ad62739a6e
In addition to using const and let, this also upgrades our linter config and removes lint (mostly whitespace).
95 lines
3.0 KiB
JavaScript
95 lines
3.0 KiB
JavaScript
/**
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* @module ol/geom/flat/textpath
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*/
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import {lerp} from '../../math.js';
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const _ol_geom_flat_textpath_ = {};
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/**
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* @param {Array.<number>} flatCoordinates Path to put text on.
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* @param {number} offset Start offset of the `flatCoordinates`.
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* @param {number} end End offset of the `flatCoordinates`.
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* @param {number} stride Stride.
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* @param {string} text Text to place on the path.
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* @param {function(string):number} measure Measure function returning the
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* width of the character passed as 1st argument.
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* @param {number} startM m along the path where the text starts.
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* @param {number} maxAngle Max angle between adjacent chars in radians.
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* @return {Array.<Array.<*>>} The result array of null if `maxAngle` was
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* exceeded. Entries of the array are x, y, anchorX, angle, chunk.
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*/
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_ol_geom_flat_textpath_.lineString = function(
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flatCoordinates, offset, end, stride, text, measure, startM, maxAngle) {
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const result = [];
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// Keep text upright
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const reverse = flatCoordinates[offset] > flatCoordinates[end - stride];
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const numChars = text.length;
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let x1 = flatCoordinates[offset];
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let y1 = flatCoordinates[offset + 1];
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offset += stride;
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let x2 = flatCoordinates[offset];
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let y2 = flatCoordinates[offset + 1];
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let segmentM = 0;
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let segmentLength = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
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let chunk = '';
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let chunkLength = 0;
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let data, index, previousAngle;
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for (let i = 0; i < numChars; ++i) {
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index = reverse ? numChars - i - 1 : i;
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const char = text.charAt(index);
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chunk = reverse ? char + chunk : chunk + char;
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const charLength = measure(chunk) - chunkLength;
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chunkLength += charLength;
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const charM = startM + charLength / 2;
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while (offset < end - stride && segmentM + segmentLength < charM) {
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x1 = x2;
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y1 = y2;
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offset += stride;
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x2 = flatCoordinates[offset];
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y2 = flatCoordinates[offset + 1];
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segmentM += segmentLength;
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segmentLength = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
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}
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const segmentPos = charM - segmentM;
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let angle = Math.atan2(y2 - y1, x2 - x1);
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if (reverse) {
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angle += angle > 0 ? -Math.PI : Math.PI;
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}
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if (previousAngle !== undefined) {
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let delta = angle - previousAngle;
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delta += (delta > Math.PI) ? -2 * Math.PI : (delta < -Math.PI) ? 2 * Math.PI : 0;
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if (Math.abs(delta) > maxAngle) {
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return null;
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}
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}
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const interpolate = segmentPos / segmentLength;
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const x = lerp(x1, x2, interpolate);
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const y = lerp(y1, y2, interpolate);
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if (previousAngle == angle) {
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if (reverse) {
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data[0] = x;
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data[1] = y;
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data[2] = charLength / 2;
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}
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data[4] = chunk;
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} else {
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chunk = char;
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chunkLength = charLength;
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data = [x, y, charLength / 2, angle, chunk];
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if (reverse) {
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result.unshift(data);
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} else {
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result.push(data);
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}
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previousAngle = angle;
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}
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startM += charLength;
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}
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return result;
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};
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export default _ol_geom_flat_textpath_;
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