139 lines
4.7 KiB
JavaScript
139 lines
4.7 KiB
JavaScript
var pg = require('./pg');
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var _ = require('underscore')
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var svg_width = 1024.0;
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var svg_height = 768.0;
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var svg_ratio = svg_width/svg_height;
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function SvgFormat() {}
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SvgFormat.prototype = new pg('svg');
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SvgFormat.prototype.getQuery = function(sql, options) {
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var gn = options.gn;
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var dp = options.dp;
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return 'WITH source AS ( ' + sql + '), extent AS ( '
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+ ' SELECT ST_Extent(' + gn + ') AS e FROM source '
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+ '), extent_info AS ( SELECT e, '
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+ 'st_xmin(e) as ex0, st_ymax(e) as ey0, '
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+ 'st_xmax(e)-st_xmin(e) as ew, '
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+ 'st_ymax(e)-st_ymin(e) as eh FROM extent )'
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+ ', trans AS ( SELECT CASE WHEN '
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+ 'eh = 0 THEN ' + svg_width
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+ '/ COALESCE(NULLIF(ew,0),' + svg_width +') WHEN '
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+ svg_ratio + ' <= (ew / eh) THEN ('
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+ svg_width + '/ew ) ELSE ('
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+ svg_height + '/eh ) END as s '
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+ ', ex0 as x0, ey0 as y0 FROM extent_info ) '
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+ 'SELECT st_TransScale(e, -x0, -y0, s, s)::box2d as '
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+ gn + '_box, ST_Dimension(' + gn + ') as ' + gn
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+ '_dimension, ST_AsSVG(ST_TransScale(' + gn + ', '
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+ '-x0, -y0, s, s), 0, ' + dp + ') as ' + gn
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//+ ', ex0, ey0, ew, eh, s ' // DEBUG ONLY
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+ ' FROM trans, extent_info, source';
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};
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SvgFormat.prototype._contentType = "image/svg+xml; charset=utf-8";
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SvgFormat.prototype.transform = function(result, options, callback) {
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toSVG(result.rows, options.gn, callback);
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};
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function toSVG(rows, gn, callback) {
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var radius = 5; // in pixels (based on svg_width and svg_height)
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var stroke_width = 1; // in pixels (based on svg_width and svg_height)
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var stroke_color = 'black';
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// fill settings affect polygons and points (circles)
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var fill_opacity = 0.5; // 0.0 is fully transparent, 1.0 is fully opaque
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// unused if fill_color='none'
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var fill_color = 'none'; // affects polygons and circles
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var bbox; // will be computed during the results scan
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var polys = [];
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var lines = [];
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var points = [];
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_.each(rows, function(ele){
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if ( ! ele.hasOwnProperty(gn) ) {
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throw new Error('column "' + gn + '" does not exist');
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}
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var g = ele[gn];
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if ( ! g ) return; // null or empty
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var gdims = ele[gn + '_dimension'];
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// TODO: add an identifier, if any of "cartodb_id", "oid", "id", "gid" are found
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// TODO: add "class" attribute to help with styling ?
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if ( gdims == '0' ) {
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points.push('<circle r="[RADIUS]" ' + g + ' />');
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} else if ( gdims == '1' ) {
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// Avoid filling closed linestrings
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var linetag = '<path ';
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if ( fill_color != 'none' ) linetag += 'fill="none" ';
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linetag += 'd="' + g + '" />';
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lines.push(linetag);
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} else if ( gdims == '2' ) {
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polys.push('<path d="' + g + '" />');
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}
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if ( ! bbox ) {
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// Parse layer extent: "BOX(x y, X Y)"
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// NOTE: the name of the extent field is
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// determined by the same code adding the
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// ST_AsSVG call (in queryResult)
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//
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bbox = ele[gn + '_box'];
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bbox = bbox.match(/BOX\(([^ ]*) ([^ ,]*),([^ ]*) ([^)]*)\)/);
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bbox = {
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xmin: parseFloat(bbox[1]),
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ymin: parseFloat(bbox[2]),
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xmax: parseFloat(bbox[3]),
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ymax: parseFloat(bbox[4])
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};
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}
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});
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// Set point radius
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for (var i=0; i<points.length; ++i) {
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points[i] = points[i].replace('[RADIUS]', radius);
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}
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var header_tags = [
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'<?xml version="1.0" standalone="no"?>',
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'<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">',
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];
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var root_tag = '<svg ';
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if ( bbox ) {
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// expand box by "radius" + "stroke-width"
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// TODO: use a Box2d class for these ops
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var growby = radius+stroke_width;
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bbox.xmin -= growby;
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bbox.ymin -= growby;
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bbox.xmax += growby;
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bbox.ymax += growby;
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bbox.width = bbox.xmax - bbox.xmin;
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bbox.height = bbox.ymax - bbox.ymin;
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root_tag += 'viewBox="' + bbox.xmin + ' ' + (-bbox.ymax) + ' '
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+ bbox.width + ' ' + bbox.height + '" ';
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}
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root_tag += 'style="fill-opacity:' + fill_opacity
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+ '; stroke:' + stroke_color
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+ '; stroke-width:' + stroke_width
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+ '; fill:' + fill_color
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+ '" ';
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root_tag += 'xmlns="http://www.w3.org/2000/svg" version="1.1">';
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header_tags.push(root_tag);
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// Render points on top of lines and lines on top of polys
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var out = header_tags.concat(polys, lines, points);
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out.push('</svg>');
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// return payload
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callback(null, out.join("\n"));
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}
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module.exports = SvgFormat;
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