ReShiki 0.15.0

ReShiki 0.15.0 adds enhanced stereo groups (abs, AND, OR), arrows with nodes in the middle, and pictures that reopen in ReShiki as editable drawings. SVG files and clipboard SVG draw their text as outlines, and a bundled Arial-compatible font keeps labels in place on computers without Arial. The chemistry follows RDKit 2026.09, names come from nazuchem 0.2.0, and many SMILES, CXSMILES, MOL and RXN inputs that earlier versions refused now import with a warning that says what changed. Installed applications still work on your computer without Python, RDKit or uv.

Release downloads · Previous release · Release validation.

File compatibility

ReShiki saves each drawing at the lowest document version that can hold it: the version of the newest feature in the table that the drawing uses, or 30 if it uses none of them. Most drawings saved in 0.15.0 therefore still use version 30 and open in ReShiki 0.13.1 and 0.14.0. The newest version is 37.

Version	Feature in the drawing	Opens in
31	A reaction label with a custom gap to its arrow	0.14.0
32	ORTEP thermal ellipsoids or molecule-only display on a crystal model	0.14.0
33	A 3D model generated from a structure in 0.14.0 or later, 3D atom labels, or a plain XYZ model	0.14.0
34	An amino-acid residue collapsed with two attachment points, such as -Ala- between Boc and OMe	0.14.0
35	An arrow with nodes in the middle, or a drawing style with a Crossing clearance other than 1.1 pt	0.15.0
36	A stereocentre in an AND or OR stereo group	0.15.0
37	An atom with three or four unpaired electrons, such as [C] or [CH] from SMILES	0.15.0

ReShiki 0.14.0 and earlier say that a version 35–37 drawing was made with a newer version and ask you to update. Older drawings still open in 0.15.0.

A .reshiki-style file has no document version. One with a Crossing clearance other than 1.1 pt cannot be loaded by ReShiki 0.14.0 or earlier, which report an unknown field crossing_clearance_pt. A moved polymer repeat label does not raise the version; it opens in 0.14.0 at its automatic position.

If you share files with someone on an older version, keep a copy saved by that version.

Highlights

• Enhanced stereo groups. Mark stereocentres as absolute (abs), racemic (and1) or relative (or1) in the Stereo groups inspector. MOL V3000, RXN V3000, CXSMILES, CDXML/CDX and the ChemDraw clipboard keep the groups.
• Arrows with nodes. Mechanism arrows can follow an S-shaped path with editable nodes, like a pen path, and stay attached at both ends.
• Pictures that reopen as drawings. PNG, SVG and single-figure PDF pictures from ReShiki carry the drawing inside them. Paste, drop or open one in ReShiki to get the editable drawing back.
• SVG text as outlines. SVG export, clipboard SVG, the agent tools, reshiki --cli and the Python package draw text as outlines, so labels look the same in every viewer. Keep text editable writes live text.
• Labels without Arial. A bundled Arial-compatible font (Liberation Sans) measures and draws labels on Linux and other systems without Arial.
• More inputs import. SMILES features ReShiki cannot draw, atoms with three or four unpaired electrons, charged RXN participants, MOL superatom groups and atropisomer axes the drawing cannot show now import, with a warning where something was dropped or assumed.
• RDKit 2026.09 and nazuchem 0.2.0. Layout, CIP labels, atropisomer detection and kekulization follow RDKit 2026.09.1. Generated names follow the IUPAC 2013 recommendations more closely.
• Coordination chemistry. Join bonds every selected donor to its nearest metal, dative arrows never disappear, and Relaxed chemistry checks optimize metal complexes in 3D.
• Office and clipboard. On Linux, Copy also gives plain-text SMILES. On Windows, Copy pastes a picture into new Outlook and web apps, and edited Office drawings keep their size.

The changes below keep their links to their issues and reviews. All changes in this release are by @Ameyanagi.

