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