Add GPX trail maps to blog posts

This adds a trail flow block so posts can include attached GPX files as
interactive maps with route display, elevation charts, activity
summaries, and start/finish markers.

The trail assets are loaded only when needed, keeping the shared
templates clean while vendoring the Leaflet dependencies required for
offline, self-hosted map rendering.

1 files changed, 783 insertions, 0 deletions

diff --git a/assets/static/vendor/leaflet-elevation/src/components/chart.js b/assets/static/vendor/leaflet-elevation/src/components/chart.js
new file mode 100644
index 0000000..b0b5458
--- /dev/null
+++ b/assets/static/vendor/leaflet-elevation/src/components/chart.js
@@ -0,0 +1,783 @@
+import * as D3 from './d3.js';
+
+const _ = L.Control.Elevation.Utils;
+
+export var Chart = L.Control.Elevation.Chart = L.Class.extend({
+
+	includes: L.Evented ? L.Evented.prototype : L.Mixin.Events,
+
+	initialize(opts, control) {
+		this.options       = opts;
+		this.control       = control;
+
+		this._data         = control._data || [];
+
+		// cache registered components
+		this._props        = {
+			scales      : {},
+			paths       : {},
+			areas       : {},
+			grids       : {},
+			axes        : {},
+			legendItems : {},
+			tooltipItems: {},
+		};
+
+		this._scales       = {};
+		this._domains      = {};
+		this._ranges       = {};
+		this._paths        = {};
+
+		this._brushEnabled = opts.dragging;
+		this._zoomEnabled  = opts.zooming;
+
+		opts.xTicks = this._xTicks();
+		opts.yTicks = this._yTicks();
+		
+		let chart       = this._chart = D3.Chart(opts);
+
+		// SVG Container
+		this._container = chart.svg;
+
+		// Panes
+		this._grid      = chart.pane('grid');
+		this._area      = chart.pane('area');
+		this._point     = chart.pane('point');
+		this._axis      = chart.pane('axis');
+		this._legend    = chart.pane('legend');
+		this._tooltip   = chart.pane('tooltip');
+		this._ruler     = chart.pane('ruler');
+
+		// Scales
+		this._initScale();
+
+		// Helpers
+		this._mask      = chart.get('mask');
+		this._context   = chart.get('context');
+		this._brush     = chart.get('brush');
+
+		this._zoom      = d3.zoom();
+		this._drag      = d3.drag();
+
+		// Interactions
+		this._initInteractions();
+
+		// svg.on('resize', (e)=>console.log(e.detail));
+
+		// Handle multi-track segments
+		this._maskGaps = [];
+		control.on('eletrack_added', ({index}) => {
+			this._maskGaps.push(index);
+			control.once('elepoint_added', ({index}) => this._maskGaps.push(index));
+		});
+
+	},
+
+	update(props) {
+		if (props) {
+			if (props.data) this._data = props.data;
+			if (props.options) this.options = props.options;
+		}
+
+		this.options.xTicks = this._xTicks();
+		this.options.yTicks = this._yTicks();
+
+		this._updateScale();
+		this._updateAxis();
+		this._updateMargins();
+		this._updateLegend();
+		this._updateClipper();
+		this._updateArea();
+
+		return this;
+	},
+
+	render() {
+		return container => container.append(() => this._container.node());
+	},
+
+	clear() {
+		this._resetDrag();
+		this._hideDiagramIndicator()
+		this._area.selectAll('path').attr("d", "M0 0");
+		this._context.clearRect(0, 0, this._width(), this._height());
+		this._mask.selectAll(".gap").remove();
+		this._maskGaps = [];
+
+		// if (this._path) {
+			// this._x.domain([0, 1]);
+			// this._y.domain([0, 1]);
+		// }
+	},
+
+	_drawPath(name) {
+		let path   = this._paths[name];
+		let area   = this._props.areas[name];
+
+		path.datum(this._data).attr("d",
+			D3.Area(
+				L.extend({}, area, {
+					width        : this._width(),
+					height       : this._height(),
+					scaleX       : this._scales[area.scaleX],
+					scaleY       : this._scales[area.scaleY]
+				})
+			)
+		);
+
+		if (!path.classed('leaflet-hidden')) {
+			this.options.preferCanvas
+				? _.drawCanvas(this._context, path)
+				: _.append(this._area.node(), path.node());
+		}
+	},
+
+	_hasActiveLayers() {
+		const paths = this._paths;
+		for (var i in paths) {
+			if (!paths[i].classed('leaflet-hidden')) {
+				return true;
+			}
+		}
+		return false;
+	},
+
+	/**
+	 * Initialize "d3-brush".
