:
                    point = im_point_2x8_2x8;
                    break;
                case 3:
                    point = im_point_3x8_3x8;
                    break;
                case 4:
                    point = im_point_4x8_4x8;
                    break;
                default:
                    /* this cannot really happen */
                    point = im_point_8_8;
                    break;
            }
        } else {
            point = im_point_8_32;
        }
    } else {
        point = im_point_32_8;
    }

    ImagingCopyPalette(imOut, imIn);

    ImagingSectionEnter(&cookie);

    context.table = table;
    point(imOut, imIn, &context);

    ImagingSectionLeave(&cookie);

    return imOut;

mode_mismatch:
    return (Imaging
    )ImagingError_ValueError("point operation not supported for this mode");
}

Imaging
ImagingPointTransform(Imaging imIn, double scale, double offset) {
    /* scale/offset transform */

    ImagingSectionCookie cookie;
    Imaging imOut;
    int x, y;

    if (!imIn || (strcmp(imIn->mode, "I") != 0 && strcmp(imIn->mode, "I;16") != 0 &&
                  strcmp(imIn->mode, "F") != 0)) {
        return (Imaging)ImagingError_ModeError();
    }

    imOut = ImagingNew(imIn->mode, imIn->xsize, imIn->ysize);
    if (!imOut) {
        return NULL;
    }

    switch (imIn->type) {
        case IMAGING_TYPE_INT32:
            ImagingSectionEnter(&cookie);
            for (y = 0; y < imIn->ysize; y++) {
                INT32 *in = imIn->image32[y];
                INT32 *out = imOut->image32[y];
                /* FIXME: add clipping? */
                for (x = 0; x < imIn->xsize; x++) {
                    out[x] = in[x] * scale + offset;
                }
            }
            ImagingSectionLeave(&cookie);
            break;
        case IMAGING_TYPE_FLOAT32:
            ImagingSectionEnter(&cookie);
            for (y = 0; y < imIn->ysize; y++) {
                FLOAT32 *in = (FLOAT32 *)imIn->image32[y];
                FLOAT32 *out = (FLOAT32 *)imOut->image32[y];
                for (x = 0; x < imIn->xsize; x++) {
                    out[x] = in[x] * scale + offset;
                }
            }
            ImagingSectionLeave(&cookie);
            break;
        case IMAGING_TYPE_SPECIAL:
            if (strcmp(imIn->mode, "I;16") == 0) {
                ImagingSectionEnter(&cookie);
                for (y = 0; y < imIn->ysize; y++) {
                    char *in = (char *)imIn->image[y];
                    char *out = (char *)imOut->image[y];
                    /* FIXME: add clipping? */
                    for (x = 0; x < imIn->xsize; x++) {
                        UINT16 v;
                        memcpy(&v, in + x * sizeof(v), sizeof(v));
                        v = v * scale + offset;
                        memcpy(out + x * sizeof(UINT16), &v, sizeof(v));
                    }
                }
                ImagingSectionLeave(&cookie);
                break;
            }
            /* FALL THROUGH */
        default:
            ImagingDelete(imOut);
            return (Imaging)ImagingError_ValueError("internal error");
    }

    return imOut;
}