1 /*
2 * feDisplacementMap filter primitive renderer
3 *
4 * Authors:
5 * Felipe CorrĂȘa da Silva Sanches <juca@members.fsf.org>
6 *
7 * Copyright (C) 2007 authors
8 *
9 * Released under GNU GPL, read the file 'COPYING' for more information
10 */
12 #include "display/nr-filter-displacement-map.h"
13 #include "display/nr-filter-types.h"
14 #include "display/nr-filter-units.h"
15 #include "libnr/nr-blit.h"
16 #include "libnr/nr-pixops.h"
18 namespace Inkscape {
19 namespace Filters {
21 FilterDisplacementMap::FilterDisplacementMap()
22 {}
24 FilterPrimitive * FilterDisplacementMap::create() {
25 return new FilterDisplacementMap();
26 }
28 FilterDisplacementMap::~FilterDisplacementMap()
29 {}
31 struct pixel_t {
32 unsigned char channels[4];
33 inline unsigned char operator[](int c) const { return channels[c]; }
34 inline unsigned char& operator[](int c) { return channels[c]; }
35 static inline pixel_t blank() {
36 pixel_t p;
37 for(unsigned int i=0; i<4; i++) {
38 p[i] = 0;
39 }
40 return p;
41 }
42 };
44 static inline pixel_t pixelValue(NRPixBlock const* pb, int x, int y) {
45 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)
46 pixel_t const* data = reinterpret_cast<pixel_t const*>(NR_PIXBLOCK_PX(pb));
47 int offset = (x-pb->area.x0) + (pb->area.x1-pb->area.x0)*(y-pb->area.y0);
48 return data[offset];
49 }
51 template<bool PREMULTIPLIED>
52 static pixel_t interpolatePixels(NRPixBlock const* pb, double x, double y) {
53 // NOTE: The values of x and y are shifted by -0.5 (the "true" values would be x+0.5 and y+0.5).
54 // This is done because otherwise the pixel values first have to be shifted by +0.5 and then by -0.5 again...
55 unsigned int const sfl = 8u;
56 unsigned int const sf = 1u<<sfl;
57 unsigned int const sf2h = 1u<<(2u*sfl-1);
58 int xi = (int)floor(x), yi = (int)floor(y);
59 unsigned int xf = static_cast<unsigned int>(round(sf * (x - xi))),
60 yf = static_cast<unsigned int>(round(sf * (y - yi)));
61 pixel_t p00 = pixelValue(pb, xi+0, yi+0);
62 pixel_t p01 = pixelValue(pb, xi+1, yi+0);
63 pixel_t p10 = pixelValue(pb, xi+0, yi+1);
64 pixel_t p11 = pixelValue(pb, xi+1, yi+1);
66 /* It's a good idea to interpolate premultiplied colors:
67 *
68 * Consider two pixels, one being rgba(255,0,0,0), which is fully transparent,
69 * and the other being rgba(0,0,255,255), or blue (fully opaque).
70 * If these two colors are interpolated the expected result would be bluish pixels
71 * containing no red.
72 *
73 * However, if our final alpha value is zero, then the RGB values aren't really determinate.
74 * We might as well avoid premultiplication in this case, which still gives us a fully
75 * transparent result, but with interpolated RGB parts. */
77 /* First calculate interpolated alpha value. */
78 unsigned ra = 0;
79 if (!PREMULTIPLIED) {
80 unsigned const y0 = sf*p00[3] + xf*(p01[3]-p00[3]); // range [0,a*sf]
81 unsigned const y1 = sf*p10[3] + xf*(p11[3]-p10[3]);
82 ra = sf*y0 + yf*(y1-y0); // range [0,a*sf*sf]
83 }
85 pixel_t r;
86 if (ra == 0) {
87 /* Either premultiplied or the interpolated alpha value is zero,
88 * so do simple interpolation. */
89 for (unsigned i = 0; i != 4; ++i) {
90 // y0,y1 have range [0,a*sf]
91 unsigned const y0 = sf*p00[i] + xf*((unsigned int)p01[i]-(unsigned int)p00[i]);
92 unsigned const y1 = sf*p10[i] + xf*((unsigned int)p11[i]-(unsigned int)p10[i]);
94 unsigned const ri = sf*y0 + yf*(y1-y0); // range [0,a*sf*sf]
95 r[i] = (ri + sf2h)>>(2*sfl); // range [0,a]
96 }
97 } else {
98 /* Do premultiplication ourselves. */
99 for (unsigned i = 0; i != 3; ++i) {
100 // Premultiplied versions. Range [0,255*a].
101 unsigned const c00 = p00[i]*p00[3];
102 unsigned const c01 = p01[i]*p01[3];
103 unsigned const c10 = p10[i]*p10[3];
104 unsigned const c11 = p11[i]*p11[3];
106 // Interpolation.
107 unsigned const y0 = sf*c00 + xf*(c01-c00); // range [0,255*a*sf]
108 unsigned const y1 = sf*c10 + xf*(c11-c10); // range [0,255*a*sf]
109 unsigned const ri = sf*y0 + yf*(y1-y0); // range [0,255*a*sf*sf]
110 r[i] = (ri + ra/2) / ra; // range [0,255]
111 }
112 r[3] = (ra + sf2h)>>(2*sfl); // range [0,a]
113 }
115 return r;
116 }
118 template<bool MAP_PREMULTIPLIED, bool DATA_PREMULTIPLIED>
119 static void performDisplacement(NRPixBlock const* texture, NRPixBlock const* map, int Xchannel, int Ychannel, NRPixBlock* out, double scalex, double scaley) {
120 pixel_t *out_data = reinterpret_cast<pixel_t*>(NR_PIXBLOCK_PX(out));
122 bool Xneedsdemul = MAP_PREMULTIPLIED && Xchannel<3;
123 bool Yneedsdemul = MAP_PREMULTIPLIED && Ychannel<3;
124 if (!Xneedsdemul) scalex /= 255.0;
125 if (!Yneedsdemul) scaley /= 255.0;
127 for (int yout=out->area.y0; yout < out->area.y1; yout++){
128 for (int xout=out->area.x0; xout < out->area.x1; xout++){
129 int xmap = xout;
130 int ymap = yout;
132 pixel_t mapValue = pixelValue(map, xmap, ymap);
133 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).
134 (mapValue[3]==0?0:(scalex * (mapValue[Xchannel] - mapValue[3]*0.5) / mapValue[3])) :
135 (scalex * (mapValue[Xchannel] - 127.5)));
136 double ytex = yout + (Yneedsdemul ?
137 (mapValue[3]==0?0:(scaley * (mapValue[Ychannel] - mapValue[3]*0.5) / mapValue[3])) :
138 (scaley * (mapValue[Ychannel] - 127.5)));
140 out_data[(xout-out->area.x0) + (out->area.x1-out->area.x0)*(yout-out->area.y0)] = interpolatePixels<DATA_PREMULTIPLIED>(texture, xtex, ytex);
141 }
142 }
143 }
145 int FilterDisplacementMap::render(FilterSlot &slot, FilterUnits const &units) {
146 NRPixBlock *texture = slot.get(_input);
147 NRPixBlock *map = slot.get(_input2);
149 // Bail out if either one of source images is missing
150 if (!map || !texture) {
151 g_warning("Missing source image for feDisplacementMap (map=%d texture=%d)", _input, _input2);
152 return 1;
153 }
155 //TODO: check whether do we really need this check:
156 if (map->area.x1 <= map->area.x0 || map->area.y1 <= map->area.y0) return 0; //nothing to do!
