diff options
Diffstat (limited to 'Imaging/libImaging/Histo.c')
| -rw-r--r-- | Imaging/libImaging/Histo.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/Imaging/libImaging/Histo.c b/Imaging/libImaging/Histo.c new file mode 100644 index 0000000..b69b1db --- /dev/null +++ b/Imaging/libImaging/Histo.c @@ -0,0 +1,169 @@ +/* + * The Python Imaging Library + * $Id: Histo.c 2134 2004-10-06 08:55:20Z fredrik $ + * + * histogram support + * + * history: + * 1995-06-15 fl Created. + * 1996-04-05 fl Fixed histogram for multiband images. + * 1997-02-23 fl Added mask support + * 1998-07-01 fl Added basic 32-bit float/integer support + * + * Copyright (c) 1997-2003 by Secret Labs AB. + * Copyright (c) 1995-2003 by Fredrik Lundh. + * + * See the README file for information on usage and redistribution. + */ + + +#include "Imaging.h" + + +/* HISTOGRAM */ +/* -------------------------------------------------------------------- + * Take a histogram of an image. Returns a histogram object containing + * 256 slots per band in the input image. + */ + +void +ImagingHistogramDelete(ImagingHistogram h) +{ + if (h->histogram) + free(h->histogram); + free(h); +} + +ImagingHistogram +ImagingHistogramNew(Imaging im) +{ + ImagingHistogram h; + + /* Create histogram descriptor */ + h = calloc(1, sizeof(struct ImagingHistogramInstance)); + strcpy(h->mode, im->mode); + h->bands = im->bands; + h->histogram = calloc(im->pixelsize, 256 * sizeof(long)); + + return h; +} + +ImagingHistogram +ImagingGetHistogram(Imaging im, Imaging imMask, void* minmax) +{ + ImagingSectionCookie cookie; + int x, y, i; + ImagingHistogram h; + INT32 imin, imax; + FLOAT32 fmin, fmax, scale; + + if (!im) + return ImagingError_ModeError(); + + if (imMask) { + /* Validate mask */ + if (im->xsize != imMask->xsize || im->ysize != imMask->ysize) + return ImagingError_Mismatch(); + if (strcmp(imMask->mode, "1") != 0 && strcmp(imMask->mode, "L") != 0) + return ImagingError_ValueError("bad transparency mask"); + } + + h = ImagingHistogramNew(im); + + if (imMask) { + /* mask */ + if (im->image8) { + ImagingSectionEnter(&cookie); + for (y = 0; y < im->ysize; y++) + for (x = 0; x < im->xsize; x++) + if (imMask->image8[y][x] != 0) + h->histogram[im->image8[y][x]]++; + ImagingSectionLeave(&cookie); + } else { /* yes, we need the braces. C isn't Python! */ + if (im->type != IMAGING_TYPE_UINT8) + return ImagingError_ModeError(); + ImagingSectionEnter(&cookie); + for (y = 0; y < im->ysize; y++) { + UINT8* in = (UINT8*) im->image32[y]; + for (x = 0; x < im->xsize; x++) + if (imMask->image8[y][x] != 0) { + h->histogram[(*in++)]++; + h->histogram[(*in++)+256]++; + h->histogram[(*in++)+512]++; + h->histogram[(*in++)+768]++; + } else + in += 4; + } + ImagingSectionLeave(&cookie); + } + } else { + /* mask not given; process pixels in image */ + if (im->image8) { + ImagingSectionEnter(&cookie); + for (y = 0; y < im->ysize; y++) + for (x = 0; x < im->xsize; x++) + h->histogram[im->image8[y][x]]++; + ImagingSectionLeave(&cookie); + } else { + switch (im->type) { + case IMAGING_TYPE_UINT8: + ImagingSectionEnter(&cookie); + for (y = 0; y < im->ysize; y++) { + UINT8* in = (UINT8*) im->image[y]; + for (x = 0; x < im->xsize; x++) { + h->histogram[(*in++)]++; + h->histogram[(*in++)+256]++; + h->histogram[(*in++)+512]++; + h->histogram[(*in++)+768]++; + } + } + ImagingSectionLeave(&cookie); + break; + case IMAGING_TYPE_INT32: + if (!minmax) + return ImagingError_ValueError("min/max not given"); + if (!im->xsize || !im->ysize) + break; + imin = ((INT32*) minmax)[0]; + imax = ((INT32*) minmax)[1]; + if (imin >= imax) + break; + ImagingSectionEnter(&cookie); + scale = 255.0F / (imax - imin); + for (y = 0; y < im->ysize; y++) { + INT32* in = im->image32[y]; + for (x = 0; x < im->xsize; x++) { + i = (int) (((*in++)-imin)*scale); + if (i >= 0 && i < 256) + h->histogram[i]++; + } + } + ImagingSectionLeave(&cookie); + break; + case IMAGING_TYPE_FLOAT32: + if (!minmax) + return ImagingError_ValueError("min/max not given"); + if (!im->xsize || !im->ysize) + break; + fmin = ((FLOAT32*) minmax)[0]; + fmax = ((FLOAT32*) minmax)[1]; + if (fmin >= fmax) + break; + ImagingSectionEnter(&cookie); + scale = 255.0F / (fmax - fmin); + for (y = 0; y < im->ysize; y++) { + FLOAT32* in = (FLOAT32*) im->image32[y]; + for (x = 0; x < im->xsize; x++) { + i = (int) (((*in++)-fmin)*scale); + if (i >= 0 && i < 256) + h->histogram[i]++; + } + } + ImagingSectionLeave(&cookie); + break; + } + } + } + + return h; +} |