1 /* brushlib - The MyPaint Brush Library
2 * Copyright (C) 2007-2011 Martin Renold <martinxyz@gmx.ch>
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
23 #include "brushsettings.hpp"
24 #include "mapping.hpp"
26 #define ACTUAL_RADIUS_MIN 0.2
27 #define ACTUAL_RADIUS_MAX 800 // safety guard against radius like 1e20 and against rendering overload with unexpected brush dynamics
29 /* The Brush class stores two things:
30 b) settings: constant during a stroke (eg. size, spacing, dynamics, color selected by the user)
31 a) states: modified during a stroke (eg. speed, smudge colors, time/distance to next dab, position filter states)
33 FIXME: Actually those are two orthogonal things. Should separate them:
34 a) brush settings class that is saved/loaded/selected (without states)
35 b) brush core class to draw the dabs (using an instance of the above)
37 In python, there are two kinds of instances from this: a "global
38 brush" which does the cursor tracking, and the "brushlist" where
39 the states are ignored. When a brush is selected, its settings are
40 copied into the global one, leaving the state intact.
46 bool print_inputs; // debug menu
47 // for stroke splitting (undo/redo)
48 double stroke_total_painting_time;
49 double stroke_current_idling_time;
52 // see also brushsettings.py
54 // the states (get_state, set_state, reset) that change during a stroke
55 float states[STATE_COUNT];
58 // Those mappings describe how to calculate the current value for each setting.
59 // Most of settings will be constant (eg. only their base_value is used).
60 Mapping * settings[BRUSH_SETTINGS_COUNT];
62 // the current value of all settings (calculated using the current state)
63 float settings_value[BRUSH_SETTINGS_COUNT];
65 // cached calculation results
66 float speed_mapping_gamma[2], speed_mapping_m[2], speed_mapping_q[2];
72 for (int i=0; i<BRUSH_SETTINGS_COUNT; i++) {
73 settings[i] = new Mapping(INPUT_COUNT);
78 for (int i=0; i<STATE_COUNT; i++) {
83 settings_base_values_have_changed();
85 reset_requested = true;
89 for (int i=0; i<BRUSH_SETTINGS_COUNT; i++) {
92 g_rand_free (rng); rng = NULL;
97 reset_requested = true;
102 stroke_current_idling_time = 0;
103 stroke_total_painting_time = 0;
106 void set_base_value (int id, float value) {
107 g_assert (id >= 0 && id < BRUSH_SETTINGS_COUNT);
108 settings[id]->base_value = value;
110 settings_base_values_have_changed ();
113 void set_mapping_n (int id, int input, int n) {
114 g_assert (id >= 0 && id < BRUSH_SETTINGS_COUNT);
115 settings[id]->set_n (input, n);
118 void set_mapping_point (int id, int input, int index, float x, float y) {
119 g_assert (id >= 0 && id < BRUSH_SETTINGS_COUNT);
120 settings[id]->set_point (input, index, x, y);
124 // returns the fraction still left after t seconds
125 float exp_decay (float T_const, float t)
127 // the argument might not make mathematical sense (whatever.)
128 if (T_const <= 0.001) {
131 return exp(- t / T_const);
136 void settings_base_values_have_changed ()
138 // precalculate stuff that does not change dynamically
140 // Precalculate how the physical speed will be mapped to the speed input value.
141 // The forumla for this mapping is:
143 // y = log(gamma+x)*m + q;
145 // x: the physical speed (pixels per basic dab radius)
146 // y: the speed input that will be reported
147 // gamma: parameter set by ths user (small means a logarithmic mapping, big linear)
148 // m, q: parameters to scale and translate the curve
150 // The code below calculates m and q given gamma and two hardcoded constraints.
152 for (int i=0; i<2; i++) {
154 gamma = settings[(i==0)?BRUSH_SPEED1_GAMMA:BRUSH_SPEED2_GAMMA]->base_value;
157 float fix1_x, fix1_y, fix2_x, fix2_dy;
165 c1 = log(fix1_x+gamma);
166 m = fix2_dy * (fix2_x + gamma);
169 speed_mapping_gamma[i] = gamma;
170 speed_mapping_m[i] = m;
171 speed_mapping_q[i] = q;
175 // This function runs a brush "simulation" step. Usually it is
176 // called once or twice per dab. In theory the precision of the
177 // "simulation" gets better when it is called more often. In
178 // practice this only matters if there are some highly nonlinear
179 // mappings in critical places or extremely few events per second.
