FadeTo method
JuMiLo opened this issue · 15 comments
Hi and thanks for your awesome library! The only feature im missing is something like a FadeTo(duration) method, which works like FadeOn/FadeOff, but without switching the LED on or off.
JLed(pin).FadeTo(duration).MaxBrightness(155) should fade the LED from any level to level 155.
Being an Arduino/C++ beginner, i don't know if this would be possible with a user class but maybe the method would be usefull for others too :)
The current output level of an LED is determined by evaluation the associated brightness evaluator, which is basically a function of time and period that returns a brightness level between 0 and 255. JLed does not "store" the currently output brightness value, it is evaluated when needed. So I think there is currently no easy way for a "new" effect to take over the "current" brightness level into account.
Generally, a user defined brightness evaluator (for an example look here https://github.com/jandelgado/jled/blob/master/examples/user_func/user_func.ino) could be used to have a general Fade(fromLevel, toLevel, period) where both start and end brightness level are specified.
how to make a Fade(fromLevel, toLevel, period) function ?
That's left as an excercise to the reader ;) - I'll try to provide an example in the next days...
Look at #72 for another example for a user defined brightness function.
Amazing library, thanks @jandelgado for the work you put into this! I agree that the addition of a basic FadeTo would really be of great value here. An example how to do this with a user defined brightness function would certainly help a lot, however I still think that a generic fade from current value X to target value Y capability would be a good addition to the library.
The following should work for a user defined "fade from value x to value y":
#include <jled.h>
#include <math.h>
class FadeFromTo : public jled::BrightnessEvaluator {
const uint8_t from_;
const uint8_t to_;
const uint16_t period_;
public:
explicit FadeFromTo(uint8_t from = 0, uint8_t to = 255, uint16_t period = 1000)
: from_(from), to_(to), period_(period) {}
uint8_t Eval(uint32_t t) const override {
const uint8_t pos_ = jled::fadeon_func(t, period_);
const uint8_t pos = map(pos_, 0, 255, from_, to_);
return pos;
}
uint16_t Period() const override { return period_; }
};
However, when trying to call it:
int pin = 12;
FadeFromTo userfade(50, 200, 1000);
JLed(pin).UserFunc(&userfade);
I run into an exception. Did I miss anything?
Hi, could you pleas post the complete sketch? On which micro controller are you testing?
This issue is stale because it has been open 90 days with no activity. Remove stale label or comment or this will be closed in 5 days
Any news about this feature? It would be super useful to make a smooth fade affect within a specified amount of time, starting at the current brightness level.
I've put the request ob top of the backlog and will start working on it
I think the best solution, which also would work with other effects, would be to introduce a MinBrightness method and scale all effects to [minBrightness, maxBrightness]. That would also allow to fade from on value to another, e.g.
auto led = JLed(2).MinBrightness(100).MaxBrightness(200).FadeOn(1000);
would fade from 100 to 200. Would that help? @maxmlr @Mark-81 @JuMiLo @simonchen007 @leistungszentrum
From my point of view, it's still limited in the way you proposed. No need to specify a MinBrightness neither to use brightness only. In my opinion, any effect should specify the desired target configuration (i.e. color, brightness, etc...) to be reached in a specified amount of time.
The code should just calculate the steps not from 0 but from the current state, even if the previous fade is still running.
Just to make sure we are thinking in the same directions: in the case of the FadeOn effect for example, when starting the fade with some value (which is currently always 0 like in (A)), we want to see a "scaled" version of the effect, like in (B) in this example:
Exactly!
@Mark-81 @JuMiLo: i have add a Fade(from, to, duration) method. Please check out commit a8c40a310b1eac325243d92103cbd0b656455ba0 to test it - thanks
Released with 4.12.0 https://github.com/jandelgado/jled/releases/tag/v4.12.0