MyVOLT is a browser-based tool designed to help font developers and linguists work with Myanmar script and related Southeast Asian scripts. It provides a visual glyph panel and a VOLT-style rule builder for creating OpenType font features.
Note: MyVOLT works best with fonts that support Myanmar script, such as Ayar, Myanmar Text, Padauk or Noto Sans Myanmar.
MyVOLT is an interactive workbench for mapping glyphs, building substitution/encoding rules, and validating output against your font. You can define a glyph set, drag chips into rule inputs/outputs, preview changes, and export everything for downstream tooling.
uni1000 uni1001 …).VOLT (Visual OpenType Layout Tool) is a Microsoft tool for creating and editing OpenType layout features. MyVOLT brings similar functionality to the browser with a focus on Myanmar script.
OpenType features are sets of rules that tell the font how to substitute or position glyphs in specific contexts. Common features for Myanmar script include:
| Feature | Purpose | Example |
|---|---|---|
locl |
Localized forms | Language-specific glyph variants |
ccmp |
Glyph composition | Component decomposition/composition |
rphf |
Reph form | Positioning of reph marker |
To begin using MyVOLT:
| Feature | Description | Status |
|---|---|---|
| Tools Modal | Floating panel with Proofing, Compile, and QA tabs | Available |
| Proofing | GSUB simulation, Myanmar cluster checks, and per-cluster diagnostics | Available |
| Compile | Export .fea, project.json, hb-tests, mark-only, mkmk, gpos, gdef; ZIP bundling | Available |
| QA | Conflicts & coverage meters; anchor validation; rule tags & filters | Available |
| Anchors | CSV-driven anchors, presets, auto-build from glyphSet, mark-to-mark (mkmk) | Available |
| Project Import | Import project.json (glyphSet, groups, rules) into the UI |
Available |
| Glyph Panel | Interactive panel to explore and test Myanmar script characters | Available |
| Rule Builder | Create and test OpenType substitution rules | Available |
| Script Reference | Detailed information on Myanmar script and related scripts | Available |
| Pangram Collection | Test sentences covering all characters | Available |
| Export Functionality | Export rules and test results | Available |
The Glyph Panel allows you to explore characters from Myanmar script and related writing systems. You can:
The Rule Builder helps you create OpenType substitution rules for font development:
Replaces one glyph with another in specific contexts
substitute uni1005 uni103B uni1004 by uni1005_medial_kinzi;
Replaces SA (U+1005) followed by medial YA (U+103B) and NGA (U+1004) with a special SA+Kinzi ligature.
Combines multiple glyphs into a single ligature
substitute uni1000 uni103B by uni1000_103B_lig;
Combines KA (U+1000) and medial YA (U+103B) into a KA+YA ligature glyph.
Substitutes glyphs based on surrounding context
substitute uni1009' uni103A uni1039 by uni1009_asat_virama;
Replaces NYA (U+1009) when followed by ASAT (U+103A) and VIRAMA (U+1039).
Replaces a single glyph with multiple glyphs
substitute uni100C by uni100B uni103A;
Replaces DDA (U+100C) with DDA (U+100B) and ASAT (U+103A) for proper rendering.
Paste glyph names as space-separated tokens. Preferred naming is uniXXXX (e.e., uni1000 for U+1000 KA). You can include aliases like ka if your font uses them.
.notdef .null uni1000 uni1001 uni1002 uni1031 uni103B uni103C uni103D uni103E uni103A uni1039Tip: Your chips and info panels derive from this list; keep it focused to speed up the UI.
Groups are named subsets of your glyph set. Use them to build rules quickly (e.g., "consonants", "vowels", "digits").
consonants → uni1000 uni1001 …
medials → uni103B uni103C uni103D uni103E
prebase → uni1031Drag group chips into the rule inputs. The engine expands group members when evaluating rules.
Shows totals by category. Use this to verify coverage and spot missing glyphs.
uniXXXX and present in your fontClick ➕ Add Rule (bottom-right) to open the modal. You can:
gsub_single, gsub_ligature, encoding, reorder.Type: gsub_ligature
Name: KA+Medial-Ya
Before: (empty) Input: uni1000 uni103B After: (empty)
Output: uni1000_ya_lig (or your ligature glyph name)For reorder, use Output to represent the new order (e.g., put uni1031 before the base).
Provides "text → text" replacements, ideal for normalizing legacy input before rule processing.
# one per line: from => to
ေ က => ကေ
ြ က => ကြ
သြကင်္န် => သင်္ကြန်Rules apply left-to-right with longest patterns first. Use the test box to preview results live.
Type Unicode text in Input (Unicode). You will see:
Enable "Auto-preview" to re-run after each change.
Save state snapshots as you iterate. Each checkpoint contains project info, glyph set, rules, groups, kerns, anchors.
Pick A and B via radio buttons in the Timeline, then click Compare. You can export the diff to JSON or CSV:
Ensure you have Myanmar script fonts installed on your system. Recommended fonts:
Check your rule syntax carefully. Remember that OpenType rules are case-sensitive and require precise glyph names.
The Proofing tools help you test and validate your OpenType rules before final implementation.
Enter text in the "Sample text" field that represents typical usage of your font:
Click "Simulate GSUB" or press Ctrl/Cmd+Enter to process your sample text through all enabled rules.
The simulation will show a step-by-step transformation process:
MyVOLT includes specialized checks for Myanmar script requirements:
Leading Vowel Position: Ensures U+1031 appears at the start of clusters
Leading Medial Position: Ensures U+103C appears at the start of clusters after U+1031 (ေ) appears. Not like other Medials, -ျ (ya), -ွ (wa), -ှ (ha).
Duplicate Marks: Flags duplicate asat (U+103A) or tone marks
Kinzi Validation: Checks for properly formed Kinzi sequences (U+1004 U+103A U+1039)
The tool automatically breaks text into typographic clusters and highlights any issues with color coding:
Convert your rules and configurations into production-ready OpenType feature files.
Generate standard OpenType feature code that can be compiled with font tools:
Click the Export .fea button in the main toolbar
The generated file will include:
Save your entire project configuration for later editing or sharing with team members:
Use Export JSON to save your project file
The exported file contains:
Create automated test scripts for validating your font with HarfBuzz:
Go to the Compile tab in the Tools panel
Click Download hb-tests.sh to create validation scripts
The generated script includes:
Export everything in a single package for easy sharing or archiving:
Click Export ZIP in the main toolbar
The ZIP file contains:
Comprehensive checks to ensure your font implementation is robust and consistent.
Identifies rules that might interfere with each other:
Conflicts are highlighted with details about the rules involved.
Measures how well your rules cover the glyphs in your set:
75% Coverage
Visual progress indicator shows percentage of glyphs used in rules
Lists glyphs not referenced by any rules
Organize and filter your rules with custom tags:
Enter a rule index in the QA panel
Add descriptive tags (e.g., "ligature", "reorder", "kinzi")
Click "Save Tag" to apply
Use "Filter by Tag" to focus on specific rule subsets
For GPOS features, validates anchor positioning:
m_* for mark-to-mark positioningWork more efficiently with these keyboard commands:
The Myanmar script is used by several languages in Southeast Asia, each with unique characteristics and requirements. Understanding these differences is crucial for proper font development.
The standard Myanmar script used for the Burmese language. Features complex stacking behavior and reordering rules.
# Pre-base vowel reordering
Type: reorder
Input: uni1000 uni1031 # KA + E
Output: uni1031 uni1000 # E + KA
# Medial ordering
Type: reorder
Input: uni1000 uni103D uni103B # KA + WA + YA
Output: uni103B uni103D uni1000 # YA + WA + KAUsed for the Shan language, with additional vowels and tone marks extending the Myanmar block.
# Shan vowel ligature
Type: gsub_ligature
Input: uni1010 uni1083 # TA + Shan vowel AA
Output: uni1010_1083_lig
# Tone mark placement
Type: reorder
Input: uni1000 uni1086 # KA + Shan tone mark
Output: uni1000 uni1086 # Typically remains afterUsed for the Mon language, with some unique characters and stacking behavior.
# Mon-specific reordering
Type: reorder
Input: uni1000 uni1064 uni1031 # KA + Mon medial + E
Output: uni1031 uni1064 uni1000 # E + Mon medial + KA
# Mon digit substitution
Type: gsub_single
Input: uni1040 # Myanmar digit zero
Output: uni1090 # Mon digit zeroUsed for various Karen languages, with extended vowels and tone marks.
# Karen tone mark handling
Type: gsub_single
Input: uni1000 uni1062 # KA + Karen tone
Output: uni1000_1062_lig
# Vowel reordering
Type: reorder
Input: uni1000 uni1031 uni1062 # KA + E + Karen tone
Output: uni1031 uni1000 uni1062 # E + KA + Karen tone| Feature | Burmese | Shan | Mon | Karen |
|---|---|---|---|---|
| Pre-base Vowel Reordering | Yes (U+1031) | Yes (U+1031, U+1083, etc.) | Yes (U+1031) | Yes (U+1031) |
| Tone Marks | Limited | Extensive (U+1082, U+1085, etc.) | Some | Extensive |
| Additional Characters | Standard set | U+1075–U+1081, U+1083–U+1084, etc. | U+1060–U+1069, U+106E–U+1086 | U+1060–U+109F (selected) |
| Stacking Behavior | Complex | Moderate | Complex | Moderate |
| Common Ligatures | Many | Vowel+tone combinations | Medial combinations | Tone mark combinations |
Myanmar script is used for Burmese, Shan, Karen, Mon, and other languages in Myanmar and surrounding regions. The script has unique characteristics including circular baselines, numerous stacked characters, and context-dependent shaping.
The primary language using Myanmar script, with 33 consonants and numerous vowel diacritics.
Sample: "Myanmar language is very beautiful."
A Tai language spoken in Shan State, using Myanmar script with additional tone markers.
Sample: "Shan language and culture is progressively developing."
An Austroasiatic language with historical importance throughout Southeast Asia.
Sample: "The Mon language as a root lineage."
Several related languages including S'gaw Karen and Pwo Karen.
Sample: "We Karen people love our culture."
| Block Name | Range | Description |
|---|---|---|
| Myanmar | U+1000–U+109F | Basic Myanmar characters |
| Myanmar Extended-A | U+AA60–U+AA7F | Additional characters for Shan, Mon, etc. |
| Myanmar Extended-B | U+A9E0–U+A9FF | Extended characters for minority languages |
Use this interactive panel to explore Myanmar script characters and test how they combine.
MyVOLT supports several types of OpenType substitution rules that are essential for proper Myanmar script rendering.
Replaces a single glyph with another single glyph.
substitute a -> a.alt;
Use this for alternate glyph forms or stylistic variants.
Replaces a single glyph with multiple glyphs.
substitute ka -> k + a;
Useful for decomposing complex glyphs into components.
Replaces multiple glyphs with a single glyph.
substitute k + sha -> ksha;
Essential for creating conjunct forms in Myanmar script.
Replaces glyphs based on surrounding context.
substitute k' i -> ki_special;
Critical for proper Myanmar script rendering where glyphs change form based on position.
Create and test OpenType substitution rules for Myanmar script.
# Rule will appear here
| Rule | Type | Actions |
|---|
This tool helps quickly normalize Myanmar text sequences (e.e., moving pre-base vowel "ေ" before the base consonant).
The following rules are applied from longest patterns first. This is a literal replacement system. For regex patterns, use the advanced option below.
| Enabled | From | ⇒ | To | Notes |
|---|---|---|---|---|
| ⇒ | Pre-base vowel "ေ" reordering (word-level) | |||
| ⇒ | Medial "ျ" handling (no change by default, modify as needed) |
Myanmar Pre-base "ေ" (U+1031) reordering using Regex — applies to the entire text:
Pattern : ([\u1000-\u1021])\u1031
Replace : \u1031$1နမူနာ)Quickly test a Unicode-aware JavaScript regex on your input. Nothing is stored.
