Special Characters Technical Specification
Overview
Special character access through long-press popups, short swipe subkeys, and symbol keyboard layers.
Key Components
| Component | File | Purpose |
|---|---|---|
| KeyValue | KeyValue.kt | Character and action definitions |
| KeyModifier | KeyModifier.kt | Modifier state handling |
| Pointers | Pointers.kt:400-600 | Long-press and swipe detection |
| KeyboardData | KeyboardData.kt | Layout and subkey definitions |
| KeyPopup | KeyPopup.kt | Long-press popup rendering |
Subkey System
Each key can have up to 8 subkeys in cardinal and diagonal directions:
// KeyboardData.kt - Key definition structure
data class Key(
val key0: KeyValue, // Main key (tap)
val key1: KeyValue?, // North (swipe up)
val key2: KeyValue?, // North-East
val key3: KeyValue?, // East (swipe right)
val key4: KeyValue?, // South-East
val key5: KeyValue?, // South (swipe down)
val key6: KeyValue?, // South-West
val key7: KeyValue?, // West (swipe left)
val key8: KeyValue? // North-West
)Layout XML Format
Subkeys defined in layout XML files (res/xml/):
<!-- Example: latn_qwerty_us.xml -->
<key
key0="e"
key1="3"
key2="ê"
key3="ë"
key4="ē"
key5="é"
key6="è"
key7="€"
key8="ę" />Long-Press Detection
// Pointers.kt:~450
private fun handleLongPress(ptr: Pointer) {
if (ptr.flags and FLAG_P_LONG_PRESS == 0) {
ptr.flags = ptr.flags or FLAG_P_LONG_PRESS
val key = ptr.key
if (key.hasSubkeys()) {
showKeyPopup(key, ptr)
}
}
}Character Categories
| Category | Unicode Range | Example |
|---|---|---|
| Latin Extended | U+00C0-U+00FF | àáâãäå |
| Latin Extended-A | U+0100-U+017F | āăą |
| Currency | U+20A0-U+20CF | €£¥₹ |
| Math Operators | U+2200-U+22FF | ×÷±≠ |
| General Punctuation | U+2000-U+206F | —–… |
Configuration
| Setting | Key | Default |
|---|---|---|
| Long-Press Timeout | longpress_timeout | 400ms |
| Short Gesture Min | short_gesture_min_distance | 28% |
| Short Gesture Max | short_gesture_max_distance | 65% |
Modifier Interaction
Special characters interact with shift/caps lock:
// KeyValue.kt
fun withModifiers(mods: Int): KeyValue {
return when {
mods and MOD_SHIFT != 0 -> this.uppercase()
else -> this
}
}Related Specifications
- Gesture System - Swipe detection
- Short Swipes Specification - Subkey activation
- Layout System - XML format