Stereochemistry

• Enhanced stereo groups. Select stereocentres or whole molecules and open Stereo groups in the inspector. Choose abs, an existing group, New AND group or New OR group; Renumber groups closes gaps in the numbering. Centres with the same label flip together anywhere in the drawing, as in a MOL file or CXSMILES. Labels abs, and1 and or1 appear beside the centres; turn them off with Show stereo groups (abs, and1, or1) under Atom labels & numbering, or with Show/Hide stereo groups in the command palette. Pasting gives incoming groups unused numbers, so a pasted racemate never joins an existing group. MOL and RXN V3000 read and write STEABS, STERACn and STERELn, and a drawing with groups is written as V3000. SMILES output adds the CXSMILES group field, for example C[C@H](https://github.com/Ameyanagi/ReShiki/blob/main/docs/N)C(=O)O |&1:1|. CDXML and CDX read and write the ChemDraw group properties. Files with stereo groups used to be refused. Atom labels · PR #1141, part of issue #766.
• Relative CXSMILES. A relative flag, |r| or r: on chosen fragments of a molecule or reaction, imports as an AND group of the configured centres, as RDKit reads it. Before, r: was ignored, so a reaction reactant came in as a single enantiomer (#1087, #1141; fixes issue #998).
• CXSMILES stereo groups with large numbers no longer merge into another group (#1086; fixes issue #1006).
• Wedge flags follow the SMILES. A wU or wD flag on the / or \ bond that states a double bond’s E/Z keeps that E/Z. Without coordinates, the @/@@ tag decides the configuration in reaction SMILES and next to wavy bonds, as it already did for molecules. An empty CX coordinate block, or one with every atom at the same point, keeps the stereo the SMILES states (#1095, #1100, #1099, #1084; fixes issues #1042, #1048, #1049, #1046).
• Atropisomer axes.
  • New drawings choose wedges that show every atropisomer axis and stereocentre. RDKit’s AtropManyChirals example now imports (#1098; fixes issue #1060).
  • When no wedges can show an axis or centre, the structure imports without it and a warning names it, for example “The wedges in this layout cannot show the atropisomer axis C17–N19; ReShiki drew the structure without that axis”. Earlier versions refused the input (#1137).
  • A crossed double bond no longer hides an axis at its atom, so RXN files with such an axis import with it (#1093; fixes issue #1064).
  • A 3D MOL file whose drawing cannot keep its axis imports with a warning that editing, Clean Up and export will not include it (#1092; fixes issue #1057).
  • Plain SMILES has no notation for an axis. The Properties panel, Copy SMILES, SMILES export, reshiki --cli analyze and the Python Properties now say that the axial configuration was dropped (#1089; fixes issue #1007).
• Importing an atropisomer whose axis wedge sits on a ring amide nitrogen gives that nitrogen the same R/S label at import that Analyze, export and reopening the drawing compute from the wedges. Before, the label appeared only after the next analysis (#1173).
• An allene no longer keeps a false configuration when another component of the drawing makes CIP labelling fail (#1085; fixes issue #1061).
• CIP labels follow RDKit 2026.09.1. R/S labels change on some cationic heteroaromatics, partially unsaturated rings and isotope-labelled centres; for example, the stereocentre of F[C@H](https://github.com/Ameyanagi/ReShiki/blob/main/docs/c1[o+]cccc1)C(O)N is now S (#1130, #1131).

Chemical names

• Generated names follow the IUPAC 2013 recommendations more closely, with the naming engine updated to nazuchem 0.2.0. Symmetric structures get multiplicative preferred names, such as 1,1'-oxybis(4-bromobenzene) and 4,4'-(propane-2,2-diyl)diphenol. Salts list their ions alphabetically, ignoring stereo, isotope and italic descriptors (disodium tert-butoxide methoxide). A charged ring or nitrogen becomes the parent (4-(hydroxymethyl)-1-methylpyridin-1-ium), and charged substituents use the preferred prefixes (N,N-dimethylmethanaminiumyl) and diazyn-1-ium-1-yl. Isotope labels inside a substituent are named, as in (2H3)methoxybenzene, where ReShiki refused before. Diamines cite N^1 and N^3, a nitrile in a substituent is cyano, ring ketones use indicated hydrogen (1,3-dihydro-2H-1,4-benzodiazepin-2-one), and parentheses and fusion locants are simpler (hydroxy(phenyl)acetic acid, 2H-benzo[cd][1]benzothiophene). [2.2]Paracyclophane now shows a von Baeyer name with its phane name as the alternative, like other cyclophanes (#1167).
• The naming engines now live in their own library, nazuchem, which ReShiki builds in. Names and their status did not change with the move, and naming still works offline (#1072–#1083).
• docs/feature-status.md lists the opt-in PubChem name lookup that 0.14.0 added (#1097; fixes issue #1004).

Import and export

• Partial imports with warnings. A SMILES, CXSMILES or reaction SMILES input with one feature ReShiki cannot draw now imports the rest and says what was dropped or assumed. Square-planar, trigonal-bipyramidal and octahedral centres (@SP, @TB, @OH) import without a configuration, an invalid @AL tag is dropped, CXSMILES query features (u, rb, s, query labels) are ignored, a ~ bond becomes single, and a CXSMILES zero-order (Z) bond is left out. A bare * with a CX suffix imports with no warning (#1155, #1165; part of issue #1138).
• Three or four unpaired electrons. SMILES like [C] and [Si] now import as written: a bare carbon or silicon atom with four unpaired electrons, and [CH], [N] and [B] with three, as RDKit reads them. The formula, mass and InChI match the input ([C] is C, 12.011, InChI=1S/C), SMILES and MOL export keep these atoms exactly, and RDKit’s MOL files for them open. Drawing a bond to such an atom recounts its unpaired electrons instead of reporting an error. CDXML cannot store three or four unpaired electrons, so ChemDraw files keep the hydrogen count and show a doublet or triplet. Drawings with these atoms save as document version 37. Scientific symbols · PR #1168.
• RXN participants with a charge, isotope or radical import like any other atom. Earlier versions refused the whole file as a query reaction (#1152).
• MOL superatom groups. MOL export writes each collapsed abbreviation, including two-sided amino-acid residues, as a superatom (SUP) group with its attachment points. MOL files with superatom groups open collapsed; a group that cannot be one label stays expanded, with a notice (#1143; fixes issue #870). Abbreviations.
• CDXML generic nicknames. A and a import as labelled dummy atoms with a warning that their any-atom meaning is not kept, and * imports as a wildcard atom. Before, A refused the file and a became carbon (#1131).
• File → Open refuses files it has no reader for, such as .sdf and .txt, with “Can’t import .sdf”, instead of reading them as SMILES. .smi and .smiles still open as SMILES (#1094; fixes issue #1001).
• Layout. 2D layout follows RDKit 2026.09.1: substituent placement, collision detection and ring order (#1139, #1129). Porphyrins import as regular macrocycles, as after Clean Up (#1114; fixes issue #1113). Rings next to a spiro centre stay regular instead of being squashed (#1116; fixes issue #1112). Imported components such as an HCl beside an amine keep one bond length between their labels (#1088; fixes issue #1033).
• Non-canonical SMILES output keeps atom maps, as in RDKit 2026.09.1 (#1125).

Arrows, drawing and styles

• Arrows with nodes. Select one arrow and choose Edit points. Click the shaft to add a node; drag nodes and their direction controls, and switch them between Corner, Smooth and Symmetric as on pen paths. Delete node removes one. Attached ends stay attached when molecules move. Smooth, Symmetrise, Straighten, Reverse and Flip bend work on these arrows. CDXML and CDX write them as one multi-segment ChemDraw curve. Drawings with such arrows save as document version 35. Arrows · PR #1140; fixes issue #761.
• Move the repeat label. With a polymer bracket selected, Repeating unit → Position repeat label shows a handle on its label (n). Drag it, or type Label X and Label Y; Restore automatic label position puts it back. The label follows the bracket when it moves. Generic structures · PR #1110; fixes issue #1069.
• Crossing clearance. Properties → Drawing style → Edit drawing style… → Advanced stroke settings → Crossing clearance sets the gap where a rear bond passes behind a front one, from 0 to 12 pt. The default, 1.1 pt, draws as before. A drawing with another clearance saves as document version 35. The Python package takes crossing_clearance; binary CDX reopens at 1.1 pt. See File compatibility. Drawing styles · PR #1111; fixes issue #1070.
• Join coordinates donors. With a metal in the selection, Join (⌘J / Ctrl+J) adds a donor → metal bond from every selected N, O, S or P to its nearest selected metal within two bond lengths, in one Undo step. Selecting all of Co(en)₃ and pressing Join draws all six contacts. The status bar names what was added and what was skipped. Two atoms of the same metal now share like any other pair (#1128; fixes issue #246). Move and attach.
• Dative arrows. A metal’s automatic charge sits in a gap between its contacts, a dative contact is never dropped, and its arrowhead scales with a short contact (#1124, #1126).

Pictures, SVG and fonts

• Pictures that reopen as drawings. Copy, Copy image and Copy as → PNG / SVG / PDF put the ReShiki drawing inside their PNG, SVG and PDF pictures. Paste such a picture into ReShiki, drop the file on the window or open it with File → Open to get the editable drawing back. File export does the same while Include editable drawing is on, below the export button. It is on by default; turn it off for figures you send to a journal. The drawing inside holds exactly what the picture shows. Drawings over 2 MB compressed, Export pages as PDF and EMF for Office do not carry it. Keep the drawing editable inside a picture · PR #1153, PR #1154, part of issue #462.
• SVG files look the same in every viewer. Export → Figure → SVG and the agent tools export, file_save and render draw text as outlines, as reshiki --cli and the Python package do. Live <text> used the viewer’s own fonts, so labels shifted between apps, and a renderer without Arial could drop them. To keep text editable, turn on Keep text editable below the export button (off by default; ReShiki remembers it), pass svg_text: "live" to the tools, --svg-text live to the CLI or text="live" in Python. An editable drawing inside the SVG still reopens in ReShiki. SVG for Office is unchanged. Text in SVG files · PR #1158, PR #1163.
• The SVG that ReShiki puts on the clipboard draws its text as outlines on macOS, Linux and in the browser editor, as Copy image on Windows already did. Copy, Copy image and Copy as → SVG used live <text> there, so an app that pastes the SVG flavor substituted its own fonts. The SVG keeps its physical size, transparent background and the editable drawing inside it. Clipboard · PR #1164.
• Labels without Arial. Every build carries Liberation Sans, which has Arial’s character widths. When no Arial is installed, ReShiki measures and draws labels with it, in the desktop app, the CLI and the Python package, so Linux labels no longer come out wider with DejaVu Sans. In 0.14.0 a computer with no fonts at all lost every atom label. Where Arial is installed, nothing changes. Missing fonts · PR #1158, PR #1081.

Clipboard and Office

• On Linux, Copy (Ctrl+C) also puts the selection’s SMILES on the clipboard as plain text, the same text Copy SMILES gives, so a plain-text box gets the SMILES. LibreOffice, Chromium pages and ReShiki still paste the drawing or picture, and when ReShiki quits with its window focused, GNOME still keeps the picture. A reaction, or a selection without molecules, gets no text. Windows and macOS are unchanged, because Excel and PowerPoint there would paste the text instead of the drawing. Clipboard compatibility · PR #1161.
• On Windows, Copy keeps a bitmap next to the editable Office object, so new Outlook, Outlook on the web, Gmail, Teams and other browser-based apps paste a picture. Word, PowerPoint and Excel still paste the editable drawing (#1148; fixes issue #1146).
• On Windows, editing an embedded drawing in PowerPoint and saving no longer enlarges its frame and leaves a blank band at the right and bottom. Office pictures are recorded at a fixed resolution, so a new paste comes out at the drawing’s real size on every display. Objects already embedded keep their size until you edit them (#1127, #1144; fixes issues #1123, #1132).
• Clipboard compatibility. A new page lists, for each app on Windows, macOS, Linux and in the browser, what Copy and Copy image paste as, and the exact clipboard formats. Clipboard compatibility · #1147, #1157.

