Index: test/tools/llvm-xray/X86/graph-color-simple-case.yaml
===================================================================
--- test/tools/llvm-xray/X86/graph-color-simple-case.yaml
+++ test/tools/llvm-xray/X86/graph-color-simple-case.yaml
@@ -32,15 +32,15 @@
 
 
 #EDGE:     digraph xray {
-#EDGE-DAG: F0 -> F7 [label="7.{{[0-9]*}}e+01" color="#B00100"];
-#EDGE-DAG: F0 -> F2 [label="2.{{[0-9]*}}e+01" color="#FD9965"];
+#EDGE-DAG: F0 -> F7 [label="7.{{[0-9]*}}e+01" color="#B00000"];
+#EDGE-DAG: F0 -> F2 [label="2.{{[0-9]*}}e+01" color="#FC9963"];
 #EDGE-DAG: F0 -> F9 [label="9.{{[0-9]*}}e+01" color="#7F0000"];
-#EDGE-DAG: F0 -> F4 [label="4.{{[0-9]*}}e+01" color="#E8543b"];
-#EDGE-DAG: F0 -> F6 [label="6.{{[0-9]*}}e+01" color="#C5140a"];
-#EDGE-DAG: F0 -> F1 [label="1.{{[0-9]*}}e+01" color="#FDC58c"];
-#EDGE-DAG: F0 -> F8 [label="8.{{[0-9]*}}e+01" color="#990101"];
-#EDGE-DAG: F0 -> F3 [label="3.{{[0-9]*}}e+01" color="#F5744d"];
-#EDGE-DAG: F0 -> F5 [label="5.{{[0-9]*}}e+01" color="#D83323"];
+#EDGE-DAG: F0 -> F4 [label="4.{{[0-9]*}}e+01" color="#E75339"];
+#EDGE-DAG: F0 -> F6 [label="6.{{[0-9]*}}e+01" color="#C4150D"];
+#EDGE-DAG: F0 -> F1 [label="1.{{[0-9]*}}e+01" color="#FDC48D"];
+#EDGE-DAG: F0 -> F8 [label="8.{{[0-9]*}}e+01" color="#970000"];
+#EDGE-DAG: F0 -> F3 [label="3.{{[0-9]*}}e+01" color="#F4744E"];
+#EDGE-DAG: F0 -> F5 [label="5.{{[0-9]*}}e+01" color="#D83220"];
 #EDGE-DAG: F7 [label="@(7)"];
 #EDGE-DAG: F2 [label="@(2)"];
 #EDGE-DAG: F9 [label="@(9)"];
@@ -63,13 +63,13 @@
 #VERTEX-DAG: F0 -> F8 [label=""];
 #VERTEX-DAG: F0 -> F3 [label=""];
 #VERTEX-DAG: F0 -> F5 [label=""];
-#VERTEX-DAG: F7 [label="{@(7)|7.{{[0-9]*}}e+01}" color="#B00100"];
-#VERTEX-DAG: F2 [label="{@(2)|2.{{[0-9]*}}e+01}" color="#FD9965"];
+#VERTEX-DAG: F7 [label="{@(7)|7.{{[0-9]*}}e+01}" color="#B00000"];
+#VERTEX-DAG: F2 [label="{@(2)|2.{{[0-9]*}}e+01}" color="#FC9963"];
 #VERTEX-DAG: F9 [label="{@(9)|9.{{[0-9]*}}e+01}" color="#7F0000"];
-#VERTEX-DAG: F4 [label="{@(4)|4.{{[0-9]*}}e+01}" color="#E8543b"];
-#VERTEX-DAG: F6 [label="{@(6)|6.{{[0-9]*}}e+01}" color="#C5140a"];
-#VERTEX-DAG: F1 [label="{@(1)|1.{{[0-9]*}}e+01}" color="#FDC58c"];
-#VERTEX-DAG: F8 [label="{@(8)|8.{{[0-9]*}}e+01}" color="#990101"];
-#VERTEX-DAG: F3 [label="{@(3)|3.{{[0-9]*}}e+01}" color="#F5744d"];
-#VERTEX-DAG: F5 [label="{@(5)|5.{{[0-9]*}}e+01}" color="#D83323"];
+#VERTEX-DAG: F4 [label="{@(4)|4.{{[0-9]*}}e+01}" color="#E75339"];
+#VERTEX-DAG: F6 [label="{@(6)|6.{{[0-9]*}}e+01}" color="#C4150D"];
+#VERTEX-DAG: F1 [label="{@(1)|1.{{[0-9]*}}e+01}" color="#FDC48D"];
+#VERTEX-DAG: F8 [label="{@(8)|8.{{[0-9]*}}e+01}" color="#970000"];
+#VERTEX-DAG: F3 [label="{@(3)|3.{{[0-9]*}}e+01}" color="#F4744E"];
+#VERTEX-DAG: F5 [label="{@(5)|5.{{[0-9]*}}e+01}" color="#D83220"];
 #VERTEX-NEXT: }
Index: tools/llvm-xray/CMakeLists.txt
===================================================================
--- tools/llvm-xray/CMakeLists.txt
