#include "display/nr-filter-displacement-map.h"

#include "display/nr-filter-types.h"

#include "display/nr-filter-units.h"

#include "libnr/nr-blit.h"

#include "libnr/nr-pixops.h"

namespace Inkscape {

namespace Filters {

FilterDisplacementMap::FilterDisplacementMap()

{}

FilterPrimitive * FilterDisplacementMap::create() {

return new FilterDisplacementMap();

}

FilterDisplacementMap::~FilterDisplacementMap()

{}

struct pixel_t {

unsigned char channels[4];

inline unsigned char operator[](int c) const { return channels[c]; }

inline unsigned char& operator[](int c) { return channels[c]; }

static inline pixel_t blank() {

pixel_t p;

for(unsigned int i=0; i<4; i++) {

p[i] = 0;

}

return p;

}

};

static inline pixel_t pixelValue(NRPixBlock const* pb, int x, int y) {

if ( x < pb->area.x0 || x >= pb->area.x1 || y < pb->area.y0 || y >= pb->area.y1 ) return pixel_t::blank(); // This assumes anything outside the defined range is (0,0,0,0)

pixel_t const* data = reinterpret_cast<pixel_t const*>(NR_PIXBLOCK_PX(pb));

int offset = (x-pb->area.x0) + (pb->area.x1-pb->area.x0)*(y-pb->area.y0);

return data[offset];

}

template<bool PREMULTIPLIED>

static pixel_t interpolatePixels(NRPixBlock const* pb, double x, double y) {

unsigned int const sfl = 8u;

unsigned int const sf = 1u<<sfl;

unsigned int const sf2h = 1u<<(2u*sfl-1);

int xi = (int)floor(x), yi = (int)floor(y);

unsigned int xf = static_cast<unsigned int>(floor(sf*(x-xi)+.5)), yf = static_cast<unsigned int>(floor(sf*(y-yi)+.5));

pixel_t p00 = pixelValue(pb, xi+0, yi+0);

pixel_t p01 = pixelValue(pb, xi+1, yi+0);

pixel_t p10 = pixelValue(pb, xi+0, yi+1);

pixel_t p11 = pixelValue(pb, xi+1, yi+1);

/* It's a good idea to interpolate premultiplied colors:

/* First calculate interpolated alpha value. */

unsigned ra = 0;

if (!PREMULTIPLIED) {

unsigned const y0 = sf*p00[3] + xf*(p01[3]-p00[3]); // range [0,a*sf]

unsigned const y1 = sf*p10[3] + xf*(p11[3]-p10[3]);

ra = sf*y0 + yf*(y1-y0); // range [0,a*sf*sf]

}

pixel_t r;

if (ra == 0) {

/* Either premultiplied or the interpolated alpha value is zero,

for (unsigned i = 0; i != 4; ++i) {

// y0,y1 have range [0,a*sf]

unsigned const y0 = sf*p00[i] + xf*((unsigned int)p01[i]-(unsigned int)p00[i]);

unsigned const y1 = sf*p10[i] + xf*((unsigned int)p11[i]-(unsigned int)p10[i]);

unsigned const ri = sf*y0 + yf*(y1-y0); // range [0,a*sf*sf]

r[i] = (ri + sf2h)>>(2*sfl); // range [0,a]

}

} else {

/* Do premultiplication ourselves. */

for (unsigned i = 0; i != 3; ++i) {

// Premultiplied versions. Range [0,255*a].

unsigned const c00 = p00[i]*p00[3];

unsigned const c01 = p01[i]*p01[3];

unsigned const c10 = p10[i]*p10[3];

unsigned const c11 = p11[i]*p11[3];

// Interpolation.

unsigned const y0 = sf*c00 + xf*(c01-c00); // range [0,255*a*sf]

unsigned const y1 = sf*c10 + xf*(c11-c10); // range [0,255*a*sf]

unsigned const ri = sf*y0 + yf*(y1-y0); // range [0,255*a*sf*sf]

r[i] = (ri + ra/2) / ra; // range [0,255]

}

r[3] = (ra + sf2h)>>(2*sfl); // range [0,a]

}

return r;

}

template<bool MAP_PREMULTIPLIED, bool DATA_PREMULTIPLIED>

static void performDisplacement(NRPixBlock const* texture, NRPixBlock const* map, int Xchannel, int Ychannel, NRPixBlock* out, double scalex, double scaley) {

pixel_t *out_data = reinterpret_cast<pixel_t*>(NR_PIXBLOCK_PX(out));

bool Xneedsdemul = MAP_PREMULTIPLIED && Xchannel<3;

bool Yneedsdemul = MAP_PREMULTIPLIED && Ychannel<3;

if (!Xneedsdemul) scalex /= 255.0;

if (!Yneedsdemul) scaley /= 255.0;

for (int xout=out->area.x0; xout < out->area.x1; xout++){

for (int yout=out->area.y0; yout < out->area.y1; yout++){

int xmap = xout;

int ymap = yout;

pixel_t mapValue = pixelValue(map, xmap, ymap);

double xtex = xout + (Xneedsdemul ? // Although the value of the pixel corresponds to the MIDDLE of the pixel, no +0.5 is needed because we're interpolating pixels anyway (so to get the actual pixel locations 0.5 would have to be subtracted again).

