/*global require*/
"use strict";
var defaultValue = require('terriajs-cesium/Source/Core/defaultValue');
var defineProperties = require('terriajs-cesium/Source/Core/defineProperties');
var defined = require('terriajs-cesium/Source/Core/defined');
var LegendUrl = require('./LegendUrl');
/**
* Legend object for generating and displaying a legend.
* Constructor: new Legend(props), where props is an object containing many properties.
* Other than the "items" property, it is preferable to leave other properties to their defaults
* for style consistency.
*/
var Legend = function(props) {
props = defaultValue(props, {});
this.title = props.title;
/**
* Gets or sets the list of items, ordered from bottom to top, with properties:
* * `color`: CSS color description,
* * `multipleColors`: An array of CSS color descriptions. A grid of these colors will be displayed in the box to the left of the item label.
* * `title`: label placed level with middle of box
* * `titleAbove`: label placed level with top of box
* * `titleBelow`: label placed level with bottom of box
* * `imageUrl`: url of image that will be drawn instead of a coloured box
* * `imageWidth`, `imageHeight`: image dimensions
* * `spacingAbove`: adds to itemSpacing for this item only.
* @type {Object[]}
*/
this.items = defaultValue(props.items, []);
/**
* Gets or sets a color map used to draw a smooth gradient instead of discrete color boxes.
* @type {ColorMap}
*/
this.gradientColorMap = props.gradientColorMap;
/**
* Gets or sets the maximum height of the whole color bar, unless very many items.
* @type {Number}
* @default 130
*/
this.barHeightMax = defaultValue(props.barHeightMax, 130);
/**
* Gets or sets the minimum height of the whole color bar.
* @type {Number}
* @default 30
*/
this.barHeightMin = defaultValue(props.barHeightMax, 30);
/**
* Gets or sets the width of each color box (and hence, the color bar)
* @type {Number}
* @default 30
*/
this.itemWidth = defaultValue(props.itemWidth, 30);
/**
* Gets or sets the asbolute minimum height of each color box, overruling barHeightMax.
* @type {Number}
* @default 12
*/
this.itemHeightMin = defaultValue(props.itemHeightMin, 12);
/**
* Gets or sets the forced height of each color box. Better to leave unset.
* @type {Number}
* @default the smaller of `props.barHeightMax / props.items.length` and 30.
*/
this.itemHeight = props.itemHeight;
/**
* Gets or sets the gap between each pair of color boxes.
* @type {Number}
* @default 0
*/
this.itemSpacing = defaultValue(props.itemSpacing, 0);
/**
* Gets or sets the spacing to the left of the color bar.
* @type {Number}
* @default 5
*/
this.barLeft = defaultValue(props.barLeft, 5);
/**
* Gets or sets the spacing between the title and color bar.
* @type {Number}
* @default 5
*/
this.barTop = defaultValue(props.barTop, 5);
/**
* Gets or sets the forced total width of the legend.
* @type {Number}
* @default 315
*/
this.width = defaultValue(props.width, 315);
/**
* Gets or sets the horizontal offset of variable title.
* @type {Number}
* @default 5
*/
this.variableNameLeft = defaultValue(props.variableNameLeft, 5);
/**
* Gets or sets the vertical offset of variable title.
* @type {Number}
* @default 17
*/
this.variableNameTop = defaultValue(props.variableNameTop, 17);
/**
* Gets or sets the CSS class that will be applied to the legend when it is displayed.
* This is used to ensure that the correct font is used when measuring text for word wrapping.
* @type {String}
*/
this.cssClass = defaultValue(props.cssClass, 'tjs-legend__legend');
this._svg = undefined;
};
defineProperties(Legend.prototype, {
computedItemHeight: {
get: function() {
return defaultValue(this.itemHeight, Math.max(Math.min(this.barHeightMax / this.items.length, 30), this.itemHeightMin));
},
set: function(h) {
this.itemHeight = h;
}
}
});
function initSvg(legend) {
legend._svgns = 'http://www.w3.org/2000/svg';
legend._svg = document.createElementNS(legend._svgns, 'svg');
//legend._svg.setAttribute('xmlns:xlink', 'http://www.w3.org/1999/xlink');
legend._svg.setAttribute('version', "1.1");
legend._svg.setAttribute('width', legend.width);
legend._svg.setAttribute('class', 'generated-legend now-viewing-legend-image-background');
}
function finishSvg(legend, background, height) {
background.setAttribute('height', height);
legend._svg.setAttribute('height', height);
legend._svg.setAttribute('style', 'height: ' + height + 'px');
// we create this temporary wrapper because IE doesn't allow innerHTML on SVG nodes.
var temp = document.createElement('div');
var node = legend._svg.cloneNode(true);
temp.appendChild(node);
return temp.innerHTML;
}
function addSvgElement(legend, element, attributes, className, innerText) {
return legend._svg.appendChild(svgElement(legend, element, attributes, className, innerText));
}
function svgElement(legend, element, attributes, className, innerText) {
var ele = document.createElementNS(legend._svgns, element);
Object.keys(attributes).forEach(function(att) {
if (att.indexOf('xlink:') === 0) {
ele.setAttributeNS('http://www.w3.org/1999/xlink', att.substring('xlink:'.length), attributes[att]);
} else {
ele.setAttribute(att, attributes[att]);
}
});
if (defined(innerText)) {
ele.textContent = innerText;
}
if (defined(className)) {
ele.setAttribute('class', className);
}
return ele;
}
/*
* The name of the active data variable, drawn above the ramp or gradient.
*/
function drawVariableName(legend) {
// Create a hidden DOM element to use to measure text.
var measureElement = document.createElement('span');
measureElement.className = legend.cssClass;
measureElement.style.opacity = 0;
measureElement.style.position = 'fixed';
document.body.appendChild(measureElement);
var parts = (legend.title || '').split(' ');
var start = 0;
var end = parts.length;
var y = legend.variableNameTop;
while (start < parts.length) {
var text = parts.slice(start, end).join(' ');
measureElement.textContent = text;
var dimensions = measureElement.getBoundingClientRect();
// Add this text if it fits on the line, or if we're down to just one word.
// Ideally, if we have one word and it doesn't fit on the line, we'd wrap
// mid-word, but that would be a hassle: we'd have to find the portion of the
// word that fits using a search-by-character much like the one we're already doing for
// words. Since this is a pretty unlikely corner case anyway (I hope), let's just
// stick it all on one line and let the browser clip it on overflow.
if (dimensions.width <= legend.width || start === end - 1) {
addSvgElement(legend, 'text', {
x: legend.variableNameLeft,
y: y,
}, 'variable-label', text);
y += dimensions.height;
start = end;
end = parts.length;
} else {
--end;
}
}
document.body.removeChild(measureElement);
return y;
}
var gradientCount = 0;
/* The older, non-quantised, smooth gradient. */
function drawGradient(legend, barGroup, y) {
var id = 'terriajs-legend-gradient' + (++gradientCount);
var defs = addSvgElement(legend, 'defs', {}); // apparently it's ok to have the defs anywhere in the doc
var linearGradient = svgElement(legend, 'linearGradient', {
x1: '0',
x2: '0',
y1: '1',
y2: '0',
id: id
});
legend.gradientColorMap.forEach(function(c, i) {
linearGradient.appendChild(svgElement(legend, 'stop', {
offset: c.offset,
'stop-color': c.color
}));
});
defs.appendChild(linearGradient);
var gradientItems = legend.items.filter(function(item) {
return !defined(item.color);
});
var totalSpacingAbove = gradientItems.reduce(function(prev, item) {
return prev + (item.spacingAbove || 0);
}, 0);
var barHeight = Math.max((legend.computedItemHeight + legend.itemSpacing) * gradientItems.length + totalSpacingAbove, legend.barHeightMin);
addSvgElement(legend, 'rect', {
x: legend.barLeft,
y: y,
width: legend.itemWidth,
height: barHeight,
fill: 'url(#' + id + ')'
}, 'gradient-bar');
return barHeight;
}
/*
* Draw each of the colored boxes.
