[WIP] Add export density to canvas renderer

[lucasdinonolte]

• Makes canvas previews crisp on retina displays
• Allows users to choose the desired pixel density before exporting

[runemadsen]

I was just thinking about this, and I think this is the right implementation. We should make sure that the getCanvas function throws an error if it doesn't have the needed width and height, whether that comes from inputs, the getCanvas arguments, or both. A nice error message with a call for the user to add the dimensions would be very helpful.

[lucasdinonolte]

I was just thinking about this, and I think this is the right implementation. We should make sure that the getCanvas function throws an error if it doesn't have the needed width and height, whether that comes from inputs, the getCanvas arguments, or both. A nice error message with a call for the user to add the dimensions would be very helpful.

I had the same notion and added some first drafts for error messages. https://github.com/designsystemsinternational/mechanic/pull/146/files#diff-cea56d01b8f19fd6436a19f2b4bbd9d2258c6edbeef3df917df2026fcf1ed520R82 😊

[fdoflorenzano]

I think it's a bit odd from the interface that we ask for the canvas and context from this function and then are supposed to give it back through frame and done. Would it make sense to keep a reference inside the engine and then use it when frame and done get called?

[runemadsen]

I like that idea!

[lucasdinonolte]

Oh, I like it. I tried it and it's very nice. The only situation this is problematic is, when you also want to pass a name to onDone. So I changed done to accept an object as arguments. Let me know what you think.

[fdoflorenzano]

I do like it! It does made me realize there's no mention in the documentation about the name argument for done. Maybe this is an opportunity to streamline arguments for the frame and done functions and leave all of them as single argument functions on all engines. Can be done in a separate PR tho.

[runemadsen]

I'm all in for this!