(mapValue[3]==0?0:(scalex * (mapValue[Xchannel] - mapValue[3]*0.5) / mapValue[3])) :

(scalex * (mapValue[Xchannel] - 127.5)));

double ytex = yout + (Yneedsdemul ?

(mapValue[3]==0?0:(scaley * (mapValue[Ychannel] - mapValue[3]*0.5) / mapValue[3])) :

(scaley * (mapValue[Ychannel] - 127.5)));

out_data[(xout-out->area.x0) + (out->area.x1-out->area.x0)*(yout-out->area.y0)] = interpolatePixels<DATA_PREMULTIPLIED>(texture, xtex, ytex);

}

}

}

int FilterDisplacementMap::render(FilterSlot &slot, FilterUnits const &units) {

NRPixBlock *texture = slot.get(_input);

NRPixBlock *map = slot.get(_input2);

// Bail out if either one of source images is missing

if (!map || !texture) {

g_warning("Missing source image for feDisplacementMap (map=%d texture=%d)", _input, _input2);

return 1;

}

//TODO: check whether do we really need this check:

if (map->area.x1 <= map->area.x0 || map->area.y1 <= map->area.y0) return 0; //nothing to do!

if (texture->mode != NR_PIXBLOCK_MODE_R8G8B8A8N && texture->mode != NR_PIXBLOCK_MODE_R8G8B8A8P) {

g_warning("Source images without an alpha channel are not supported by feDisplacementMap at the moment.");

return 1;

}

NRPixBlock *out = new NRPixBlock;

out->area.x0 = map->area.x0;

out->area.y0 = map->area.y0;

out->area.x1 = map->area.x1;

out->area.y1 = map->area.y1;

nr_pixblock_setup_fast(out, texture->mode, out->area.x0, out->area.y0, out->area.x1, out->area.y1, true);

// convert to a suitable format

bool free_map_on_exit = false;

if (map->mode != NR_PIXBLOCK_MODE_R8G8B8A8N && map->mode != NR_PIXBLOCK_MODE_R8G8B8A8P) {

NRPixBlock *original_map = map;

map = new NRPixBlock;

nr_pixblock_setup_fast(map, NR_PIXBLOCK_MODE_R8G8B8A8N,

original_map->area.x0, original_map->area.y0,

original_map->area.x1, original_map->area.y1,

false);

nr_blit_pixblock_pixblock(map, original_map);

free_map_on_exit = true;

}

bool map_premultiplied = (map->mode == NR_PIXBLOCK_MODE_R8G8B8A8P);

bool data_premultiplied = (out->mode == NR_PIXBLOCK_MODE_R8G8B8A8P);

Geom::Matrix trans = units.get_matrix_primitiveunits2pb();

double scalex = scale * trans.expansionX();

double scaley = scale * trans.expansionY();

if (map_premultiplied && data_premultiplied) {

performDisplacement<true,true>(texture, map, Xchannel, Ychannel, out, scalex, scaley);

} else if (map_premultiplied && !data_premultiplied) {

performDisplacement<true,false>(texture, map, Xchannel, Ychannel, out, scalex, scaley);

} else if (data_premultiplied) {

performDisplacement<false,true>(texture, map, Xchannel, Ychannel, out, scalex, scaley);

} else {

performDisplacement<false,false>(texture, map, Xchannel, Ychannel, out, scalex, scaley);

}

if (free_map_on_exit) {

nr_pixblock_release(map);

delete map;

}

out->empty = FALSE;

slot.set(_output, out);

return 0;

}

void FilterDisplacementMap::set_input(int slot) {

_input = slot;

}

void FilterDisplacementMap::set_scale(double s) {

scale = s;

}

void FilterDisplacementMap::set_input(int input, int slot) {

if (input == 0) _input = slot;

if (input == 1) _input2 = slot;

}

void FilterDisplacementMap::set_channel_selector(int s, FilterDisplacementMapChannelSelector channel) {

if (channel > DISPLACEMENTMAP_CHANNEL_ALPHA || channel < DISPLACEMENTMAP_CHANNEL_RED) {

g_warning("Selected an invalid channel value. (%d)", channel);

return;

}

if (s == 0) Xchannel = channel;

if (s == 1) Ychannel = channel;

}

void FilterDisplacementMap::area_enlarge(NRRectL &area, Geom::Matrix const &trans)

{

//I assume scale is in user coordinates (?!?)

//FIXME: trans should be multiplied by some primitiveunits2user, shouldn't it?

double scalex = scale/2.*(std::fabs(trans[0])+std::fabs(trans[1]));

double scaley = scale/2.*(std::fabs(trans[2])+std::fabs(trans[3]));

//FIXME: no +2 should be there!... (noticable only for big scales at big zoom factor)

area.x0 -= (int)(scalex)+2;

area.x1 += (int)(scalex)+2;

area.y0 -= (int)(scaley)+2;

area.y1 += (int)(scaley)+2;

}

FilterTraits FilterDisplacementMap::get_input_traits() {

return TRAIT_PARALLER;

}

} /* namespace Filters */

} /* namespace Inkscape */