How the selection nobs should work

[Alecaddd]

Introduction

Detailed analysis of how the Selection nobs and effect should behave when the user interacts with one or multiple shapes.
This is a detailed overview that will guide development to reach completeness of this feature.
Once this feature is complete, this discussion can be converted into static documentation in the Wiki section.

Definitions

• Selection nobs: The 8 small rectangles that appear around the edges of an item (or multiple items) when selected.

• Rotation nob: The small circle that appears above the item (or multiple items) when selected, connected to the selection effect by a 1px grey line.

• Selection effect: The thin grey bordered rectangle representing the boundaries of an item (or multiple items) when selected.

Default nobs visibility

On a single selected item
The selection effect, the 8 selection nobs, and the rotation nob appear to represent the bounding box of the selected item.

On multiple selected items
The selection effect, the 8 selection nobs, and the rotation nob appear to represent the combined bounding box of all selected items.

Nobs visibility when resizing/rotating

When the user interacts with one of the nob, all other selection nobs and the selection effect should disappear in order to guarantee correct visibility of the edges of the selected item.
Only currently clicked nob should remain visible, to properly represent the interaction point from which the user is modifying the selected item.

By adopting this solution we can avoid hiding the center nobs or shifting position of the corner nobs when the item is resized below a certain threshold.

Nobs visibility when translating

All selection nobs and the selection effect should disappear in order to guarantee correct visibility of the edges of the selected item.
All the elements listed above should reappear with the click release event is triggered.

Nobs visibility when items' properties are changed

When a property of a selected item is modified by an action not triggered by a direct interaction with the Canvas (eg. fill color, opacity, position via the transform panel, etc.), all selection nobs and the selection effect should disappear in order to guarantee correct visibility of the modified property.
For example if the user is changing the fill or border color, hiding the selection nobs and the selection effect will drastically improve the decision making process by removing items that visually interfere with the item's final (and real) look.

All items listed above should reappear after ~2 seconds delay from the end of the interaction with the items' property.