1 #define __NR_PIXBLOCK_SCALER_CPP__
3 /*
4 * Functions for blitting pixblocks using matrix transformation
5 *
6 * Author:
7 * Niko Kiirala <niko@kiirala.com>
8 *
9 * Copyright (C) 2006,2009 Niko Kiirala
10 *
11 * Released under GNU GPL, read the file 'COPYING' for more information
12 */
14 #include <glib.h>
15 #include <cmath>
16 #if defined (SOLARIS) && (SOLARIS == 8)
17 #include "round.h"
18 using Inkscape::round;
19 #endif
20 using std::floor;
22 #include "display/nr-filter-utils.h"
24 #include "libnr/nr-blit.h"
25 #include "libnr/nr-pixblock.h"
26 #include <2geom/matrix.h>
28 namespace NR {
30 struct RGBA {
31 double r, g, b, a;
32 };
33 struct RGBAi {
34 int r, g, b, a;
35 };
37 /**
38 * Sanity check function for indexing pixblocks.
39 * Catches reading and writing outside the pixblock area.
40 * When enabled, decreases filter rendering speed massively.
41 */
42 inline void _check_index(NRPixBlock const * const pb, int const location, int const line)
43 {
44 if(false) {
45 int max_loc = pb->rs * (pb->area.y1 - pb->area.y0);
46 if (location < 0 || (location + 4) > max_loc)
47 g_warning("Location %d out of bounds (0 ... %d) at line %d", location, max_loc, line);
48 }
49 }
51 void transform_nearest(NRPixBlock *to, NRPixBlock *from, Geom::Matrix const &trans)
52 {
53 if (NR_PIXBLOCK_BPP(from) != 4 || NR_PIXBLOCK_BPP(to) != 4) {
54 g_warning("A non-32-bpp image passed to transform_nearest: scaling aborted.");
55 return;
56 }
58 bool free_from_on_exit = false;
59 if (from->mode != to->mode){
60 NRPixBlock *o_from = from;
61 from = new NRPixBlock;
62 nr_pixblock_setup_fast(from, to->mode, o_from->area.x0, o_from->area.y0, o_from->area.x1, o_from->area.y1, false);
63 nr_blit_pixblock_pixblock(from, o_from);
64 free_from_on_exit = true;
65 }
67 // Precalculate sizes of source and destination pixblocks
68 int from_width = from->area.x1 - from->area.x0;
69 int from_height = from->area.y1 - from->area.y0;
70 int to_width = to->area.x1 - to->area.x0;
71 int to_height = to->area.y1 - to->area.y0;
73 Geom::Matrix itrans = trans.inverse();
75 // Loop through every pixel of destination image, a line at a time
76 for (int to_y = 0 ; to_y < to_height ; to_y++) {
77 for (int to_x = 0 ; to_x < to_width ; to_x++) {
78 RGBAi result = {0,0,0,0};
80 int from_x = (int)floor(itrans[0] * (to_x + 0.5 + to->area.x0)
81 + itrans[2] * (to_y + 0.5 + to->area.y0)
82 + itrans[4]);
83 from_x -= from->area.x0;
84 int from_y = (int)floor(itrans[1] * (to_x + 0.5 + to->area.x0)
85 + itrans[3] * (to_y + 0.5 + to->area.y0)
86 + itrans[5]);
87 from_y -= from->area.y0;
89 if (from_x >= 0 && from_x < from_width
90 && from_y >= 0 && from_y < from_height) {
91 _check_index(from, from_y * from->rs + from_x * 4, __LINE__);
92 result.r = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4];
93 result.g = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4 + 1];
94 result.b = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4 + 2];
95 result.a = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4 + 3];
96 }
98 _check_index(to, to_y * to->rs + to_x * 4, __LINE__);
99 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4] = result.r;
100 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1] = result.g;
101 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2] = result.b;
102 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3] = result.a;
103 }
104 }
105 if (free_from_on_exit) {
106 nr_pixblock_release(from);
107 delete from;
108 }
109 }
111 /** Calculates cubically interpolated value of the four given pixel values.
112 * The pixel values should be from four adjacent pixels in source image or
113 * four adjacent interpolated values. len should be the x- or y-coordinate
114 * (depending on interpolation direction) of the center of the target pixel
115 * in source image coordinates.
