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/*
* Canvas cropping.
* Copyright (C) 2006 - 2017 René Rebe, ExactCODE
*
* 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; version 2. A copy of the GNU General
* Public License can be found in the file LICENSE.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANT-
* ABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
* Public License for more details.
*
* Alternatively, commercial licensing options are available from the
* copyright holder ExactCODE GmbH Germany.
*/
#include <string.h> // memmove
#include <iostream>
#include <algorithm>
#ifndef _MSC_VER
#include <vector>
#endif
#include "Image.hh"
#include "Codecs.hh"
#include "Colorspace.hh"
#include "crop.hh"
void crop (Image& image, int x, int y, unsigned int w, unsigned int h)
{
// limit to valid boundaries
if (x < 0) { w += x; x = 0; };
if (y < 0) { h += y; y = 0; };
x = std::min (x, image.w-1);
y = std::min (y, image.h-1);
w = std::min (w, (unsigned)image.w-x);
h = std::min (h, (unsigned)image.h-y);
// something to do?
if (x == 0 && y == 0 && w == (unsigned int)image.w && h == (unsigned int)image.h)
return;
if (!image.isModified() && image.getCodec())
if (image.getCodec()->crop(image, x, y, w, h))
return;
/*
std::cerr << "after limiting: " << x << " " << y
<< " " << w << " " << h << std::endl;
*/
// truncate the height, this is optimized for the "just height" case
// (of e.g. fastAutoCrop)
if (x == 0 && y == 0 && w == (unsigned int)image.w) {
image.setRawData (); // invalidate
image.h = h;
return;
}
// bit shifting is too expensive, crop at least byte-wide
int orig_bps = image.bps;
if (orig_bps < 8)
colorspace_grayX_to_gray8 (image);
int stride = image.stride();
int cut_stride = image.spp * image.bps * w / 8; // sub-byte avoided above
uint8_t* dst = image.getRawData ();
uint8_t* src = dst + stride * y + (stride * x / image.w);
for (unsigned int i = 0; i < h; ++i) {
memmove (dst, src, cut_stride);
dst += cut_stride;
src += stride;
}
image.setRawData (); // invalidate
image.rowstride = 0; // re-set to native stride
image.w = w;
image.h = h;
switch (orig_bps) {
case 1:
colorspace_gray8_to_gray1 (image);
break;
case 2:
colorspace_gray8_to_gray2 (image);
break;
case 4:
colorspace_gray8_to_gray4 (image);
break;
default:
;
}
}
// auto crop just the bottom of an image filled in the same, solid color
// optimization: for sub-byte depth we compare a 8bit pattern unit at-a-time
void fastAutoCrop (Image& image)
{
if (!image.getRawData())
return;
const int stride = image.stride();
const int stridefill = image.stridefill();
int h = image.h - 1;
uint8_t* data = image.getRawData() + stride * h;
uint8_t* ref = data; // ref value to compare against
// decrement at begining, to compare one line earlier with reference
for (--h, data -= stride; h >= 0; --h, data -= stride) {
// data row
int i = 0;
for (; i < stridefill; ++i)
{
if (data[i] != ref[i]) {
break; // pixel differs, break out
}
}
if (i != stridefill)
break; // non-solid line, break out
}
++h; // we are at the line that differs
if (h == 0) // do not crop if the image is totally empty
return;
// We could just tweak the image height here, but using the generic
// code we benefit from possible optimization, such as lossless
// jpeg cropping.
// We do not explicitly check if we crop, the crop function will optimize
// a NOP crop away for all callers.
return crop (image, 0, 0, image.w, h);
}
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