add draw_align for graphics::Text

[Chen1Plus]

resolve #343

[17cupsofcoffee]

Thanks for picking this up!

I've tested this locally and it seems to work - my only concern is that this approach (aligning as part of drawing, rather than as part of layout) gives you some surprising behaviour with multi-line text:

The Text as a whole is centered, but each line is still left-aligned.

If possible, I think it would be better to do the centering as part of the layout (which lives in src/graphics/text/cache.rs). The way I've seen this done in other libraries is:

• At the start of laying out the text, calculate the width of the first line up-front.
  • The existing measure_word function will most of this for you, I think - you'd just need to also include spaces in the total.
• If the text is centered, set cursor.x to -line_width / 2.0; if the text is right-aligned, set cursor.x to -line_width.
• The rest of the existing layout logic should then place the characters in the right place.
• Repeat the line width calculation and offsetting of the cursor every time a new line starts.

This should make multi-line text work as you'd expect, and it also has the nice side effect of making it so Text::get_bounds gives you bounds that take into account alignment.

The only slightly annoying thing about this approach is that you can't re-use the same Text for multiple alignments (at least not without repeatng the layout, like we do when you change the content/font).

Let me know what you think - maybe I'm overthinking this 😄

[Chen1Plus]

I agree with you. It would be a better solution. However, I've been a bit busy lately, so I might need some more time to open next PR for this.

[17cupsofcoffee]

I agree with you. It would be a better solution. However, I've been a bit busy lately, so I might need some more time to open next PR for this.

That's no problem, appreciate the work you've done up to this point!