audio_utils/include/audio_utils/LogPlot.h - platform/system/media - Git at Google

 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef LOG_PLOT_H
 #define LOG_PLOT_H

 #include <algorithm>
 #include <cmath>
 #include <iomanip>      // setw
 #include <iostream>
 #include <map>
 #include <sstream>
 #include <string>

 // TODO Make a class called LogPlot and put this functionality in it.
 // Actually maybe this file can be called AsciiPlot or something...
 /**
  * \brief Creates a std::string graph representation of equally-spaced time-series data points.
  *
  * \param first     RandomAccessIterator iterator to initial position of sequence.
  *                  Iterator shall point to a pair<float, bool>, where the float is the data value
  *                  and the bool is whether the data value is the start of a new data point in time
  *                  (i.e. a break in time continuity).
  * \param last      RandomAccessIterator iterator to final position of sequence.
  * \return the std::string of the graph.
  *
  */
 template <class RandomAccessIterator>
 std::string audio_utils_log_plot(RandomAccessIterator first, RandomAccessIterator last)
 {
     using T = decltype((*first).first);

     constexpr int HEIGHT = 14;                    // Character height of the plot
     // Leave 20% display space before min and after max data points
     constexpr float RANGE_BUFFER_ROOM = 0.2f;
     // Minimum range of lowest and highest y-axis value to display
     constexpr int RANGE_MIN = 14;
     constexpr unsigned int WIDTH_MAX = 200U;      // Max character width of plot
     const size_t size = last - first;

     if (size <= 0) {
         return "";
     }

     // Find min and max element in the vector.
     const auto result = std::minmax_element(first, last);
     const T minVal = (*result.first).first;
     const T maxVal = (*result.second).first;

     const T range = maxVal - minVal;
     T graphMin, graphMax;
     if (range < RANGE_MIN) {
         T avg = (maxVal + minVal) / 2;
         graphMin = avg - RANGE_MIN / 2;
         graphMax = avg + RANGE_MIN / 2;
     } else {
         graphMin = minVal - range * RANGE_BUFFER_ROOM;
         graphMax = maxVal + range * RANGE_BUFFER_ROOM;
     }

     // Value of one character height increase on the graph
     const T increment = (graphMax - graphMin) / HEIGHT;
     // Something went wrong if we reached this statement..
     if (increment <= 0.0f) {
         return "";
     }

     std::stringstream ss;
     ss << std::fixed << std::setprecision(1);

     // Start storing the graph into string.
     // TODO store everything into a preallocated string rather than use stringstream.
     // This may make the code easier to maintain.
     ss << "\n";
     for (int height = HEIGHT - 1; height >= 0; height--) {
         int spaces = 1;     // Amount of spaces before the data point
         ss << std::setw(9) << graphMin + increment * height;
         ss << std::setw(3) << "-|";
         auto it = size <= WIDTH_MAX ? first : first + size - WIDTH_MAX;
         for (; it < last; ++it) {
             const T power = it->first;
             const bool start = it->second;
             // TODO explicitly do type conversion for parameter passed to round()?
             int px = (int)round((power - graphMin) / increment);
             // The it != last - 1 is a temporary workaround to prevent vertical bar
             // separators after the last data point entry.
             if ((start || px == height) && it != last - 1) {
                 ss << std::setw(spaces) << (start ? "|" : "*");
                 spaces = 1;
             } else {
                 spaces++;
             }
         }
         ss << "\n";
     }
     ss << std::setw(12) << "|";
     ss << std::string(std::min(size - (size_t)1, (size_t)WIDTH_MAX), '_') << "\n\n";

     return ss.str();
 }

 // determines how many character spaces an integer takes up.
 inline int widthOf(int x) {
     int width = 0;
     if (x < 0) {
         ++width;
         x = x == INT_MIN ? INT_MAX : -x;
     }
     // assert (x >= 0)
     do {
         ++width;
         x /= 10;
     } while (x > 0);
     return width;
 }

 // computes the column width required for a specific histogram value
 inline int numberWidth(double number, int leftPadding) {
     // Added values account for whitespaces needed around numbers, and for the
     // dot and decimal digit not accounted for by widthOf
     return std::max(std::max(widthOf(static_cast<int>(number)) + 3, 2), leftPadding + 1);
 }

 // TODO Make this templated and add comments.
 inline std::string audio_utils_plot_histogram(const std::map<double, int> &buckets,
         const char *title = "", const char *label = "", int maxHeight = 10)
 {
     if (buckets.empty()) {
         return "";
     }

     auto it = buckets.begin();
     double maxDelta = it->first;
     int maxCount = it->second;
     // Compute maximum values
     while (++it != buckets.end()) {
         if (it->first > maxDelta) {
             maxDelta = it->first;
         }
         if (it->second > maxCount) {
             maxCount = it->second;
         }
     }
     int height = log2(maxCount) + 1; // maxCount > 0, safe to call log2
     const int leftPadding = widthOf(1 << height);
     const int bucketWidth = numberWidth(maxDelta, leftPadding);
     int scalingFactor = 1;
     // scale data if it exceeds maximum height
     if (height > maxHeight) {
         scalingFactor = (height + maxHeight) / maxHeight;
         height /= scalingFactor;
     }
     std::stringstream ss;
     ss << title << "\n " << std::setw(leftPadding) << " ";
     // write histogram label line with bucket values
     for (auto const &x : buckets) {
         const int colWidth = numberWidth(x.first, leftPadding);
         ss << std::setw(colWidth) << x.second;
     }
     // write histogram ascii art
     // underscores and spaces length corresponds to maximum width of histogram
     constexpr int kLen = 200;
     static const std::string underscores(kLen, '_');
     static const std::string spaces(kLen, ' ');
     auto getTail = [](const size_t n, const std::string &s) {
         return s.c_str() + s.size() - std::min(n, s.size());
     };

     ss << "\n ";
     for (int row = height * scalingFactor; row >= 0; row -= scalingFactor) {
         // TODO explain how value is derived from log2 and why it doesn't overflow.
         const int value = 1 << row;
         ss << getTail(leftPadding, spaces);
         for (auto const &x : buckets) {
             const int colWidth = numberWidth(x.first, leftPadding);
             ss << getTail(colWidth - 1, spaces) <<
                 (x.second < value ? " " : "|");
         }
         ss << "\n ";
     }
     // print x-axis
     const int columns = static_cast<int>(buckets.size());
     ss << std::setw(leftPadding) << " "
         << getTail((columns + 1) * bucketWidth, underscores) << "\n ";

     // write footer with bucket labels
     ss << std::setw(leftPadding) << " ";
     for (auto const &x : buckets) {
         const int colWidth = numberWidth(x.first, leftPadding);
         ss << std::setw(colWidth) << std::fixed << std::setprecision(1) << x.first;
     }
     ss << getTail(bucketWidth, spaces) << label << "\n";

     return ss.str();
 }

 #endif // !LOG_PLOT_H
	/*
	* Copyright (C) 2018 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef LOG_PLOT_H
	#define LOG_PLOT_H

	#include <algorithm>
	#include <cmath>
	#include <iomanip> // setw
	#include <iostream>
	#include <map>
	#include <sstream>
	#include <string>

	// TODO Make a class called LogPlot and put this functionality in it.
	// Actually maybe this file can be called AsciiPlot or something...
	/**
	* \brief Creates a std::string graph representation of equally-spaced time-series data points.
	*
	* \param first RandomAccessIterator iterator to initial position of sequence.
	* Iterator shall point to a pair<float, bool>, where the float is the data value
	* and the bool is whether the data value is the start of a new data point in time
	* (i.e. a break in time continuity).
	* \param last RandomAccessIterator iterator to final position of sequence.
	* \return the std::string of the graph.
	*
	*/
	template <class RandomAccessIterator>
	std::string audio_utils_log_plot(RandomAccessIterator first, RandomAccessIterator last)
	{
	using T = decltype((*first).first);

	constexpr int HEIGHT = 14; // Character height of the plot
	// Leave 20% display space before min and after max data points
	constexpr float RANGE_BUFFER_ROOM = 0.2f;
	// Minimum range of lowest and highest y-axis value to display
	constexpr int RANGE_MIN = 14;
	constexpr unsigned int WIDTH_MAX = 200U; // Max character width of plot
	const size_t size = last - first;

	if (size <= 0) {
	return "";
	}

	// Find min and max element in the vector.
	const auto result = std::minmax_element(first, last);
	const T minVal = (*result.first).first;
	const T maxVal = (*result.second).first;

	const T range = maxVal - minVal;
	T graphMin, graphMax;
	if (range < RANGE_MIN) {
	T avg = (maxVal + minVal) / 2;
	graphMin = avg - RANGE_MIN / 2;
	graphMax = avg + RANGE_MIN / 2;
	} else {
	graphMin = minVal - range * RANGE_BUFFER_ROOM;
	graphMax = maxVal + range * RANGE_BUFFER_ROOM;
	}

	// Value of one character height increase on the graph
	const T increment = (graphMax - graphMin) / HEIGHT;
	// Something went wrong if we reached this statement..
	if (increment <= 0.0f) {
	return "";
	}

	std::stringstream ss;
	ss << std::fixed << std::setprecision(1);

	// Start storing the graph into string.
	// TODO store everything into a preallocated string rather than use stringstream.
	// This may make the code easier to maintain.
	ss << "\n";
	for (int height = HEIGHT - 1; height >= 0; height--) {
	int spaces = 1; // Amount of spaces before the data point
	ss << std::setw(9) << graphMin + increment * height;
	ss << std::setw(3) << "-\|";
	auto it = size <= WIDTH_MAX ? first : first + size - WIDTH_MAX;
	for (; it < last; ++it) {
	const T power = it->first;
	const bool start = it->second;
	// TODO explicitly do type conversion for parameter passed to round()?
	int px = (int)round((power - graphMin) / increment);
	// The it != last - 1 is a temporary workaround to prevent vertical bar
	// separators after the last data point entry.
	if ((start \|\| px == height) && it != last - 1) {
	ss << std::setw(spaces) << (start ? "\|" : "*");
	spaces = 1;
	} else {
	spaces++;
	}
	}
	ss << "\n";
	}
	ss << std::setw(12) << "\|";
	ss << std::string(std::min(size - (size_t)1, (size_t)WIDTH_MAX), '_') << "\n\n";

	return ss.str();
	}

	// determines how many character spaces an integer takes up.
	inline int widthOf(int x) {
	int width = 0;
	if (x < 0) {
	++width;
	x = x == INT_MIN ? INT_MAX : -x;
	}
	// assert (x >= 0)
	do {
	++width;
	x /= 10;
	} while (x > 0);
	return width;
	}

	// computes the column width required for a specific histogram value
	inline int numberWidth(double number, int leftPadding) {
	// Added values account for whitespaces needed around numbers, and for the
	// dot and decimal digit not accounted for by widthOf
	return std::max(std::max(widthOf(static_cast<int>(number)) + 3, 2), leftPadding + 1);
	}

	// TODO Make this templated and add comments.
	inline std::string audio_utils_plot_histogram(const std::map<double, int> &buckets,
	const char title = "", const char label = "", int maxHeight = 10)
	{
	if (buckets.empty()) {
	return "";
	}

	auto it = buckets.begin();
	double maxDelta = it->first;
	int maxCount = it->second;
	// Compute maximum values
	while (++it != buckets.end()) {
	if (it->first > maxDelta) {
	maxDelta = it->first;
	}
	if (it->second > maxCount) {
	maxCount = it->second;
	}
	}
	int height = log2(maxCount) + 1; // maxCount > 0, safe to call log2
	const int leftPadding = widthOf(1 << height);
	const int bucketWidth = numberWidth(maxDelta, leftPadding);
	int scalingFactor = 1;
	// scale data if it exceeds maximum height
	if (height > maxHeight) {
	scalingFactor = (height + maxHeight) / maxHeight;
	height /= scalingFactor;
	}
	std::stringstream ss;
	ss << title << "\n " << std::setw(leftPadding) << " ";
	// write histogram label line with bucket values
	for (auto const &x : buckets) {
	const int colWidth = numberWidth(x.first, leftPadding);
	ss << std::setw(colWidth) << x.second;
	}
	// write histogram ascii art
	// underscores and spaces length corresponds to maximum width of histogram
	constexpr int kLen = 200;
	static const std::string underscores(kLen, '_');
	static const std::string spaces(kLen, ' ');
	auto getTail = [](const size_t n, const std::string &s) {
	return s.c_str() + s.size() - std::min(n, s.size());
	};

	ss << "\n ";
	for (int row = height * scalingFactor; row >= 0; row -= scalingFactor) {
	// TODO explain how value is derived from log2 and why it doesn't overflow.
	const int value = 1 << row;
	ss << getTail(leftPadding, spaces);
	for (auto const &x : buckets) {
	const int colWidth = numberWidth(x.first, leftPadding);
	ss << getTail(colWidth - 1, spaces) <<
	(x.second < value ? " " : "\|");
	}
	ss << "\n ";
	}
	// print x-axis
	const int columns = static_cast<int>(buckets.size());
	ss << std::setw(leftPadding) << " "
	<< getTail((columns + 1) * bucketWidth, underscores) << "\n ";

	// write footer with bucket labels
	ss << std::setw(leftPadding) << " ";
	for (auto const &x : buckets) {
	const int colWidth = numberWidth(x.first, leftPadding);
	ss << std::setw(colWidth) << std::fixed << std::setprecision(1) << x.first;
	}
	ss << getTail(bucketWidth, spaces) << label << "\n";

	return ss.str();
	}

	#endif // !LOG_PLOT_H