+	 */
+	_initBrush(e) {
+		const brush   = ({selection}) => {
+			if (selection && this._data.length) {
+				let start = this._findIndexForXCoord(selection[0]);
+				let end   = this._findIndexForXCoord(selection[1]);
+				this.fire('dragged', { dragstart: this._data[start], dragend: this._data[end] });
+			}
+		}
+
+		const focus   = (e) => {
+			if (this._data.length && (e.type != 'brush' /*|| e.sourceEvent*/)) {
+				let rect    = this._chart.panes.brush.select('.overlay').node();
+				let coords  = d3.pointers(e, rect)[0];
+				let xCoord  = _.clamp(coords[0], [0, this._width()]); // Clamps cursor position to chart's bounds (see issues: #270, #301)
+				let item    = this._data[this._findIndexForXCoord(xCoord)];
+
+				this.fire("mouse_move", { item: item, xCoord: xCoord });
+			}
+		};
+
+		this._brush
+			.filter(({shiftKey, button}) => !shiftKey && !button && this._brushEnabled)
+			.on("end.update", brush)
+			.on("brush.update", focus);
+
+		this._chart.panes.brush
+			.on("mouseenter.focus touchstart.focus", this.fire.bind(this, "mouse_enter"))
+			.on("mouseout.focus touchend.focus",     this.fire.bind(this, "mouse_out")  )
+			.on("mousemove.focus touchmove.focus",   focus                              );
+
+	},
+
+	/**
+	 * Initialize "d3-zoom"
+	 */
+	_initClipper() {
+		let svg       = this._container;
+		let margin    = this.options.margins;
+
+		const zoom    = this._zoom;
+
+		const onStart = ({transform, sourceEvent}) => {
+			if (sourceEvent && sourceEvent.type == "mousedown") svg.style('cursor', 'grabbing');
+			if (transform.k == 1 && transform.x == 0) {
+				this._container.classed('zoomed', true);
+				// Apply d3-zoom and bind <mask>
+				if (this._mask) {
+					this._point.attr('mask', 'url(#' + this._mask.attr('id') + ')');
+				}
+			}
+			this.zooming = true;
+		};
+
+		const onEnd  = ({transform}) => {
+			if (transform.k ==1 && transform.x == 0) {
+				this._container.classed('zoomed', false);
+				// Reset d3-zoom and remove <mask>
+				if (this._mask) {
+					this._point.attr('mask', null);
+				}
+			}
+			this.zooming = false;
+			svg.style('cursor', '');
+		};
+
+		const onZoom = ({transform, sourceEvent}) => {
+			// TODO: find a faster way to redraw the chart.
+			this.zooming = false;
+			this._updateScale(); // hacky way for restoring x scale when zooming out
+			this.zooming = true;
+			this._scales.distance = this._x = transform.rescaleX(this._x); // calculate x scale at zoom level
+			if (this._scales.time) this._scales.time = transform.rescaleX(this._scales.time); // calculate x scale at zoom level
+			this._resetDrag();
+			if (sourceEvent && sourceEvent.type == "mousemove") {
+				this._hideDiagramIndicator();
+			}
+			this.fire('zoom');
+		};
+
+		zoom
+			.scaleExtent([1, 10])
+			.extent([
+				[margin.left, 0],
+				[this._width() - margin.right, this._height()]
+			])
+			.translateExtent([
+				[margin.left, -Infinity],
+				[this._width() - margin.right, Infinity]
+			])
+			.filter(({shiftKey, buttons}) => (shiftKey || buttons == 4) && this._zoomEnabled)
+			.on("start", onStart)
+			.on("end", onEnd)
+			.on("zoom", onZoom);
+
+		svg.call(zoom); // add zoom functionality to "svg" group
+
+		// d3.select("body").on("keydown.grabzoom keyup.grabzoom", (e) => svg.style('cursor', e.shiftKey ? 'move' : ''));
+
+	},
+
+	_initInteractions() {
+		this._initBrush();
+		this._initRuler();
+		this._initClipper();
+		this._initLegend();
+	},
+
+	/**
+	 * Toggle chart data on legend click
+	 */
+	_initLegend() {
+		this._container.on('legend_clicked', ({detail}) => {
+			let { path, legend, name, enabled } = detail;
+			if (path) {
+				let label = _.select('text', legend);
+				let rect  = _.select('rect', legend);
+				_.toggleStyle(label, 'text-decoration-line', 'line-through', enabled);
+				_.toggleStyle(rect,  'fill-opacity',         '0',            enabled);
+				_.toggleClass(path,  'leaflet-hidden',                       enabled);
+				this._updateArea();
+				this.fire("elepath_toggle", { path, name, legend, enabled })
+			}
+		});
+	},
+
+	/**
+	 * Initialize "ruler".
