Various fixes

[t-bltg]

• add optional flags to draw glyph bounding boxes and background bboxes in renderstring! (debug), not perfect yet (some unit offsets can be observed on specific glyphs), but quite ok on average
• fix incorrect bearing computation: https://github.com/JuliaGraphics/FreeTypeAbstraction.jl/blob/53b4655d51e2bd62f651ede9368abe561fa81db2/src/types.jl#L106
• add optional gstr to fill background for distinct characters (needed for UnicodePlots, for e.g. a row of blocks █)
• add optional incx to offset x advance (needed for UnicodePlots in heatmap, histogram)
• :arrow_up: coverage 76% -> 91%
• code style inconsistencies fixes

Needed for https://github.com/JuliaPlots/UnicodePlots.jl/pull/242.

Visual inspection of bounding boxes on individual characters is tested with the following code:

using FreeTypeAbstraction
using ColorTypes
using FileIO

const black = RGBA(0., 0., 0., 1.)
const white = RGBA(1., 1., 1., 1.)
const red = RGBA(1., 0., 0., 1.)
const green = RGBA(0., 1., 0., 1.)
const blue = RGBA(0., 0., 1., 1.)
const cyan = RGBA(0., 1., 1., 1.)
const yellow = RGBA(1., 1., 0., 1.)
const magenta = RGBA(1., 0., 1., 1.)

main() = begin
  face = findfont("JuliaMono")

  for pixelsize in (16, 32, 64, 128)
    for char in vcat(collect('a':'z'), collect('A':'Z'), collect('0':'9'))
      img = fill(RGBA(RGB(black), 0.), pixelsize, pixelsize)
      renderstring!(
        img, [char], face, pixelsize, pixelsize ÷ 2, pixelsize ÷ 2;
        fcolor=red,
        bcolor=nothing,
        gcolor=RGBA(RGB(green), .5),
        bbox_glyph=RGBA(RGB(blue), .5),
        bbox=RGBA(RGB(black), .5),
        valign=:vcenter,
        halign=:hcenter,
      )
      save("char-$pixelsize-$char.png", img)
    end
  end
end

main()

Updated UnicodePlots plots with this PR are show here: https://github.com/JuliaPlots/UnicodePlots.jl/pull/243/files.

Here is an example using bounding boxes and braille or block characters + background filling (height correctly adjusted per row):

using FreeTypeAbstraction
using ColorTypes
using FileIO

const black = RGBA(0., 0., 0., 1.)
const white = RGBA(1., 1., 1., 1.)
const red = RGBA(1., 0., 0., 1.)
const green = RGBA(0., 1., 0., 1.)
const blue = RGBA(0., 0., 1., 1.)
const cyan = RGBA(0., 1., 1., 1.)
const yellow = RGBA(1., 1., 0., 1.)
const magenta = RGBA(1., 0., 1., 1.)

main() = begin
  pixelsize = 64

  kr = 4 / 3  # aspect ratio
  kc = kr / 2

  paragraph = " █▞▀▄▘▝\nAbcdeF \n⡇⢷⠅ ⣿⠠⡏\nGhiJ kL"
  lines = string.(split(paragraph, '\n'))

  nr = length(lines)
  nc = maximum(length.(lines))
  font = "DejaVu Sans"

  img = fill(RGBA(RGB(black), 0.), ceil(Int, (nr + 2) * kr * pixelsize), ceil(Int, (nc + 2) * kc * pixelsize))
  face = findfont(font)

  y0 = round(Int, 2 * kr * pixelsize)
  x0 = pixelsize ÷ 4
  for (r, line) in enumerate(lines)
    y = round(Int, y0 + (kr * pixelsize) * (r - 1))
    renderstring!(
      img, line, face, pixelsize, y, x0;
      fcolor=red,
      bcolor=nothing,
      gcolor=RGBA(RGB(green), .5),
      bbox_glyph=RGBA(RGB(blue), .5),
      bbox=RGBA(RGB(black), .5),
    )
  end
  save("multiple.png", img)
end

main()

[codecov[bot]]

Codecov Report

Merging #71 (4e381e7) into master (cdcddd0) will increase coverage by 15.35%. The diff coverage is 96.03%.

@@             Coverage Diff             @@
##           master      #71       +/-   ##
===========================================
+ Coverage   75.90%   91.26%   +15.35%     
===========================================
  Files           6        6               
  Lines         303      332       +29     
===========================================
+ Hits          230      303       +73     
+ Misses         73       29       -44     

Impacted Files	Coverage Δ
src/types.jl	83.83% <80.00%> (+15.87%)	:arrow_up:
src/findfonts.jl	93.65% <88.88%> (+3.02%)	:arrow_up:
src/layout.jl	97.67% <100.00%> (+45.40%)	:arrow_up:
src/rendering.jl	97.32% <100.00%> (+3.81%)	:arrow_up:
src/FreeTypeAbstraction.jl	100.00% <0.00%> (+30.00%)	:arrow_up:

---

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[t-bltg]

@SimonDanisch, if you have 5min to review, it'd be appreciated ...

[t-bltg]

So, I'm failing to understand all the subtleties of the previous bearing computations and why this was chosen, but the examples given in https://github.com/JuliaGraphics/FreeTypeAbstraction.jl/pull/71#issue-1181220071 now work without changing the bearing definition :shrug:, and I'm fine with that.

Code style have been (hopefully) reverted, minus fixing the code style inconsistencies.

[SimonDanisch]

Alright thanks a lot, this works with Makie! :)

[t-bltg]

Thank you very much for your time, saving correct pngs is a nice improvement for UnicodePlots ;)