+++ tools/llvm-xray/CMakeLists.txt
@@ -9,6 +9,7 @@
 set(LLVM_XRAY_TOOLS
   func-id-helper.cc
   xray-account.cc
+  xray-color-helper.cc
   xray-converter.cc
   xray-extract.cc
   xray-extract.cc
Index: tools/llvm-xray/xray-color-helper.h
===================================================================
--- /dev/null
+++ tools/llvm-xray/xray-color-helper.h
@@ -0,0 +1,104 @@
+//===-- xray-graph.h - XRay Function Call Graph Renderer --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// A class to get a color from a specified gradient.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef XRAY_COLOR_HELPER_H
+#define XRAY_COLOR_HELPER_H
+
+#include <tuple>
+
+#include "llvm/ADT/ArrayRef.h"
+
+namespace llvm {
+namespace xray {
+
+/// The color helper class it a healper class which allows you to easily get a
+/// color in a gradient. This is used to color-code edges in XRay-Graph tools.
+///
+/// There are two types of color schemes in this class:
+///   - Sequential schemes, which are used to represent information from some
+///     minimum to some maximum. These take an input in the range [0,1]
+///   - Diverging schemes, which are used to represent information representing
+///     differenes, or a range that goes from negative to positive. These take
+///     an input in the range [-1,1].
+/// Usage;
+/// ColorHelper S(ColorHelper::SequentialScheme::OrRd); //Chose a color scheme.
+/// for (double p = 0.0; p <= 1; p += 0.1){
+///   cout() << S.getColor(p) << " \n"; // Sample the gradient at 0.1 intervals
+/// }
+///
+/// ColorHelper D(ColorHelper::DivergingScheme::Spectral); // Choose a color
+///                                                        // scheme.
+/// for (double p= -1; p <= 1 ; p += 0.1){
+///   cout() << D.getColor(p) << " \n"; // sample the gradient at 0.1 intervals
+/// }
+class ColorHelper {
+  double MinIn;
+  double MaxIn;
+
+  ArrayRef<std::tuple<uint8_t, uint8_t, uint8_t>> ColorMap;
+
+public:
+  /// Enum of the availible Sequential Color Schemes
+  enum class SequentialScheme {
+    // Schemes based on the ColorBrewer Color schemes of the same name from
+    // http://www.colorbrewer.org/ by Cynthis A Brewer Penn State University.
+    Blues,
+    Greens,
+    Greys,
+    Oranges,
+    Purples,
+    Reds,
+    BuGn,
+    BuPu,
+    GnBu,
+    OrRd,
+    PuBu,
+    PuBuGn,
+    PuRd,
+    RdPu,
+    YlGn,
+    YlGnBu,
+    YlOrBr,
+    YlOrRd
+  };
+
+  ColorHelper(SequentialScheme S);
+
+  /// Enum of the availible Diverging Color Schemes
+  enum class DivergingScheme {
+    // Schemes based on the ColorBrewer Color schemes of the same name from
+    // http://www.colorbrewer.org/ by Cynthis A Brewer Penn State University.
+    BrBG,
+    PiYG,
+    PRGn,
+    PuOr,
+    RdBu,
+    RdGy,
+    RdYlBu,
+    RdYlGn,
+    Spectral
+  };
+
+  ColorHelper(DivergingScheme S);
+
+  // Sample the gradient at the input point.
