hachem.wtf
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-rw-r--r--kernel/ttf.rv286
1 files changed, 286 insertions, 0 deletions
diff --git a/kernel/ttf.rv b/kernel/ttf.rv
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+++ b/kernel/ttf.rv
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+# so many fucking hours wasted man i hate fonts so much
+# fuck bezier
+# fuck revo
+# fuck revel
+# fuck ttf
+# fuck lung
+# fuck me
+# im like 90% confident this works, but im like 10% confident its fucked
+fn ttf_mod(a, b) a - math.floor(a / b) * b
+
+fn ttf_u8(d, o) mem_read(d + o, 1)
+fn ttf_u16(d, o) mem_read(d + o, 1) * 256 + mem_read(d + o + 1, 1)
+fn ttf_i16(d, o) do
+ const v = ttf_u16(d, o)
+ if v >= 32768 return v - 65536
+ return v
+end
+fn ttf_u32(d, o) ((mem_read(d + o, 1) * 256 + mem_read(d + o + 1, 1)) * 256 + mem_read(d + o + 2, 1)) * 256 + mem_read(d + o + 3, 1)
+
+fn ttf_tag_eq(d, o, tag) do
+ for i in 0..4 do if mem_read(d + o + i, 1) != tag[i]:ascii() return :false end
+ return :true
+end
+
+fn ttf_table(d, tag) do
+ const n = ttf_u16(d, 4)
+ for i in 0..n do
+ const rec = 12 + i * 16
+ if ttf_tag_eq(d, rec, tag) return ttf_u32(d, rec + 8)
+ end
+ return -1
+end
+
+fn ttf_cmap_sub(d, cmap_off) do
+ const n = ttf_u16(d, cmap_off + 2)
+ let best = -1
+ for i in 0..n do
+ const rec = cmap_off + 4 + i * 8
+ const plat = ttf_u16(d, rec)
+ const enc = ttf_u16(d, rec + 2)
+ if (plat == 3 and (enc == 1 or enc == 0)) or plat == 0 do best = cmap_off + ttf_u32(d, rec + 4) end
+ end
+ return best
+end
+
+fn ttf_glyph_of(d, sub, c) do
+ if ttf_u16(d, sub) != 4 return 0
+ const segCount = ttf_u16(d, sub + 6) / 2
+ const endBase = sub + 14
+ const startBase = endBase + segCount * 2 + 2
+ const deltaBase = startBase + segCount * 2
+ const rangeBase = deltaBase + segCount * 2
+ for i in 0..segCount do
+ if c <= ttf_u16(d, endBase + i * 2) do
+ const startC = ttf_u16(d, startBase + i * 2)
+ if c < startC return 0
+ const idro = ttf_u16(d, rangeBase + i * 2)
+ if idro == 0 return (c + ttf_i16(d, deltaBase + i * 2)) band 0xFFFF
+ const g = ttf_u16(d, rangeBase + i * 2 + idro + (c - startC) * 2)
+ if g == 0 return 0
+ return (g + ttf_i16(d, deltaBase + i * 2)) band 0xFFFF
+ end
+ end
+ return 0
+end
+
+fn ttf_glyph_offset(d, loca, long, g) do
+ if long return ttf_u32(d, loca + g * 4)
+ return ttf_u16(d, loca + g * 2) * 2
+end
+
+fn ttf_advance(d, hmtx, numH, g) do
+ if g < numH return ttf_u16(d, hmtx + g * 4)
+ return ttf_u16(d, hmtx + (numH - 1) * 4)
+end
+
+fn ttf_add_line(edges, x0, y0, x1, y1) edges:push({ ax = x0, ay = y0, bx = x1, by = y1 })
+
+fn ttf_add_quad(edges, x0, y0, cx, cy, x1, y1, n) do
+ let px = x0
+ let py = y0
+ for i in 1..(n + 1) do
+ const t = i / n
+ const mt = 1 - t
+ const qx = mt * mt * x0 + 2 * mt * t * cx + t * t * x1
+ const qy = mt * mt * y0 + 2 * mt * t * cy + t * t * y1
+ ttf_add_line(edges, px, py, qx, qy)
+ px = qx
+ py = qy
+ end
+end
+
+fn ttf_contour(pts, edges, nsub) do
+ const m = pts:len()
+ if m < 2 return :nil
+ let exp = {}
+ for i in 0..m do
+ exp:push(pts[i])
+ const j = ttf_mod(i + 1, m)
+ if (pts[i].on == :false and pts[j].on == :false) do
+ exp:push({ x = (pts[i].x + pts[j].x) / 2, y = (pts[i].y + pts[j].y) / 2, on = :true })
+ end
+ end
+ const n = exp:len()
+ let s = -1
+ for i in 0..n do if (s < 0 and exp[i].on) do s = i end end
+ if s < 0 return :nil
+ let cx = exp[s].x
+ let cy = exp[s].y
+ let k = 1
+ while k <= n do
+ const a = exp[ttf_mod(s + k, n)]
+ if a.on do
+ ttf_add_line(edges, cx, cy, a.x, a.y)
+ cx = a.x
+ cy = a.y
+ k += 1
+ end
+ else do
+ const b = exp[ttf_mod(s + k + 1, n)]
+ ttf_add_quad(edges, cx, cy, a.x, a.y, b.x, b.y, nsub)
+ cx = b.x
+ cy = b.y
+ k += 2
+ end
+ end
+end
+
+# how about you contour my fucking asshole
+fn ttf_glyph_edges(d, glyf, loca, long, g, scale, ox, baseline, edges, nsub) do
+ const off = ttf_glyph_offset(d, loca, long, g)
+ const next = ttf_glyph_offset(d, loca, long, g + 1)
+ if next <= off return :nil # empty glyph
+ const base = glyf + off
+ const nc = ttf_i16(d, base)
+ if nc < 0 return :nil # skip
+ let ends = {}
+ for i in 0..nc do ends:push(ttf_u16(d, base + 10 + i * 2)) end
+ const npts = ends[nc - 1] + 1
+ let p = base + 10 + nc * 2
+ p += 2 + ttf_u16(d, p) # skip instructions
+ let flags = {}
+ while flags:len() < npts do
+ const f = ttf_u8(d, p)
+ p += 1
+ flags:push(f)
+ if (f band 0x08) != 0 do
+ let rep = ttf_u8(d, p)
+ p += 1
+ while rep > 0 do flags:push(f) rep -= 1 end
+ end
+ end
+ let xs = {}
+ let x = 0
+ for i in 0..npts do
+ const f = flags[i]
+ if (f band 0x02) != 0 do
+ const dx = ttf_u8(d, p)
+ p += 1
+ if (f band 0x10) != 0 do x += dx end else do x -= dx end
+ end
+ else do
+ if (f band 0x10) == 0 do x += ttf_i16(d, p) p += 2 end
+ end
+ xs:push(x)
+ end
+ let ys = {}
+ let y = 0
+ for i in 0..npts do
+ const f = flags[i]
+ if (f band 0x04) != 0 do
+ const dy = ttf_u8(d, p)
+ p += 1
+ if (f band 0x20) != 0 do y += dy end else do y -= dy end
+ end
+ else do
+ if (f band 0x20) == 0 do y += ttf_i16(d, p) p += 2 end
+ end
+ ys:push(y)
+ end
+ # split into contours
+ let start = 0
+ for ci in 0..nc do
+ const stop = ends[ci]
+ let pts = {}
+ for i in start..(stop + 1) do
+ pts:push({ x = xs[i] * scale + ox, y = baseline - ys[i] * scale, on = (flags[i] band 0x01) != 0 })
+ end
+ ttf_contour(pts, edges, nsub)
+ start = stop + 1
+ end
+end
+
+fn ttf_fill(edges, w, h) do
