Non-linear increments

[VororRich]

Scenario - I'm wanting a knob where I can select every (whole) number between 0 and 720.

Problem - It doesn't seem to be possible to set values causing the step increments to be 1.

Reproduction - With a starting setup as follows...

[min]="0" [max]="720" [startDegree]="0" [endDegree]="360" (change)="log($event)"

I would have expected each "step" of the knob to be 2 (i.e. 720/360). However, in testing, this gives increase in output value of 6. Assuming this to be graphical precision due to the size of the knob, I expected that Increasing the [endDegree] to "720" (i.e. 2 full rotations), each "step" of the knob would now be 3. However, the step is still 6, the knob instead just moves twice as far (i.e. 2 degrees). This can be more clearly seen by setting [endDegree] to "3600" (i.e. 10 full rotations). The step is still 6 but the knob rotation occurs in very large jumps.

I'll have a work through the maths and submit a pull request if I figure anything out.

[VororRich]

I think it comes down to the constructor and the calculation of maxDistance. I can kinda see why the code is there (though I'm not sure why this.maxDistance = Math.round((this.maxDistance * 10) / 100); isnt just this.maxDistance = Math.round(this.maxDistance / 10);?).

Perhaps one approach would be to have pixel based rotation (boolean @input flag)? So 1 pixel of mouse movement is +/- 1 meterValue? That would allow the user precise knob values whereas at the moment, the precision is determined by screen width.

[spheras]

Hello.
First: Of course Math.round((this.maxDistance * 10) / 100) == Math.round(this.maxDistance / 10)
😆
It was just an initial calculation, and it is still there.

Second: this is done mainly for "small" screens. ie, I use it in an ionic app for mobile devices, but not only, It seems reasonable to calculate a (more or less) physical distance and put in relation with the total degrees you can move. This way, the calculated distance (maxDistance=10% of your screen) is the correlation for the maximum degrees you can move. If you put 1 pixel for 1 degree correlation, then you will need to move 1 pixel for each degree, and it depends on the screen if this is a reasonable distance or not. ie, if you configure a knob with 10 degrees, you only move 10 pixels?? Think in a touch movement, is much more difficult, you need a good distance to be precise.. in fact, now this distance is small (I think it should be a 20% or 30%), but too much distance could be hard for mouse users... it depends.

Third: What we can do is to put the % of the distance in a configuration variable (now is 10, but you can put 50%, 100%, whatever).. or even, just put the distance in pixels in a variable (you know, in case this variable is filled, then don't calculate the % of the screen, and just put the number of pixels you want to move for the knob).