181 // note: parameters are is dx/ddab, ..., dtime/ddab (dab is the number, 5.0 = 5th dab)
182 void update_states_and_setting_values (float step_dx, float step_dy, float step_dpressure, float step_declination, float step_ascension, float step_dtime)
185 float inputs[INPUT_COUNT];
187 if (step_dtime < 0.0) {
188 printf("Time is running backwards!\n");
190 } else if (step_dtime == 0.0) {
191 // FIXME: happens about every 10th start, workaround (against division by zero)
195 states[STATE_X] += step_dx;
196 states[STATE_Y] += step_dy;
197 states[STATE_PRESSURE] += step_dpressure;
199 states[STATE_DECLINATION] += step_declination;
200 states[STATE_ASCENSION] += step_ascension;
202 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
204 // FIXME: does happen (interpolation problem?)
205 states[STATE_PRESSURE] = CLAMP(states[STATE_PRESSURE], 0.0, 1.0);
206 pressure = states[STATE_PRESSURE];
208 { // start / end stroke (for "stroke" input only)
209 if (!states[STATE_STROKE_STARTED]) {
210 if (pressure > settings[BRUSH_STROKE_THRESHOLD]->base_value + 0.0001) {
212 //printf("stroke start %f\n", pressure);
213 states[STATE_STROKE_STARTED] = 1;
214 states[STATE_STROKE] = 0.0;
217 if (pressure <= settings[BRUSH_STROKE_THRESHOLD]->base_value * 0.9 + 0.0001) {
219 //printf("stroke end\n");
220 states[STATE_STROKE_STARTED] = 0;
225 // now follows input handling
227 float norm_dx, norm_dy, norm_dist, norm_speed;
228 norm_dx = step_dx / step_dtime / base_radius;
229 norm_dy = step_dy / step_dtime / base_radius;
230 norm_speed = sqrt(SQR(norm_dx) + SQR(norm_dy));
231 norm_dist = norm_speed * step_dtime;
233 inputs[INPUT_PRESSURE] = pressure;
234 inputs[INPUT_SPEED1] = log(speed_mapping_gamma[0] + states[STATE_NORM_SPEED1_SLOW])*speed_mapping_m[0] + speed_mapping_q[0];
235 inputs[INPUT_SPEED2] = log(speed_mapping_gamma[1] + states[STATE_NORM_SPEED2_SLOW])*speed_mapping_m[1] + speed_mapping_q[1];
236 inputs[INPUT_RANDOM] = g_rand_double (rng);
237 inputs[INPUT_STROKE] = MIN(states[STATE_STROKE], 1.0);
238 inputs[INPUT_DIRECTION] = fmodf (atan2f (states[STATE_DIRECTION_DY], states[STATE_DIRECTION_DX])/(2*M_PI)*360 + 180.0, 180.0);
239 inputs[INPUT_TILT_DECLINATION] = states[STATE_DECLINATION];
240 inputs[INPUT_TILT_ASCENSION] = states[STATE_ASCENSION];
241 inputs[INPUT_CUSTOM] = states[STATE_CUSTOM_INPUT];
243 g_print("press=% 4.3f, speed1=% 4.4f\tspeed2=% 4.4f\tstroke=% 4.3f\tcustom=% 4.3f\n", (double)inputs[INPUT_PRESSURE], (double)inputs[INPUT_SPEED1], (double)inputs[INPUT_SPEED2], (double)inputs[INPUT_STROKE], (double)inputs[INPUT_CUSTOM]);
245 // FIXME: this one fails!!!
246 //assert(inputs[INPUT_SPEED1] >= 0.0 && inputs[INPUT_SPEED1] < 1e8); // checking for inf
248 for (int i=0; i<BRUSH_SETTINGS_COUNT; i++) {
249 settings_value[i] = settings[i]->calculate (inputs);
253 float fac = 1.0 - exp_decay (settings_value[BRUSH_SLOW_TRACKING_PER_DAB], 1.0);
254 states[STATE_ACTUAL_X] += (states[STATE_X] - states[STATE_ACTUAL_X]) * fac; // FIXME: should this depend on base radius?
255 states[STATE_ACTUAL_Y] += (states[STATE_Y] - states[STATE_ACTUAL_Y]) * fac;
260 fac = 1.0 - exp_decay (settings_value[BRUSH_SPEED1_SLOWNESS], step_dtime);
261 states[STATE_NORM_SPEED1_SLOW] += (norm_speed - states[STATE_NORM_SPEED1_SLOW]) * fac;
262 fac = 1.0 - exp_decay (settings_value[BRUSH_SPEED2_SLOWNESS], step_dtime);
263 states[STATE_NORM_SPEED2_SLOW] += (norm_speed - states[STATE_NORM_SPEED2_SLOW]) * fac;
266 { // slow speed, but as vector this time
268 // FIXME: offset_by_speed should be removed.
269 // Is it broken, non-smooth, system-dependent math?!
270 // A replacement could be a directed random offset.
272 float time_constant = exp(settings_value[BRUSH_OFFSET_BY_SPEED_SLOWNESS]*0.01)-1.0;
273 // Workaround for a bug that happens mainly on Windows, causing
274 // individual dabs to be placed far far away. Using the speed
275 // with zero filtering is just asking for trouble anyway.
276 if (time_constant < 0.002) time_constant = 0.002;
277 float fac = 1.0 - exp_decay (time_constant, step_dtime);
278 states[STATE_NORM_DX_SLOW] += (norm_dx - states[STATE_NORM_DX_SLOW]) * fac;
279 states[STATE_NORM_DY_SLOW] += (norm_dy - states[STATE_NORM_DY_SLOW]) * fac;
282 { // orientation (similar lowpass filter as above, but use dabtime instead of wallclock time)
283 float dx = step_dx / base_radius;
284 float dy = step_dy / base_radius;
285 float step_in_dabtime = hypotf(dx, dy); // FIXME: are we recalculating something here that we already have?
286 float fac = 1.0 - exp_decay (exp(settings_value[BRUSH_DIRECTION_FILTER]*0.5)-1.0, step_in_dabtime);
288 float dx_old = states[STATE_DIRECTION_DX];
289 float dy_old = states[STATE_DIRECTION_DY];
290 // use the opposite speed vector if it is closer (we don't care about 180 degree turns)
291 if (SQR(dx_old-dx) + SQR(dy_old-dy) > SQR(dx_old-(-dx)) + SQR(dy_old-(-dy))) {
295 states[STATE_DIRECTION_DX] += (dx - states[STATE_DIRECTION_DX]) * fac;
296 states[STATE_DIRECTION_DY] += (dy - states[STATE_DIRECTION_DY]) * fac;
301 fac = 1.0 - exp_decay (settings_value[BRUSH_CUSTOM_INPUT_SLOWNESS], 0.1);
302 states[STATE_CUSTOM_INPUT] += (settings_value[BRUSH_CUSTOM_INPUT] - states[STATE_CUSTOM_INPUT]) * fac;
308 frequency = expf(-settings_value[BRUSH_STROKE_DURATION_LOGARITHMIC]);
309 states[STATE_STROKE] += norm_dist * frequency;
310 // can happen, probably caused by rounding
311 if (states[STATE_STROKE] < 0) states[STATE_STROKE] = 0;
312 wrap = 1.0 + settings_value[BRUSH_STROKE_HOLDTIME];
313 if (states[STATE_STROKE] > wrap) {
314 if (wrap > 9.9 + 1.0) {
315 // "inifinity", just hold stroke somewhere >= 1.0
316 states[STATE_STROKE] = 1.0;
318 states[STATE_STROKE] = fmodf(states[STATE_STROKE], wrap);
320 if (states[STATE_STROKE] < 0) states[STATE_STROKE] = 0;
325 // calculate final radius
327 radius_log = settings_value[BRUSH_RADIUS_LOGARITHMIC];
328 states[STATE_ACTUAL_RADIUS] = expf(radius_log);
329 if (states[STATE_ACTUAL_RADIUS] < ACTUAL_RADIUS_MIN) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MIN;
330 if (states[STATE_ACTUAL_RADIUS] > ACTUAL_RADIUS_MAX) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MAX;
332 // aspect ratio (needs to be caluclated here because it can affect the dab spacing)
333 states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO] = settings_value[BRUSH_ELLIPTICAL_DAB_RATIO];
334 states[STATE_ACTUAL_ELLIPTICAL_DAB_ANGLE] = settings_value[BRUSH_ELLIPTICAL_DAB_ANGLE];
337 // Called only from stroke_to(). Calculate everything needed to
338 // draw the dab, then let the surface do the actual drawing.
340 // This is only gets called right after update_states_and_setting_values().
341 // Returns true if the surface was modified.
342 bool prepare_and_draw_dab (Surface * surface)
347 // ensure we don't get a positive result with two negative opaque values
348 if (settings_value[BRUSH_OPAQUE] < 0) settings_value[BRUSH_OPAQUE] = 0;
349 opaque = settings_value[BRUSH_OPAQUE] * settings_value[BRUSH_OPAQUE_MULTIPLY];
350 opaque = CLAMP(opaque, 0.0, 1.0);
351 //if (opaque == 0.0) return false; <-- cannot do that, since we need to update smudge state.
352 if (settings_value[BRUSH_OPAQUE_LINEARIZE]) {
353 // OPTIMIZE: no need to recalculate this for each dab
354 float alpha, beta, alpha_dab, beta_dab;
355 float dabs_per_pixel;
356 // dabs_per_pixel is just estimated roughly, I didn't think hard
357 // about the case when the radius changes during the stroke
359 settings[BRUSH_DABS_PER_ACTUAL_RADIUS]->base_value +
360 settings[BRUSH_DABS_PER_BASIC_RADIUS]->base_value
363 // the correction is probably not wanted if the dabs don't overlap
364 if (dabs_per_pixel < 1.0) dabs_per_pixel = 1.0;
366 // interpret the user-setting smoothly
367 dabs_per_pixel = 1.0 + settings[BRUSH_OPAQUE_LINEARIZE]->base_value*(dabs_per_pixel-1.0);
369 // see doc/brushdab_saturation.png
370 // beta = beta_dab^dabs_per_pixel
371 // <==> beta_dab = beta^(1/dabs_per_pixel)
374 beta_dab = powf(beta, 1.0/dabs_per_pixel);
375 alpha_dab = 1.0-beta_dab;
379 x = states[STATE_ACTUAL_X];
380 y = states[STATE_ACTUAL_Y];
382 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
384 if (settings_value[BRUSH_OFFSET_BY_SPEED]) {
385 x += states[STATE_NORM_DX_SLOW] * settings_value[BRUSH_OFFSET_BY_SPEED] * 0.1 * base_radius;
386 y += states[STATE_NORM_DY_SLOW] * settings_value[BRUSH_OFFSET_BY_SPEED] * 0.1 * base_radius;
389 if (settings_value[BRUSH_OFFSET_BY_RANDOM]) {
390 float amp = settings_value[BRUSH_OFFSET_BY_RANDOM];
391 if (amp < 0.0) amp = 0.0;
392 x += rand_gauss (rng) * amp * base_radius;
393 y += rand_gauss (rng) * amp * base_radius;
397 radius = states[STATE_ACTUAL_RADIUS];
398 if (settings_value[BRUSH_RADIUS_BY_RANDOM]) {
399 float radius_log, alpha_correction;
400 // go back to logarithmic radius to add the noise
401 radius_log = settings_value[BRUSH_RADIUS_LOGARITHMIC];
402 radius_log += rand_gauss (rng) * settings_value[BRUSH_RADIUS_BY_RANDOM];
403 radius = expf(radius_log);
404 radius = CLAMP(radius, ACTUAL_RADIUS_MIN, ACTUAL_RADIUS_MAX);
405 alpha_correction = states[STATE_ACTUAL_RADIUS] / radius;
406 alpha_correction = SQR(alpha_correction);
407 if (alpha_correction <= 1.0) {
408 opaque *= alpha_correction;
414 float color_h = settings[BRUSH_COLOR_H]->base_value;
415 float color_s = settings[BRUSH_COLOR_S]->base_value;
416 float color_v = settings[BRUSH_COLOR_V]->base_value;
417 float eraser_target_alpha = 1.0;
418 if (settings_value[BRUSH_SMUDGE] > 0.0) {
419 // mix (in RGB) the smudge color with the brush color
420 hsv_to_rgb_float (&color_h, &color_s, &color_v);
421 float fac = settings_value[BRUSH_SMUDGE];
422 if (fac > 1.0) fac = 1.0;
423 // If the smudge color somewhat transparent, then the resulting
424 // dab will do erasing towards that transparency level.
425 // see also ../doc/smudge_math.png
426 eraser_target_alpha = (1-fac)*1.0 + fac*states[STATE_SMUDGE_A];
427 // fix rounding errors (they really seem to happen in the previous line)
428 eraser_target_alpha = CLAMP(eraser_target_alpha, 0.0, 1.0);
429 if (eraser_target_alpha > 0) {
430 color_h = (fac*states[STATE_SMUDGE_RA] + (1-fac)*color_h) / eraser_target_alpha;
431 color_s = (fac*states[STATE_SMUDGE_GA] + (1-fac)*color_s) / eraser_target_alpha;
432 color_v = (fac*states[STATE_SMUDGE_BA] + (1-fac)*color_v) / eraser_target_alpha;
434 // we are only erasing; the color does not matter
439 rgb_to_hsv_float (&color_h, &color_s, &color_v);
442 if (settings_value[BRUSH_SMUDGE_LENGTH] < 1.0 and
443 // optimization, since normal brushes have smudge_length == 0.5 without actually smudging
444 (settings_value[BRUSH_SMUDGE] != 0.0 or not settings[BRUSH_SMUDGE]->is_constant())) {
446 float smudge_radius = radius * expf(settings_value[BRUSH_SMUDGE_RADIUS_LOG]);
447 smudge_radius = CLAMP(smudge_radius, ACTUAL_RADIUS_MIN, ACTUAL_RADIUS_MAX);
449 float fac = settings_value[BRUSH_SMUDGE_LENGTH];
450 if (fac < 0.0) fac = 0;
456 surface->get_color (px, py, smudge_radius, &r, &g, &b, &a);
457 // updated the smudge color (stored with premultiplied alpha)
458 states[STATE_SMUDGE_A ] = fac*states[STATE_SMUDGE_A ] + (1-fac)*a;
459 // fix rounding errors
460 states[STATE_SMUDGE_A ] = CLAMP(states[STATE_SMUDGE_A], 0.0, 1.0);
462 states[STATE_SMUDGE_RA] = fac*states[STATE_SMUDGE_RA] + (1-fac)*r*a;
463 states[STATE_SMUDGE_GA] = fac*states[STATE_SMUDGE_GA] + (1-fac)*g*a;
464 states[STATE_SMUDGE_BA] = fac*states[STATE_SMUDGE_BA] + (1-fac)*b*a;
468 if (settings_value[BRUSH_ERASER]) {
469 eraser_target_alpha *= (1.0-settings_value[BRUSH_ERASER]);
473 color_h += settings_value[BRUSH_CHANGE_COLOR_H];
474 color_s += settings_value[BRUSH_CHANGE_COLOR_HSV_S];
475 color_v += settings_value[BRUSH_CHANGE_COLOR_V];
478 if (settings_value[BRUSH_CHANGE_COLOR_L] || settings_value[BRUSH_CHANGE_COLOR_HSL_S]) {
479 // (calculating way too much here, can be optimized if neccessary)
480 // this function will CLAMP the inputs
481 hsv_to_rgb_float (&color_h, &color_s, &color_v);
482 rgb_to_hsl_float (&color_h, &color_s, &color_v);
483 color_v += settings_value[BRUSH_CHANGE_COLOR_L];
484 color_s += settings_value[BRUSH_CHANGE_COLOR_HSL_S];
485 hsl_to_rgb_float (&color_h, &color_s, &color_v);
486 rgb_to_hsv_float (&color_h, &color_s, &color_v);
489 float hardness = settings_value[BRUSH_HARDNESS];
491 // the functions below will CLAMP most inputs
492 hsv_to_rgb_float (&color_h, &color_s, &color_v);
493 return surface->draw_dab (x, y, radius, color_h, color_s, color_v, opaque, hardness, eraser_target_alpha,
494 states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO], states[STATE_ACTUAL_ELLIPTICAL_DAB_ANGLE],
495 settings_value[BRUSH_LOCK_ALPHA]);
498 // How many dabs will be drawn between the current and the next (x, y, pressure, +dt) position?
