feat: Added ability to render spritesheet-based fonts

[st-pasha]

Description

This PR adds [SpriteFontRenderer], which is a new implementation of [TextRenderer], allowing to render text based on fonts embedded into a spritesheet.

See the T-Rex game example, where the score is now rendered based on a spritesheet font.

(Also added highscore tracking for the TRex game).

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs: etc).
• I have read the Contributor Guide and followed the process outlined for submitting PRs.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples.

Breaking Change

• [-] Yes, this is a breaking change.
• No, this is not a breaking change.

Related Issues

Closes #1621

[erickzanardo]

Nice one! I have one suggestion though.

TextPaint is an immutable class IIRC, and for consistency I think we should that on this renderer too, so instead of a addGlyph method, we could have a new attribute on the constructor to receive the metadata of mapped glyphs. Other than that, this looks great!

wdyt?

[spydon]

Good job, glad to see that the T-Rex game is already getting improvements too!
I agree with Erick's suggestions too.

[st-pasha]

TextPaint is an immutable class IIRC, and for consistency I think we should that on this renderer too, so instead of a addGlyph method, we could have a new attribute on the constructor to receive the metadata of mapped glyphs. Other than that, this looks great!

wdyt?

We could make something like SpriteFontBuilder which would have the addGlyph() method, and then .build() will return an instance of SpriteFontRenderer (which would not be constructible directly).

Need to keep an eye on future ability of create new SpriteFontRenderers out of an existing SpriteFontRenderer. For example, create a different-sized variant of the same font.

[erickzanardo]

Need to keep an eye on future ability of create new SpriteFontRenderers out of an existing SpriteFontRenderer. For example, create a different-sized variant of the same font.

I don't think that making this immutable would disallow that, we can take TextStyle from flutter itself as an example, where it provides a copyWith method, that same approach would work great on this too IMO

[erickzanardo]

LGTM, can't wait to use this.