exponentla trend graph example

Author: monkstone

external_library/java/grafica/exponential_trend.rb

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+#!/usr/bin/env jruby
+# frozen_string_literal: true
+
+require 'picrate'
+
+class ExponentialTrend < Processing::App
+
+  load_library 'grafica'
+  java_import 'grafica.GPointsArray'
+  java_import 'grafica.GPlot'
+  java_import 'java.util.Random'
+
+  N_POINTS = 1_000
+  attr_reader :plot, :log_scale, :random, :points
+
+  def settings
+    size(450, 450)
+  end
+
+  def setup
+    sketch_title 'Exponential Trend'
+    @random = Random.new
+    # Prepare the points for the plot
+    @points = GPointsArray.new(N_POINTS)
+    @plot = GPlot.new(self)
+    puts plot.inspect
+    @log_scale = false
+    N_POINTS.times do
+      x_value = rand(10..200)
+      y_value = 10**(0.015 * x_value)
+      x_error = 2 * random.next_gaussian
+      y_error = 2 * random.next_gaussian
+      points.add(x_value + x_error, y_value + y_error)
+    end
+    # Create the plot
+    plot.set_pos(25, 25)
+    plot.set_dim(300, 300)
+    # or all in one go
+    # plot = GPlot.new(self, 25, 25, 300, 300)
+    # Set the plot title and the axis labels
+    plot.set_title_text('Exponential law')
+    # NB: cannot use snake for getXAxis etc
+    plot.getXAxis.set_axis_label_text('x')
+    toggle_y_axis
+    # Add the points to the plot
+    plot.set_points(points)
+    plot.set_point_color(color(100, 100, 255, 50))
+  end
+
+  def draw
+    background(150)
+    plot.begin_draw
+    plot.draw_background
+    plot.draw_box
+    plot.drawXAxis
+    plot.drawYAxis
+    plot.draw_top_axis
+    plot.draw_right_axis
+    plot.draw_title
+    plot.draw_points
+    plot.end_draw
+  end
+
+  def toggle_y_axis
+    y_axis = plot.getYAxis
+    if log_scale
+      plot.set_log_scale('y')
+      y_axis.set_axis_label_text('log y')
+    else
+      plot.set_log_scale('')
+      y_axis.set_axis_label_text('y')
+    end
+  end
+
+  def mouse_clicked
+    @log_scale = !log_scale
+    toggle_y_axis
+  end
+end
+
+ExponentialTrend.new