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#define __NR_PIXBLOCK_SCALER_CPP__
/*
* Functions for blitting pixblocks using scaling
*
* Author:
* Niko Kiirala <niko@kiirala.com>
*
* Copyright (C) 2006,2009 Niko Kiirala
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#include <glib.h>
#include <cmath>
#if defined (SOLARIS) && (SOLARIS == 8)
#include "round.h"
using Inkscape::round;
#endif
using std::floor;
#include "display/nr-filter-utils.h"
#include "libnr/nr-pixblock.h"
#include "libnr/nr-blit.h"
#include <2geom/forward.h>
namespace NR {
struct RGBA {
double r, g, b, a;
};
/** Calculates cubically interpolated value of the four given pixel values.
* The pixel values should be from four adjacent pixels in source image or
* four adjacent interpolated values. len should be the x- or y-coordinate
* (depending on interpolation direction) of the center of the target pixel
* in source image coordinates.
*/
__attribute__ ((const))
inline static double sample(double const a, double const b,
double const c, double const d,
double const len)
{
double lena = 1.5 + (len - round(len));
double lenb = 0.5 + (len - round(len));
double lenc = 0.5 - (len - round(len));
double lend = 1.5 - (len - round(len));
double const f = -0.5; // corresponds to cubic Hermite spline
double sum = 0;
sum += ((((f * lena) - 5.0 * f) * lena + 8.0 * f) * lena - 4 * f) * a;
sum += (((f + 2.0) * lenb - (f + 3.0)) * lenb * lenb + 1.0) * b;
sum += (((f + 2.0) * lenc - (f + 3.0)) * lenc * lenc + 1.0) * c;
sum += ((((f * lend) - 5.0 * f) * lend + 8.0 * f) * lend - 4 * f) * d;
return sum;
}
/**
* Sanity check function for indexing pixblocks.
* Catches reading and writing outside the pixblock area.
* When enabled, decreases filter rendering speed massively.
*/
inline static void _check_index(NRPixBlock const * const pb, int const location, int const line)
{
if(false) {
int max_loc = pb->rs * (pb->area.y1 - pb->area.y0);
if (location < 0 || (location + 4) > max_loc)
g_warning("Location %d out of bounds (0 ... %d) at line %d", location, max_loc, line);
}
}
static void scale_bicubic_rgba(NRPixBlock *to, NRPixBlock *from,
Geom::Matrix const &trans)
{
if (NR_PIXBLOCK_BPP(from) != 4 || NR_PIXBLOCK_BPP(to) != 4) {
g_warning("A non-32-bpp image passed to scale_bicubic_rgba: scaling aborted.");
return;
}
bool free_from_on_exit = false;
if (from->mode != to->mode){
NRPixBlock *o_from = from;
from = new NRPixBlock;
nr_pixblock_setup_fast(from, to->mode, o_from->area.x0, o_from->area.y0, o_from->area.x1, o_from->area.y1, false);
nr_blit_pixblock_pixblock(from, o_from);
free_from_on_exit = true;
}
// Precalculate sizes of source and destination pixblocks
int from_width = from->area.x1 - from->area.x0;
int from_height = from->area.y1 - from->area.y0;
int to_width = to->area.x1 - to->area.x0;
int to_height = to->area.y1 - to->area.y0;
// from_step: when advancing one pixel in destination image,
// how much we should advance in source image
double from_stepx = 1.0 / trans[0];
double from_stepy = 1.0 / trans[3];
double from_diffx = from_stepx * (-trans[4]);
double from_diffy = from_stepy * (-trans[5]);
from_diffx = (to->area.x0 * from_stepx + from_diffx) - from->area.x0;
from_diffy = (to->area.y0 * from_stepy + from_diffy) - from->area.y0;
// Loop through every pixel of destination image, a line at a time
for (int to_y = 0 ; to_y < to_height ; to_y++) {
double from_y = (to_y + 0.5) * from_stepy + from_diffy;
// Pre-calculate beginning of the four horizontal lines, from
// which we should read
int from_line[4];
for (int i = 0 ; i < 4 ; i++) {
int fy_line = (int)round(from_y) + i - 2;
if (fy_line >= 0) {
if (fy_line < from_height) {
from_line[i] = fy_line * from->rs;
} else {
from_line[i] = (from_height - 1) * from->rs;
}
} else {
from_line[i] = 0;
}
}
// Loop through this horizontal line in destination image
// For every pixel, calculate the color of pixel with
// bicubic interpolation and set the pixel value in destination image
for (int to_x = 0 ; to_x < to_width ; to_x++) {
double from_x = (to_x + 0.5) * from_stepx + from_diffx;
RGBA line[4];
for (int i = 0 ; i < 4 ; i++) {
int k = (int)round(from_x) + i - 2;
if (k < 0) k = 0;
if (k >= from_width) k = from_width - 1;
k *= 4;
_check_index(from, from_line[0] + k, __LINE__);
_check_index(from, from_line[1] + k, __LINE__);
_check_index(from, from_line[2] + k, __LINE__);
_check_index(from, from_line[3] + k, __LINE__);
line[i].r = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k],
NR_PIXBLOCK_PX(from)[from_line[1] + k],
NR_PIXBLOCK_PX(from)[from_line[2] + k],
NR_PIXBLOCK_PX(from)[from_line[3] + k],
from_y);
line[i].g = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k + 1],
NR_PIXBLOCK_PX(from)[from_line[1] + k + 1],
NR_PIXBLOCK_PX(from)[from_line[2] + k + 1],
NR_PIXBLOCK_PX(from)[from_line[3] + k + 1],
from_y);
line[i].b = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k + 2],
NR_PIXBLOCK_PX(from)[from_line[1] + k + 2],
NR_PIXBLOCK_PX(from)[from_line[2] + k + 2],
NR_PIXBLOCK_PX(from)[from_line[3] + k + 2],
from_y);
line[i].a = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k + 3],
NR_PIXBLOCK_PX(from)[from_line[1] + k + 3],
NR_PIXBLOCK_PX(from)[from_line[2] + k + 3],
NR_PIXBLOCK_PX(from)[from_line[3] + k + 3],
from_y);
}
RGBA result;
result.r = round(sample(line[0].r, line[1].r, line[2].r, line[3].r,
from_x));
result.g = round(sample(line[0].g, line[1].g, line[2].g, line[3].g,
from_x));
result.b = round(sample(line[0].b, line[1].b, line[2].b, line[3].b,
from_x));
result.a = round(sample(line[0].a, line[1].a, line[2].a, line[3].a,
from_x));
_check_index(to, to_y * to->rs + to_x * 4, __LINE__);
using Inkscape::Filters::clamp;
using Inkscape::Filters::clamp_alpha;
if (to->mode == NR_PIXBLOCK_MODE_R8G8B8A8P) {
/* Clamp the colour channels to range from 0 to result.a to
* make sure, we don't exceed 100% per colour channel with
* images that have premultiplied alpha */
int const alpha = clamp((int)result.a);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4]
= clamp_alpha((int)result.r, alpha);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1]
= clamp_alpha((int)result.g, alpha);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2]
= clamp_alpha((int)result.b, alpha);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3] = alpha;
} else {
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4]
= clamp((int)result.r);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1]
= clamp((int)result.g);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2]
= clamp((int)result.b);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3]
= clamp((int)result.a);
}
}
}
if (free_from_on_exit) {
nr_pixblock_release(from);
delete from;
}
}
void scale_bicubic_alpha(NRPixBlock *to, NRPixBlock *from,
Geom::Matrix const &trans)
{
if (NR_PIXBLOCK_BPP(from) != 1 || NR_PIXBLOCK_BPP(to) != 1) {
g_warning("A non-8-bpp image passed to scale_bicubic_alpha: scaling aborted.");
return;
}
// Precalculate sizes of source and destination pixblocks
int from_width = from->area.x1 - from->area.x0;
int from_height = from->area.y1 - from->area.y0;
int to_width = to->area.x1 - to->area.x0;
int to_height = to->area.y1 - to->area.y0;
// from_step: when advancing one pixel in destination image,
// how much we should advance in source image
double from_stepx = 1.0 / trans[0];
double from_stepy = 1.0 / trans[3];
double from_diffx = from_stepx * (-trans[4]);
double from_diffy = from_stepy * (-trans[5]);
from_diffx = (to->area.x0 * from_stepx + from_diffx) - from->area.x0;
from_diffy = (to->area.y0 * from_stepy + from_diffy) - from->area.y0;
// Loop through every pixel of destination image, a line at a time
for (int to_y = 0 ; to_y < to_height ; to_y++) {
double from_y = (to_y + 0.5) * from_stepy - from_diffy;
// Pre-calculate beginning of the four horizontal lines, from
// which we should read
int from_line[4];
for (int i = 0 ; i < 4 ; i++) {
int fy_line = (int)round(from_y) + i - 2;
if (fy_line >= 0) {
if (fy_line < from_height) {
from_line[i] = fy_line * from->rs;
} else {
from_line[i] = (from_height - 1) * from->rs;
}
} else {
from_line[i] = 0;
}
}
// Loop through this horizontal line in destination image
// For every pixel, calculate the color of pixel with
// bicubic interpolation and set the pixel value in destination image
for (int to_x = 0 ; to_x < to_width ; to_x++) {
double from_x = (to_x + 0.5) * from_stepx - from_diffx;
double line[4];
for (int i = 0 ; i < 4 ; i++) {
int k = (int)round(from_x) + i - 2;
if (k < 0) k = 0;
if (k >= from_width) k = from_width - 1;
_check_index(from, from_line[0] + k, __LINE__);
_check_index(from, from_line[1] + k, __LINE__);
_check_index(from, from_line[2] + k, __LINE__);
_check_index(from, from_line[3] + k, __LINE__);
line[i] = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k],
NR_PIXBLOCK_PX(from)[from_line[1] + k],
NR_PIXBLOCK_PX(from)[from_line[2] + k],
NR_PIXBLOCK_PX(from)[from_line[3] + k],
from_y);
}
int result;
result = (int)round(sample(line[0], line[1], line[2], line[3],
from_x));
_check_index(to, to_y * to->rs + to_x, __LINE__);
NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x]
= Inkscape::Filters::clamp(result);
}
}
}
void scale_bicubic(NRPixBlock *to, NRPixBlock *from, Geom::Matrix const &trans)
{
if (NR_PIXBLOCK_BPP(to) == 4 && NR_PIXBLOCK_BPP(from) == 4) {
scale_bicubic_rgba(to, from, trans);
} else if (NR_PIXBLOCK_BPP(to) == 1 && NR_PIXBLOCK_BPP(from) == 1) {
scale_bicubic_alpha(to, from, trans);
} else {
g_warning("NR::scale_bicubic: unsupported bitdepths for scaling: to %d, from %d", NR_PIXBLOCK_BPP(to), NR_PIXBLOCK_BPP(from));
}
}
} /* namespace NR */
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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