File size: 2,995 Bytes
ae4627d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | "use strict";
var _ = require("underscore");
var Layer = require("../../layer/Layer");
const _default_config = {
highInput: "high",
lowInput: "low",
volumeInput: "volume",
relativeWidth: 0.3333,
vertexCount: 120,
color: "rgba(153, 180, 255, 0.7)"
};
/**
* Represents a volume profile chart layer.
* <br><br>
* @extends layer.Layer
* @memberof layer.indicator
*/
class VolumeProfileLayer extends Layer {
/**
* Instantiate VolumeProfileLayer
* @constructor
* @param {Object} config
*/
constructor(config) {
config = _.extend({}, _default_config, config);
super(config);
}
/**
* Render layer onto canvas
* @param {timeseries.TimeSeriesData} data
* @param {number} count
* @param {number} offset
* @param {valueToPixel} valueToPixel
* @param {indexToPixel} indexToPixel
* @param {timeseries.ValueBounds} value_bounds
*/
draw(data, count, offset, valueToPixel, indexToPixel, value_bounds) {
var context = this._getContext();
var field_map = data.getFieldMap();
var data_arr = data.getRawData();
this.elements = [];
var vertex_count = this.vertexCount;
var min = value_bounds.min;
var max = value_bounds.max;
var range = max - min;
var pixel_width = this.profileWidth || (this.getDrawingWidth() * this.relativeWidth);
var pixel_height = this.getHeight();
var bar_width = pixel_height / vertex_count;
var half_bar_width = bar_width * 0.5;
var hist = [];
var high_field = field_map[this.highInput];
var low_field = field_map[this.lowInput];
var volume_field = field_map[this.volumeInput];
var max_value = 0;
for(var i = 0; i < vertex_count; i++)
{
hist[i] = 0;
}
for(i = offset >= 0 ? offset : 0; i < offset + count && i < data_arr.length; i++)
{
var dat = data_arr[i];
var high = dat[high_field], low = dat[low_field], vol = dat[volume_field];
var hist_index_low = Math.floor((low - min) / range * vertex_count); // e.g. (4475 - 4450) / 2000 * 20 = floor(0.25) = 0
var hist_index_high = Math.floor((high - min) / range * vertex_count);
var vol_fract = 1 / ((hist_index_high - hist_index_low) + 1);
for(var h = hist_index_low; h <= hist_index_high; h++)
{
hist[h] += Math.round(vol * vol_fract);
}
}
for(var j = 0; j < vertex_count; j++)
{
if(hist[j] > max_value)
{
max_value = hist[j];
}
}
context.fillStyle = this.color;
context.beginPath();
context.moveTo(0, pixel_height);
for(j = 0; j < vertex_count; j++)
{
var val = hist[j];
var x = val / max_value * pixel_width;
var y = pixel_height - (j + 1) / vertex_count * pixel_height * 1.0; // index + 1 because we flip y
context.lineTo(x, y + half_bar_width);
context.lineTo(x, y - half_bar_width);
}
context.lineTo(0, 0);
context.closePath();
context.fill();
}
}
module.exports = VolumeProfileLayer;
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