2 files changed, 48 insertions, 1 deletions
diff --git a/src/language.test.ts b/src/language.test.ts
index 62b03a2..3564363 100644
--- a/src/language.test.ts
+++ b/src/language.test.ts
@@ -130,7 +130,6 @@ test('all consonants can be selected', () => {
 		},
 	]);
 
-
 	expect(lang.pickConsonants(
 		[ lang.ConsonantPlace.Bilabial, lang.ConsonantPlace.Alveolar ],
 		[ lang.ConsonantManner.Plosive, lang.ConsonantManner.Tap ],
@@ -139,3 +138,19 @@ test('all consonants can be selected', () => {
 		'p', 'b', 'ⱱ̟', 't', 'd', 'ɾ̥', 'ɾ',
 	]);
 });
+
+
+test('vowel positions work correctly', () => {
+	expect(
+		lang._vowelXY(lang.VowelHeight.Open, lang.VowelDepth.Back)
+	).toEqual([0, 0]);
+	expect(
+		lang._vowelXY(lang.VowelHeight.NearOpen, lang.VowelDepth.Central)
+	).toEqual([1.5, 1]);
+	expect(
+		lang._vowelXY(lang.VowelHeight.Close, lang.VowelDepth.Front)
+	).toEqual([8, 6]);
+	expect(
+		lang._vowelXY(lang.VowelHeight.Close, lang.VowelDepth.Back)
+	).toEqual([0, 6]);
+});
diff --git a/src/language.ts b/src/language.ts
index c0360b8..dd96b8d 100644
--- a/src/language.ts
+++ b/src/language.ts
@@ -20,6 +20,36 @@ export interface VowelFeatures {
 	nasal: boolean;
 }
 
+
+// convert a vowel height/depth combo to an x/y position
+// (for use in creating nicely spaced vowel inventories)
+export function _vowelXY(
+	height: VowelHeight, 
+	depth: VowelDepth
+): [number, number] {
+	const y = {
+		[VowelHeight.Open]: 0,
+		[VowelHeight.NearOpen]: 1,
+		[VowelHeight.OpenMid]: 2,
+		[VowelHeight.Mid]: 3,
+		[VowelHeight.CloseMid]: 4,
+		[VowelHeight.NearClose]: 5,
+		[VowelHeight.Close]: 6,
+	}[height];
+
+	const slope = {
+		[VowelDepth.Front]: 1,
+		[VowelDepth.Central]: 2,
+		[VowelDepth.Back]: 3,
+	}[depth];
+
+	if (slope === 3) { return [ 0, y ]; }
+
+	const x = (y + 2) / slope;
+	return [x, y];
+}
+
+
 // convert a set of vowel features to an IPA representation
 export function vowelFeaturesToIpa(features: VowelFeatures): string {
 	const ipa = () => {
@@ -141,6 +171,8 @@ export interface ConsonantFeatures {
 }
 
 
+// convert a set of consonant features to IPA
+// returns the empty string if the proposed consonant does not exist
 export function consonantFeaturesToIpa(features: ConsonantFeatures): string {
 	switch (features.place) {
 		case ConsonantPlace.Bilabial: