[Enhancement] DrawingView multiple line support

[VladislavAntonyuk]

Summary

Allow drawing multiple lines

API Changes

new
properties:

• Lines. It is a Collection of Lines.
• MultiLineMode. "False" -> Erase the image on Starting drawing. (Default value). "true" -> Add as many lines as you need

classes:

• Line. I should have an Observable Collection of Points.

update:
rename DrawingCompletedCommand to DrawingLineCompletedCommand

Intended Use Case

The same as for the current DrawingView.
Most likely for the cross-platform Paint application.

Further improvements (most likely out of scope of this story):

1. Each line has its own settings (LineColor, LineWidth).
2. Line can be selected.

Who Will Do The Work?

• I am willing to take this on myself
• Just putting this out there for someone to pick up

[jfversluis]

Sounds good to me! The only thing we need to think about is how this works together with ClearOnFinish.

I guess we need some property to enable “multi line mode”? Because right now if you start drawing one line and then the second it erases the first, or with ClearOnFinish enabled it erases as soon as you stop the first line.

you have a proposal for that?

[VladislavAntonyuk]

ClearOnFinish = "True" -> Erase the image on Finish drawing. It will be independent from MultiLineMode.
MultiLineMode = "False" -> Erase the image on Starting drawing. (Default value)
MultiLineMode = "true" -> Add as many lines as you need

[jfversluis]

And what happens when someone sets MultiLineMode to true and ClearOnFinish to true? 😬

When do you know when the drawing is finished in a multi line scenario? Additionally, when will we fire the DrawingCompletedCommand and those things. Should we specify some timeout? That can be set by the user as well?

We would also need to have loading points methods with the new strokes collections

[VladislavAntonyuk]

Just when you finished the line it will be cleared. It’s independent from MultiLineMode. ClearOnFinish always wins.
It is a simplest scenario. We can extend with time-out property later. I think it is now out of scope

[jfversluis]

Ah so that means the drawing completed command is fired after each line then?

[VladislavAntonyuk]

yes, But I think it's better to name it DrawingLineCompletedCommand

[jfversluis]

Could you update the initial post with some C# code of the changes you want to make? Which properties you want to add, remove, rename, etc.

[VladislavAntonyuk]

I am still thinking about the possible changes which we'll have. let's update what we have so far

[VladislavAntonyuk]

@jfversluis I created a draft PR #1475. What do you think?

[VladislavAntonyuk]

@jfversluis implemented for all platforms. Verified on Android,
I will check it on iOS. If everything is fine, I will publish the PR.