Xiaohan-Tian
43 lines
1.1 KiB
TypeScript
43 lines
1.1 KiB
TypeScript
import type { KeySignature, KGProject } from '../../core/KGProject';
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import { getEffectiveKeySignatureAtBeat } from '../../util/globalTrackUtil';
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import { getChordGuideModeFromKeySignature } from '../../util/scaleUtil';
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export type ChordGuideFunction = 'N' | 'T' | 'S' | 'D';
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export type ChordGuideMode = 'ionian' | 'aeolian';
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export function getNextChordGuideSelection(current: ChordGuideFunction): ChordGuideFunction {
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switch (current) {
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case 'N':
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return 'T';
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case 'T':
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return 'S';
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case 'S':
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return 'D';
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default:
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return 'N';
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}
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}
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export function getNextChordCandidateIndex(
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currentIndex: number,
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candidateCount: number,
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direction: 1 | -1
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): number {
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if (candidateCount <= 1) {
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return currentIndex;
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}
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return (currentIndex + direction + candidateCount) % candidateCount;
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}
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export function resolveChordGuideContext(project: KGProject, beat: number): {
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keySignature: KeySignature;
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mode: ChordGuideMode;
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} {
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const keySignature = getEffectiveKeySignatureAtBeat(project, beat);
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return {
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keySignature,
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mode: getChordGuideModeFromKeySignature(keySignature),
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};
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}
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