158 if (texture->mode != NR_PIXBLOCK_MODE_R8G8B8A8N && texture->mode != NR_PIXBLOCK_MODE_R8G8B8A8P) {
159 g_warning("Source images without an alpha channel are not supported by feDisplacementMap at the moment.");
160 return 1;
161 }
163 NRPixBlock *out = new NRPixBlock;
165 out->area.x0 = map->area.x0;
166 out->area.y0 = map->area.y0;
167 out->area.x1 = map->area.x1;
168 out->area.y1 = map->area.y1;
170 nr_pixblock_setup_fast(out, texture->mode, out->area.x0, out->area.y0, out->area.x1, out->area.y1, true);
172 // convert to a suitable format
173 bool free_map_on_exit = false;
174 if (map->mode != NR_PIXBLOCK_MODE_R8G8B8A8N && map->mode != NR_PIXBLOCK_MODE_R8G8B8A8P) {
175 NRPixBlock *original_map = map;
176 map = new NRPixBlock;
177 nr_pixblock_setup_fast(map, NR_PIXBLOCK_MODE_R8G8B8A8N,
178 original_map->area.x0, original_map->area.y0,
179 original_map->area.x1, original_map->area.y1,
180 false);
181 nr_blit_pixblock_pixblock(map, original_map);
182 free_map_on_exit = true;
183 }
184 bool map_premultiplied = (map->mode == NR_PIXBLOCK_MODE_R8G8B8A8P);
185 bool data_premultiplied = (out->mode == NR_PIXBLOCK_MODE_R8G8B8A8P);
187 Geom::Matrix trans = units.get_matrix_primitiveunits2pb();
188 double scalex = scale * trans.expansionX();
189 double scaley = scale * trans.expansionY();
191 if (map_premultiplied && data_premultiplied) {
192 performDisplacement<true,true>(texture, map, Xchannel, Ychannel, out, scalex, scaley);
193 } else if (map_premultiplied && !data_premultiplied) {
194 performDisplacement<true,false>(texture, map, Xchannel, Ychannel, out, scalex, scaley);
195 } else if (data_premultiplied) {
196 performDisplacement<false,true>(texture, map, Xchannel, Ychannel, out, scalex, scaley);
197 } else {
198 performDisplacement<false,false>(texture, map, Xchannel, Ychannel, out, scalex, scaley);
199 }
201 if (free_map_on_exit) {
202 nr_pixblock_release(map);
203 delete map;
204 }
206 out->empty = FALSE;
207 slot.set(_output, out);
208 return 0;
209 }
211 void FilterDisplacementMap::set_input(int slot) {
212 _input = slot;
213 }
215 void FilterDisplacementMap::set_scale(double s) {
216 scale = s;
217 }
219 void FilterDisplacementMap::set_input(int input, int slot) {
220 if (input == 0) _input = slot;
221 if (input == 1) _input2 = slot;
222 }
224 void FilterDisplacementMap::set_channel_selector(int s, FilterDisplacementMapChannelSelector channel) {
225 if (channel > DISPLACEMENTMAP_CHANNEL_ALPHA || channel < DISPLACEMENTMAP_CHANNEL_RED) {
226 g_warning("Selected an invalid channel value. (%d)", channel);
227 return;
228 }
230 if (s == 0) Xchannel = channel;
231 if (s == 1) Ychannel = channel;
232 }
234 void FilterDisplacementMap::area_enlarge(NRRectL &area, Geom::Matrix const &trans)
235 {
236 //I assume scale is in user coordinates (?!?)
237 //FIXME: trans should be multiplied by some primitiveunits2user, shouldn't it?
239 double scalex = scale/2.*(std::fabs(trans[0])+std::fabs(trans[1]));
240 double scaley = scale/2.*(std::fabs(trans[2])+std::fabs(trans[3]));
242 //FIXME: no +2 should be there!... (noticable only for big scales at big zoom factor)
243 area.x0 -= (int)(scalex)+2;
244 area.x1 += (int)(scalex)+2;
245 area.y0 -= (int)(scaley)+2;
246 area.y1 += (int)(scaley)+2;
247 }
249 FilterTraits FilterDisplacementMap::get_input_traits() {
250 return TRAIT_PARALLER;
251 }
253 } /* namespace Filters */
254 } /* namespace Inkscape */
256 /*
257 Local Variables:
258 mode:c++
259 c-file-style:"stroustrup"
260 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
261 indent-tabs-mode:nil
262 fill-column:99
263 End:
264 */
265 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :