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 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 "libnr/nr-matrix.h"
28 namespace NR {
30 struct RGBA {
31 int r, g, b, a;
32 };
34 /**
35 * Sanity check function for indexing pixblocks.
36 * Catches reading and writing outside the pixblock area.
37 * When enabled, decreases filter rendering speed massively.
38 */
39 inline void _check_index(NRPixBlock const * const pb, int const location, int const line)
40 {
41 if(false) {
42 int max_loc = pb->rs * (pb->area.y1 - pb->area.y0);
43 if (location < 0 || (location + 4) > max_loc)
44 g_warning("Location %d out of bounds (0 ... %d) at line %d", location, max_loc, line);
45 }
46 }
48 void transform_nearest(NRPixBlock *to, NRPixBlock *from, Matrix &trans)
49 {
50 if (NR_PIXBLOCK_BPP(from) != 4 || NR_PIXBLOCK_BPP(to) != 4) {
51 g_warning("A non-32-bpp image passed to transform_nearest: scaling aborted.");
52 return;
53 }
55 bool free_from_on_exit = false;
56 if (from->mode != to->mode){
57 NRPixBlock *o_from = from;
58 from = new NRPixBlock;
59 nr_pixblock_setup_fast(from, to->mode, o_from->area.x0, o_from->area.y0, o_from->area.x1, o_from->area.y1, false);
60 nr_blit_pixblock_pixblock(from, o_from);
61 free_from_on_exit = true;
62 }
64 // Precalculate sizes of source and destination pixblocks
65 int from_width = from->area.x1 - from->area.x0;
66 int from_height = from->area.y1 - from->area.y0;
67 int to_width = to->area.x1 - to->area.x0;
68 int to_height = to->area.y1 - to->area.y0;
70 Matrix itrans = trans.inverse();
72 // Loop through every pixel of destination image, a line at a time
73 for (int to_y = 0 ; to_y < to_height ; to_y++) {
74 for (int to_x = 0 ; to_x < to_width ; to_x++) {
75 RGBA result = {0,0,0,0};
77 int from_x = (int)round(itrans[0] * (to_x + to->area.x0)
78 + itrans[2] * (to_y + to->area.y0)
79 + itrans[4]);
80 from_x -= from->area.x0;
81 int from_y = (int)round(itrans[1] * (to_x + to->area.x0)
82 + itrans[3] * (to_y + to->area.y0)
83 + itrans[5]);
84 from_y -= from->area.y0;
86 if (from_x >= 0 && from_x < from_width
87 && from_y >= 0 && from_y < from_height) {
88 _check_index(from, from_y * from->rs + from_x * 4, __LINE__);
89 result.r = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4];
90 result.g = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4 + 1];
91 result.b = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4 + 2];
92 result.a = NR_PIXBLOCK_PX(from)[from_y * from->rs + from_x * 4 + 3];
93 }
95 _check_index(to, to_y * to->rs + to_x * 4, __LINE__);
96 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4] = result.r;
97 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1] = result.g;
98 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2] = result.b;
99 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3] = result.a;
100 }
101 }
102 if (free_from_on_exit) {
103 nr_pixblock_release(from);
104 delete from;
105 }
106 }
108 /** Calculates cubically interpolated value of the four given pixel values.
109 * The pixel values should be from four vertically adjacent pixels.
110 * If we are calculating a pixel, whose y-coordinate in source image is
111 * i, these pixel values a, b, c and d should come from lines
112 * floor(i) - 1, floor(i), floor(i) + 1, floor(i) + 2, respectively.
113 * Parameter len should be set to i.
114 * Returns the interpolated value in fixed point format with 8 bit
115 * decimal part. (24.8 assuming 32-bit int)
116 */
117 __attribute__ ((const))
118 inline static int sampley(unsigned const char a, unsigned const char b,
119 unsigned const char c, unsigned const char d,
120 const double len)
121 {
122 double lenf = len - floor(len);
123 int sum = 0;
124 sum += (int)((((-1.0 / 3.0) * lenf + 4.0 / 5.0) * lenf - 7.0 / 15.0)
125 * lenf * 256 * a);
126 sum += (int)((((lenf - 9.0 / 5.0) * lenf - 1.0 / 5.0) * lenf + 1.0)
127 * 256 * b);
128 sum += (int)(((((1 - lenf) - 9.0 / 5.0) * (1 - lenf) - 1.0 / 5.0)
129 * (1 - lenf) + 1.0) * 256 * c);
130 sum += (int)((((-1.0 / 3.0) * (1 - lenf) + 4.0 / 5.0) * (1 - lenf)
131 - 7.0 / 15.0) * (1 - lenf) * 256 * d);
132 return sum;
133 }
135 /** Calculates cubically interpolated value of the four given pixel values.
136 * The pixel values should be interpolated values from sampley, from four
137 * horizontally adjacent vertical lines. The parameters a, b, c and d
138 * should be in fixed point format with 8-bit decimal part.
139 * If we are calculating a pixel, whose x-coordinate in source image is
140 * i, these vertical lines from where a, b, c and d are calculated, should be
141 * floor(i) - 1, floor(i), floor(i) + 1, floor(i) + 2, respectively.
142 * Parameter len should be set to i.
143 * Returns the interpolated value in 8-bit format, ready to be written
144 * to output buffer.
145 */
146 inline static int samplex(const int a, const int b, const int c, const int d, const double len) {
147 double lenf = len - floor(len);
148 int sum = 0;
149 sum += (int)(a * (((-1.0 / 3.0) * lenf + 4.0 / 5.0) * lenf - 7.0 / 15.0) * lenf);
150 sum += (int)(b * (((lenf - 9.0 / 5.0) * lenf - 1.0 / 5.0) * lenf + 1.0));
151 sum += (int)(c * ((((1 - lenf) - 9.0 / 5.0) * (1 - lenf) - 1.0 / 5.0) * (1 - lenf) + 1.0));
152 sum += (int)(d * (((-1.0 / 3.0) * (1 - lenf) + 4.0 / 5.0) * (1 - lenf) - 7.0 / 15.0) * (1 - lenf));
153 //if (sum < 0) sum = 0;
154 //if (sum > 255 * 256) sum = 255 * 256;
155 return sum / 256;
156 }
158 void transform_bicubic(NRPixBlock *to, NRPixBlock *from, Matrix &trans)
159 {
160 if (NR_PIXBLOCK_BPP(from) != 4 || NR_PIXBLOCK_BPP(to) != 4) {
161 g_warning("A non-32-bpp image passed to transform_bicubic: scaling aborted.");
162 return;
163 }
165 bool free_from_on_exit = false;
166 if (from->mode != to->mode){
167 NRPixBlock *o_from = from;
168 from = new NRPixBlock;
169 nr_pixblock_setup_fast(from, to->mode, o_from->area.x0, o_from->area.y0, o_from->area.x1, o_from->area.y1, false);
170 nr_blit_pixblock_pixblock(from, o_from);
171 free_from_on_exit = true;
172 }
174 // Precalculate sizes of source and destination pixblocks
175 int from_width = from->area.x1 - from->area.x0;
176 int from_height = from->area.y1 - from->area.y0;
177 int to_width = to->area.x1 - to->area.x0;
178 int to_height = to->area.y1 - to->area.y0;
180 Matrix itrans = trans.inverse();
182 // Loop through every pixel of destination image, a line at a time
183 for (int to_y = 0 ; to_y < to_height ; to_y++) {
184 for (int to_x = 0 ; to_x < to_width ; to_x++) {
185 double from_x = itrans[0] * (to_x + to->area.x0)
186 + itrans[2] * (to_y + to->area.y0)
187 + itrans[4] - from->area.x0;
188 double from_y = itrans[1] * (to_x + to->area.x0)
189 + itrans[3] * (to_y + to->area.y0)
190 + itrans[5] - from->area.y0;