*/
function drawItemBoxes(legend, barGroup) {
legend.items.forEach(function(item, i) {
var itemTop = itemY(legend, i);
if (defined(item.imageUrl)) {
barGroup.appendChild(svgElement(legend, 'image', {
'xlink:href': item.imageUrl,
x: 0,
y: itemTop,
width: Math.min(item.imageWidth, legend.itemWidth + 4), // let them overlap slightly
height: Math.min(item.imageHeight, legend.computedItemHeight + 4)
}, 'item-icon'));
return;
}
if (defined(item.multipleColors)) {
var columns = Math.sqrt(item.multipleColors.length) | 0;
var rows = Math.ceil(item.multipleColors.length / columns) | 0;
var colorCount = item.multipleColors.length;
var index = 0;
var y = itemTop;
for (var row = 0; index < colorCount && row < rows; ++row) {
var height = row === rows - 1 ? legend.computedItemHeight - (y - itemTop) : legend.computedItemHeight / rows;
var x = 0;
for (var column = 0; index < colorCount && column < columns; ++column) {
var color = item.multipleColors[index++];
var width = column === columns - 1 ? legend.itemWidth - x : legend.itemWidth / columns;
barGroup.appendChild(svgElement(legend, 'rect', {
fill: color,
x: x,
y: y,
width: width,
height: height
}, 'item-box'));
x += width;
}
y += height;
}
} else if (defined(item.color)) {
barGroup.appendChild(svgElement(legend, 'rect', {
fill: item.color,
x: 0,
y: itemTop,
width: legend.itemWidth,
height: legend.computedItemHeight
}, 'item-box'));
}
});
}
/*
* The Y position of the top of a given item number, relative to the top of the bar.
*/
function itemY(legend, itemNumber) {
var cumSpacingAbove = legend.items.slice(itemNumber).reduce(function(prev, item) { return prev + (item.spacingAbove || 0); }, 0);
return (legend.items.length - itemNumber - 1) * (legend.computedItemHeight + legend.itemSpacing) + cumSpacingAbove;
}
/*
* Label the thresholds between bins for numeric columns, or the color boxes themselves in other cases.
*/
function drawItemLabels(legend, barGroup) {
// draw a subtle tick to help indicate what the label refers to
function drawTick (y) {
barGroup.appendChild(svgElement(legend, 'line', {
x1: legend.itemWidth,
x2: legend.itemWidth + 5,
y1: y,
y2: y
}, 'tick-mark'));
}
function drawLabel(y, text) {
var textOffsetX = 7;
var textOffsetY = 3; // pixel shuffling to get the text to line up just right.
barGroup.appendChild(svgElement(legend, 'text', {
x: legend.itemWidth + textOffsetX,
y: y + textOffsetY
}, 'item-label' + (legend.items.length > 6 ? '-small' : ''), text));
}
legend.items.forEach(function(item, i) {
var y = itemY(legend, i);
if (defined(item.titleAbove)) {
drawLabel(y, item.titleAbove);
drawTick(y);
}
if (defined(item.title)) {
drawLabel(y + legend.computedItemHeight / 2, item.title);
}
if (defined(item.titleBelow)) {
drawLabel(y + legend.computedItemHeight, item.titleBelow);
drawTick(y + legend.computedItemHeight);
}
});
return itemY(legend, -1);
}
function drawBackground(legend) {
return addSvgElement(legend, 'rect', {
x: 0,
y: 0,
width: legend.width,
height: 1, // reset in finishSvg
}, 'background'); // same class as in LegendSection.html
}
/**
* Generate legend and return it as an SVG string
* @return {String}
*/
Legend.prototype.drawSvg = function() {
initSvg(this);
var background = drawBackground(this);
var y = drawVariableName(this);
var barGroup = addSvgElement(this, 'g', {
transform: 'translate(' + this.barLeft + ',' + (y + this.barTop) + ')'
}, 'legend-bar-group');
var gradientY = y + this.barTop;
var labelsY = y + this.barTop;
if (defined(this.gradientColorMap)) {
gradientY += drawGradient(this, barGroup, gradientY);
}
if (this.items.length > 0) {
drawItemBoxes(this, barGroup);
labelsY += drawItemLabels(this, barGroup);
}
y = Math.max(gradientY, labelsY);
return finishSvg(this, background, y + this.computedItemHeight / 2);
};
/**
* Generate legend and return it as a data URI containing an SVG. Note that this SVG does
* not contain inline styles.
* @return {String}
*/
Legend.prototype.asSvgUrl = function() {
return "data:image/svg+xml," + this.drawSvg();
};
/**
* Return a LegendUrl object which actually contains the SVG as a property, .safeSvgContent.
*/
Legend.prototype.getLegendUrl = function() {
var svg = this.drawSvg();
var legendUrl = new LegendUrl('data:image/svg+xml,' + svg, 'image/svg+xml');
legendUrl.safeSvgContent = svg;
return legendUrl;
};
module.exports = Legend;