116 */
117 __attribute__ ((const))
118 inline static double sample(double const a, double const b,
119 double const c, double const d,
120 double const len)
121 {
122 double lena = 1.5 + (len - round(len));
123 double lenb = 0.5 + (len - round(len));
124 double lenc = 0.5 - (len - round(len));
125 double lend = 1.5 - (len - round(len));
126 double const f = -0.5; // corresponds to cubic Hermite spline
127 double sum = 0;
128 sum += ((((f * lena) - 5.0 * f) * lena + 8.0 * f) * lena - 4 * f) * a;
129 sum += (((f + 2.0) * lenb - (f + 3.0)) * lenb * lenb + 1.0) * b;
130 sum += (((f + 2.0) * lenc - (f + 3.0)) * lenc * lenc + 1.0) * c;
131 sum += ((((f * lend) - 5.0 * f) * lend + 8.0 * f) * lend - 4 * f) * d;
133 return sum;
134 }
136 void transform_bicubic(NRPixBlock *to, NRPixBlock *from, Geom::Matrix const &trans)
137 {
138 if (NR_PIXBLOCK_BPP(from) != 4 || NR_PIXBLOCK_BPP(to) != 4) {
139 g_warning("A non-32-bpp image passed to transform_bicubic: scaling aborted.");
140 return;
141 }
143 bool free_from_on_exit = false;
144 if (from->mode != to->mode){
145 NRPixBlock *o_from = from;
146 from = new NRPixBlock;
147 nr_pixblock_setup_fast(from, to->mode, o_from->area.x0, o_from->area.y0, o_from->area.x1, o_from->area.y1, false);
148 nr_blit_pixblock_pixblock(from, o_from);
149 free_from_on_exit = true;
150 }
152 // Precalculate sizes of source and destination pixblocks
153 int from_width = from->area.x1 - from->area.x0;
154 int from_height = from->area.y1 - from->area.y0;
155 int to_width = to->area.x1 - to->area.x0;
156 int to_height = to->area.y1 - to->area.y0;
158 Geom::Matrix itrans = trans.inverse();
160 // Loop through every pixel of destination image, a line at a time
161 for (int to_y = 0 ; to_y < to_height ; to_y++) {
162 for (int to_x = 0 ; to_x < to_width ; to_x++) {
163 double from_x = itrans[0] * (to_x + 0.5 + to->area.x0)
164 + itrans[2] * (to_y + 0.5 + to->area.y0)
165 + itrans[4] - from->area.x0;
166 double from_y = itrans[1] * (to_x + 0.5 + to->area.x0)
167 + itrans[3] * (to_y + 0.5 + to->area.y0)
168 + itrans[5] - from->area.y0;
170 if (from_x < 0 || from_x >= from_width ||
171 from_y < 0 || from_y >= from_height) {
172 continue;
173 }
175 RGBA line[4];
177 int from_line[4];
178 for (int i = 0 ; i < 4 ; i++) {
179 int fy_line = (int)round(from_y) + i - 2;
180 if (fy_line >= 0) {
181 if (fy_line < from_height) {
182 from_line[i] = fy_line * from->rs;
183 } else {
184 from_line[i] = (from_height - 1) * from->rs;
185 }
186 } else {
187 from_line[i] = 0;
188 }
189 }
191 for (int i = 0 ; i < 4 ; i++) {
192 int k = (int)round(from_x) + i - 2;
193 if (k < 0) k = 0;
194 if (k >= from_width) k = from_width - 1;
195 k *= 4;
196 _check_index(from, from_line[0] + k, __LINE__);
197 _check_index(from, from_line[1] + k, __LINE__);
198 _check_index(from, from_line[2] + k, __LINE__);
199 _check_index(from, from_line[3] + k, __LINE__);
200 line[i].r = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k],
201 NR_PIXBLOCK_PX(from)[from_line[1] + k],
202 NR_PIXBLOCK_PX(from)[from_line[2] + k],
203 NR_PIXBLOCK_PX(from)[from_line[3] + k],
204 from_y);
205 line[i].g = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k + 1],
206 NR_PIXBLOCK_PX(from)[from_line[1] + k + 1],
207 NR_PIXBLOCK_PX(from)[from_line[2] + k + 1],
208 NR_PIXBLOCK_PX(from)[from_line[3] + k + 1],
209 from_y);
210 line[i].b = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k + 2],
211 NR_PIXBLOCK_PX(from)[from_line[1] + k + 2],
212 NR_PIXBLOCK_PX(from)[from_line[2] + k + 2],
213 NR_PIXBLOCK_PX(from)[from_line[3] + k + 2],
214 from_y);
215 line[i].a = sample(NR_PIXBLOCK_PX(from)[from_line[0] + k + 3],
216 NR_PIXBLOCK_PX(from)[from_line[1] + k + 3],
217 NR_PIXBLOCK_PX(from)[from_line[2] + k + 3],
218 NR_PIXBLOCK_PX(from)[from_line[3] + k + 3],
219 from_y);
220 }
221 RGBA result;
222 result.r = round(sample(line[0].r, line[1].r, line[2].r, line[3].r,
223 from_x));
224 result.g = round(sample(line[0].g, line[1].g, line[2].g, line[3].g,
225 from_x));
226 result.b = round(sample(line[0].b, line[1].b, line[2].b, line[3].b,
227 from_x));
228 result.a = round(sample(line[0].a, line[1].a, line[2].a, line[3].a,
229 from_x));
231 using Inkscape::Filters::clamp;
232 using Inkscape::Filters::clamp_alpha;
233 _check_index(to, to_y * to->rs + to_x * 4, __LINE__);
234 if (to->mode == NR_PIXBLOCK_MODE_R8G8B8A8P) {
235 /* Make sure, none of the RGB channels exceeds 100% intensity
236 * in premultiplied output */
237 int const alpha = clamp((int)result.a);
238 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4] =
239 clamp_alpha((int)result.r, alpha);
240 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1] =
241 clamp_alpha((int)result.g, alpha);
242 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2] =
243 clamp_alpha((int)result.b, alpha);
244 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3] = alpha;
245 } else {
246 /* Clamp the output to unsigned char range */
247 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4]
248 = clamp((int)result.r);
249 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1]
250 = clamp((int)result.g);
251 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2]
252 = clamp((int)result.b);
253 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3]
254 = clamp((int)result.a);
255 }
256 }
257 }
258 if (free_from_on_exit) {
259 nr_pixblock_release(from);
260 delete from;
261 }
262 }
264 } /* namespace NR */
265 /*
266 Local Variables:
267 mode:c++
268 c-file-style:"stroustrup"
269 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
270 indent-tabs-mode:nil
271 fill-column:99
272 End:
273 */
274 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :