llvm/tools/llvm-xray/xray-color-helper.cpp

   1 //===-- xray-graph.cpp: XRay Function Call Graph Renderer -----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // A class to get a color from a specified gradient.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "xray-color-helper.h"
  14 #include "llvm/Support/FormatVariadic.h"
  15 #include "llvm/Support/raw_ostream.h"
  16 #include <cmath>
  17
  18 using namespace llvm;
  19 using namespace xray;
  20
  21 //  Sequential ColorMaps, which are used to represent information
  22 //  from some minimum to some maximum.
  23
  24 const std::tuple<uint8_t, uint8_t, uint8_t> SequentialMaps[][9] = {
  25     {// The greys color scheme from http://colorbrewer2.org/
  26      std::make_tuple(255, 255, 255), std::make_tuple(240, 240, 240),
  27      std::make_tuple(217, 217, 217), std::make_tuple(189, 189, 189),
  28      std::make_tuple(150, 150, 150), std::make_tuple(115, 115, 115),
  29      std::make_tuple(82, 82, 82), std::make_tuple(37, 37, 37),
  30      std::make_tuple(0, 0, 0)},
  31     {// The OrRd color scheme from http://colorbrewer2.org/
  32      std::make_tuple(255, 247, 236), std::make_tuple(254, 232, 200),
  33      std::make_tuple(253, 212, 158), std::make_tuple(253, 187, 132),
  34      std::make_tuple(252, 141, 89), std::make_tuple(239, 101, 72),
  35      std::make_tuple(215, 48, 31), std::make_tuple(179, 0, 0),
  36      std::make_tuple(127, 0, 0)},
  37     {// The PuBu color scheme from http://colorbrewer2.org/
  38      std::make_tuple(255, 247, 251), std::make_tuple(236, 231, 242),
  39      std::make_tuple(208, 209, 230), std::make_tuple(166, 189, 219),
  40      std::make_tuple(116, 169, 207), std::make_tuple(54, 144, 192),
  41      std::make_tuple(5, 112, 176), std::make_tuple(4, 90, 141),
  42      std::make_tuple(2, 56, 88)}};
  43
  44 // Sequential Maps extend the last colors given out of range inputs.
  45 const std::tuple<uint8_t, uint8_t, uint8_t> SequentialBounds[][2] = {
  46     {// The Bounds for the greys color scheme
  47      std::make_tuple(255, 255, 255), std::make_tuple(0, 0, 0)},
  48     {// The Bounds for the OrRd color Scheme
  49      std::make_tuple(255, 247, 236), std::make_tuple(127, 0, 0)},
  50     {// The Bounds for the PuBu color Scheme
  51      std::make_tuple(255, 247, 251), std::make_tuple(2, 56, 88)}};
  52
  53 ColorHelper::ColorHelper(ColorHelper::SequentialScheme S)
  54     : MinIn(0.0), MaxIn(1.0), ColorMap(SequentialMaps[static_cast<int>(S)]),
  55       BoundMap(SequentialBounds[static_cast<int>(S)]) {}
  56
  57 // Diverging ColorMaps, which are used to represent information
  58 // representing differenes, or a range that goes from negative to positive.
  59 // These take an input in the range [-1,1].
  60
  61 const std::tuple<uint8_t, uint8_t, uint8_t> DivergingCoeffs[][11] = {
  62     {// The PiYG color scheme from http://colorbrewer2.org/
  63      std::make_tuple(142, 1, 82), std::make_tuple(197, 27, 125),
  64      std::make_tuple(222, 119, 174), std::make_tuple(241, 182, 218),
  65      std::make_tuple(253, 224, 239), std::make_tuple(247, 247, 247),
  66      std::make_tuple(230, 245, 208), std::make_tuple(184, 225, 134),
  67      std::make_tuple(127, 188, 65), std::make_tuple(77, 146, 33),
  68      std::make_tuple(39, 100, 25)}};
  69
  70 // Diverging maps use out of bounds ranges to show missing data. Missing Right
  71 // Being below min, and missing left being above max.
  72 const std::tuple<uint8_t, uint8_t, uint8_t> DivergingBounds[][2] = {
  73     {// The PiYG color scheme has green and red for missing right and left
  74      // respectively.
  75      std::make_tuple(255, 0, 0), std::make_tuple(0, 255, 0)}};
  76
  77 ColorHelper::ColorHelper(ColorHelper::DivergingScheme S)
  78     : MinIn(-1.0), MaxIn(1.0), ColorMap(DivergingCoeffs[static_cast<int>(S)]),
  79       BoundMap(DivergingBounds[static_cast<int>(S)]) {}
  80
  81 // Takes a tuple of uint8_ts representing a color in RGB and converts them to
  82 // HSV represented by a tuple of doubles
  83 static std::tuple<double, double, double>
  84 convertToHSV(const std::tuple<uint8_t, uint8_t, uint8_t> &Color) {
  85   double Scaled[3] = {std::get<0>(Color) / 255.0, std::get<1>(Color) / 255.0,
  86                       std::get<2>(Color) / 255.0};
  87   int Min = 0;
  88   int Max = 0;
  89   for (int i = 1; i < 3; ++i) {
  90     if (Scaled[i] < Scaled[Min])
  91       Min = i;
  92     if (Scaled[i] > Scaled[Max])
  93       Max = i;
  94   }
  95
  96   double C = Scaled[Max] - Scaled[Min];
  97
  98   double HPrime =
  99       (C == 0) ? 0 : (Scaled[(Max + 1) % 3] - Scaled[(Max + 2) % 3]) / C;
 100   HPrime = HPrime + 2.0 * Max;
 101
 102   double H = (HPrime < 0) ? (HPrime + 6.0) * 60
 103                           : HPrime * 60; // Scale to between 0 and 360
 104   double V = Scaled[Max];
 105
 106   double S = (V == 0.0) ? 0.0 : C / V;
 107
 108   return std::make_tuple(H, S, V);
 109 }
 110
 111 // Takes a double precision number, clips it between 0 and 1 and then converts
 112 // that to an integer between 0x00 and 0xFF with proxpper rounding.
 113 static uint8_t unitIntervalTo8BitChar(double B) {
 114   double n = std::max(std::min(B, 1.0), 0.0);
 115   return static_cast<uint8_t>(255 * n + 0.5);
 116 }
 117
 118 // Takes a typle of doubles representing a color in HSV and converts them to
 119 // RGB represented as a tuple of uint8_ts
 120 static std::tuple<uint8_t, uint8_t, uint8_t>
 121 convertToRGB(const std::tuple<double, double, double> &Color) {
 122   const double &H = std::get<0>(Color);
 123   const double &S = std::get<1>(Color);
 124   const double &V = std::get<2>(Color);
 125
 126   double C = V * S;
 127
 128   double HPrime = H / 60;
 129   double X = C * (1 - std::abs(std::fmod(HPrime, 2.0) - 1));
 130
 131   double RGB1[3];
 132   int HPrimeInt = static_cast<int>(HPrime);
 133   if (HPrimeInt % 2 == 0) {
 134     RGB1[(HPrimeInt / 2) % 3] = C;
 135     RGB1[(HPrimeInt / 2 + 1) % 3] = X;
 136     RGB1[(HPrimeInt / 2 + 2) % 3] = 0.0;
 137   } else {
 138     RGB1[(HPrimeInt / 2) % 3] = X;
 139     RGB1[(HPrimeInt / 2 + 1) % 3] = C;
 140     RGB1[(HPrimeInt / 2 + 2) % 3] = 0.0;
 141   }
 142
 143   double Min = V - C;
 144   double RGB2[3] = {RGB1[0] + Min, RGB1[1] + Min, RGB1[2] + Min};
 145
 146   return std::make_tuple(unitIntervalTo8BitChar(RGB2[0]),
 147                          unitIntervalTo8BitChar(RGB2[1]),
 148                          unitIntervalTo8BitChar(RGB2[2]));
 149 }
 150
 151 // The Hue component of the HSV interpolation Routine
 152 static double interpolateHue(double H0, double H1, double T) {
 153   double D = H1 - H0;
 154   if (H0 > H1) {
 155     std::swap(H0, H1);
 156
 157     D = -D;
 158     T = 1 - T;
 159   }
 160
 161   if (D <= 180) {
 162     return H0 + T * (H1 - H0);
 163   } else {
 164     H0 = H0 + 360;
 165     return std::fmod(H0 + T * (H1 - H0) + 720, 360);
 166   }
 167 }
 168
 169 // Interpolates between two HSV Colors both represented as a tuple of doubles
 170 // Returns an HSV Color represented as a tuple of doubles
 171 static std::tuple<double, double, double>
 172 interpolateHSV(const std::tuple<double, double, double> &C0,
 173                const std::tuple<double, double, double> &C1, double T) {
 174   double H = interpolateHue(std::get<0>(C0), std::get<0>(C1), T);
 175   double S = std::get<1>(C0) + T * (std::get<1>(C1) - std::get<1>(C0));
 176   double V = std::get<2>(C0) + T * (std::get<2>(C1) - std::get<2>(C0));
 177   return std::make_tuple(H, S, V);
 178 }
 179
 180 // Get the Color as a tuple of uint8_ts
 181 std::tuple<uint8_t, uint8_t, uint8_t>
 182 ColorHelper::getColorTuple(double Point) const {
 183   assert(!ColorMap.empty() && "ColorMap must not be empty!");
 184   assert(!BoundMap.empty() && "BoundMap must not be empty!");
 185
 186   if (Point < MinIn)
 187     return BoundMap[0];
 188   if (Point > MaxIn)
 189     return BoundMap[1];
 190
 191   size_t MaxIndex = ColorMap.size() - 1;
 192   double IntervalWidth = MaxIn - MinIn;
 193   double OffsetP = Point - MinIn;
 194   double SectionWidth = IntervalWidth / static_cast<double>(MaxIndex);
 195   size_t SectionNo = std::floor(OffsetP / SectionWidth);
 196   double T = (OffsetP - SectionNo * SectionWidth) / SectionWidth;
 197
 198   auto &RGBColor0 = ColorMap[SectionNo];
 199   auto &RGBColor1 = ColorMap[std::min(SectionNo + 1, MaxIndex)];
 200
 201   auto HSVColor0 = convertToHSV(RGBColor0);
 202   auto HSVColor1 = convertToHSV(RGBColor1);
 203
 204   auto InterpolatedHSVColor = interpolateHSV(HSVColor0, HSVColor1, T);
 205   return convertToRGB(InterpolatedHSVColor);
 206 }
 207
 208 // A helper method to convert a color represented as tuple of uint8s to a hex
 209 // string.
 210 std::string
 211 ColorHelper::getColorString(std::tuple<uint8_t, uint8_t, uint8_t> t) {
 212   return std::string(llvm::formatv("#{0:X-2}{1:X-2}{2:X-2}", std::get<0>(t),
 213                                    std::get<1>(t), std::get<2>(t)));
 214 }
 215
 216 // Gets a color in a gradient given a number in the interval [0,1], it does this
 217 // by evaluating a polynomial which maps [0, 1] -> [0, 1] for each of the R G
 218 // and B values in the color. It then converts this [0,1] colors to a 24 bit
 219 // color as a hex string.
 220 std::string ColorHelper::getColorString(double Point) const {
 221   return getColorString(getColorTuple(Point));
 222 }