feature/strictscale: add possibility to restrict user scale, fix issue #85

[EArminjon]

Actual behavior :
User can scale image in or out. When user release scale gesture, app will rescale if current user scale choice is behind defined limit (maxScale and minScale).

Proposition :
A new property to prevent the user to scale behind theses limit.

[EArminjon]

Ready

[EArminjon]

@renancaraujo can you take a look please :'( ?

[renancaraujo]

We have wey too many proeprties on those widgets, we will have to do a cleanup eventually

[EArminjon]

@renancaraujo do you plan to release soon this PR on pub dev :) ?

[EArminjon]

@renancaraujo seems like the auto deployment didn't push the new version on pub dev. Do you plan it soon :'( ?

[EArminjon]

@renancaraujo please :'(

[EArminjon]

@renancaraujo ?

[phamconganh]

@EArminjon strictScale makes it impossible to scale back to minScale. Example: minScale 1, but only zoomOut to 1.0043980003016804. I think clamp newScale and update if different from previous scale at line code:

    if (widget.strictScale && (newScale > widget.scaleBoundaries.maxScale ||
        newScale < widget.scaleBoundaries.minScale)) {
      return;
    }

[EArminjon]

@EArminjon strictScale makes it impossible to scale back to minScale. Example: minScale 1, but only zoomOut to 1.0043980003016804. I think clamp newScale and update if different from previous scale at line code:

    if (widget.strictScale && (newScale > widget.scaleBoundaries.maxScale ||
        newScale < widget.scaleBoundaries.minScale)) {
      return;
    }

Create an issue with reproductible steps please. Commenting merged PR is not a good practice.