+	 */
+	_initRuler() {
+		if (!this.options.ruler) return;
+
+		// const yMax      = this._height();
+		const formatNum = d3.format(".0f");
+		const drag      = this._drag;
+
+		const label     = (e, d) => {
+			let yMax      = this._height();
+			let y         = this._ruler.data()[0].y;
+			if (y >= yMax || y <= 0) this._ruler.select(".horizontal-drag-label").text('');
+			this._hideDiagramIndicator();
+		};
+
+		const position  = (e, d) => {
+			let yCoord    = d3.pointers(e, this._area.node())[0][1];
+			let yMax      = this._height();
+			let y         = _.clamp(yCoord, [0, yMax]);
+
+			this._ruler
+				.data([L.extend(this._ruler.data()[0], { y: y })])
+				.attr("transform", d => "translate(" + d.x + "," + d.y + ")")
+				.classed('active', y < yMax);
+
+			this._container
+				.select(".horizontal-drag-label")
+				.text(formatNum(this._y.invert(y)) + " " + (this.options.imperial ? 'ft' : 'm'));
+
+			this.fire('ruler_filter', { coords: yCoord < yMax && yCoord > 0 ? this._findCoordsForY(yCoord) : [] });
+		}
+
+		drag
+			.on("start end", label)
+			.on("drag", position);
+
+		this._ruler.call(drag);
+
+	},
+
+	/**
+	 * Initialize x and y scales
+	 */
+	_initScale() {
+		let opts = this.options;
+
+		this._registerAxisScale({
+			axis    : 'x',
+			position: 'bottom',
+			attr    : opts.xAttr,
+			min     : opts.xAxisMin,
+			max     : opts.xAxisMax,
+			name    : 'distance'
+		});
+
+		this._registerAxisScale({
+			axis     : 'y',
+			position : 'left',
+			attr     : opts.yAttr,
+			min      : opts.yAxisMin,
+			max      : opts.yAxisMax,
+			name     : 'altitude'
+		});
+
+		this._x = this._scales.distance;
+		this._y = this._scales.altitude;
+	},
+
+	_registerAreaPath(props) {
+		if (props.scale == 'y') props.scale = this._y;
+		else if (props.scale == 'x') props.scale = this._x;
+
+		let opts = this.options;
+
+		if (!props.xAttr) props.xAttr = opts.xAttr;
+		if (!props.yAttr) props.yAttr = opts.yAttr;
+		if (typeof props.preferCanvas === "undefined") props.preferCanvas = opts.preferCanvas;
+
+		// Save paths in memory for latter usage
+		this._paths[props.name]       = D3.Path(props);
+		this._props.areas[props.name] = props;
+
+		if (opts.legend) {
+			this._props.legendItems[props.name] = {
+				name     : props.name,
+				label    : props.label,
+				color    : props.color,
+				className: props.className,
+				path     : this._paths[props.name]
+			};
+		}
+
+	},
+
+	_registerAxisGrid(props) {
+		if (props.scale == 'y') props.scale = this._y;
+		else if (props.scale == 'x') props.scale = this._x;
+
+		this._props.grids[props.name || props.axis] = props;
+	},
+
+	_registerAxisScale(props) {
+		if (props.scale == 'y') props.scale = this._y;
+		else if (props.scale == 'x') props.scale = this._x;
+
+		let opts  = this.options;
+		let scale = props.scale;
+
+		if (typeof this._scales[props.name] === 'function') {
+			props.scale = this._scales[props.name]; // retrieve cached scale
+		} else if (typeof scale !== 'function') {
+			scale       = L.extend({
+				data       : this._data,
+				forceBounds: opts.forceAxisBounds
+			}, scale);
+
+			scale.attr   = scale.attr || props.name;
+
+			let domain   = this._domains[props.name] = D3.Domain(props);
+			let range    = this._ranges[props.name]  = D3.Range(props);
+			scale.range  = scale.range  || range(this._width(),this._height());
