/* string-lerp - progressively turn one string into another
Copyright 2014 Joe Wreschnig
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
+ Licensed under the terms of the GNU GPL v2 or later
+ @license http://www.gnu.org/licenses/gpl-2.0.html
+ @source: http://yukkurigames.com/string-lerp/
+*//*
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ As additional permission, you may distribute the program or works
+ based on it without the copy of the GNU GPL normally required,
+ provided you include this license notice and a URL through which
+ recipients can access the corresponding source code.
*/
-/* @license Copyright 2014 Joe Wreschnig - GNU GPL v2 or later */
+/*globals exports, Uint32Array */
(function (exports) {
"use strict";
return editPath(costMatrix(source, target, ins, del, sub), target);
}
- function patch(diff, source) {
- /** Apply a list of edits to source */
- var edit;
- var i;
-
- if (Array.isArray(source)) {
- for (i = 0; i < diff.length; ++i) {
- edit = diff[i];
- source.splice(edit[1], edit[0], edit[2]);
- }
- } else {
- for (i = 0; i < diff.length; ++i) {
- edit = diff[i];
- var head = source.slice(0, edit[1]);
- var tail = source.slice(edit[1] + edit[0]);
- source = head + edit[2] + tail;
- }
+ function patchArray(diff, source) {
+ for (var i = 0; i < diff.length; ++i) {
+ var edit = diff[i];
+ source.splice(edit[1], edit[0], edit[2]);
}
return source;
}
- var MULTI = /[\uD800-\uDBFF][\uDC00-\uDFFF]|[\u0300-\u036F\u1DC0-\u1DFF\u20D0-\u20FF\uFE20-\uFE2F]/;
+ function patchString(diff, source) {
+ for (var i = 0; i < diff.length; ++i) {
+ var edit = diff[i];
+ var head = source.slice(0, edit[1]);
+ var tail = source.slice(edit[1] + edit[0]);
+ source = head + edit[2] + tail;
+ }
+ return source;
+ }
- var GLYPH = /([\0-\u02FF\u0370-\u1DBF\u1E00-\u20CF\u2100-\uD7FF\uDC00-\uFE1F\uFE30-\uFFFF]|[\uD800-\uDBFF][\uDC00-\uDFFF]|[\uD800-\uDBFF])([\u0300-\u036F\u1DC0-\u1DFF\u20D0-\u20FF\uFE20-\uFE2F]*)/g;
+ function patch(diff, source) {
+ /** Apply a list of edits to source */
+ var patcher = Array.isArray(source) ? patchArray : patchString;
+ return patcher(diff, source);
+ }
- function diffLerp(source, target, amount ) {
- /** Interpolate between two strings using edit operations
+ // Matches if a string contains combining characters or astral
+ // codepoints (technically, the first half surrogate of an astral
+ // codepoint).
+ var MULTI = /[\u0300-\u036F\u1DC0-\u1DFF\u20D0-\u20FF\uD800-\uDBFF\uFE20-\uFE2F]/;
- This interpolation algorithm applys a partial edit of one
- string into the other. This produces nice looking results,
- but can take a significant amount of time and memory to
- compute the edits. It is not recommended for strings
- longer than a few hundred characters.
- */
+ // Match an entire (potentially astral) codepoint and any
+ // combining characters following it.
+ var GLYPH = /[\0-\u02FF\u0370-\u1DBF\u1E00-\u20CF\u2100-\uD7FF\uD800-\uFE1F\uFE30-\uFFFF][\u0300-\u036F\u1DC0-\u1DFF\u20D0-\u20FF\uDC00-\uDFFF\uFE20-\uFE2F]*/g;
- // If given strings with astral codepoints or combining
- // characters, split them into arrays of "glyphs" first,
- // do the edit on the list of "glyphs", and rejoin them.
- //
+ function diffLerpAstral(source, target, amount) {
// This split is not perfect for all languages, but at least
// it won't create invalid surrogate pairs or orphaned
// combining characters.
- if (source.match && (source.match(MULTI) || target.match(MULTI))) {
- var sourceGlyphs = source.match(GLYPH) || [];
- var targetGlyphs = target.match(GLYPH) || [];
- return diffLerp(sourceGlyphs, targetGlyphs, amount).join("");
- }
-
+ var sourceGlyphs = source.match(GLYPH) || [];
+ var targetGlyphs = target.match(GLYPH) || [];
+ var edits = diff(targetGlyphs, sourceGlyphs, 2, 2, 3);
// The edit path works from the string end, forwards, because
// that's how Levenshtein edits work. To match LTR reading
// direction (and the behavior of fastLerp), swap the strings
// and invert the parameter when editing.
+ var partial = edits.slice(0, Math.round((1 - amount) * edits.length));
+ return patchArray(partial, targetGlyphs).join("");
+ }
+
+ function diffLerpBasic(source, target, amount) {
var edits = diff(target, source, 2, 2, 3);
+ // The edit path works from the string end, forwards, because
+ // that's how Levenshtein edits work. To match LTR reading
+ // direction (and the behavior of fastLerp), swap the strings
+ // and invert the parameter when editing.
var partial = edits.slice(0, Math.round((1 - amount) * edits.length));
- return patch(partial, target);
+ return patchString(partial, target);
}
- var NUMBERS = /(-?\d+(?:\.\d+)?)/g;
+ function diffLerp(source, target, amount) {
+ /** Interpolate between two strings using edit operations
+
+ This interpolation algorithm applys a partial edit of one
+ string into the other. This produces nice looking results,
+ but can take a significant amount of time and memory to
+ compute the edits. It is not recommended for strings
+ longer than a few hundred characters.