+  std::tuple<uint8_t, uint8_t, uint8_t> getColorTuple(double Point) const;
+
+  std::string getColorString(double Point) const;
+
+  // Convert a tuple to a string
+  static std::string getColorString(std::tuple<uint8_t, uint8_t, uint8_t> t);
+};
+}
+}
+#endif
Index: tools/llvm-xray/xray-color-helper.cc
===================================================================
--- /dev/null
+++ tools/llvm-xray/xray-color-helper.cc
@@ -0,0 +1,461 @@
+//===-- xray-graph.cc - XRay Function Call Graph Renderer -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// A class to get a color from a specified gradient.
+//
+//===----------------------------------------------------------------------===//
+#include <algorithm>
+
+#include "xray-color-helper.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+using namespace xray;
+
+//  Sequential ColorMaps, which are used to represent information
+//  from some minimum to some maximum.
+
+static const std::tuple<uint8_t, uint8_t, uint8_t> SequentialMaps[][9] = {
+    {// The blues color scheme from http://colorbrewer2.org/
+     std::make_tuple(247, 251, 255),
+     std::make_tuple(222, 235, 247),
+     std::make_tuple(198, 219, 239),
+     std::make_tuple(158, 202, 225),
+     std::make_tuple(107, 174, 214),
+     std::make_tuple(66, 146, 198),
+     std::make_tuple(33, 113, 181),
+     std::make_tuple(8, 81, 156),
+     std::make_tuple(8, 48, 107)},
+    {// The greens color scheme from http://colorbrewer2.org/
+     std::make_tuple(247, 252, 245),
+     std::make_tuple(229, 245, 224),
+     std::make_tuple(199, 233, 192),
+     std::make_tuple(161, 217, 155),
+     std::make_tuple(116, 196, 118),
+     std::make_tuple(65, 171, 93),
+     std::make_tuple(35, 139, 69),
+     std::make_tuple(0, 109, 44),
+     std::make_tuple(0, 68, 27)},
+    {// The greys color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 255, 255),
+     std::make_tuple(240, 240, 240),
+     std::make_tuple(217, 217, 217),
+     std::make_tuple(189, 189, 189),
+     std::make_tuple(150, 150, 150),
+     std::make_tuple(115, 115, 115),
+     std::make_tuple(82, 82, 82),
+     std::make_tuple(37, 37, 37),
+     std::make_tuple(0, 0, 0)},
+    {// The oranges color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 245, 235),
+     std::make_tuple(254, 230, 206),
+     std::make_tuple(253, 208, 162),
+     std::make_tuple(253, 174, 107),
+     std::make_tuple(253, 141, 60),
+     std::make_tuple(241, 105, 19),
+     std::make_tuple(217, 72, 1),
+     std::make_tuple(166, 54, 3),
+     std::make_tuple(127, 39, 4)},
+    {// The purples color scheme from http://colorbrewer2.org/
+     std::make_tuple(252, 251, 253),
+     std::make_tuple(239, 237, 245),
+     std::make_tuple(218, 218, 235),
+     std::make_tuple(188, 189, 220),
+     std::make_tuple(158, 154, 200),
+     std::make_tuple(128, 125, 186),
+     std::make_tuple(106, 81, 163),
+     std::make_tuple(84, 39, 143),
+     std::make_tuple(63, 0, 125)},
+    {// The reds color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 245, 240),
+     std::make_tuple(254, 224, 210),
+     std::make_tuple(252, 187, 161),
+     std::make_tuple(252, 146, 114),
+     std::make_tuple(251, 106, 74),
+     std::make_tuple(239, 59, 44),
+     std::make_tuple(203, 24, 29),
+     std::make_tuple(165, 15, 21),
+     std::make_tuple(103, 0, 13)},
+    {// The BuGn color scheme from http://colorbrewer2.org/
+     std::make_tuple(247, 252, 253),
+     std::make_tuple(229, 245, 249),
+     std::make_tuple(204, 236, 230),
+     std::make_tuple(153, 216, 201),
+     std::make_tuple(102, 194, 164),
+     std::make_tuple(65, 174, 118),
+     std::make_tuple(35, 139, 69),
+     std::make_tuple(0, 109, 44),
+     std::make_tuple(0, 68, 27)},
+    {// The BuPu color scheme from http://colorbrewer2.org/
+     std::make_tuple(247, 252, 253),
+     std::make_tuple(224, 236, 244),
+     std::make_tuple(191, 211, 230),
+     std::make_tuple(158, 188, 218),
+     std::make_tuple(140, 150, 198),
+     std::make_tuple(140, 107, 177),
+     std::make_tuple(136, 65, 157),
+     std::make_tuple(129, 15, 124),
+     std::make_tuple(77, 0, 75)},