MyVOLT supports several rule types for different OpenType features:
Each rule type serves different purposes in the text shaping process.
Create glyph groups to simplify rule creation:
# Define groups
consonants: uni1000 uni1001 uni1002 ...
vowels: uni102B uni102C uni102D ...
medials: uni103B uni103C uni103D ...
# Use groups in rules
Type: gsub_ligature
Input: consonants medials
Output: ligature_glyphGroups expand to their members during rule evaluation.
MyVOLT supports advanced typographic features:
These features are essential for professional-quality fonts.
MyVOLT can export your work in multiple formats:
Choose the format that works with your font production pipeline.
MyVOLT supports several rule types that correspond to OpenType features. Understanding these will help you build effective text shaping rules.
Replaces a single glyph with another single glyph. This is used for simple glyph replacements.
Replace a basic glyph with an alternate form:
Input: uni1000 (KA)
Output: uni1000.alt (Alternate KA)Mon script digit substitution:
Input: uni1040 (Myanmar digit zero)
Output: uni1090 (Mon digit zero)Replaces a sequence of glyphs with a single glyph. Essential for complex script rendering.
Create a consonant+medial ligature:
Input: uni1000 uni103B (KA + YA)
Output: uni1000_103B_lig (KA-YA ligature)Shan vowel+tone ligature:
Input: uni1010 uni1083 (TA + Shan vowel AA)
Output: uni1010_1083_lig (TA with AA ligature)Performs simple text-to-text replacement, useful for normalizing input before complex processing.
Fix common input errors:
Input: ြ က (Separated medial RA + KA)
Output: ကြ (Proper KA-RA combination)Normalize legacy encoding:
Input: သြကင်္န် (Legacy encoding)
Output: သင်္ကြန် (Standard encoding)Changes the order of glyphs in a sequence without substituting them. Critical for Myanmar script rendering.
Reposition pre-base vowel:
Input: uni1000 uni1031 (KA + E vowel)
Output: uni1031 uni1000 (E vowel + KA)Reorder medials in Burmese:
Input: uni1000 uni103D uni103B (KA + WA + YA)
Output: uni103B uni103D uni1000 (YA + WA + KA)| Rule Type | Burmese | Shan | Mon | Karen |
|---|---|---|---|---|
| Single Substitution | Rarely used | For tone mark variants | For digit forms | For tone mark variants |
| Ligature Substitution | Extensive (medials, Kinzi) | Vowel+tone combinations | Medial combinations | Tone mark combinations |
| Encoding Map | Input method correction | Legacy encoding conversion | Legacy encoding conversion | Input method correction |
| Reorder | Critical (vowels, medials) | Important (vowels, tones) | Important (vowels, medials) | Important (vowels, tones) |
Apply substitutions based on surrounding characters:
Before: uni1000 (KA)
Input: uni1031 (E vowel)
After: uni103B (YA medial)
Output: uni1031.special (Special E form)Create sequences of rules that apply in order:
1. First reorder: KA + E → E + KA
2. Then ligature: E + KA → E_KA_ligPangrams are sentences that contain all letters of a script. Use these to test font coverage and rendering.
A representative Karen sentence for testing glyph coverage and tone placement.
"The genius from Sri Lanka read the life-extending medical prescription under the almond tree in Zalun market with determination."
"Shan language and culture is progressively developing and flourishing everywhere."
"The Mon language as a root lineage has had wealth and dignity in this world since ancient times."
| Keyboard | Platform | Description |
|---|---|---|
| Ayar | Windows/macOS/Linux | Standard keyboard layout for Myanmar script |
| Ayar key | Windows/macOS | Legacy keyboard layout (not Unicode compliant) |
| Keymagic | Windows | Customizable input method editor |
If you need help using MyVOLT, check the following resources:
Consult the full User Guide section or check the Resources tab for links to documentation and community support.