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Diffstat (limited to 'backend/genesys/conv.cpp')
| -rw-r--r-- | backend/genesys/conv.cpp | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/backend/genesys/conv.cpp b/backend/genesys/conv.cpp new file mode 100644 index 0000000..a87c463 --- /dev/null +++ b/backend/genesys/conv.cpp @@ -0,0 +1,238 @@ +/* sane - Scanner Access Now Easy. + + Copyright (C) 2005, 2006 Pierre Willenbrock <pierre@pirsoft.dnsalias.org> + Copyright (C) 2010-2013 Stéphane Voltz <stef.dev@free.fr> + + This file is part of the SANE package. + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, + MA 02111-1307, USA. + + As a special exception, the authors of SANE give permission for + additional uses of the libraries contained in this release of SANE. + + The exception is that, if you link a SANE library with other files + to produce an executable, this does not by itself cause the + resulting executable to be covered by the GNU General Public + License. Your use of that executable is in no way restricted on + account of linking the SANE library code into it. + + This exception does not, however, invalidate any other reasons why + the executable file might be covered by the GNU General Public + License. + + If you submit changes to SANE to the maintainers to be included in + a subsequent release, you agree by submitting the changes that + those changes may be distributed with this exception intact. + + If you write modifications of your own for SANE, it is your choice + whether to permit this exception to apply to your modifications. + If you do not wish that, delete this exception notice. +*/ + +#define DEBUG_DECLARE_ONLY + +#include "conv.h" +#include "sane/sanei_magic.h" + +namespace genesys { + +/** + * uses the threshold/threshold_curve to control software binarization + * This code was taken from the epjistsu backend by m. allan noah + * @param dev device set up for the scan + * @param src pointer to raw data + * @param dst pointer where to store result + * @param width width of the processed line + * */ +void binarize_line(Genesys_Device* dev, std::uint8_t* src, std::uint8_t* dst, int width) +{ + DBG_HELPER(dbg); + int j, windowX, sum = 0; + int thresh; + int offset, addCol, dropCol; + unsigned char mask; + + int x; + std::uint8_t min, max; + + /* normalize line */ + min = 255; + max = 0; + for (x = 0; x < width; x++) + { + if (src[x] > max) + { + max = src[x]; + } + if (src[x] < min) + { + min = src[x]; + } + } + + /* safeguard against dark or white areas */ + if(min>80) + min=0; + if(max<80) + max=255; + for (x = 0; x < width; x++) + { + src[x] = ((src[x] - min) * 255) / (max - min); + } + + /* ~1mm works best, but the window needs to have odd # of pixels */ + windowX = (6 * dev->settings.xres) / 150; + if (!(windowX % 2)) + windowX++; + + /* second, prefill the sliding sum */ + for (j = 0; j < windowX; j++) + sum += src[j]; + + /* third, walk the input buffer, update the sliding sum, */ + /* determine threshold, output bits */ + for (j = 0; j < width; j++) + { + /* output image location */ + offset = j % 8; + mask = 0x80 >> offset; + thresh = dev->settings.threshold; + + /* move sum/update threshold only if there is a curve */ + if (dev->settings.threshold_curve) + { + addCol = j + windowX / 2; + dropCol = addCol - windowX; + + if (dropCol >= 0 && addCol < width) + { + sum -= src[dropCol]; + sum += src[addCol]; + } + thresh = dev->lineart_lut[sum / windowX]; + } + + /* use average to lookup threshold */ + if (src[j] > thresh) + *dst &= ~mask; /* white */ + else + *dst |= mask; /* black */ + + if (offset == 7) + dst++; + } +} + +/** + * software lineart using data from a 8 bit gray scan. We assume true gray + * or monochrome scan as input. + */ +void genesys_gray_lineart(Genesys_Device* dev, + std::uint8_t* src_data, std::uint8_t* dst_data, + std::size_t pixels, std::size_t lines, std::uint8_t threshold) +{ + DBG_HELPER(dbg); + std::size_t y; + + DBG(DBG_io2, "%s: converting %zu lines of %zu pixels\n", __func__, lines, pixels); + DBG(DBG_io2, "%s: threshold=%d\n", __func__, threshold); + + for (y = 0; y < lines; y++) + { + binarize_line (dev, src_data + y * pixels, dst_data, pixels); + dst_data += pixels / 8; + } +} + +/** Look in image for likely left/right/bottom paper edges, then crop image. + */ +void genesys_crop(Genesys_Scanner* s) +{ + DBG_HELPER(dbg); + Genesys_Device *dev = s->dev; + int top = 0; + int bottom = 0; + int left = 0; + int right = 0; + + // first find edges if any + TIE(sanei_magic_findEdges(&s->params, dev->img_buffer.data(), + dev->settings.xres, dev->settings.yres, + &top, &bottom, &left, &right)); + + DBG (DBG_io, "%s: t:%d b:%d l:%d r:%d\n", __func__, top, bottom, left, + right); + + // now crop the image + TIE(sanei_magic_crop (&(s->params), dev->img_buffer.data(), top, bottom, left, right)); + + /* update counters to new image size */ + dev->total_bytes_to_read = s->params.bytes_per_line * s->params.lines; +} + +/** Look in image for likely upper and left paper edges, then rotate + * image so that upper left corner of paper is upper left of image. + */ +void genesys_deskew(Genesys_Scanner *s, const Genesys_Sensor& sensor) +{ + DBG_HELPER(dbg); + Genesys_Device *dev = s->dev; + + int x = 0, y = 0, bg; + double slope = 0; + + bg=0; + if(s->params.format==SANE_FRAME_GRAY && s->params.depth == 1) + { + bg=0xff; + } + TIE(sanei_magic_findSkew(&s->params, dev->img_buffer.data(), + sensor.optical_res, sensor.optical_res, + &x, &y, &slope)); + + DBG(DBG_info, "%s: slope=%f => %f\n", __func__, slope, slope * 180 / M_PI); + + // rotate image slope is in [-PI/2,PI/2]. Positive values rotate trigonometric direction wise + TIE(sanei_magic_rotate(&s->params, dev->img_buffer.data(), + x, y, slope, bg)); +} + +/** remove lone dots + */ +void genesys_despeck(Genesys_Scanner* s) +{ + DBG_HELPER(dbg); + TIE(sanei_magic_despeck(&s->params, s->dev->img_buffer.data(), s->despeck)); +} + +/** Look if image needs rotation and apply it + * */ +void genesys_derotate(Genesys_Scanner* s) +{ + DBG_HELPER(dbg); + int angle = 0; + + TIE(sanei_magic_findTurn(&s->params, s->dev->img_buffer.data(), + s->resolution, s->resolution, &angle)); + + // apply rotation angle found + TIE(sanei_magic_turn(&s->params, s->dev->img_buffer.data(), angle)); + + // update counters to new image size + s->dev->total_bytes_to_read = s->params.bytes_per_line * s->params.lines; +} + +} // namespace genesys |