+    {// The GnBu color scheme from http://colorbrewer2.org/
+     std::make_tuple(247, 252, 240),
+     std::make_tuple(224, 243, 219),
+     std::make_tuple(204, 235, 197),
+     std::make_tuple(168, 221, 181),
+     std::make_tuple(123, 204, 196),
+     std::make_tuple(78, 179, 211),
+     std::make_tuple(43, 140, 190),
+     std::make_tuple(8, 104, 172),
+     std::make_tuple(8, 64, 129)},
+    {// The OrRd color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 247, 236),
+     std::make_tuple(254, 232, 200),
+     std::make_tuple(253, 212, 158),
+     std::make_tuple(253, 187, 132),
+     std::make_tuple(252, 141, 89),
+     std::make_tuple(239, 101, 72),
+     std::make_tuple(215, 48, 31),
+     std::make_tuple(179, 0, 0),
+     std::make_tuple(127, 0, 0)},
+    {// The PuBu color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 247, 251),
+     std::make_tuple(236, 231, 242),
+     std::make_tuple(208, 209, 230),
+     std::make_tuple(166, 189, 219),
+     std::make_tuple(116, 169, 207),
+     std::make_tuple(54, 144, 192),
+     std::make_tuple(5, 112, 176),
+     std::make_tuple(4, 90, 141),
+     std::make_tuple(2, 56, 88)},
+    {// The PuBuGn color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 247, 251),
+     std::make_tuple(236, 226, 240),
+     std::make_tuple(208, 209, 230),
+     std::make_tuple(166, 189, 219),
+     std::make_tuple(103, 169, 207),
+     std::make_tuple(54, 144, 192),
+     std::make_tuple(2, 129, 138),
+     std::make_tuple(1, 108, 89),
+     std::make_tuple(1, 70, 54)},
+    {// The PuRd color scheme from http://colorbrewer2.org/
+     std::make_tuple(247, 244, 249),
+     std::make_tuple(231, 225, 239),
+     std::make_tuple(212, 185, 218),
+     std::make_tuple(201, 148, 199),
+     std::make_tuple(223, 101, 176),
+     std::make_tuple(231, 41, 138),
+     std::make_tuple(206, 18, 86),
+     std::make_tuple(152, 0, 67),
+     std::make_tuple(103, 0, 31)},
+    {// The RdPu color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 247, 243),
+     std::make_tuple(253, 224, 221),
+     std::make_tuple(252, 197, 192),
+     std::make_tuple(250, 159, 181),
+     std::make_tuple(247, 104, 161),
+     std::make_tuple(221, 52, 151),
+     std::make_tuple(174, 1, 126),
+     std::make_tuple(122, 1, 119),
+     std::make_tuple(73, 0, 106)},
+    {// The YlGn color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 255, 229),
+     std::make_tuple(247, 252, 185),
+     std::make_tuple(217, 240, 163),
+     std::make_tuple(173, 221, 142),
+     std::make_tuple(120, 198, 121),
+     std::make_tuple(65, 171, 93),
+     std::make_tuple(35, 132, 67),
+     std::make_tuple(0, 104, 55),
+     std::make_tuple(0, 69, 41)},
+    {// The YlGnBu color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 255, 217),
+     std::make_tuple(237, 248, 177),
+     std::make_tuple(199, 233, 180),
+     std::make_tuple(127, 205, 187),
+     std::make_tuple(65, 182, 196),
+     std::make_tuple(29, 145, 192),
+     std::make_tuple(34, 94, 168),
+     std::make_tuple(37, 52, 148),
+     std::make_tuple(8, 29, 88)},
+    {// The YlOrBr color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 255, 229),
+     std::make_tuple(255, 247, 188),
+     std::make_tuple(254, 227, 145),
+     std::make_tuple(254, 196, 79),
+     std::make_tuple(254, 153, 41),
+     std::make_tuple(236, 112, 20),
+     std::make_tuple(204, 76, 2),
+     std::make_tuple(153, 52, 4),
+     std::make_tuple(102, 37, 6)},
+    {// The YlOrRd color scheme from http://colorbrewer2.org/
+     std::make_tuple(255, 255, 204),
+     std::make_tuple(255, 237, 160),
+     std::make_tuple(254, 217, 118),
+     std::make_tuple(254, 178, 76),
+     std::make_tuple(253, 141, 60),
+     std::make_tuple(252, 78, 42),
+     std::make_tuple(227, 26, 28),
+     std::make_tuple(189, 0, 38),
+     std::make_tuple(128, 0, 38)}};
+
+ColorHelper::ColorHelper(ColorHelper::SequentialScheme S)
+    : MinIn(0.0), MaxIn(1.0), ColorMap(SequentialMaps[static_cast<int>(S)]) {}
+
+// Diverging ColorMaps, which are used to represent information
+// representing differenes, or a range that goes from negative to positive.
