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Fix scalebar length for CRS in units of feet
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@mbloch
mbloch committed Feb 20, 2024
1 parent 08c7426 commit 12d1599
Showing 1 changed file with 107 additions and 69 deletions.
176 changes: 107 additions & 69 deletions src/commands/mapshaper-scalebar.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ import utils from '../utils/mapshaper-utils';
import { DataTable } from '../datatable/mapshaper-data-table';
import { stop, message } from '../utils/mapshaper-logging';
import { symbolRenderers } from '../svg/svg-symbols';
import { importLineString } from '../svg/geojson-to-svg';

cmd.scalebar = function(catalog, opts) {
var lyr = getScalebarLayer(opts);
Expand All @@ -23,99 +24,136 @@ export function getScalebarLayer(opts) {
}

// TODO: generalize to other kinds of furniture as they are developed
function getScalebarPosition(d) {
var opts = { // defaults
valign: 'top',
halign: 'left',
voffs: 10,
hoffs: 10
function getScalebarPosition(opts) {
var pos = opts.position || 'top-left';
return {
valign: pos.includes('top') ? 'top' : 'bottom',
halign: pos.includes('left') ? 'left' : 'right'
};
if (+d.left > 0) {
opts.hoffs = +d.left;
}

var styleOpts = {
a: {
bar_width: 3,
tic_length: 0
},
b: {
bar_width: 1,
tic_length: 5
}
if (+d.top > 0) {
opts.voffs = +d.top;
};

var defaultOpts = {
position: 'top-left',
label_position: 'top',
label_offset: 4,
font_size: 12,
margin: 12
};

function getScalebarOpts(d) {
var style = d.style == 'b' || d.style == 'B' ? 'b' : 'a';
return Object.assign({}, defaultOpts, styleOpts[style], d, {style: style});
}

// approximate pixel height of the scalebar
function getScalebarHeight(opts) {
return Math.round(opts.bar_width + opts.label_offset +
opts.tic_length + opts.font_size * 0.8);
}

function renderAsSvg(length, text, opts) {
// label part
var xOff = opts.style == 'b' ? Math.round(opts.font_size / 4) : 0;
var alignLeft = opts.style == 'a' && opts.position.includes('left');
var anchorX = alignLeft ? -xOff : length + xOff;
var anchorY = opts.bar_width + + opts.tic_length + opts.label_offset;
if (opts.label_position == 'top') {
anchorY = -opts.label_offset - opts.tic_length;
}
if (+d.right > 0) {
opts.hoffs = +d.right;
opts.halign = 'right';
var labelOpts = {
'label-text': text,
'font-size': opts.font_size,
'text-anchor': alignLeft ? 'start': 'end',
'dominant-baseline': opts.label_position == 'top' ? 'auto' : 'hanging'
//// 'dominant-baseline': labelPos == 'top' ? 'text-after-edge' : 'text-before-edge'
// 'text-after-edge' is buggy in Safari and unsupported by Illustrator,
// so I'm using 'hanging' and 'auto', which seem to be well supported.
// downside: requires a kludgy multiplier to calculate scalebar height (see above)
};
var labelPart = symbolRenderers.label(labelOpts, anchorX, anchorY);
var zeroOpts = Object.assign({}, labelOpts, {'label-text': '0', 'text-anchor': 'start'});
var zeroLabel = symbolRenderers.label(zeroOpts, -xOff, anchorY);

