coil 4.1 — a font made of bubbles, and a speed for every reader. • Bubbles, a new font: every letter is a soap bubble. The line drifts along as you read, and when you pause you can tap a word to pop it. Choose it under The word, on any background. • Reading speed now goes all the way down to one word a minute, for readers just starting out. The slider is easier to set at the slow end too. • Hear the words you're learning. Tap one in your list to hear it said aloud, or turn on "Say them aloud" and each one is spoken as it comes past while you read. • Zellige, a new place: a glazed tile mosaic that breathes and turns slowly, like a kaleidoscope. • Rainy Glass has real drops now. They gather, run down the glass and dry, with the street's lights caught inside them. • The glass word now appears on iPhone and iPad, and many smaller fixes.

New in 4.0: the sky takes its weather from the page. Frost in a cold chapter, rain in a wet one, the sea at sea. Plus Storm, Bubbles and Under the Lens.

See the shape of the book you're reading — its whole arc end to end, where you are on it, and where each feeling runs strongest. In the paused settings, under Controls. The atmosphere is right from the first page now, rather than spending a book's opening working out what that book's normal is. Translation works again on Android, and tells you why when it can't. It now sits with the language settings instead of hidden behind a disclosure. Gentler on your battery. Three choices in it worth knowing, in case you want to edit: - Leads with the book's shape because it's the only genuinely new surface, and the one thing in this release someone might screenshot. - The atmosphere line describes what's experienced, not the mechanism. "Reads the whole book up front to compute exact percentiles" is the truth but not the point; "right from the first page" is what a reader notices. - Translation is named plainly rather than buried. It's the one item an existing user may have tried and found dead, so saying it works again is worth more than the wording being graceful.

Here's the text with all dashes (em dashes, en dashes, and hyphens) removed: # coil 3.0.1 release notes **versionName** `3.0.1` · **versionCode** `25` · applicationId `[com.coilreader.app](http://com.coilreader.app/)` A single fix patch on top of 3.0. No new features, no settings changes, no migrations. ## What a reader sees The prismatic colour cast under the word being read used to break into **hard bands of colour standing beside narrow letters**, most obviously on short words such as "it", where every letter is a thin vertical stem. It now reads as a fine rim on the letters, which is what it does on every other word. ## What it actually was The caustic's chromatic dispersion offsets a red, a green and a blue copy of the letter and then subtracts the neutral overlap they share (`core = min(aR, aG, aB)`), leaving two prismatic rims. That only works while the three copies OVERLAP. The split had been set to 13 atlas texels, which on the 256 px/em atlas is a red to blue separation of **0.1016 em**, against a measured Playfair SemiBold stem of **0.0977 em** (i/t/l/m) to **0.1016 em** (o/e). A ratio of **0.96 to 1.00 for essentially every letter in the face**. On a narrow vertical stem the three copies therefore landed side by side with no overlap at all, so there was no neutral core to subtract and all three channels survived at full strength as separate saturated bars. Three conditions had to coincide for it to be obvious, which is why it survived into 3.0: a short word sits entirely inside the caustic's falloff so every letter runs at near full strength; `i` and `t` are isolated narrow stems with dark space around them; and the split runs along the sky light's own direction, which on a low sky is near horizontal, perpendicular to those stems. A higher sun hides it by splitting along the stroke instead of across it. The split is fixed in em, so this was never a large text only problem: it was one stem wide at every font size. **Fix:** `DISP_SPLIT_TEXELS` 13 → 4, putting red to blue at 0.031 em, about a third of a stem. `DISP_SPLIT_TEXELS_JS` mirrors it. ## Test coverage added `checkCausticDispersion` in the GlassQA harness asserted only that blue sits at least 1px OUTSIDE red, no upper bound, so it rewarded the very quantity causing the artifact and passed at 7.77px. It now also carries `DISP_MAX_SHIP_GAP_PX` (5.0), calibrated from the two measured ends on the fixed pangram stage: split 13 reads 7.77px, split 4 reads 3.60px. Verified in both directions, it passes at 4 and fails at 13 with the mechanism named in the failure message. ## Known, unchanged from 3.0 * A faint coloured mottling on the focus word's glass letters. Present in 3.0, undiagnosed. Three candidates were tested and ruled out this cycle: Cycles bake sample count, ambient occlusion, and the sky reflection's UV offset. * The two iridescence checks in GlassQA fail, and have since before 3.0. * `U+0077` ('w') carries a stray hairline extrusion spike in the bake; the packer clips it against the TTF outline. ## Word counts Unchanged from 3.0. No change to `textProcessor`, the parsers, or the bundled books.

Language & pacing - Right-to-left support for Arabic and Farsi with dedicated fonts, live translation, multilingual sentiment analysis, and CJK/Thai word segmentation - The reader now recognizes what kind of text it is — scripture, verse, or prose — and paces each differently - Better pacing for Spanish, French, and German Sky & mood - Six moods now color the atmosphere — fury, dread, romance, the eerie, awe, and mystery — blending when a passage carries more than one - Choose your own color for every mood, in Settings - Sky Ripple: a wave through the atmosphere at tense moments - Aura now follows time of day — a deep blue sky by day, mood color at the horizon; nights unchanged - New Eclipse mode: hide the sky, let the words become the atmosphere - Fixed the Moonlight theme being stuck on a permanent new moon — now shows the real current phase, with a rare ice-halo on true full-moon nights Word rendering - Words cast a real shadow that falls away from the brightest part of the sky, and bend the sky around themselves - Optional Glass Word rendering (Word Style): near-black glass letters that pick up color and light from the live sky — off by default - The app's own identity typeface is now selectable as a reading font Reading experience - Reading Lists: keep more than one, add books without leaving the reader, see time remaining in each - Progress bar now marks chapter breaks and bookmarks - A reading session now has a proper ending — see the sentence you stopped on, time spent, and share it as a card Settings rebuilt throughout