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Diffstat (limited to 'Build/source/libs/poppler/poppler-0.23.4/poppler/CairoRescaleBox.cc')
-rw-r--r-- | Build/source/libs/poppler/poppler-0.23.4/poppler/CairoRescaleBox.cc | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/Build/source/libs/poppler/poppler-0.23.4/poppler/CairoRescaleBox.cc b/Build/source/libs/poppler/poppler-0.23.4/poppler/CairoRescaleBox.cc new file mode 100644 index 00000000000..3c96f45e5d3 --- /dev/null +++ b/Build/source/libs/poppler/poppler-0.23.4/poppler/CairoRescaleBox.cc @@ -0,0 +1,378 @@ +/* -*- Mode: c; c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t; -*- */ +/* + * Copyright © 2009 Mozilla Corporation + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that + * copyright notice and this permission notice appear in supporting + * documentation, and that the name of Mozilla Corporation not be used in + * advertising or publicity pertaining to distribution of the software without + * specific, written prior permission. Mozilla Corporation makes no + * representations about the suitability of this software for any purpose. It + * is provided "as is" without express or implied warranty. + * + * MOZILLA CORPORATION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT + * SHALL MOZILLA CORPORATION BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE + * OF THIS SOFTWARE. + * + * Author: Jeff Muizelaar, Mozilla Corp. + */ + +//======================================================================== +// +// Modified under the Poppler project - http://poppler.freedesktop.org +// +// All changes made under the Poppler project to this file are licensed +// under GPL version 2 or later +// +// Copyright (C) 2012 Hib Eris <hib@hiberis.nl> +// Copyright (C) 2012 Adrian Johnson <ajohnson@redneon.com> +// +// To see a description of the changes please see the Changelog file that +// came with your tarball or type make ChangeLog if you are building from git +// +//======================================================================== + + +/* This implements a box filter that supports non-integer box sizes */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <stdint.h> +#include <stdio.h> +#include <assert.h> +#include <stdlib.h> +#include <math.h> +#include "goo/gmem.h" +#include "goo/gtypes_p.h" +#include "CairoRescaleBox.h" + + +/* we work in fixed point where 1. == 1 << 24 */ +#define FIXED_SHIFT 24 + + +static void downsample_row_box_filter ( + int start, int width, + uint32_t *src, uint32_t *dest, + int coverage[], int pixel_coverage) +{ + /* we need an array of the pixel contribution of each destination pixel on the boundaries. + * we invert the value to get the value on the other size of the box */ + /* + + value = a * contribution * 1/box_size + value += a * 1/box_size + value += a * 1/box_size + value += a * 1/box_size + value += a * (1 - contribution) * 1/box_size + a * (1/box_size - contribution * 1/box_size) + + box size is constant + + + value = a * contribtion_a * 1/box_size + b * contribution_b * 1/box_size + contribution_b = (1 - contribution_a) + = (1 - contribution_a_next) + */ + + /* box size = ceil(src_width/dest_width) */ + int x = 0; + + /* skip to start */ + /* XXX: it might be possible to do this directly instead of iteratively, however + * the iterative solution is simple */ + while (x < start) + { + int box = 1 << FIXED_SHIFT; + int start_coverage = coverage[x]; + box -= start_coverage; + src++; + while (box >= pixel_coverage) + { + src++; + box -= pixel_coverage; + } + x++; + } + + while (x < start + width) + { + uint32_t a = 0; + uint32_t