192 if (from_x < 0 || from_x >= from_width ||
193 from_y < 0 || from_y >= from_height) {
194 continue;
195 }
197 RGBA line[4];
199 int from_line[4];
200 for (int i = 0 ; i < 4 ; i++) {
201 if ((int)floor(from_y) + i - 1 >= 0) {
202 if ((int)floor(from_y) + i - 1 < from_height) {
203 from_line[i] = ((int)floor(from_y) + i - 1) * from->rs;
204 } else {
205 from_line[i] = (from_height - 1) * from->rs;
206 }
207 } else {
208 from_line[i] = 0;
209 }
210 }
212 for (int i = 0 ; i < 4 ; i++) {
213 int k = (int)floor(from_x) + i - 1;
214 if (k < 0) k = 0;
215 if (k >= from_width) k = from_width - 1;
216 k *= 4;
217 _check_index(from, from_line[0] + k, __LINE__);
218 _check_index(from, from_line[1] + k, __LINE__);
219 _check_index(from, from_line[2] + k, __LINE__);
220 _check_index(from, from_line[3] + k, __LINE__);
221 line[i].r = sampley(NR_PIXBLOCK_PX(from)[from_line[0] + k],
222 NR_PIXBLOCK_PX(from)[from_line[1] + k],
223 NR_PIXBLOCK_PX(from)[from_line[2] + k],
224 NR_PIXBLOCK_PX(from)[from_line[3] + k],
225 from_y);
226 line[i].g = sampley(NR_PIXBLOCK_PX(from)[from_line[0] + k + 1],
227 NR_PIXBLOCK_PX(from)[from_line[1] + k + 1],
228 NR_PIXBLOCK_PX(from)[from_line[2] + k + 1],
229 NR_PIXBLOCK_PX(from)[from_line[3] + k + 1],
230 from_y);
231 line[i].b = sampley(NR_PIXBLOCK_PX(from)[from_line[0] + k + 2],
232 NR_PIXBLOCK_PX(from)[from_line[1] + k + 2],
233 NR_PIXBLOCK_PX(from)[from_line[2] + k + 2],
234 NR_PIXBLOCK_PX(from)[from_line[3] + k + 2],
235 from_y);
236 line[i].a = sampley(NR_PIXBLOCK_PX(from)[from_line[0] + k + 3],
237 NR_PIXBLOCK_PX(from)[from_line[1] + k + 3],
238 NR_PIXBLOCK_PX(from)[from_line[2] + k + 3],
239 NR_PIXBLOCK_PX(from)[from_line[3] + k + 3],
240 from_y);
241 }
242 RGBA result;
243 result.r = samplex(line[0].r, line[1].r, line[2].r, line[3].r,
244 from_x);
245 result.g = samplex(line[0].g, line[1].g, line[2].g, line[3].g,
246 from_x);
247 result.b = samplex(line[0].b, line[1].b, line[2].b, line[3].b,
248 from_x);
249 result.a = samplex(line[0].a, line[1].a, line[2].a, line[3].a,
250 from_x);
252 _check_index(to, to_y * to->rs + to_x * 4, __LINE__);
253 if (to->mode == NR_PIXBLOCK_MODE_R8G8B8A8P) {
254 /* Make sure, none of the RGB channels exceeds 100% intensity
255 * in premultiplied output */
256 result.a = clamp(result.a);
257 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4] =
258 clamp_alpha(result.r, result.a);
259 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1] =
260 clamp_alpha(result.g, result.a);
261 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2] =
262 clamp_alpha(result.b, result.a);
263 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3] = result.a;
264 } else {
265 /* Clamp the output to unsigned char range */
266 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4] = clamp(result.r);
267 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 1] = clamp(result.g);
268 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 2] = clamp(result.b);
269 NR_PIXBLOCK_PX(to)[to_y * to->rs + to_x * 4 + 3] = clamp(result.a);
270 }
271 }
272 }
273 if (free_from_on_exit) {
274 nr_pixblock_release(from);
275 delete from;
276 }
277 }
279 } /* namespace NR */
280 /*
281 Local Variables:
282 mode:c++
283 c-file-style:"stroustrup"
284 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
285 indent-tabs-mode:nil
286 fill-column:99
287 End:
288 */
289 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :