// This function:
// - is called once for each motion event
// - does motion event interpolation
// - paints zero, one or several dabs
// - decides whether the stroke is finished (for undo/redo)
// returns true if the stroke is finished or empty
bool stroke_to (Surface * surface, float x, float y, float pressure, float xtilt, float ytilt, double dtime)
{
//printf("%f %f %f %f\n", (double)dtime, (double)x, (double)y, (double)pressure);
float tilt_ascension = 0.0;
float tilt_declination = 90.0;
if (xtilt != 0 || ytilt != 0) {
// shield us from insane tilt input
xtilt = CLAMP(xtilt, -1.0, 1.0);
ytilt = CLAMP(ytilt, -1.0, 1.0);
assert(std::isfinite(xtilt) && std::isfinite(ytilt));
tilt_ascension = 180.0*atan2(-xtilt, ytilt)/M_PI;
float e;
if (abs(xtilt) > abs(ytilt)) {
e = sqrt(1+ytilt*ytilt);
} else {
e = sqrt(1+xtilt*xtilt);
}
float rad = hypot(xtilt, ytilt);
float cos_alpha = rad/e;
if (cos_alpha >= 1.0) cos_alpha = 1.0; // fix numerical inaccuracy
tilt_declination = 180.0*acos(cos_alpha)/M_PI;
assert(std::isfinite(tilt_ascension));
assert(std::isfinite(tilt_declination));
}
// printf("xtilt %f, ytilt %f\n", (double)xtilt, (double)ytilt);
// printf("ascension %f, declination %f\n", (double)tilt_ascension, (double)tilt_declination);
pressure = CLAMP(pressure, 0.0, 1.0);
if (!std::isfinite(x) || !std::isfinite(y) ||
(x > 1e10 || y > 1e10 || x < -1e10 || y < -1e10)) {
// workaround attempt for https://gna.org/bugs/?14372
g_print("Warning: ignoring brush::stroke_to with insane inputs (x = %f, y = %f)\n", (double)x, (double)y);
x = 0.0;
y = 0.0;
pressure = 0.0;
}
// the assertion below is better than out-of-memory later at save time
assert(x < 1e8 && y < 1e8 && x > -1e8 && y > -1e8);
if (dtime < 0) g_print("Time jumped backwards by dtime=%f seconds!\n", dtime);
if (dtime <= 0) dtime = 0.0001; // protect against possible division by zero bugs
if (dtime > 0.100 && pressure && states[STATE_PRESSURE] == 0) {
// Workaround for tablets that don't report motion events without pressure.
// This is to avoid linear interpolation of the pressure between two events.
stroke_to (surface, x, y, 0.0, 90.0, 0.0, dtime-0.0001);
dtime = 0.0001;
}
g_rand_set_seed (rng, states[STATE_RNG_SEED]);
{ // calculate the actual "virtual" cursor position
// noise first
if (settings[BRUSH_TRACKING_NOISE]->base_value) {
// OPTIMIZE: expf() called too often
float base_radius = expf(settings[BRUSH_RADIUS_LOGARITHMIC]->base_value);
x += rand_gauss (rng) * settings[BRUSH_TRACKING_NOISE]->base_value * base_radius;
y += rand_gauss (rng) * settings[BRUSH_TRACKING_NOISE]->base_value * base_radius;
}
float fac = 1.0 - exp_decay (settings[BRUSH_SLOW_TRACKING]->base_value, 100.0*dtime);
x = states[STATE_X] + (x - states[STATE_X]) * fac;
y = states[STATE_Y] + (y - states[STATE_Y]) * fac;
}
// draw many (or zero) dabs to the next position
// see doc/stroke2dabs.png
float dist_moved = states[STATE_DIST];
float dist_todo = count_dabs_to (x, y, pressure, dtime);
//if (dtime > 5 || dist_todo > 300) {
if (dtime > 5 || reset_requested) {
reset_requested = false;
/*
TODO:
if (dist_todo > 300) {
// this happens quite often, eg when moving the cursor back into the window
// FIXME: bad to hardcode a distance treshold here - might look at zoomed image
// better detect leaving/entering the window and reset then.
g_print ("Warning: NOT drawing %f dabs.\n", dist_todo);
g_print ("dtime=%f, dx=%f\n", dtime, x-states[STATE_X]);
//must_reset = 1;
}
*/
//printf("Brush reset.\n");
for (int i=0; i<STATE_COUNT; i++) {
states[i] = 0;
}
states[STATE_X] = x;
states[STATE_Y] = y;
states[STATE_PRESSURE] = pressure;
// not resetting, because they will get overwritten below:
//dx, dy, dpress, dtime
states[STATE_ACTUAL_X] = states[STATE_X];
states[STATE_ACTUAL_Y] = states[STATE_Y];
states[STATE_STROKE] = 1.0; // start in a state as if the stroke was long finished
return true;
}
//g_print("dist = %f\n", states[STATE_DIST]);
enum { UNKNOWN, YES, NO } painted = UNKNOWN;
double dtime_left = dtime;
float step_dx, step_dy, step_dpressure, step_dtime;
float step_declination, step_ascension;
while (dist_moved + dist_todo >= 1.0) { // there are dabs pending
{ // linear interpolation (nonlinear variant was too slow, see SVN log)
float frac; // fraction of the remaining distance to move
if (dist_moved > 0) {
// "move" the brush exactly to the first dab (moving less than one dab)
frac = (1.0 - dist_moved) / dist_todo;
dist_moved = 0;
} else {
// "move" the brush from one dab to the next
frac = 1.0 / dist_todo;
}
step_dx = frac * (x - states[STATE_X]);
step_dy = frac * (y - states[STATE_Y]);
step_dpressure = frac * (pressure - states[STATE_PRESSURE]);
step_dtime = frac * (dtime_left - 0.0);
step_declination = frac * (tilt_declination - states[STATE_DECLINATION]);
step_ascension = frac * (tilt_ascension - states[STATE_ASCENSION]);
// Though it looks different, time is interpolated exactly like x/y/pressure.
}
update_states_and_setting_values (step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
bool painted_now = prepare_and_draw_dab (surface);
if (painted_now) {
painted = YES;
} else if (painted == UNKNOWN) {
painted = NO;
}
dtime_left -= step_dtime;
dist_todo = count_dabs_to (x, y, pressure, dtime_left);
}
{
// "move" the brush to the current time (no more dab will happen)
// Important to do this at least once every event, because
// brush_count_dabs_to depends on the radius and the radius can
// depend on something that changes much faster than only every
// dab (eg speed).
step_dx = x - states[STATE_X];
step_dy = y - states[STATE_Y];
step_dpressure = pressure - states[STATE_PRESSURE];
step_declination = tilt_declination - states[STATE_DECLINATION];
step_ascension = tilt_ascension - states[STATE_ASCENSION];
step_dtime = dtime_left;
//dtime_left = 0; but that value is not used any more
update_states_and_setting_values (step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
}
// save the fraction of a dab that is already done now
states[STATE_DIST] = dist_moved + dist_todo;
//g_print("dist_final = %f\n", states[STATE_DIST]);
// next seed for the RNG (GRand has no get_state() and states[] must always contain our full state)
states[STATE_RNG_SEED] = g_rand_int(rng);
// stroke separation logic (for undo/redo)
if (painted == UNKNOWN) {
if (stroke_current_idling_time > 0 || stroke_total_painting_time == 0) {
// still idling
painted = NO;
} else {
// probably still painting (we get more events than brushdabs)
painted = YES;
//if (pressure == 0) g_print ("info: assuming 'still painting' while there is no pressure\n");
}
}
if (painted == YES) {
//if (stroke_current_idling_time > 0) g_print ("idling ==> painting\n");
stroke_total_painting_time += dtime;
stroke_current_idling_time = 0;
// force a stroke split after some time
if (stroke_total_painting_time > 4 + 3*pressure) {
// but only if pressure is not being released
// FIXME: use some smoothed state for dpressure, not the output of the interpolation code
// (which might easily wrongly give dpressure == 0)
if (step_dpressure >= 0) {
return true;
}
}
} else if (painted == NO) {
//if (stroke_current_idling_time == 0) g_print ("painting ==> idling\n");
stroke_current_idling_time += dtime;
if (stroke_total_painting_time == 0) {
// not yet painted, start a new stroke if we have accumulated a lot of irrelevant motion events
if (stroke_current_idling_time > 1.0) {
return true;
}
} else {
// Usually we have pressure==0 here. But some brushes can paint
// nothing at full pressure (eg gappy lines, or a stroke that
// fades out). In either case this is the prefered moment to split.
if (stroke_total_painting_time+stroke_current_idling_time > 0.9 + 5*pressure) {
return true;
}
}
}
return false;
}
/**
* mypaint_brush_stroke_to:
* @dtime: Time since last motion event, in seconds.
*
* Should be called once for each motion event.
*
* Returns: non-0 if the stroke is finished or empty, else 0.