+ let rows = {}
+ for py in 0..h do
+ const yc = py + 0.5
+ let cross = {}
+ for e in 0..edges:len() do
+ const ed = edges[e]
+ const y0 = ed.ay
+ const y1 = ed.by
+ if ((y0 <= yc and yc < y1) or (y1 <= yc and yc < y0)) do
+ const t = (yc - y0) / (y1 - y0)
+ let dir = 1
+ if y1 < y0 do dir = -1 end
+ cross:push({ x = ed.ax + t * (ed.bx - ed.ax), dir = dir })
+ end
+ end
+ # sort crossings left to right
+ # insertion sort
+ for a in 1..cross:len() do
+ const key = cross[a]
+ let b = a - 1
+ while (b >= 0 and cross[b].x > key.x) do
+ cross[b + 1] = cross[b]
+ b -= 1
+ end
+ cross[b + 1] = key
+ end
+ let bits = 0
+ let wind = 0
+ for k in 0..cross:len() do
+ wind += cross[k].dir
+ if (wind != 0 and k + 1 < cross:len()) do
+ const xa = cross[k].x
+ const xb = cross[k + 1].x
+ if xb > xa do
+ let any = :false
+ for px in 0..w do
+ if (px + 0.5 >= xa and px + 0.5 < xb) do bits = bits bor (1 shl px) any = :true end
+ end
+ if any == :false do
+ const mid = math.floor((xa + xb) / 2)
+ if (mid >= 0 and mid < w) do bits = bits bor (1 shl mid) end
+ end
+ end
+ end
+ end
+ rows:push(bits)
+ end
+ return rows
+end
+
+global ttf_io = { buf = 0, pages = 512 }
+
+global load_ttf = fn(path, size) do
+ const total = fs:size(path)
+ if total < 12 return :nil
+ if ttf_io.buf == 0 do ttf_io.buf = alloc_contig(ttf_io.pages) end
+ if ttf_io.buf == 0 return :nil
+ if total > ttf_io.pages * 4096 return :nil
+ fs:read_into(path, ttf_io.buf)
+ const d = ttf_io.buf
+ const head = ttf_table(d, "head")
+ const maxp = ttf_table(d, "maxp")
+ const cmap = ttf_table(d, "cmap")
+ const loca = ttf_table(d, "loca")
+ const glyf = ttf_table(d, "glyf")
+ const hhea = ttf_table(d, "hhea")
+ const hmtx = ttf_table(d, "hmtx")
+ if (head < 0 or cmap < 0 or loca < 0 or glyf < 0 or hhea < 0) return :nil
+ const upm = ttf_u16(d, head + 18)
+ if upm == 0 return :nil
+ const long = ttf_i16(d, head + 50) == 1
+ const ascent = ttf_i16(d, hhea + 4)
+ const descent = ttf_i16(d, hhea + 6)
+ const numH = ttf_u16(d, hhea + 34)
+ const scale = size / upm
+ const baseline = math.floor(ascent * scale)
+ let height = math.floor((ascent - descent) * scale) + 1
+ const sub = ttf_cmap_sub(d, cmap)
+ if sub < 0 return :nil
+ const mgate = ttf_glyph_of(d, sub, 77) # 'M'
+ let width = math.floor(ttf_advance(d, hmtx, numH, mgate) * scale) + 1
+ if width < 2 do width = math.floor(size * 0.6) + 1 end
+ const nsub = 5
+ let glyphs = {}
+ for code in 32..128 do
+ const g = ttf_glyph_of(d, sub, code)
+ let edges = {}
+ ttf_glyph_edges(d, glyf, loca, long, g, scale, 1, baseline, edges, nsub)
+ glyphs:push(ttf_fill(edges, width, height))
+ end
+ return { glyphs = glyphs, width = width, height = height }
+end
<im@hachem.wtf>