499 float count_dabs_to (float x, float y, float pressure, float dt)
502 float res1, res2, res3;
505 if (states[STATE_ACTUAL_RADIUS] == 0.0) states[STATE_ACTUAL_RADIUS] = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
506 if (states[STATE_ACTUAL_RADIUS] < ACTUAL_RADIUS_MIN) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MIN;
507 if (states[STATE_ACTUAL_RADIUS] > ACTUAL_RADIUS_MAX) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MAX;
510 // OPTIMIZE: expf() called too often
511 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
512 if (base_radius < ACTUAL_RADIUS_MIN) base_radius = ACTUAL_RADIUS_MIN;
513 if (base_radius > ACTUAL_RADIUS_MAX) base_radius = ACTUAL_RADIUS_MAX;
514 //if (base_radius < 0.5) base_radius = 0.5;
515 //if (base_radius > 500.0) base_radius = 500.0;
517 xx = x - states[STATE_X];
518 yy = y - states[STATE_Y];
519 //dp = pressure - pressure; // Not useful?
520 // TODO: control rate with pressure (dabs per pressure) (dpressure is useless)
522 if (states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO] > 1.0) {
523 // code duplication, see tiledsurface::draw_dab()
524 float angle_rad=states[STATE_ACTUAL_ELLIPTICAL_DAB_ANGLE]/360*2*M_PI;
525 float cs=cos(angle_rad);
526 float sn=sin(angle_rad);
527 float yyr=(yy*cs-xx*sn)*states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO];
528 float xxr=yy*sn+xx*cs;
529 dist = sqrt(yyr*yyr + xxr*xxr);
531 dist = hypotf(xx, yy);
534 // FIXME: no need for base_value or for the range checks above IF always the interpolation
535 // function will be called before this one
536 res1 = dist / states[STATE_ACTUAL_RADIUS] * settings[BRUSH_DABS_PER_ACTUAL_RADIUS]->base_value;
537 res2 = dist / base_radius * settings[BRUSH_DABS_PER_BASIC_RADIUS]->base_value;
538 res3 = dt * settings[BRUSH_DABS_PER_SECOND]->base_value;
539 return res1 + res2 + res3;
544 // - is called once for each motion event
545 // - does motion event interpolation
546 // - paints zero, one or several dabs
547 // - decides whether the stroke is finished (for undo/redo)
548 // returns true if the stroke is finished or empty
549 bool stroke_to (Surface * surface, float x, float y, float pressure, float xtilt, float ytilt, double dtime)
551 //printf("%f %f %f %f\n", (double)dtime, (double)x, (double)y, (double)pressure);
553 float tilt_ascension = 0.0;
554 float tilt_declination = 90.0;
555 if (xtilt != 0 || ytilt != 0) {
556 // shield us from insane tilt input
557 xtilt = CLAMP(xtilt, -1.0, 1.0);
558 ytilt = CLAMP(ytilt, -1.0, 1.0);
559 assert(isfinite(xtilt) && isfinite(ytilt));
561 tilt_ascension = 180.0*atan2(-xtilt, ytilt)/M_PI;
563 if (abs(xtilt) > abs(ytilt)) {
564 e = sqrt(1+ytilt*ytilt);
566 e = sqrt(1+xtilt*xtilt);
568 float rad = hypot(xtilt, ytilt);
569 float cos_alpha = rad/e;
570 if (cos_alpha >= 1.0) cos_alpha = 1.0; // fix numerical inaccuracy
571 tilt_declination = 180.0*acos(cos_alpha)/M_PI;
573 assert(isfinite(tilt_ascension));
574 assert(isfinite(tilt_declination));
577 // printf("xtilt %f, ytilt %f\n", (double)xtilt, (double)ytilt);
578 // printf("ascension %f, declination %f\n", (double)tilt_ascension, (double)tilt_declination);
580 pressure = CLAMP(pressure, 0.0, 1.0);
581 if (!isfinite(x) || !isfinite(y) ||
582 (x > 1e10 || y > 1e10 || x < -1e10 || y < -1e10)) {
583 // workaround attempt for https://gna.org/bugs/?14372
584 g_print("Warning: ignoring brush::stroke_to with insane inputs (x = %f, y = %f)\n", (double)x, (double)y);
589 // the assertion below is better than out-of-memory later at save time
590 assert(x < 1e8 && y < 1e8 && x > -1e8 && y > -1e8);
592 if (dtime < 0) g_print("Time jumped backwards by dtime=%f seconds!\n", dtime);
593 if (dtime <= 0) dtime = 0.0001; // protect against possible division by zero bugs
595 if (dtime > 0.100 && pressure && states[STATE_PRESSURE] == 0) {
596 // Workaround for tablets that don't report motion events without pressure.
597 // This is to avoid linear interpolation of the pressure between two events.
598 stroke_to (surface, x, y, 0.0, 90.0, 0.0, dtime-0.0001);
602 g_rand_set_seed (rng, states[STATE_RNG_SEED]);
604 { // calculate the actual "virtual" cursor position
607 if (settings[BRUSH_TRACKING_NOISE]->base_value) {
608 // OPTIMIZE: expf() called too often
609 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
611 x += rand_gauss (rng) * settings[BRUSH_TRACKING_NOISE]->base_value * base_radius;
612 y += rand_gauss (rng) * settings[BRUSH_TRACKING_NOISE]->base_value * base_radius;
615 float fac = 1.0 - exp_decay (settings[BRUSH_SLOW_TRACKING]->base_value, 100.0*dtime);
616 x = states[STATE_X] + (x - states[STATE_X]) * fac;
617 y = states[STATE_Y] + (y - states[STATE_Y]) * fac;
620 // draw many (or zero) dabs to the next position
622 // see doc/stroke2dabs.png
623 float dist_moved = states[STATE_DIST];
624 float dist_todo = count_dabs_to (x, y, pressure, dtime);
626 //if (dtime > 5 || dist_todo > 300) {
627 if (dtime > 5 || reset_requested) {
628 reset_requested = false;
632 if (dist_todo > 300) {
633 // this happens quite often, eg when moving the cursor back into the window
634 // FIXME: bad to hardcode a distance treshold here - might look at zoomed image
635 // better detect leaving/entering the window and reset then.
636 g_print ("Warning: NOT drawing %f dabs.\n", dist_todo);
637 g_print ("dtime=%f, dx=%f\n", dtime, x-states[STATE_X]);
642 //printf("Brush reset.\n");
643 for (int i=0; i<STATE_COUNT; i++) {
649 states[STATE_PRESSURE] = pressure;
651 // not resetting, because they will get overwritten below:
652 //dx, dy, dpress, dtime
654 states[STATE_ACTUAL_X] = states[STATE_X];
655 states[STATE_ACTUAL_Y] = states[STATE_Y];
656 states[STATE_STROKE] = 1.0; // start in a state as if the stroke was long finished
661 //g_print("dist = %f\n", states[STATE_DIST]);
662 enum { UNKNOWN, YES, NO } painted = UNKNOWN;
663 double dtime_left = dtime;
665 float step_dx, step_dy, step_dpressure, step_dtime;
666 float step_declination, step_ascension;
667 while (dist_moved + dist_todo >= 1.0) { // there are dabs pending
668 { // linear interpolation (nonlinear variant was too slow, see SVN log)
669 float frac; // fraction of the remaining distance to move
670 if (dist_moved > 0) {
671 // "move" the brush exactly to the first dab (moving less than one dab)
672 frac = (1.0 - dist_moved) / dist_todo;
675 // "move" the brush from one dab to the next
676 frac = 1.0 / dist_todo;
678 step_dx = frac * (x - states[STATE_X]);
679 step_dy = frac * (y - states[STATE_Y]);
680 step_dpressure = frac * (pressure - states[STATE_PRESSURE]);
681 step_dtime = frac * (dtime_left - 0.0);
682 step_declination = frac * (tilt_declination - states[STATE_DECLINATION]);
683 step_ascension = frac * (tilt_ascension - states[STATE_ASCENSION]);
684 // Though it looks different, time is interpolated exactly like x/y/pressure.