// bar part
var y = 0;
var y2 = opts.tic_length + opts.bar_width / 2;
var coords;
if (opts.label_position == "top") {
y2 = -y2;
}
if (+d.bottom > 0) {
opts.voffs = +d.bottom;
opts.valign = 'bottom';
if (opts.tic_length > 0) {
coords = [[0, y2], [0, y], [length, y], [length, y2]];
} else {
coords = [[0, y], [length, y]];
}
return opts;
var barPart = importLineString(coords);
Object.assign(barPart.properties, {
stroke: 'black',
fill: 'none',
'stroke-width': opts.bar_width,
'stroke-linecap': 'butt',
'stroke-linejoin': 'miter'
});
var parts = opts.style == 'b' ? [zeroLabel, labelPart, barPart] : [labelPart, barPart];
return {
tag: 'g',
children: parts
};
}

export function renderScalebar(d, frame) {
var pos = getScalebarPosition(d);
if (!frame.crs) {
message('Unable to render scalebar: unknown CRS.');
return [];
}
if (frame.width > 0 === false) {
return [];
}

var opts = getScalebarOpts(d);
var metersPerPx = getMapFrameMetersPerPixel(frame);
var frameWidthPx = frame.width;
var unit = d.label ? parseScalebarUnits(d.label) : 'mile';
var number = d.label ? parseScalebarNumber(d.label) : null;
var label = number && unit ? d.label : getAutoScalebarLabel(frameWidthPx, metersPerPx, unit);
var scalebarKm = parseScalebarLabelToKm(label);
var barHeight = 3;
var labelOffs = 4;
var fontSize = +d.font_size || 12;
var width = Math.round(scalebarKm / metersPerPx * 1000);
var height = Math.round(barHeight + labelOffs + fontSize * 0.8);
var labelPos = d.label_position == 'top' ? 'top' : 'bottom';
var anchorX = pos.halign == 'left' ? 0 : width;
var anchorY = barHeight + labelOffs;
var dx = pos.halign == 'right' ? frameWidthPx - width - pos.hoffs : pos.hoffs;
var dy = pos.valign == 'bottom' ? frame.height - height - pos.voffs : pos.voffs;

var scalebarKm = parseScalebarLabelToKm(label);
if (scalebarKm > 0 === false) {
message('Unusable scalebar label:', label);
return [];
}

if (frameWidthPx > 0 === false) {
return [];
}

if (!frame.crs) {
message('Unable to render scalebar: unknown CRS.');
return [];
var width = Math.round(scalebarKm / metersPerPx * 1000);
if (width > 0 === false) {
stop("Null scalebar length");
}

if (labelPos == 'top') {
anchorY = -labelOffs;
dy += Math.round(labelOffs + fontSize * 0.8);
var pos = getScalebarPosition(opts);
var height = getScalebarHeight(opts);
var dx = pos.halign == 'right' ? frameWidthPx - width - opts.margin : opts.margin;
var dy = pos.valign == 'bottom' ? frame.height - height - opts.margin : opts.margin;
if (opts.label_position == 'top') {
dy += Math.round(opts.label_offset + opts.tic_length + opts.font_size * 0.8 + opts.bar_width / 2);
} else {
dy += Math.round(opts.bar_width / 2);
}

if (width > 0 === false) {
stop("Null scalebar length");
}
var barObj = {
tag: 'rect',
properties: {
fill: 'black',
x: 0,
y: 0,
width: width,
height: barHeight
}
};
var labelOpts = {
'label-text': label,
'font-size': fontSize,
'text-anchor': pos.halign == 'left' ? 'start': 'end',
'dominant-baseline': labelPos == 'top' ? 'auto' : 'hanging'
//// 'dominant-baseline': labelPos == 'top' ? 'text-after-edge' : 'text-before-edge'
// 'text-after-edge' is buggy in Safari and unsupported by Illustrator,
// so I'm using 'hanging' and 'auto', which seem to be well supported.
// downside: requires a kludgy multiplier to calculate scalebar height (see above)
};
var labelObj = symbolRenderers.label(labelOpts, anchorX, anchorY);
var g = {
tag: 'g',
children: [barObj, labelObj],
properties: {
transform: 'translate(' + dx + ' ' + dy + ')'
}
var g = renderAsSvg(width, label, opts);
g.properties = {
transform: 'translate(' + dx + ' ' + dy + ')'
};

return [g];
}

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