+ */
+
+ if (source.match(MULTI) || target.match(MULTI))
+ return diffLerpAstral(source, target, amount);
+ else
+ return diffLerpBasic(source, target, amount);
+ }
+
+ var NUMBERS = /(-?\d{1,20}(?:\.\d{1,20})?)/g;
function areNumericTwins(source, target) {
/** Check if a and b differ only in numerals */
Numbers may have a leading "-" and a single "." to mark
the decimal point, but something must be after the ".".
No other floating point syntax (e.g. 1e6) is supported.
- If both of the numbers in a pair are integers, the result
- is clamped to an integer.
+ They are treated as fixed-point values, with the point's
+ position itself interpolating.
- For example, numericLerp("0.0", "100", 0.123) === "12.3"
+ For example, numericLerp("0.0", "100".0, 0.123) === "12.3"
because the "." in "0.0" is interpreted as a decimal
point. But numericLerp("0.", "100.", 0.123) === "12."
because the strings are interpreted as integers followed
numerals gives undefined results.
*/
- // TODO: Try to preserve precision of the original numbers.
- var sourceParts = source.split(NUMBERS);
var targetParts = target.split(NUMBERS);
- var destParts = targetParts;
- for (var i = 1; i < sourceParts.length; i += 2) {
- var sourcePart = sourceParts[i];
+ var match;
+ var i = 1;
+ while ((match = NUMBERS.exec(source))) {
+ var sourcePart = match[0];
var targetPart = targetParts[i];
var part = nlerp(+sourcePart, +targetPart, amount);
var sourcePoint = sourcePart.indexOf(".");
var targetPoint = targetPart.indexOf(".");
- if (sourcePoint === -1 && targetPoint === -1)
- part = Math.round(part);
- targetParts[i] = part.toString();
+ var point = Math.round(nlerp(
+ sourcePoint >= 0 ? (sourcePart.length - 1) - sourcePoint : 0,
+ targetPoint >= 0 ? (targetPart.length - 1) - targetPoint : 0,
+ amount));
+ targetParts[i] = part.toFixed(point);
+ i += 2;
}
return targetParts.join("");
}
- function fastLerp(a, b, p) {
+ function fastLerpAstral(source, target, amount) {
+ var sourceGlyphs = source.match(GLYPH) || [];
+ var targetGlyphs = target.match(GLYPH) || [];
+ var sourceLength = Math.round(sourceGlyphs.length * amount);
+ var targetLength = Math.round(targetGlyphs.length * amount);
+ var head = targetGlyphs.slice(0, targetLength);
+ var tail = sourceGlyphs.slice(sourceLength, sourceGlyphs.length);
+ head.push.apply(head, tail);
+ return head.join("");
+ }
+
+ function fastLerpBasic(source, target, amount) {
+ var sourceLength = Math.round(source.length * amount);
+ var targetLength = Math.round(target.length * amount);
+ var head = target.substring(0, targetLength);
+ var tail = source.substring(sourceLength, source.length);
+ return head + tail;
+ }
+
+ function fastLerp(source, target, amount) {
/** Interpolate between two strings based on length
This interpolation algorithm progressively replaces the
// strings, e.g. in the megabyte range. These are large enough
// that it should be fine to just pick a codepoint and search
// for the nearest glyph start.
- if (a.match(MULTI) || b.match(MULTI)) {
- var ca = a.match(GLYPH) || [];
- var cb = b.match(GLYPH) || [];
- var calen = Math.round(ca.length * p);
- var cblen = Math.round(cb.length * p);
- var r = cb.slice(0, cblen);
- r.push.apply(r, ca.slice(calen, ca.length));
- return r.join("");
- } else {
- var alen = Math.round(a.length * p);
- var blen = Math.round(b.length * p);
- return b.substring(0, blen) + a.substring(alen, a.length);
- }
+ if (source.match(MULTI) || target.match(MULTI))
+ return fastLerpAstral(source, target, amount);
+ else
+ return fastLerpBasic(source, target, amount);
}
- function lerp(a, b, p) {
+ function lerp(source, target, amount) {
/** Interpolate between two strings as best as possible
If the strings are identical aside from numbers in them,
Otherwise, they are passed through fastLerp.
*/
- a = a.toString();
- b = b.toString();
+ source = source.toString();
+ target = target.toString();
// Fast path for boundary cases.
- if (p === 0) return a;
- if (p === 1) return b;
+ if (amount === 0) return source;
+ if (amount === 1) return target;
- if (areNumericTwins(a, b))
- return numericLerp(a, b, p);
+ if (areNumericTwins(source, target))
+ return numericLerp(source, target, amount);
// Numeric lerps should over- and under-shoot when fed numbers
// outside 0 to 1, but other types cannot.
- if (p < 0) return a;
- if (p > 1) return b;
+ if (amount < 0) return source;
+ if (amount > 1) return target;
- var n = a.length * b.length;
- return ((n && n < MAX_MATRIX_SIZE) ? diffLerp : fastLerp)(a, b, p);
+ var n = source.length * target.length;
+ var appropriate = (n && n < MAX_MATRIX_SIZE) ? diffLerp : fastLerp;
+ return appropriate(source, target, amount);
}
exports.costMatrix = costMatrix;
projects / string-lerp.git / blobdiff