687 update_states_and_setting_values (step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
688 bool painted_now = prepare_and_draw_dab (surface);
691 } else if (painted == UNKNOWN) {
695 dtime_left -= step_dtime;
696 dist_todo = count_dabs_to (x, y, pressure, dtime_left);
700 // "move" the brush to the current time (no more dab will happen)
701 // Important to do this at least once every event, because
702 // brush_count_dabs_to depends on the radius and the radius can
703 // depend on something that changes much faster than only every
706 step_dx = x - states[STATE_X];
707 step_dy = y - states[STATE_Y];
708 step_dpressure = pressure - states[STATE_PRESSURE];
709 step_declination = tilt_declination - states[STATE_DECLINATION];
710 step_ascension = tilt_ascension - states[STATE_ASCENSION];
711 step_dtime = dtime_left;
713 //dtime_left = 0; but that value is not used any more
715 update_states_and_setting_values (step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
718 // save the fraction of a dab that is already done now
719 states[STATE_DIST] = dist_moved + dist_todo;
720 //g_print("dist_final = %f\n", states[STATE_DIST]);
722 // next seed for the RNG (GRand has no get_state() and states[] must always contain our full state)
723 states[STATE_RNG_SEED] = g_rand_int(rng);
725 // stroke separation logic (for undo/redo)
727 if (painted == UNKNOWN) {
728 if (stroke_current_idling_time > 0 || stroke_total_painting_time == 0) {
732 // probably still painting (we get more events than brushdabs)
734 //if (pressure == 0) g_print ("info: assuming 'still painting' while there is no pressure\n");
737 if (painted == YES) {
738 //if (stroke_current_idling_time > 0) g_print ("idling ==> painting\n");
739 stroke_total_painting_time += dtime;
740 stroke_current_idling_time = 0;
741 // force a stroke split after some time
742 if (stroke_total_painting_time > 4 + 3*pressure) {
743 // but only if pressure is not being released
744 // FIXME: use some smoothed state for dpressure, not the output of the interpolation code
745 // (which might easily wrongly give dpressure == 0)
746 if (step_dpressure >= 0) {
750 } else if (painted == NO) {
751 //if (stroke_current_idling_time == 0) g_print ("painting ==> idling\n");
752 stroke_current_idling_time += dtime;
753 if (stroke_total_painting_time == 0) {
754 // not yet painted, start a new stroke if we have accumulated a lot of irrelevant motion events
755 if (stroke_current_idling_time > 1.0) {
759 // Usually we have pressure==0 here. But some brushes can paint
760 // nothing at full pressure (eg gappy lines, or a stroke that
761 // fades out). In either case this is the prefered moment to split.
762 if (stroke_total_painting_time+stroke_current_idling_time > 1.2 + 5*pressure) {
770 PyObject * get_state ()
772 npy_intp dims = {STATE_COUNT};
773 PyObject * data = PyArray_SimpleNew(1, &dims, NPY_FLOAT32);
774 npy_float32 * data_p = (npy_float32*)PyArray_DATA(data);
775 for (int i=0; i<STATE_COUNT; i++) {
776 data_p[i] = states[i];
781 void set_state (PyObject * data)
783 assert(PyArray_NDIM(data) == 1);
784 assert(PyArray_DIM(data, 0) == STATE_COUNT);
785 assert(PyArray_ISCARRAY(data));
786 npy_float32 * data_p = (npy_float32*)PyArray_DATA(data);
787 for (int i=0; i<STATE_COUNT; i++) {
788 states[i] = data_p[i];