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 static 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 static 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 static 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 static 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 }
223