+			scale.domain = scale.domain || domain(this._data);
+
+			this._props.scales[props.name] = scale;
+
+			props.scale = this._scales[props.name] = D3.Scale(scale);
+		}
+
+		if (!props.ticks) {
+			if (props.axis == 'x')      props.ticks = this._xTicks.bind(this);
+			else if (props.axis == 'y') props.ticks = this._yTicks.bind(this);
+		}
+
+		this._props.axes[props.name] = props;
+
+		if (props.name == this.options.yScale) this._y = scale;
+		if (props.name == this.options.xScale) this._x = scale;
+
+		return scale;
+	},
+
+	/**
+	 * Add a point of interest over the chart
+	 */
+	_registerCheckPoint(point) {
+		if (!this._data.length) return;
+
+		const {xAttr, yAttr} = this.options;
+		let item, x, y;
+
+		if (point.latlng) {
+			item = this._data[this._findIndexForLatLng(point.latlng)];
+			x    = this._x(item[xAttr]);
+			y    = this._y(item[yAttr]);
+		} else if (!isNaN(point[xAttr])) {
+			x    = this._x(point[xAttr]);
+			item = this._data[this._findIndexForXCoord(x)]
+			y    = this._y(item[yAttr]);
+		} 
+
+		this._point.call(D3.CheckPoint({
+			point: point,
+			width: this._width(),
+			height: this._height(),
+			x: x,
+			y: y,
+		}));
+	},
+
+	_registerTooltip(props) {
+		props.order = props.order ?? 1000;
+		this._props.tooltipItems[props.name] = props;
+	},
+
+	_updateArea() {
+		// Reset and update chart profiles
+		this._context.clearRect(0, 0, this._width(), this._height());
+		_.each(this._paths, (path, i) => !path.classed('leaflet-hidden') && this._drawPath(i));
+	},
+
+	_updateAxis() {
+
+		let opts = this.options;
+
+		const gridOpts = {
+			width     : this._width(),
+			height    : this._height(),
+			tickFormat: "",
+		};
+
+		const axesOpts  = {
+			width  : this._width(),
+			height : this._height(),
+		};
+
+		// Reset grids
+		this._grid.selectAll('g').remove();
+		_.each(this._props.grids, (grid, i) => {
+			if (opts[i] !== false && opts[i] !== 'summary') {
+				this._grid.call(D3.Grid(L.extend({}, gridOpts, grid)))
+			}
+		});
+
+		// Rest axis
+		this._axis.selectAll('g').remove();
+		_.each(this._props.axes,  (axis, i) => {
+			if (opts[i] !== false && opts[i] !== 'summary') {
+				this._axis.call(D3.Axis(L.extend({}, axesOpts, axis)));
+			}
+		});
+
+		// Adjust axis scale positions
+		this._axis
+			.selectAll('.y.axis.right')
+			.each((d, i, n) => {
+
+				let axis      = d3.select(n[i]);
+				let transform = axis.attr('transform');
+				let translate = transform.substring(transform.indexOf("(") + 1, transform.indexOf(")")).split(",");
+
+				axis.attr('transform', 'translate(' + (+translate[0] + (i * 40)) + ',' + translate[1] + ')')
+
+				if (i > 0) {
+					axis.select(':scope > path')         .attr('opacity', 0.25);
+					axis.selectAll(':scope > .tick line').attr('opacity', 0.75);
+				}
+
+			});
+
+	},
+
+	_updateClipper() {
+		const { xAttr, margins } = this.options;
+		const data = this._data;
+
+		this._zoom
+			.scaleExtent([1, 10])
+			.extent([
+				[margins.left, 0],
+				[this._width() - margins.right, this._height()]
+			])
+			.translateExtent([
+				[margins.left, -Infinity],
+				[this._width() - margins.right, Infinity]
+			]);
+
+		// Apply svg mask on multi-track segments
+		this._mask.selectAll(".gap").remove()
+		this._maskGaps.forEach((d, i) => {
+			if (i >= this._maskGaps.length - 2) return;
+			let x1 = this._x(data[this._findIndexForLatLng(data[this._maskGaps[i]].latlng)][xAttr]);
+			let x2 = this._x(data[this._findIndexForLatLng(data[this._maskGaps[i + 1]].latlng)][xAttr]);
+			this._mask
+				.append("rect")
+				.attr("x", x1)
+				.attr("y", 0)
+				.attr("width", x2 - x1 )
+				.attr("height", this._height())
+				.attr('class', 'gap')
+				.attr('fill-opacity', '0.8')
+				.attr("fill", 'black');  // hide = black (mask)
+		});
+	},
+
+	_updateLegend: function () {
+		let xAxesB  = this._axis.selectAll('.x.axis.bottom').nodes().length;
+		
+		// Get legend items
+		let items = Object.keys(this._paths);
+
+		// Calculate legend item positions
+		let n      = items.length;
+		let v      = Array(Math.floor(n / 2)).fill(null).map((d, i) => (i + 1) * 2 - (1 - Math.sign(n % 2)));
+		let rev    = v.slice().reverse().map((d) => -(d));
+
+		// push a fake element to handle center alignment (odd numbers)
+		if (n % 2 !== 0) {
+			rev.push(0);
+		}
+		v = rev.concat(v);
+
+		// Reset legend items
+		this._legend.selectAll('g').remove();
+
+		// Render legend items
+		_.each(this._props.legendItems, (legend) => {
+			this._legend.append("g").call(
+				D3.LegendItem(L.extend({
+					width  : this._width(),
+					height : this._height(),
+					margins: this.options.margins,
+				}, legend))
+			);
+		});
+
+		// Render legend item switcher
+		if (n > 1) {
+			this._legend.append("g").call(
+				D3.LegendSmall({
+					width  : this._width(),
+					height : this._height(),
+					items  : items,
+					onClick: (selected) => {
+						_.each(items, name => this._togglePath(name, selected == name, true));
+						this._updateArea();
+					}
+				})
+			);
+		}
+		
+		_.each(items, (name, i) => {
+			// Adjust legend item positions
+			this._legend.select('[data-name=' + name + ']').attr("transform", "translate(" + (v[i] * 55) + ", " + (xAxesB * 2) + ")");
+			// Set initial state (disabled controls)
+			this._togglePath(name, !(name in this.options && this.options[name] == 'disabled'), true);
+		});
+
+	},
+
+	_updateMargins() {
+		// Get chart margins
+		let xAxesB  = this._axis.selectAll('.x.axis.bottom').nodes().length;
+		let xAxesL  = this._axis.selectAll('.y.axis.left').nodes().length;
+		let xAxesR  = this._axis.selectAll('.y.axis.right').nodes().length;
+		let marginB = 60 + (xAxesB * 2);
+		let marginL = 10 + (xAxesL * 30);
+		let marginR = 40 + (xAxesR * 30);
+
+		let marginsUpdated = false
+
+		// Adjust right margin
+		if (xAxesR && this.options.margins.right < marginR) {
+			this.options.margins.right  = marginR;
+			marginsUpdated = true;
+		}
+
+		// Adjust left margin
+		if (xAxesL && this.options.margins.left < marginL) {
+			this.options.margins.left = marginL;
+			marginsUpdated = true;
+		}
+
+		// Adjust bottom margin
+		if (xAxesB && this.options.margins.bottom < marginB) {
+			this.options.margins.bottom = marginB;
+			marginsUpdated = true;
+		}
+
+		if (marginsUpdated) {
+			this.fire('margins_updated');
+		}
+	},
+
+	_updateScale() {
+		if (this.zooming) return { x: this._x, y: this._y };
+
+		for (let i in this._scales) {
+			this._scales[i]
+				.domain(this._domains[i](this._data))
+				.range(this._ranges[i](this._width(), this._height()))
+		}
+
+		return { x: this._x, y: this._y };
+	},
+
+	/**
+	 * Calculates chart width.