+// These take an input in the range [-1,1].
+
+static const std::tuple<uint8_t, uint8_t, uint8_t> DivergingCoeffs[][11] = {
+    {// The BrBG color scheme from http://colorbrewer2.org/
+     std::make_tuple(84, 48, 5),
+     std::make_tuple(140, 81, 10),
+     std::make_tuple(191, 129, 45),
+     std::make_tuple(223, 194, 125),
+     std::make_tuple(246, 232, 195),
+     std::make_tuple(245, 245, 245),
+     std::make_tuple(199, 234, 229),
+     std::make_tuple(128, 205, 193),
+     std::make_tuple(53, 151, 143),
+     std::make_tuple(1, 102, 94),
+     std::make_tuple(0, 60, 48)},
+    {// The PiYG color scheme from http://colorbrewer2.org/
+     std::make_tuple(142, 1, 82),
+     std::make_tuple(197, 27, 125),
+     std::make_tuple(222, 119, 174),
+     std::make_tuple(241, 182, 218),
+     std::make_tuple(253, 224, 239),
+     std::make_tuple(247, 247, 247),
+     std::make_tuple(230, 245, 208),
+     std::make_tuple(184, 225, 134),
+     std::make_tuple(127, 188, 65),
+     std::make_tuple(77, 146, 33),
+     std::make_tuple(39, 100, 25)},
+    {// The PRGn color scheme from http://colorbrewer2.org/
+     std::make_tuple(64, 0, 75),
+     std::make_tuple(118, 42, 131),
+     std::make_tuple(153, 112, 171),
+     std::make_tuple(194, 165, 207),
+     std::make_tuple(231, 212, 232),
+     std::make_tuple(247, 247, 247),
+     std::make_tuple(217, 240, 211),
+     std::make_tuple(166, 219, 160),
+     std::make_tuple(90, 174, 97),
+     std::make_tuple(27, 120, 55),
+     std::make_tuple(0, 68, 27)},
+    {// The PuOr color scheme from http://colorbrewer2.org/
+     std::make_tuple(127, 59, 8),
+     std::make_tuple(179, 88, 6),
+     std::make_tuple(224, 130, 20),
+     std::make_tuple(253, 184, 99),
+     std::make_tuple(254, 224, 182),
+     std::make_tuple(247, 247, 247),
+     std::make_tuple(216, 218, 235),
+     std::make_tuple(178, 171, 210),
+     std::make_tuple(128, 115, 172),
+     std::make_tuple(84, 39, 136),
+     std::make_tuple(45, 0, 75)},
+    {// The RdBu color scheme from http://colorbrewer2.org/
+     std::make_tuple(103, 0, 31),
+     std::make_tuple(178, 24, 43),
+     std::make_tuple(214, 96, 77),
+     std::make_tuple(244, 165, 130),
+     std::make_tuple(253, 219, 199),
+     std::make_tuple(247, 247, 247),
+     std::make_tuple(209, 229, 240),
+     std::make_tuple(146, 197, 222),
+     std::make_tuple(67, 147, 195),
+     std::make_tuple(33, 102, 172),
+     std::make_tuple(5, 48, 97)},
+    {// The RdGy color scheme from http://colorbrewer2.org/
+     std::make_tuple(103, 0, 31),
+     std::make_tuple(178, 24, 43),
+     std::make_tuple(214, 96, 77),
+     std::make_tuple(244, 165, 130),
+     std::make_tuple(253, 219, 199),
+     std::make_tuple(255, 255, 255),
+     std::make_tuple(224, 224, 224),
+     std::make_tuple(186, 186, 186),
+     std::make_tuple(135, 135, 135),
+     std::make_tuple(77, 77, 77),
+     std::make_tuple(26, 26, 26)},
+    {// The RdYlBu color scheme from http://colorbrewer2.org/
+     std::make_tuple(165, 0, 38),
+     std::make_tuple(215, 48, 39),
