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 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 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 assert (id >= 0 && id < BRUSH_SETTINGS_COUNT);
120 settings[id]->set_point (input, index, x, y);
123 float get_state (int i)
125 assert (i >= 0 && i < STATE_COUNT);
129 void set_state (int i, float value)
131 assert (i >= 0 && i < STATE_COUNT);
136 // returns the fraction still left after t seconds
137 float exp_decay (float T_const, float t)
139 // the argument might not make mathematical sense (whatever.)
140 if (T_const <= 0.001) {
143 return exp(- t / T_const);
148 void settings_base_values_have_changed ()
150 // precalculate stuff that does not change dynamically
152 // Precalculate how the physical speed will be mapped to the speed input value.
153 // The forumla for this mapping is:
155 // y = log(gamma+x)*m + q;
157 // x: the physical speed (pixels per basic dab radius)
158 // y: the speed input that will be reported
159 // gamma: parameter set by ths user (small means a logarithmic mapping, big linear)
160 // m, q: parameters to scale and translate the curve
162 // The code below calculates m and q given gamma and two hardcoded constraints.
164 for (int i=0; i<2; i++) {
166 gamma = settings[(i==0)?BRUSH_SPEED1_GAMMA:BRUSH_SPEED2_GAMMA]->base_value;
169 float fix1_x, fix1_y, fix2_x, fix2_dy;
177 c1 = log(fix1_x+gamma);
178 m = fix2_dy * (fix2_x + gamma);
181 speed_mapping_gamma[i] = gamma;
182 speed_mapping_m[i] = m;
183 speed_mapping_q[i] = q;
187 // This function runs a brush "simulation" step. Usually it is
188 // called once or twice per dab. In theory the precision of the
189 // "simulation" gets better when it is called more often. In
190 // practice this only matters if there are some highly nonlinear
191 // mappings in critical places or extremely few events per second.
193 // note: parameters are is dx/ddab, ..., dtime/ddab (dab is the number, 5.0 = 5th dab)
194 void update_states_and_setting_values (float step_dx, float step_dy, float step_dpressure, float step_declination, float step_ascension, float step_dtime)
197 float inputs[INPUT_COUNT];
199 if (step_dtime < 0.0) {
200 printf("Time is running backwards!\n");
202 } else if (step_dtime == 0.0) {
203 // FIXME: happens about every 10th start, workaround (against division by zero)
207 states[STATE_X] += step_dx;
208 states[STATE_Y] += step_dy;
209 states[STATE_PRESSURE] += step_dpressure;
211 states[STATE_DECLINATION] += step_declination;
212 states[STATE_ASCENSION] += step_ascension;
214 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
216 // FIXME: does happen (interpolation problem?)
217 states[STATE_PRESSURE] = CLAMP(states[STATE_PRESSURE], 0.0, 1.0);
218 pressure = states[STATE_PRESSURE];
220 { // start / end stroke (for "stroke" input only)
221 if (!states[STATE_STROKE_STARTED]) {
222 if (pressure > settings[BRUSH_STROKE_THRESHOLD]->base_value + 0.0001) {
224 //printf("stroke start %f\n", pressure);
225 states[STATE_STROKE_STARTED] = 1;
226 states[STATE_STROKE] = 0.0;
229 if (pressure <= settings[BRUSH_STROKE_THRESHOLD]->base_value * 0.9 + 0.0001) {
231 //printf("stroke end\n");
232 states[STATE_STROKE_STARTED] = 0;
237 // now follows input handling
239 float norm_dx, norm_dy, norm_dist, norm_speed;
240 norm_dx = step_dx / step_dtime / base_radius;
241 norm_dy = step_dy / step_dtime / base_radius;
242 norm_speed = sqrt(SQR(norm_dx) + SQR(norm_dy));
243 norm_dist = norm_speed * step_dtime;
245 inputs[INPUT_PRESSURE] = pressure;
246 inputs[INPUT_SPEED1] = log(speed_mapping_gamma[0] + states[STATE_NORM_SPEED1_SLOW])*speed_mapping_m[0] + speed_mapping_q[0];
247 inputs[INPUT_SPEED2] = log(speed_mapping_gamma[1] + states[STATE_NORM_SPEED2_SLOW])*speed_mapping_m[1] + speed_mapping_q[1];
248 inputs[INPUT_RANDOM] = g_rand_double (rng);
249 inputs[INPUT_STROKE] = MIN(states[STATE_STROKE], 1.0);
250 inputs[INPUT_DIRECTION] = fmodf (atan2f (states[STATE_DIRECTION_DY], states[STATE_DIRECTION_DX])/(2*M_PI)*360 + 180.0, 180.0);
251 inputs[INPUT_TILT_DECLINATION] = states[STATE_DECLINATION];
252 inputs[INPUT_TILT_ASCENSION] = states[STATE_ASCENSION];
253 inputs[INPUT_CUSTOM] = states[STATE_CUSTOM_INPUT];
255 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]);
257 // FIXME: this one fails!!!
258 //assert(inputs[INPUT_SPEED1] >= 0.0 && inputs[INPUT_SPEED1] < 1e8); // checking for inf
260 for (int i=0; i<BRUSH_SETTINGS_COUNT; i++) {
261 settings_value[i] = settings[i]->calculate (inputs);
265 float fac = 1.0 - exp_decay (settings_value[BRUSH_SLOW_TRACKING_PER_DAB], 1.0);
266 states[STATE_ACTUAL_X] += (states[STATE_X] - states[STATE_ACTUAL_X]) * fac; // FIXME: should this depend on base radius?
267 states[STATE_ACTUAL_Y] += (states[STATE_Y] - states[STATE_ACTUAL_Y]) * fac;
272 fac = 1.0 - exp_decay (settings_value[BRUSH_SPEED1_SLOWNESS], step_dtime);
273 states[STATE_NORM_SPEED1_SLOW] += (norm_speed - states[STATE_NORM_SPEED1_SLOW]) * fac;
274 fac = 1.0 - exp_decay (settings_value[BRUSH_SPEED2_SLOWNESS], step_dtime);
275 states[STATE_NORM_SPEED2_SLOW] += (norm_speed - states[STATE_NORM_SPEED2_SLOW]) * fac;
278 { // slow speed, but as vector this time
280 // FIXME: offset_by_speed should be removed.
281 // Is it broken, non-smooth, system-dependent math?!
282 // A replacement could be a directed random offset.
284 float time_constant = exp(settings_value[BRUSH_OFFSET_BY_SPEED_SLOWNESS]*0.01)-1.0;
285 // Workaround for a bug that happens mainly on Windows, causing
286 // individual dabs to be placed far far away. Using the speed
287 // with zero filtering is just asking for trouble anyway.
288 if (time_constant < 0.002) time_constant = 0.002;
289 float fac = 1.0 - exp_decay (time_constant, step_dtime);
290 states[STATE_NORM_DX_SLOW] += (norm_dx - states[STATE_NORM_DX_SLOW]) * fac;
291 states[STATE_NORM_DY_SLOW] += (norm_dy - states[STATE_NORM_DY_SLOW]) * fac;
294 { // orientation (similar lowpass filter as above, but use dabtime instead of wallclock time)
295 float dx = step_dx / base_radius;
296 float dy = step_dy / base_radius;
297 float step_in_dabtime = hypotf(dx, dy); // FIXME: are we recalculating something here that we already have?
298 float fac = 1.0 - exp_decay (exp(settings_value[BRUSH_DIRECTION_FILTER]*0.5)-1.0, step_in_dabtime);
300 float dx_old = states[STATE_DIRECTION_DX];
301 float dy_old = states[STATE_DIRECTION_DY];
302 // use the opposite speed vector if it is closer (we don't care about 180 degree turns)
303 if (SQR(dx_old-dx) + SQR(dy_old-dy) > SQR(dx_old-(-dx)) + SQR(dy_old-(-dy))) {
307 states[STATE_DIRECTION_DX] += (dx - states[STATE_DIRECTION_DX]) * fac;
308 states[STATE_DIRECTION_DY] += (dy - states[STATE_DIRECTION_DY]) * fac;
313 fac = 1.0 - exp_decay (settings_value[BRUSH_CUSTOM_INPUT_SLOWNESS], 0.1);
314 states[STATE_CUSTOM_INPUT] += (settings_value[BRUSH_CUSTOM_INPUT] - states[STATE_CUSTOM_INPUT]) * fac;
320 frequency = expf(-settings_value[BRUSH_STROKE_DURATION_LOGARITHMIC]);
321 states[STATE_STROKE] += norm_dist * frequency;
322 // can happen, probably caused by rounding
323 if (states[STATE_STROKE] < 0) states[STATE_STROKE] = 0;
324 wrap = 1.0 + settings_value[BRUSH_STROKE_HOLDTIME];
325 if (states[STATE_STROKE] > wrap) {
326 if (wrap > 9.9 + 1.0) {
327 // "inifinity", just hold stroke somewhere >= 1.0
328 states[STATE_STROKE] = 1.0;
330 states[STATE_STROKE] = fmodf(states[STATE_STROKE], wrap);
332 if (states[STATE_STROKE] < 0) states[STATE_STROKE] = 0;
337 // calculate final radius
339 radius_log = settings_value[BRUSH_RADIUS_LOGARITHMIC];
340 states[STATE_ACTUAL_RADIUS] = expf(radius_log);
341 if (states[STATE_ACTUAL_RADIUS] < ACTUAL_RADIUS_MIN) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MIN;
342 if (states[STATE_ACTUAL_RADIUS] > ACTUAL_RADIUS_MAX) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MAX;
344 // aspect ratio (needs to be caluclated here because it can affect the dab spacing)
345 states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO] = settings_value[BRUSH_ELLIPTICAL_DAB_RATIO];
346 states[STATE_ACTUAL_ELLIPTICAL_DAB_ANGLE] = settings_value[BRUSH_ELLIPTICAL_DAB_ANGLE];
349 // Called only from stroke_to(). Calculate everything needed to
350 // draw the dab, then let the surface do the actual drawing.
352 // This is only gets called right after update_states_and_setting_values().
353 // Returns true if the surface was modified.
354 bool prepare_and_draw_dab (Surface * surface)
359 // ensure we don't get a positive result with two negative opaque values
360 if (settings_value[BRUSH_OPAQUE] < 0) settings_value[BRUSH_OPAQUE] = 0;
361 opaque = settings_value[BRUSH_OPAQUE] * settings_value[BRUSH_OPAQUE_MULTIPLY];
362 opaque = CLAMP(opaque, 0.0, 1.0);
363 //if (opaque == 0.0) return false; <-- cannot do that, since we need to update smudge state.
364 if (settings_value[BRUSH_OPAQUE_LINEARIZE]) {
365 // OPTIMIZE: no need to recalculate this for each dab
366 float alpha, beta, alpha_dab, beta_dab;
367 float dabs_per_pixel;
368 // dabs_per_pixel is just estimated roughly, I didn't think hard
369 // about the case when the radius changes during the stroke
371 settings[BRUSH_DABS_PER_ACTUAL_RADIUS]->base_value +
372 settings[BRUSH_DABS_PER_BASIC_RADIUS]->base_value
375 // the correction is probably not wanted if the dabs don't overlap
376 if (dabs_per_pixel < 1.0) dabs_per_pixel = 1.0;
378 // interpret the user-setting smoothly
379 dabs_per_pixel = 1.0 + settings[BRUSH_OPAQUE_LINEARIZE]->base_value*(dabs_per_pixel-1.0);
381 // see doc/brushdab_saturation.png
382 // beta = beta_dab^dabs_per_pixel
383 // <==> beta_dab = beta^(1/dabs_per_pixel)
386 beta_dab = powf(beta, 1.0/dabs_per_pixel);
387 alpha_dab = 1.0-beta_dab;
391 x = states[STATE_ACTUAL_X];
392 y = states[STATE_ACTUAL_Y];
394 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
396 if (settings_value[BRUSH_OFFSET_BY_SPEED]) {
397 x += states[STATE_NORM_DX_SLOW] * settings_value[BRUSH_OFFSET_BY_SPEED] * 0.1 * base_radius;
398 y += states[STATE_NORM_DY_SLOW] * settings_value[BRUSH_OFFSET_BY_SPEED] * 0.1 * base_radius;
401 if (settings_value[BRUSH_OFFSET_BY_RANDOM]) {
402 float amp = settings_value[BRUSH_OFFSET_BY_RANDOM];
403 if (amp < 0.0) amp = 0.0;
404 x += rand_gauss (rng) * amp * base_radius;
405 y += rand_gauss (rng) * amp * base_radius;
409 radius = states[STATE_ACTUAL_RADIUS];
410 if (settings_value[BRUSH_RADIUS_BY_RANDOM]) {
411 float radius_log, alpha_correction;
412 // go back to logarithmic radius to add the noise
413 radius_log = settings_value[BRUSH_RADIUS_LOGARITHMIC];
414 radius_log += rand_gauss (rng) * settings_value[BRUSH_RADIUS_BY_RANDOM];
415 radius = expf(radius_log);
416 radius = CLAMP(radius, ACTUAL_RADIUS_MIN, ACTUAL_RADIUS_MAX);
417 alpha_correction = states[STATE_ACTUAL_RADIUS] / radius;
418 alpha_correction = SQR(alpha_correction);
419 if (alpha_correction <= 1.0) {
420 opaque *= alpha_correction;
426 float color_h = settings[BRUSH_COLOR_H]->base_value;
427 float color_s = settings[BRUSH_COLOR_S]->base_value;
428 float color_v = settings[BRUSH_COLOR_V]->base_value;
429 float eraser_target_alpha = 1.0;
430 if (settings_value[BRUSH_SMUDGE] > 0.0) {
431 // mix (in RGB) the smudge color with the brush color
432 hsv_to_rgb_float (&color_h, &color_s, &color_v);
433 float fac = settings_value[BRUSH_SMUDGE];
434 if (fac > 1.0) fac = 1.0;
435 // If the smudge color somewhat transparent, then the resulting
436 // dab will do erasing towards that transparency level.
437 // see also ../doc/smudge_math.png
438 eraser_target_alpha = (1-fac)*1.0 + fac*states[STATE_SMUDGE_A];
439 // fix rounding errors (they really seem to happen in the previous line)
440 eraser_target_alpha = CLAMP(eraser_target_alpha, 0.0, 1.0);
441 if (eraser_target_alpha > 0) {
442 color_h = (fac*states[STATE_SMUDGE_RA] + (1-fac)*color_h) / eraser_target_alpha;
443 color_s = (fac*states[STATE_SMUDGE_GA] + (1-fac)*color_s) / eraser_target_alpha;
444 color_v = (fac*states[STATE_SMUDGE_BA] + (1-fac)*color_v) / eraser_target_alpha;
446 // we are only erasing; the color does not matter
451 rgb_to_hsv_float (&color_h, &color_s, &color_v);
454 if (settings_value[BRUSH_SMUDGE_LENGTH] < 1.0 and
455 // optimization, since normal brushes have smudge_length == 0.5 without actually smudging
456 (settings_value[BRUSH_SMUDGE] != 0.0 or not settings[BRUSH_SMUDGE]->is_constant())) {
458 float fac = settings_value[BRUSH_SMUDGE_LENGTH];
459 if (fac < 0.0) fac = 0;
464 // Calling get_color() is almost as expensive as rendering a
465 // dab. Because of this we use the previous value if it is not
466 // expected to hurt quality too much.
468 states[STATE_LAST_GETCOLOR_RECENTNESS] *= fac;
469 if (states[STATE_LAST_GETCOLOR_RECENTNESS] < 0.5*fac) {
470 states[STATE_LAST_GETCOLOR_RECENTNESS] = 1.0;
472 float smudge_radius = radius * expf(settings_value[BRUSH_SMUDGE_RADIUS_LOG]);
473 smudge_radius = CLAMP(smudge_radius, ACTUAL_RADIUS_MIN, ACTUAL_RADIUS_MAX);
474 surface->get_color (px, py, smudge_radius, &r, &g, &b, &a);
476 states[STATE_LAST_GETCOLOR_R] = r;
477 states[STATE_LAST_GETCOLOR_G] = g;
478 states[STATE_LAST_GETCOLOR_B] = b;
479 states[STATE_LAST_GETCOLOR_A] = a;
481 r = states[STATE_LAST_GETCOLOR_R];
482 g = states[STATE_LAST_GETCOLOR_G];
483 b = states[STATE_LAST_GETCOLOR_B];
484 a = states[STATE_LAST_GETCOLOR_A];
487 // updated the smudge color (stored with premultiplied alpha)
488 states[STATE_SMUDGE_A ] = fac*states[STATE_SMUDGE_A ] + (1-fac)*a;
489 // fix rounding errors
490 states[STATE_SMUDGE_A ] = CLAMP(states[STATE_SMUDGE_A], 0.0, 1.0);
492 states[STATE_SMUDGE_RA] = fac*states[STATE_SMUDGE_RA] + (1-fac)*r*a;
493 states[STATE_SMUDGE_GA] = fac*states[STATE_SMUDGE_GA] + (1-fac)*g*a;
494 states[STATE_SMUDGE_BA] = fac*states[STATE_SMUDGE_BA] + (1-fac)*b*a;
498 if (settings_value[BRUSH_ERASER]) {
499 eraser_target_alpha *= (1.0-settings_value[BRUSH_ERASER]);
503 color_h += settings_value[BRUSH_CHANGE_COLOR_H];
504 color_s += settings_value[BRUSH_CHANGE_COLOR_HSV_S];
505 color_v += settings_value[BRUSH_CHANGE_COLOR_V];
508 if (settings_value[BRUSH_CHANGE_COLOR_L] || settings_value[BRUSH_CHANGE_COLOR_HSL_S]) {
509 // (calculating way too much here, can be optimized if neccessary)
510 // this function will CLAMP the inputs
511 hsv_to_rgb_float (&color_h, &color_s, &color_v);
512 rgb_to_hsl_float (&color_h, &color_s, &color_v);
513 color_v += settings_value[BRUSH_CHANGE_COLOR_L];
514 color_s += settings_value[BRUSH_CHANGE_COLOR_HSL_S];
515 hsl_to_rgb_float (&color_h, &color_s, &color_v);
516 rgb_to_hsv_float (&color_h, &color_s, &color_v);
519 float hardness = CLAMP(settings_value[BRUSH_HARDNESS], 0.0, 1.0);
521 // anti-aliasing attempt (works surprisingly well for ink brushes)
522 float current_fadeout_in_pixels = radius * (1.0 - hardness);
523 float min_fadeout_in_pixels = settings_value[BRUSH_ANTI_ALIASING];
524 if (current_fadeout_in_pixels < min_fadeout_in_pixels) {
525 // need to soften the brush (decrease hardness), but keep optical radius
526 // so we tune both radius and hardness, to get the desired fadeout_in_pixels
527 float current_optical_radius = radius - (1.0-hardness)*radius/2.0;
529 // Equation 1: (new fadeout must be equal to min_fadeout)
530 // min_fadeout_in_pixels = radius_new*(1.0 - hardness_new)
531 // Equation 2: (optical radius must remain unchanged)
532 // current_optical_radius = radius_new - (1.0-hardness_new)*radius_new/2.0
534 // Solved Equation 1 for hardness_new, using Equation 2: (thanks to mathomatic)
535 float hardness_new = ((current_optical_radius - (min_fadeout_in_pixels/2.0))/(current_optical_radius + (min_fadeout_in_pixels/2.0)));
537 float radius_new = (min_fadeout_in_pixels/(1.0 - hardness_new));
539 hardness = hardness_new;
543 // the functions below will CLAMP most inputs
544 hsv_to_rgb_float (&color_h, &color_s, &color_v);
545 return surface->draw_dab (x, y, radius, color_h, color_s, color_v, opaque, hardness, eraser_target_alpha,
546 states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO], states[STATE_ACTUAL_ELLIPTICAL_DAB_ANGLE],
547 settings_value[BRUSH_LOCK_ALPHA]);
550 // How many dabs will be drawn between the current and the next (x, y, pressure, +dt) position?
551 float count_dabs_to (float x, float y, float pressure, float dt)
554 float res1, res2, res3;
557 if (states[STATE_ACTUAL_RADIUS] == 0.0) states[STATE_ACTUAL_RADIUS] = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
558 if (states[STATE_ACTUAL_RADIUS] < ACTUAL_RADIUS_MIN) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MIN;
559 if (states[STATE_ACTUAL_RADIUS] > ACTUAL_RADIUS_MAX) states[STATE_ACTUAL_RADIUS] = ACTUAL_RADIUS_MAX;
562 // OPTIMIZE: expf() called too often
563 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
564 if (base_radius < ACTUAL_RADIUS_MIN) base_radius = ACTUAL_RADIUS_MIN;
565 if (base_radius > ACTUAL_RADIUS_MAX) base_radius = ACTUAL_RADIUS_MAX;
566 //if (base_radius < 0.5) base_radius = 0.5;
567 //if (base_radius > 500.0) base_radius = 500.0;
569 xx = x - states[STATE_X];
570 yy = y - states[STATE_Y];
571 //dp = pressure - pressure; // Not useful?
572 // TODO: control rate with pressure (dabs per pressure) (dpressure is useless)
574 if (states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO] > 1.0) {
575 // code duplication, see tiledsurface::draw_dab()
576 float angle_rad=states[STATE_ACTUAL_ELLIPTICAL_DAB_ANGLE]/360*2*M_PI;
577 float cs=cos(angle_rad);
578 float sn=sin(angle_rad);
579 float yyr=(yy*cs-xx*sn)*states[STATE_ACTUAL_ELLIPTICAL_DAB_RATIO];
580 float xxr=yy*sn+xx*cs;
581 dist = sqrt(yyr*yyr + xxr*xxr);
583 dist = hypotf(xx, yy);
586 // FIXME: no need for base_value or for the range checks above IF always the interpolation
587 // function will be called before this one
588 res1 = dist / states[STATE_ACTUAL_RADIUS] * settings[BRUSH_DABS_PER_ACTUAL_RADIUS]->base_value;
589 res2 = dist / base_radius * settings[BRUSH_DABS_PER_BASIC_RADIUS]->base_value;
590 res3 = dt * settings[BRUSH_DABS_PER_SECOND]->base_value;
591 return res1 + res2 + res3;
596 // - is called once for each motion event
597 // - does motion event interpolation
598 // - paints zero, one or several dabs
599 // - decides whether the stroke is finished (for undo/redo)
600 // returns true if the stroke is finished or empty
601 bool stroke_to (Surface * surface, float x, float y, float pressure, float xtilt, float ytilt, double dtime)
603 //printf("%f %f %f %f\n", (double)dtime, (double)x, (double)y, (double)pressure);
605 float tilt_ascension = 0.0;
606 float tilt_declination = 90.0;
607 if (xtilt != 0 || ytilt != 0) {
608 // shield us from insane tilt input
609 xtilt = CLAMP(xtilt, -1.0, 1.0);
610 ytilt = CLAMP(ytilt, -1.0, 1.0);
611 assert(isfinite(xtilt) && isfinite(ytilt));
613 tilt_ascension = 180.0*atan2(-xtilt, ytilt)/M_PI;
615 if (abs(xtilt) > abs(ytilt)) {
616 e = sqrt(1+ytilt*ytilt);
618 e = sqrt(1+xtilt*xtilt);
620 float rad = hypot(xtilt, ytilt);
621 float cos_alpha = rad/e;
622 if (cos_alpha >= 1.0) cos_alpha = 1.0; // fix numerical inaccuracy
623 tilt_declination = 180.0*acos(cos_alpha)/M_PI;
625 assert(isfinite(tilt_ascension));
626 assert(isfinite(tilt_declination));
629 // printf("xtilt %f, ytilt %f\n", (double)xtilt, (double)ytilt);
630 // printf("ascension %f, declination %f\n", (double)tilt_ascension, (double)tilt_declination);
632 pressure = CLAMP(pressure, 0.0, 1.0);
633 if (!isfinite(x) || !isfinite(y) ||
634 (x > 1e10 || y > 1e10 || x < -1e10 || y < -1e10)) {
635 // workaround attempt for https://gna.org/bugs/?14372
636 g_print("Warning: ignoring brush::stroke_to with insane inputs (x = %f, y = %f)\n", (double)x, (double)y);
641 // the assertion below is better than out-of-memory later at save time
642 assert(x < 1e8 && y < 1e8 && x > -1e8 && y > -1e8);
644 if (dtime < 0) g_print("Time jumped backwards by dtime=%f seconds!\n", dtime);
645 if (dtime <= 0) dtime = 0.0001; // protect against possible division by zero bugs
647 if (dtime > 0.100 && pressure && states[STATE_PRESSURE] == 0) {
648 // Workaround for tablets that don't report motion events without pressure.
649 // This is to avoid linear interpolation of the pressure between two events.
650 stroke_to (surface, x, y, 0.0, 90.0, 0.0, dtime-0.0001);
654 g_rand_set_seed (rng, states[STATE_RNG_SEED]);
656 { // calculate the actual "virtual" cursor position
659 if (settings[BRUSH_TRACKING_NOISE]->base_value) {
660 // OPTIMIZE: expf() called too often
661 float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
663 x += rand_gauss (rng) * settings[BRUSH_TRACKING_NOISE]->base_value * base_radius;
664 y += rand_gauss (rng) * settings[BRUSH_TRACKING_NOISE]->base_value * base_radius;
667 float fac = 1.0 - exp_decay (settings[BRUSH_SLOW_TRACKING]->base_value, 100.0*dtime);
668 x = states[STATE_X] + (x - states[STATE_X]) * fac;
669 y = states[STATE_Y] + (y - states[STATE_Y]) * fac;
672 // draw many (or zero) dabs to the next position
674 // see doc/stroke2dabs.png
675 float dist_moved = states[STATE_DIST];
676 float dist_todo = count_dabs_to (x, y, pressure, dtime);
678 //if (dtime > 5 || dist_todo > 300) {
679 if (dtime > 5 || reset_requested) {
680 reset_requested = false;
684 if (dist_todo > 300) {
685 // this happens quite often, eg when moving the cursor back into the window
686 // FIXME: bad to hardcode a distance treshold here - might look at zoomed image
687 // better detect leaving/entering the window and reset then.
688 g_print ("Warning: NOT drawing %f dabs.\n", dist_todo);
689 g_print ("dtime=%f, dx=%f\n", dtime, x-states[STATE_X]);
694 //printf("Brush reset.\n");
695 for (int i=0; i<STATE_COUNT; i++) {
701 states[STATE_PRESSURE] = pressure;
703 // not resetting, because they will get overwritten below:
704 //dx, dy, dpress, dtime
706 states[STATE_ACTUAL_X] = states[STATE_X];
707 states[STATE_ACTUAL_Y] = states[STATE_Y];
708 states[STATE_STROKE] = 1.0; // start in a state as if the stroke was long finished
713 //g_print("dist = %f\n", states[STATE_DIST]);
714 enum { UNKNOWN, YES, NO } painted = UNKNOWN;
715 double dtime_left = dtime;
717 float step_dx, step_dy, step_dpressure, step_dtime;
718 float step_declination, step_ascension;
719 while (dist_moved + dist_todo >= 1.0) { // there are dabs pending
720 { // linear interpolation (nonlinear variant was too slow, see SVN log)
721 float frac; // fraction of the remaining distance to move
722 if (dist_moved > 0) {
723 // "move" the brush exactly to the first dab (moving less than one dab)
724 frac = (1.0 - dist_moved) / dist_todo;
727 // "move" the brush from one dab to the next
728 frac = 1.0 / dist_todo;
730 step_dx = frac * (x - states[STATE_X]);
731 step_dy = frac * (y - states[STATE_Y]);
732 step_dpressure = frac * (pressure - states[STATE_PRESSURE]);
733 step_dtime = frac * (dtime_left - 0.0);
734 step_declination = frac * (tilt_declination - states[STATE_DECLINATION]);
735 step_ascension = frac * (tilt_ascension - states[STATE_ASCENSION]);
736 // Though it looks different, time is interpolated exactly like x/y/pressure.
739 update_states_and_setting_values (step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
740 bool painted_now = prepare_and_draw_dab (surface);
743 } else if (painted == UNKNOWN) {
747 dtime_left -= step_dtime;
748 dist_todo = count_dabs_to (x, y, pressure, dtime_left);
752 // "move" the brush to the current time (no more dab will happen)
753 // Important to do this at least once every event, because
754 // brush_count_dabs_to depends on the radius and the radius can
755 // depend on something that changes much faster than only every
758 step_dx = x - states[STATE_X];
759 step_dy = y - states[STATE_Y];
760 step_dpressure = pressure - states[STATE_PRESSURE];
761 step_declination = tilt_declination - states[STATE_DECLINATION];
762 step_ascension = tilt_ascension - states[STATE_ASCENSION];
763 step_dtime = dtime_left;
765 //dtime_left = 0; but that value is not used any more
767 update_states_and_setting_values (step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
770 // save the fraction of a dab that is already done now
771 states[STATE_DIST] = dist_moved + dist_todo;
772 //g_print("dist_final = %f\n", states[STATE_DIST]);
774 // next seed for the RNG (GRand has no get_state() and states[] must always contain our full state)
775 states[STATE_RNG_SEED] = g_rand_int(rng);
777 // stroke separation logic (for undo/redo)
779 if (painted == UNKNOWN) {
780 if (stroke_current_idling_time > 0 || stroke_total_painting_time == 0) {
784 // probably still painting (we get more events than brushdabs)
786 //if (pressure == 0) g_print ("info: assuming 'still painting' while there is no pressure\n");
789 if (painted == YES) {
790 //if (stroke_current_idling_time > 0) g_print ("idling ==> painting\n");
791 stroke_total_painting_time += dtime;
792 stroke_current_idling_time = 0;
793 // force a stroke split after some time
794 if (stroke_total_painting_time > 4 + 3*pressure) {
795 // but only if pressure is not being released
796 // FIXME: use some smoothed state for dpressure, not the output of the interpolation code
797 // (which might easily wrongly give dpressure == 0)
798 if (step_dpressure >= 0) {
802 } else if (painted == NO) {
803 //if (stroke_current_idling_time == 0) g_print ("painting ==> idling\n");
804 stroke_current_idling_time += dtime;
805 if (stroke_total_painting_time == 0) {
806 // not yet painted, start a new stroke if we have accumulated a lot of irrelevant motion events
807 if (stroke_current_idling_time > 1.0) {
811 // Usually we have pressure==0 here. But some brushes can paint
812 // nothing at full pressure (eg gappy lines, or a stroke that
813 // fades out). In either case this is the prefered moment to split.
814 // if (stroke_total_painting_time+stroke_current_idling_time > 0.9 + 5*pressure) {