+	 */
+	_width() {
+		if (this._chart) this._chart._width;
+		const { width, margins } = this.options;
+		return width - margins.left - margins.right;
+	},
+
+	/**
+	 * Calculates chart height.
+	 */
+	_height() {
+		if (this._chart) return this._chart._height;
+		const { height, margins } = this.options;
+		return height - margins.top - margins.bottom;
+	},
+
+	/*
+	 * Finds data entries above a given y-elevation value and returns geo-coordinates
+	 */
+	_findCoordsForY(y) {
+		let data = this._data;
+		let z    = this._y.invert(y);
+
+		// save indexes of elevation values above the horizontal line
+		const list = data.reduce((array, item, index) => {
+			if (item[this.options.yAttr] >= z) array.push(index);
+			return array;
+		}, []);
+
+		let start = 0;
+		let next;
+
+		// split index list into blocks of coordinates
+		const coords = list.reduce((array, _, curr) => {
+			next = curr + 1;
+			if (list[next] !== list[curr] + 1 || next === list.length) {
+				array.push(
+					list
+					.slice(start, next)
+					.map(i => data[i].latlng)
+				);
+				start = next;
+			}
+			return array;
+		}, []);
+
+		return coords;
+	},
+
+	/*
+	 * Finds a data entry for a given x-coordinate of the diagram
+	 */
+	_findIndexForXCoord(x) {
+		return d3
+			.bisector(d => d[this.options.xAttr])
+			.left(this._data || [0, 1], this._x.invert(x));
+	},
+
+	/*
+	 * Finds a data entry for a given latlng of the map
+	 */
+	_findIndexForLatLng(latlng) {
+		let result = null;
+		let d      = Infinity;
+		this._data.forEach((item, index) => {
+			let dist = latlng.distanceTo(item.latlng);
+			if (dist < d) {
+				d = dist;
+				result = index;
+			}
+		});
+		return result;
+	},
+
+	/*
+	 * Removes the drag rectangle and zoms back to the total extent of the data.
+	 */
+	_resetDrag() {
+		if (this._chart.panes.brush.select(".selection").attr('width')) {
+			this._chart.panes.brush.call(this._brush.clear);
+			this._hideDiagramIndicator();
+			this.fire('reset_drag');
+		}
+	},
+
+	_resetZoom() {
+		if (this._zoom) {
+			this._zoom.transform(this._chart.svg, d3.zoomIdentity);
+		}
+	},
+
+	/**
+	 * Display distance and altitude level ("focus-rect").
+	 */
+	_showDiagramIndicator(item, xCoordinate) {
+		this._tooltip
+			.attr("display", null)
+			.call(D3.Tooltip({
+				xCoord: xCoordinate,
+				yCoord: this._y(item[this.options.yAttr]),
+				height: this._height(),
+				width : this._width(),
+				labels: this._props.tooltipItems,
+				item: item
+			}));
+	},
+
+	_togglePath(name, enabled = true, lazy = false) {
+		let path    = this._paths[name];
+		let legend  = this._container.select('.legend [data-name=' + name + ']');
+		path.classed('leaflet-hidden', !enabled);
+		legend.select('text').style('text-decoration-line', enabled ? '' : 'line-through');
+		legend.select('rect').style('fill-opacity', enabled ? '': '0');
+		// Apply d3-zoom (bind <clipPath> mask)
+		if (this._mask) {
+			path.attr('mask', 'url(#' + this._mask.attr('id') + ')');
+		}
+		if (!lazy) {
+			this._updateArea();
+		}
+	},
+
+	_hideDiagramIndicator() {
+		this._tooltip.attr("display", 'none');
+	},
+
+	/**
+	 * Calculate chart xTicks
+	 */
+	_xTicks() {
+	if (this.__xTicks) this.__xTicks = this.options.xTicks;
+	return this.__xTicks || Math.round(this._width() / 75);
+},
+
+	/**
+	 * Calculate chart yTicks
+	 */
+	_yTicks() {
+		if (this.__yTicks) this.__yTicks = this.options.yTicks;
+		return this.__yTicks || Math.round(this._height() / 30);
+	}
+});