109 lines
3.7 KiB
TypeScript
109 lines
3.7 KiB
TypeScript
import type { Token } from '../core/types';
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import { joinTokens } from '../core/joinTokens';
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import { measureWidthCached } from '../measure/measureWidthCached';
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import type { ApplyOverflowFallbackInput } from './types';
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const DEFAULT_TC_PUNCTS = ['，', '。', '！', '？', '；', '：', '、'];
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export function cleanLineBeforeEllipsis(line: string, lang: 'TC' | 'EN', tcPunctuations?: string[]): string {
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const s = String(line ?? '');
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const trimmed = s.replace(/\s+$/g, '');
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if (trimmed === '') return '';
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if (lang === 'TC') {
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const puncts = new Set(tcPunctuations && tcPunctuations.length > 0 ? tcPunctuations : DEFAULT_TC_PUNCTS);
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const last = trimmed.slice(-1);
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if (puncts.has(last)) return trimmed.slice(0, -1);
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}
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return trimmed;
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}
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async function measureIfPossible(args: {
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text: string;
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input: ApplyOverflowFallbackInput;
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}): Promise<number | null> {
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const { input, text } = args;
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if (!input.measure) return null;
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const enabled =
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typeof input.measure.measureWidthImpl === 'function' &&
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(input.measure.context === 'APP' || input.measure.widgetEnableMeasure === true);
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if (!enabled) return null;
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const res = await measureWidthCached({
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text,
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context: input.measure.context,
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contextProfile: input.measure.contextProfile,
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fontSpec: input.measure.fontSpec,
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measureWidthImpl: input.measure.measureWidthImpl,
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widgetEnableMeasure: input.measure.widgetEnableMeasure,
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});
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return res.width;
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}
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/**
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* 给最后一行加省略号，并在可测量时保证不超宽：
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* - EN 回退单位：整词（token）
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* - TC 回退单位：grapheme（token）
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*/
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export async function applyEllipsisToLastLine(args: {
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input: ApplyOverflowFallbackInput;
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baseLines: Array<{ start: number; end: number; text: string }>;
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}): Promise<{ lines: string[] }> {
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const { input } = args;
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const maxLines = Math.max(1, input.maxLines | 0);
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const lines = args.baseLines.slice(0, maxLines);
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if (lines.length === 0) return { lines: [] };
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const lastIdx = lines.length - 1;
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const last = lines[lastIdx]!;
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// 先按规则清理，再拼接 ellipsisToken
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const cleaned = cleanLineBeforeEllipsis(last.text, input.lang, input.tcPunctuations);
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let candidateText = `${cleaned}${input.ellipsisToken}`;
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// 若无测量能力：直接输出（确定性）
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const measured = await measureIfPossible({ text: candidateText, input });
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if (measured === null) {
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const out = lines.map((l, idx) => (idx === lastIdx ? candidateText : l.text));
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return { lines: out };
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}
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// 有测量能力：若超宽则按 token 回退
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if (measured <= input.availableWidth) {
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const out = lines.map((l, idx) => (idx === lastIdx ? candidateText : l.text));
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return { lines: out };
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}
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// 回退：逐步减少最后一行 token 数再加省略号
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let end = last.end;
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const start = last.start;
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let foundFit = false;
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while (end > start) {
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end -= 1;
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const base = joinTokens(input.tokens, start, end);
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const cleaned2 = cleanLineBeforeEllipsis(base, input.lang, input.tcPunctuations);
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const nextCandidate = `${cleaned2}${input.ellipsisToken}`;
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const w = await measureIfPossible({ text: nextCandidate, input });
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if (w !== null && w <= input.availableWidth) {
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candidateText = nextCandidate;
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foundFit = true;
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break;
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}
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}
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// 若连“仅省略号”都无法满足宽度（极窄场景），也必须给出确定性输出：直接输出 ellipsisToken
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// 注意：这可能仍然超宽，但已是最小可表达形式；上层可通过 meta 做治理。
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if (!foundFit) {
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candidateText = input.ellipsisToken;
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}
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const out = lines.map((l, idx) => (idx === lastIdx ? candidateText : l.text));
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return { lines: out };
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}
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