*/
int mypaint_brush_stroke_to (MyPaintBrush *self, MyPaintSurface *surface,
float x, float y, float pressure,
float xtilt, float ytilt, double dtime)
{
//printf("%f %f %f %f\n", (double)dtime, (double)x, (double)y, (double)pressure);
float tilt_ascension = 0.0;
float tilt_declination = 90.0;
if (xtilt != 0 || ytilt != 0) {
// shield us from insane tilt input
xtilt = CLAMP(xtilt, -1.0, 1.0);
ytilt = CLAMP(ytilt, -1.0, 1.0);
assert(isfinite(xtilt) && isfinite(ytilt));
tilt_ascension = 180.0*atan2(-xtilt, ytilt)/M_PI;
const float rad = hypot(xtilt, ytilt);
tilt_declination = 90-(rad*60);
assert(isfinite(tilt_ascension));
assert(isfinite(tilt_declination));
}
// printf("xtilt %f, ytilt %f\n", (double)xtilt, (double)ytilt);
// printf("ascension %f, declination %f\n", (double)tilt_ascension, (double)tilt_declination);
if (pressure <= 0.0) pressure = 0.0;
if (!isfinite(x) || !isfinite(y) ||
(x > 1e10 || y > 1e10 || x < -1e10 || y < -1e10)) {
// workaround attempt for https://gna.org/bugs/?14372
printf("Warning: ignoring brush::stroke_to with insane inputs (x = %f, y = %f)\n", (double)x, (double)y);
x = 0.0;
y = 0.0;
pressure = 0.0;
}
// the assertion below is better than out-of-memory later at save time
assert(x < 1e8 && y < 1e8 && x > -1e8 && y > -1e8);
if (dtime < 0) printf("Time jumped backwards by dtime=%f seconds!\n", dtime);
if (dtime <= 0) dtime = 0.0001; // protect against possible division by zero bugs
/* way too slow with the new rng, and not working any more anyway...
rng_double_set_seed (self->rng, self->states[MYPAINT_BRUSH_STATE_RNG_SEED]*0x40000000);
*/
if (dtime > 0.100 && pressure && self->states[MYPAINT_BRUSH_STATE_PRESSURE] == 0) {
// Workaround for tablets that don't report motion events without pressure.
// This is to avoid linear interpolation of the pressure between two events.
mypaint_brush_stroke_to (self, surface, x, y, 0.0, 90.0, 0.0, dtime-0.0001);
dtime = 0.0001;
}
{ // calculate the actual "virtual" cursor position
// noise first
if (mypaint_mapping_get_base_value(self->settings[MYPAINT_BRUSH_SETTING_TRACKING_NOISE])) {
// OPTIMIZE: expf() called too often
const float base_radius = expf(mypaint_mapping_get_base_value(self->settings[MYPAINT_BRUSH_SETTING_RADIUS_LOGARITHMIC]));
x += rand_gauss (self->rng) * mypaint_mapping_get_base_value(self->settings[MYPAINT_BRUSH_SETTING_TRACKING_NOISE]) * base_radius;
y += rand_gauss (self->rng) * mypaint_mapping_get_base_value(self->settings[MYPAINT_BRUSH_SETTING_TRACKING_NOISE]) * base_radius;
}
const float fac = 1.0 - exp_decay (mypaint_mapping_get_base_value(self->settings[MYPAINT_BRUSH_SETTING_SLOW_TRACKING]), 100.0*dtime);
x = self->states[MYPAINT_BRUSH_STATE_X] + (x - self->states[MYPAINT_BRUSH_STATE_X]) * fac;
y = self->states[MYPAINT_BRUSH_STATE_Y] + (y - self->states[MYPAINT_BRUSH_STATE_Y]) * fac;
}
// draw many (or zero) dabs to the next position
// see doc/images/stroke2dabs.png
float dabs_moved = self->states[MYPAINT_BRUSH_STATE_PARTIAL_DABS];
float dabs_todo = count_dabs_to (self, x, y, pressure, dtime);
if (dtime > 5 || self->reset_requested) {
self->reset_requested = FALSE;
//printf("Brush reset.\n");
int i=0;
for (i=0; i<MYPAINT_BRUSH_STATES_COUNT; i++) {
self->states[i] = 0;
}
self->states[MYPAINT_BRUSH_STATE_X] = x;
self->states[MYPAINT_BRUSH_STATE_Y] = y;
self->states[MYPAINT_BRUSH_STATE_PRESSURE] = pressure;
// not resetting, because they will get overwritten below:
//dx, dy, dpress, dtime
self->states[MYPAINT_BRUSH_STATE_ACTUAL_X] = self->states[MYPAINT_BRUSH_STATE_X];
self->states[MYPAINT_BRUSH_STATE_ACTUAL_Y] = self->states[MYPAINT_BRUSH_STATE_Y];
self->states[MYPAINT_BRUSH_STATE_STROKE] = 1.0; // start in a state as if the stroke was long finished
return TRUE;
}
enum { UNKNOWN, YES, NO } painted = UNKNOWN;
double dtime_left = dtime;
float step_ddab, step_dx, step_dy, step_dpressure, step_dtime;
float step_declination, step_ascension;
while (dabs_moved + dabs_todo >= 1.0) { // there are dabs pending
{ // linear interpolation (nonlinear variant was too slow, see SVN log)
float frac; // fraction of the remaining distance to move
if (dabs_moved > 0) {
// "move" the brush exactly to the first dab
step_ddab = 1.0 - dabs_moved; // the step "moves" the brush by a fraction of one dab
dabs_moved = 0;
} else {
step_ddab = 1.0; // the step "moves" the brush by exactly one dab
}
frac = step_ddab / dabs_todo;
step_dx = frac * (x - self->states[MYPAINT_BRUSH_STATE_X]);
step_dy = frac * (y - self->states[MYPAINT_BRUSH_STATE_Y]);
step_dpressure = frac * (pressure - self->states[MYPAINT_BRUSH_STATE_PRESSURE]);
step_dtime = frac * (dtime_left - 0.0);
// Though it looks different, time is interpolated exactly like x/y/pressure.
step_declination = frac * (tilt_declination - self->states[MYPAINT_BRUSH_STATE_DECLINATION]);
step_ascension = frac * smallest_angular_difference(self->states[MYPAINT_BRUSH_STATE_ASCENSION], tilt_ascension);
}
update_states_and_setting_values (self, step_ddab, step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
gboolean painted_now = prepare_and_draw_dab (self, surface);
if (painted_now) {
painted = YES;
} else if (painted == UNKNOWN) {
painted = NO;
}
dtime_left -= step_dtime;
dabs_todo = count_dabs_to (self, x, y, pressure, dtime_left);
}
{
// "move" the brush to the current time (no more dab will happen)
// Important to do this at least once every event, because
// brush_count_dabs_to depends on the radius and the radius can
// depend on something that changes much faster than just every
// dab.
step_ddab = dabs_todo; // the step "moves" the brush by a fraction of one dab
step_dx = x - self->states[MYPAINT_BRUSH_STATE_X];
step_dy = y - self->states[MYPAINT_BRUSH_STATE_Y];
step_dpressure = pressure - self->states[MYPAINT_BRUSH_STATE_PRESSURE];
step_declination = tilt_declination - self->states[MYPAINT_BRUSH_STATE_DECLINATION];
step_ascension = smallest_angular_difference(self->states[MYPAINT_BRUSH_STATE_ASCENSION], tilt_ascension);
step_dtime = dtime_left;
//dtime_left = 0; but that value is not used any more
update_states_and_setting_values (self, step_ddab, step_dx, step_dy, step_dpressure, step_declination, step_ascension, step_dtime);
}
// save the fraction of a dab that is already done now
self->states[MYPAINT_BRUSH_STATE_PARTIAL_DABS] = dabs_moved + dabs_todo;
/* not working any more with the new rng...
// next seed for the RNG (GRand has no get_state() and states[] must always contain our full state)
self->states[MYPAINT_BRUSH_STATE_RNG_SEED] = rng_double_next(self->rng);
*/
// stroke separation logic (for undo/redo)
if (painted == UNKNOWN) {
if (self->stroke_current_idling_time > 0 || self->stroke_total_painting_time == 0) {
// still idling
painted = NO;
} else {
// probably still painting (we get more events than brushdabs)
painted = YES;
//if (pressure == 0) g_print ("info: assuming 'still painting' while there is no pressure\n");
}
}
if (painted == YES) {
//if (stroke_current_idling_time > 0) g_print ("idling ==> painting\n");
self->stroke_total_painting_time += dtime;
self->stroke_current_idling_time = 0;
// force a stroke split after some time
if (self->stroke_total_painting_time > 4 + 3*pressure) {
// but only if pressure is not being released
// FIXME: use some smoothed state for dpressure, not the output of the interpolation code
// (which might easily wrongly give dpressure == 0)
if (step_dpressure >= 0) {
return TRUE;
}
}
} else if (painted == NO) {
//if (stroke_current_idling_time == 0) g_print ("painting ==> idling\n");
self->stroke_current_idling_time += dtime;
if (self->stroke_total_painting_time == 0) {
// not yet painted, start a new stroke if we have accumulated a lot of irrelevant motion events
if (self->stroke_current_idling_time > 1.0) {
return TRUE;
}
} else {
// Usually we have pressure==0 here. But some brushes can paint
// nothing at full pressure (eg gappy lines, or a stroke that
// fades out). In either case this is the prefered moment to split.
if (self->stroke_total_painting_time+self->stroke_current_idling_time > 0.9 + 5*pressure) {
return TRUE;
}
}
}
return FALSE;
}
