allow various alignment corners & centers

[ladyada]

easy text alignment based on x, y would allow for pretty UI elements!
needs adafruit/Adafruit_CircuitPython_Bitmap_Font#5

[ladyada]

@tannewt @jerryneedell @makermelissa @djecken @jedgarpark FYI - im gonna change the way text displays right now because all text is Y offset (i eyeballed it and didnt notice till now)

ill make it so the top left corner is the origin point - perhaps it was at one point and we messed with it

[ladyada]

https://nerdparadise.com/programming/pygame/part5

[tannewt]

https://pico-8.fandom.com/wiki/Print

[ladyada]

adafruit gfx does baseline https://github.com/adafruit/Adafruit-GFX-Library/blob/master/Adafruit_GFX.cpp#L1033

[tannewt]

Cairo does baseline: https://www.cairographics.org/manual/cairo-text.html#cairo-show-text
https://www.cairographics.org/samples/text_align_center/

[tannewt]

Thinking more about this I don't think we want baseline because it handles multiline text poorly. The examples above don't handle multiline layout themselves but TextArea does.

Before we add anchor options, I think defaulting to vertical center of the left edge of the text would provide the best default behavior for both single and multiline text.

Since the overall bounding box is much larger than most glyphs, I think we should use the capital M's measurements to determine line size. Therefore, the vertical center would be (number_of_lines * height_of_M + (number_of_lines - 1) * line_spacing) / 2 + ascender_height relative to the top left. Ascender height is the difference between the max height and the height of capital M after baseline adjustments.

We cannot base the origin on the actual glyphs because that risks different alignment across aligned TextAreas.

Does that make sense?

Later we can add top left and bottom left anchors based on the M too. We'll also want to expose a bounding box or vertical padding so the user can account for ascenders and descenders.

I also think we should remove width and height in favor a flat max_glyph_count. Width and height are confusing and make no sense with variable font spacing.

[ladyada]

ok - how would you calculate size of a text area before creating it? we'd have the bounding box be a static function?

[tannewt]

Why do you need the size before creating it? The vertical alignment should be done for you.

[ladyada]

word-wrap calculation?

[ladyada]

@tannewt ok now that default is center left... i could add justifications like left (default), center and right
want it as an initializer arg?

[tannewt]

Would justification change the origin or just the layout? __init__ arg is the way to go.

[ladyada]

easiest would be changing origin: center would now be center of label (how else could you know for a single line what centering is?) and right would be center-right of label

[tannewt]

Asking for clarity. Justification and origin location don't need to be tied to one another. You could center against the widest line.

[ladyada]

ok if you have a center or right-justified label with text that changes, you'd have to move it every time you changed the text