You can "identify" value objects by their values! However, they are immutable. Two identical value objects are the same value. If you want another value you just create it — you don't have to tell anyone. In and of themselves, values are not captured authoritatively; they don't represent system state.
We generally don't catalog mere values on their own in a database (table), because such a value's key/identity would be all its attributes. (And also because what would you put in the table: all possible values?) Using such a value from another table would just repeat the whole thing in the foreign key.
An entity, on the other hand is a (generally mutable) association of a stable identity and other values (and/or other entities, e.g. their identity values).
Values don't mean anything on their own, whereas entities make assertions or statements of fact on the record, that there is this thing that currently is recorded to have these particular attributes. Such statements are collected and captured and compose into system state.
Taking a point as an example, let's expand it to include a color. Now we can look at one such colored point as a mere value in the space of all possible colored points — treated as such that makes a colored point a value.
Or, we can look at a colored point as a point identity associated with a particular color — as a matter of record — as a matter of captured system state — that is captured by a designated authority.
An authority like a particular table in a particular database, or an in-memory collection or other data structure meant for this capture, such as a canvas.
The difference is whether we are authoritatively capturing such colored point as a statement of record, which means that if I say this point 1,2 has this color, blue, then any other color for that particular point should be considered untrue -or- would require a change in state of the system of record.
Treated this way, the colored point is an entity — because we are capturing the current value of the entity. Given an authority, we can ask: what is the current color of 1,2? We can't do that with mere values alone — there is no authority to ask!
Further, another color for that same point cannot simultaneously coexist, so assigning another color to that entity requires a formal (transactional) update to the formally captured, authoritative system state.
In short, a colored point is just a value unless it is in the context of an authority that captures the current color of point entities.
Is a point drawn on a canvas considered an entity in domain driven design?
Yes, if you consider the canvas as an authority and system of record that, from the DDD perspective, communicates with the world outside the bounded context regarding the points' identities, as their own aggregate root in a common canvas, or as multiple canvases attached to other aggregate roots.
Each point is conceptually an entity on the canvas — but that doesn't necessarily mean that each point needs to be manifest as its own object instance: there are lots of possible (better) implementations.