restaurant-search/client/scripts/grapher.js

/*

   The MIT License (MIT)

   Copyright (c) 2014 Alex Yatskov

   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.

*/

(function(grapher) {
    'use strict';

    //
    //  Range
    //

    function Range(min, max) {
        this.min = Math.min(min, max);
        this.max = Math.max(min, max);

        this.contains = function(value) {
            return value >= this.min && value <= this.max;
        };

        this.length = function() {
            return this.max - this.min;
        };

        this.clamp = function(value) {
            if (value < this.min) {
                return this.min;
            }

            if (value > this.max) {
                return this.max;
            }

            return value;
        };

        this.include = function(range) {
            this.min = Math.min(this.min, range.min);
            this.max = Math.max(this.max, range.max);
        };

        this.offset = function(value) {
            return (value - this.min) / this.length();
        };

        this.project = function(value) {
            return this.min + this.length() * value;
        };
    }


    //
    //  Column
    //

    function Column(params) {
        var _backdropColor = '#eeeeec';
        var _borderColor   = '#babdb6';
        var _fillColorNeg  = '#3465a4';
        var _fillColorPos  = '#cc0000';
        var _panelColor    = '#babdb6';
        var _tickColor     = '#888a85';

        var _densitySize = 10;
        var _desatOffset = -0.3;
        var _height      = 500;
        var _padding     = 10;
        var _panelSize   = 20;
        var _tickSize    = 5;
        var _width       = 125;

        var _enabled        = true;
        var _canvas         = params.canvas;
        var _data           = params.data;
        var _index          = params.index;
        var _name           = params.name;
        var _onValueChanged = params.onValueChanged;
        var _range          = params.range;
        var _scale          = params.scale;
        var _steps          = params.steps;
        var _elements       = {};

        function createShapes() {
            // backdrop
            _elements.backdrop = _canvas.rect(
                _tickSize, 0, _width - (_densitySize + _tickSize), _height - _panelSize
            ).attr({cursor: 'crosshair', stroke: _borderColor, fill: _backdropColor}).click(clicked);

            // density
            _elements.density = _canvas.rect(
                _width - _densitySize, 0, _densitySize, _height - _panelSize
            ).attr({stroke: _borderColor});

            // panel
            _elements.panel = _canvas.rect( _tickSize,
                _height - _panelSize, _width - _tickSize, _panelSize
            ).attr({fill: _panelColor});

            // label
            _elements.label = _canvas.text(
                _tickSize + (_width - _tickSize) / 2, _height - _panelSize / 2, _name
            ).attr({'dominant-baseline': 'middle', 'text-anchor': 'middle'});

            // indicator
            var range = computeIndicatorRange();
            _elements.indicator = _canvas.rect(
                _tickSize, range.min, _width - (_densitySize + _tickSize), (range.max - range.min)
            ).attr({cursor: 'crosshair', fill: computeIndicatorColor()}).click(clicked);

            // tick
            if (_range.contains(0.0)) {
                var origin = valueToIndicator(0.0);
                _elements.tick = _canvas.line(0, origin, _width - _densitySize, origin
                ).attr({stroke: _tickColor});
            }

            _elements.group = _canvas.group(
                _elements.backdrop,
                _elements.indicator,
                _elements.density,
                _elements.panel,
                _elements.tick,
                _elements.label
            );

            _elements.group.transform(
                Snap.format('t{x},{y}', {x: _index * (_width + _padding), y: 0})
            );

            updateShapes();
        }

        function updateShapes() {
            var fill = _data.hints.length === 0 ? _backdropColor : _canvas.gradient(decimateHints());
            _elements.density.attr({ fill: fill });

            var range = computeIndicatorRange();
            _elements.indicator.attr({
                y:      range.min,
                height: range.max - range.min,
                fill:   computeIndicatorColor()
            });
        }

        function decimateHints() {
            var colorStops = 'l(0,0,0,1)';

            var groups = groupHints();
            for (var i = 0, count = groups.length; i < count; ++i) {
                var groupSize = groups[i];

                var colorPercent = 0;
                if (_scale.length() > 0) {
                    colorPercent = Math.max(0, groupSize - _scale.min) / _scale.length();
                }

                var colorByte = 0xff - Math.min(0xff, Math.round(0xff * colorPercent));
                var colorObj  = tinycolor({ r: colorByte, g: colorByte, b: colorByte });
                var colorStr  = colorObj.toHexString();

                colorStops += colorStr;
                if (i + 1 < count) {
                    colorStops += '-';
                }
            }

            return colorStops;
        }

        function groupHints() {
            var stepSize = _range.length() / _steps;

            var hintGroups = [];
            for (var i = 0; i < _steps; ++i) {
                var stepMax = _range.max - stepSize * i;
                var stepMin = stepMax - stepSize;

                var hintCount = 0;
                for (var j = 0, count = _data.hints.length; j < count; ++j) {
                    var hint = _data.hints[j];
                    if (hint.sample > stepMin && hint.sample <= stepMax) {
                        hintCount += hint.count;
                    }
                }

                hintGroups.push(hintCount);
            }

            return hintGroups;
        }

        function updateValue(value) {
            _data.value = _range.clamp(value);

            if (_onValueChanged) {
                _onValueChanged(_name, _data.value);
            }

            updateShapes();
        }

        function valueColorAdjust(color, offset) {
            var colorObj = tinycolor(color);
            var rangeEnd = _data.value >= 0.0 ? _range.max : _range.min;
            var rangeMid = (_range.min + _range.max) / 2.0;
            var rangeRat = (_data.value - rangeMid) / (rangeEnd - rangeMid);
            var desatVal = Math.max(0.0, 1.0 - rangeRat + offset) * 100.0;
            return colorObj.desaturate(desatVal).toHexString();
        }

        function computeIndicatorColor() {
            var color = _data.value >= 0.0 ? _fillColorPos : _fillColorNeg;
            return valueColorAdjust(color, _desatOffset);
        }

        function computeIndicatorRange() {
            return new Range(valueToIndicator(0.0), valueToIndicator(_data.value));
        }

        function valueToIndicator(scalar) {
            var box    = _elements.backdrop.getBBox();
            var offset = _range.offset(scalar);
            return box.y + box.height * (1.0 - offset);
        }

        function indicatorToValue(scalar) {
            var box   = _elements.backdrop.getBBox();
            var range = new Range(box.y, box.y + box.height);
            return -_range.project(range.offset(scalar));
        }

        function clicked(event, x, y) {
            if (_enabled) {
                var rect = _canvas.node.getBoundingClientRect();
                updateValue(indicatorToValue(y - rect.top));
            }
        }

        this.update = function(data, scale) {
            _data  = data;
            _scale = scale;
            updateShapes();
        };

        this.enable = function(enable) {
            _enabled = enable;
        };

        createShapes();
    }


    //
    //  Grapher
    //

    grapher.Grapher = function(params) {
        var _canvas           = params.canvas;
        var _columns          = {};
        var _data             = {};
        var _range            = new Range(params.range.min || -1.0, params.range.max || 1.0);
        var _steps            = params.steps || 20;
        var _useLocalScale    = params.useLocalScale || true;
        var _useRelativeScale = params.useRelativeScale || true;
        var _onValueChanged   = params.onValueChanged;

        function computeLocalScale(hints) {
            var counts = _.pluck(hints, 'count');
            var min = _useRelativeScale ? _.min(counts) : 0;
            return new Range(min, _.max(counts));
        }

        function computeGlobalScale(hintData) {
            var globalScale = null;
            for (var i = 0, count = hintData.length; i < count; ++i) {
                var localScale = computeLocalScale(hintData[i]);
                if (globalScale) {
                    globalScale.include(localScale);
                }
                else {
                    globalScale = localScale;
                }
            }

            return globalScale;
        }

        this.setColumns = function(columns) {
            var scale = 0;
            if (!_useLocalScale) {
                var hintData = _.pluck(columns, 'hints');
                scale = computeGlobalScale(hintData);
            }

            var index = 0;
            for (var name in columns) {
                var data = _data[name] = columns[name];
                if (_useLocalScale) {
                    scale = computeLocalScale(data.hints);
                }

                var column = _columns[name];
                if (column) {
                    column.update(data, scale);
                }
                else {
                    _columns[name] = new Column({
                        onValueChanged: _onValueChanged,
                        steps:          _steps,
                        range:          _range,
                        canvas:         _canvas,
                        data:           data,
                        name:           name,
                        scale:          scale,
                        index:          index++,
                    });
                }
            }
        };

        this.setUseLocalScale = function(useLocalScale) {
            if (useLocalScale != _useLocalScale) {
                _useLocalScale = useLocalScale;
                this.setColumns(_data);
            }
        };

        this.setUseRelativeScale = function(useRelativeScale) {
            if (useRelativeScale != _useRelativeScale) {
                _useRelativeScale = useRelativeScale;
                this.setColumns(_data);
            }
        };

        this.enable = function(enable) {
            for (var name in _columns) {
                _columns[name].enable(enable);
            }
        };
    };
}(window.grapher = window.grapher || {}));