r = 0; + uint32_t g = 0; + uint32_t b = 0; + int box = 1 << FIXED_SHIFT; + int start_coverage = coverage[x]; + + a = ((*src >> 24) & 0xff) * start_coverage; + r = ((*src >> 16) & 0xff) * start_coverage; + g = ((*src >> 8) & 0xff) * start_coverage; + b = ((*src >> 0) & 0xff) * start_coverage; + src++; + x++; + box -= start_coverage; + + while (box >= pixel_coverage) + { + a += ((*src >> 24) & 0xff) * pixel_coverage; + r += ((*src >> 16) & 0xff) * pixel_coverage; + g += ((*src >> 8) & 0xff) * pixel_coverage; + b += ((*src >> 0) & 0xff) * pixel_coverage; + src++; + + box -= pixel_coverage; + } + + /* multiply by whatever is leftover + * this ensures that we don't bias down. + * i.e. start_coverage + n*pixel_coverage + box == 1 << 24 */ + if (box > 0) + { + a += ((*src >> 24) & 0xff) * box; + r += ((*src >> 16) & 0xff) * box; + g += ((*src >> 8) & 0xff) * box; + b += ((*src >> 0) & 0xff) * box; + } + + a >>= FIXED_SHIFT; + r >>= FIXED_SHIFT; + g >>= FIXED_SHIFT; + b >>= FIXED_SHIFT; + + *dest = (a << 24) | (r << 16) | (g << 8) | b; + dest++; + } +} + +static void downsample_columns_box_filter ( + int n, + int start_coverage, + int pixel_coverage, + uint32_t *src, uint32_t *dest) +{ + int stride = n; + while (n--) { + uint32_t a = 0; + uint32_t r = 0; + uint32_t g = 0; + uint32_t b = 0; + uint32_t *column_src = src; + int box = 1 << FIXED_SHIFT; + + a = ((*column_src >> 24) & 0xff) * start_coverage; + r = ((*column_src >> 16) & 0xff) * start_coverage; + g = ((*column_src >> 8) & 0xff) * start_coverage; + b = ((*column_src >> 0) & 0xff) * start_coverage; + column_src += stride; + box -= start_coverage; + + while (box >= pixel_coverage) + { + a += ((*column_src >> 24) & 0xff) * pixel_coverage; + r += ((*column_src >> 16) & 0xff) * pixel_coverage; + g += ((*column_src >> 8) & 0xff) * pixel_coverage; + b += ((*column_src >> 0) & 0xff) * pixel_coverage; + column_src += stride; + box -= pixel_coverage; + } + + if (box > 0) { + a += ((*column_src >> 24) & 0xff) * box; + r += ((*column_src >> 16) & 0xff) * box; + g += ((*column_src >> 8) & 0xff) * box; + b += ((*column_src >> 0) & 0xff) * box; + } + + a >>= FIXED_SHIFT; + r >>= FIXED_SHIFT; + g >>= FIXED_SHIFT; + b >>= FIXED_SHIFT; + + *dest = (a << 24) | (r << 16) | (g << 8) | b; + dest++; + src++; + } +} + +static int compute_coverage (int coverage[], int src_length, int dest_length) +{ + int i; + /* num = src_length/dest_length + total = sum(pixel) / num + + pixel * 1/num == pixel * dest_length / src_length + */ + /* the average contribution of each source pixel */ + int ratio = ((1 << 24)*(long long int)dest_length)/src_length; + /* because ((1 << 24)*(long long int)dest_length) won't always be divisible by src_length + * we'll need someplace to put the other bits. + * + * We want to ensure a + n*ratio < 1<<24 + * + * 1<<24 + * */ + + double scale = (double)src_length/dest_length; + + /* for each destination pixel compute the coverage of the left most pixel included in the box */ + /* I have a proof of this, which this margin is too narrow to contain */ + for (i=0; i<dest_length; i++) + { + float left_side = i*scale; + float right_side = (i+1)*scale; + float right_fract = right_side - floor (right_side); + float left_fract = ceil (left_side) - left_side; + int overage; + /* find out how many source pixels will be used to fill the box */ + int count = floor (right_side) - ceil (left_side); + /* what's the maximum value this expression can become? + floor((i+1)*scale) - ceil(i*scale) + + (i+1)*scale - i*scale == scale + + since floor((i+1)*scale) <= (i+1)*scale + and ceil(i*scale) >= i*scale + + floor((i+1)*scale) - ceil(i*scale) <= scale + + further since: floor((i+1)*scale) - ceil(i*scale) is an integer + + therefore: + floor((i+1)*scale) - ceil(i*scale) <= floor(scale) + */ + + if (left_fract == 0.) + count--; + + /* compute how much the right-most pixel contributes */ + overage = ratio*(right_fract); + + /* the remainder is the the amount that the left-most pixel + * contributes */ + coverage[i] = (1<<24) - (count * ratio + overage); + } + + return ratio; +} + + +GBool CairoRescaleBox::downScaleImage(unsigned orig_width, unsigned orig_height, + signed scaled_width, signed scaled_height, + unsigned short int start_column, unsigned short int start_row, + unsigned short int width, unsigned short int height, + cairo_surface_t *dest_surface) { + int pixel_coverage_x, pixel_coverage_y; + int dest_y; + int src_y = 0; + uint32_t *scanline; + int *x_coverage = NULL; + int *y_coverage = NULL; + uint32_t *temp_buf = NULL; + GBool retval = gFalse; + unsigned int *dest; + int dst_stride; + + dest = (unsigned int *)cairo_image_surface_get_data (dest_surface); + dst_stride = cairo_image_surface_get_stride (dest_surface); + + scanline = (uint32_t*)gmallocn3 (orig_width, 1, sizeof(int)); + + x_coverage = (int *)gmallocn3 (orig_width, 1, sizeof(int)); + y_coverage = (int *)gmallocn3 (orig_height, 1, sizeof(int)); + + /* we need to allocate enough room for ceil(src_height/dest_height)+1 + Example: + src_height = 140 + dest_height = 50 + src_height/dest_height = 2.8 + + |-------------| 2.8 pixels + |----|----|----|----| 4 pixels + need to sample 3 pixels + + |-------------| 2.8 pixels + |----|----|----|----| 4 pixels + need to sample 4 pixels + */ + + temp_buf = (uint32_t *)gmallocn3 ((orig_height + scaled_height-1)/scaled_height+1, scaled_width, sizeof(uint32_t)); + + if (!x_coverage || !y_coverage || !scanline || !temp_buf) + goto cleanup; + + pixel_coverage_x = compute_coverage (x_coverage, orig_width, scaled_width); + pixel_coverage_y = compute_coverage (y_coverage, orig_height, scaled_height); + + assert (width + start_column <= scaled_width); + + + + /* skip the rows at the beginning */ + for (dest_y = 0; dest_y < start_row; dest_y++) + { + int box = 1 << FIXED_SHIFT; + int start_coverage_y = y_coverage[dest_y]; + box -= start_coverage_y; + src_y++; + while (box >= pixel_coverage_y) + { + box -= pixel_coverage_y; + src_y++; + } + } + + for (; dest_y < start_row + height; dest_y++) + { + int columns = 0; + int box = 1 << FIXED_SHIFT; + int start_coverage_y = y_coverage[dest_y]; + + getRow(src_y, scanline); + downsample_row_box_filter (start_column, width, scanline, temp_buf + width * columns, x_coverage, pixel_coverage_x); + columns++; + src_y++; + box -= start_coverage_y; + + while (box >= pixel_coverage_y) + { + getRow(src_y, scanline); + downsample_row_box_filter (start_column, width, scanline, temp_buf + width * columns, x_coverage, pixel_coverage_x); + columns++; + src_y++; + box -= pixel_coverage_y; + } + + /* downsample any leftovers */ + if (box > 0) + { + getRow(src_y, scanline); + downsample_row_box_filter (start_column, width, scanline, temp_buf + width * columns, x_coverage, pixel_coverage_x); + columns++; + } + + /* now scale the rows we just downsampled in the y direction */ + downsample_columns_box_filter (width, start_coverage_y, pixel_coverage_y, temp_buf, dest); + dest += dst_stride / 4; + +// assert(width*columns <= ((orig_height + scaled_height-1)/scaled_height+1) * width); + } +// assert (src_y<=orig_height); + + retval = gTrue; + +cleanup: + free (x_coverage); + free (y_coverage); + free (temp_buf); + free (scanline); + + return retval; +} |