3D models and crystals

• Relaxed chemistry checks. The 3D preview has Chemistry checks: Strict and Relaxed. When Strict refuses a metal complex or an atom with an unusual bond count, such as 18-crown-6 holding K⁺, the preview opens with Strict checks failed and the reason. Choose Relaxed to optimize the molecule as drawn; molecules with metals use UFF. The panel shows Relaxed: chemistry not validated and lists each check it skipped and each approximation (#1145, part of issue #371).
• After Repeat 2 × 2 × 2, rock salt’s automatic view leaves a word space between Na and Cl labels on the same line (#1091; fixes issue #614).

Python package and browser editor

• Online name lookup and reusable styles in Python. reshiki.Molecule.from_name("aspirin", online=True) asks PubChem; offline lookup stays the default. reshiki.with_style(...) makes a reusable style context for constructors, parse, render, convert and render_many (#1081). Python.
• Import warnings. The Python package issues the app’s import warnings as reshiki.StructureWarning; render_many returns them in .warnings. The browser library has read(data, format), which returns { drawing, warnings }, and the editor’s load() resolves to { warnings } (#1135). Import warnings.
• Python wheels include the license and third-party notice files (#1079; fixes issue #1077).

Desktop

• Idle windows release GPU memory: a focused text field stops blinking after 10 seconds, and antialiasing buffers shrink with the window. On macOS, with the Import tab open, the app now settles at about 206 MB instead of about 310 MB (#1096; fixes issue #1002).
• On Linux, starting ReShiki from the launcher while it runs brings the open window forward instead of opening a second one (#1115, part of issue #100).
• macOS 27: debug builds no longer crash when the Print panel draws its preview. Release builds were not affected (#1136; fixes issue #1134).

Known limits

• Naming: some structures still get a non-preferred name or no name, including cumulene E/Z and some phane, salt and fused-ring names. Open naming issues are tracked in the nazuchem issue list.
• Stereo groups: InChI export and naming refuse grouped structures instead of giving the drawn enantiomer’s identifier. Canonical SMILES does not yet pick one representative for an AND or OR group, so two drawings of the same racemate can give different SMILES. A group cannot hold an atropisomer axis; its atom members import and a warning names the loss (issue #766).
• Stereochemistry:
  • A wedge drawn from a ring amide N makes that N a stereocentre (issue #1150).
  • Pasting into an empty drawing turns off Show stereodescriptors (issue #1151).
  • A 3D MOL file with an atropisomer axis opens without the axis in the drawing, with a warning.
• Layout: layout can shorten an exocyclic bond, such as a C=O, to clear a clash, and Clean Up with Keep orientation can mirror a drawing (issues #1122, #1121).
• Arrows: a multi-segment arrowed curve read from CDXML or CDX opens as a pen path with arrowheads, not as an arrow.
• Relaxed 3D: like RDKit’s UFF, it bends the trans ligands of square-planar complexes such as cisplatin and makes K⁺–O contacts short. Haptic bonds and query atoms are not supported (issue #371).
• Fonts: in the browser editor, an Arial added with addFont is still drawn with the bundled Liberation Sans (issue #1160).
• Desktop: on macOS, keyboard focus does not return to the drawing after the Print panel closes; click the drawing (issue #1149). Two drawings from the same Office document open as tabs with the same title (issue #1119).
• Windows signing: public Windows downloads are unsigned while the SignPath Foundation release certificate is pending (issue #489). Linux downloads are unsigned.

Build and verification

• RDKit 2026.09.1. The reference suites, oracles and captured goldens follow RDKit 2026.9.1; ReShiki keeps its own ring-finding basis (#1162, #1142; fixes issue #1117). The live reference failures on main were cleared before the release (#1159).
• nazuchem. The naming engines moved into nazuchem, with their history, licenses and a frozen snapshot of the naming worker’s responses that guarded the move (#1067, #1071–#1083, #1167).
• CI. Linux jobs run in prebuilt images, native tests are partitioned with cargo-nextest, and lint and golden replay run in one job per platform (#1104–#1108, #1102, #1103, #1133). Nightly builds accept their version suffix again (#1101). Two Windows tests no longer fail on a brief file lock or a slow debug build (#1109, #1166). Source files are formatted with bun fmt (#1068).
• 0.14.0 release validation. The publication record of the tagged source, tag run and public downloads. Validation record · PR #1066.
• Release preparation. Update the version, the release notes and the documentation for 0.15.0.