+     std::make_tuple(244, 109, 67),
+     std::make_tuple(253, 174, 97),
+     std::make_tuple(254, 224, 144),
+     std::make_tuple(255, 255, 191),
+     std::make_tuple(224, 243, 248),
+     std::make_tuple(171, 217, 233),
+     std::make_tuple(116, 173, 209),
+     std::make_tuple(69, 117, 180),
+     std::make_tuple(49, 54, 149)},
+    {// The RdYlGn color scheme from http://colorbrewer2.org/
+     std::make_tuple(165, 0, 38),
+     std::make_tuple(215, 48, 39),
+     std::make_tuple(244, 109, 67),
+     std::make_tuple(253, 174, 97),
+     std::make_tuple(254, 224, 139),
+     std::make_tuple(255, 255, 191),
+     std::make_tuple(217, 239, 139),
+     std::make_tuple(166, 217, 106),
+     std::make_tuple(102, 189, 99),
+     std::make_tuple(26, 152, 80),
+     std::make_tuple(0, 104, 55)},
+    {// The Spectral color scheme from http://colorbrewer2.org/
+     std::make_tuple(158, 1, 66),
+     std::make_tuple(213, 62, 79),
+     std::make_tuple(244, 109, 67),
+     std::make_tuple(253, 174, 97),
+     std::make_tuple(254, 224, 139),
+     std::make_tuple(255, 255, 191),
+     std::make_tuple(230, 245, 152),
+     std::make_tuple(171, 221, 164),
+     std::make_tuple(102, 194, 165),
+     std::make_tuple(50, 136, 189),
+     std::make_tuple(94, 79, 162)}};
+
+ColorHelper::ColorHelper(ColorHelper::DivergingScheme S)
+    : MinIn(-1.0), MaxIn(1.0), ColorMap(DivergingCoeffs[static_cast<int>(S)]) {}
+
+// Takes a tuple of uint8_ts representing a color in RGB and converts them to
+// HSV represented by a tuple of doubles
+static std::tuple<double, double, double>
+convertToHSV(const std::tuple<uint8_t, uint8_t, uint8_t> &Color) {
+  double Scaled[3] = {std::get<0>(Color) / 255.0, std::get<1>(Color) / 255.0,
+                      std::get<2>(Color) / 255.0};
+  int Min = 0;
+  int Max = 0;
+  for (int i = 1; i < 3; ++i) {
+    if (Scaled[i] < Scaled[Min])
+      Min = i;
+    if (Scaled[i] > Scaled[Max])
+      Max = i;
+  }
+
+  double C = Scaled[Max] - Scaled[Min];
+
+  double HPrime = (Scaled[(Max + 1) % 3] - Scaled[(Max + 2) % 3]) / C;
+  HPrime = HPrime + 2.0 * Max;
+
+  double H = (HPrime < 0) ? (HPrime + 6.0) * 60
+                          : HPrime * 60; // Scale to between 0 and 360
+
+  double V = Scaled[Max];
+
+  double S = (V == 0.0) ? 0.0 : C / V;
+
+  return std::make_tuple(H, S, V);
+}
+
+// Takes a double precision number, clips it between 0 and 1 and then converts
+// that to an integer between 0x00 and 0xFF with proxpper rounding.
+static uint8_t unitIntervalTo8BitChar(double B) {
+  double n = std::max(std::min(B, 1.0), 0.0);
+  return static_cast<uint8_t>(255 * n + 0.5);
+}
+
+// Takes a typle of doubles representing a color in HSV and converts them to
+// RGB represented as a tuple of uint8_ts
+static std::tuple<uint8_t, uint8_t, uint8_t>
+convertToRGB(const std::tuple<double, double, double> &Color) {
+  const double &H = std::get<0>(Color);
+  const double &S = std::get<1>(Color);
+  const double &V = std::get<2>(Color);
+
+  double C = V * S;
+
+  double HPrime = H / 60;
+  double X = C * (1 - std::abs(std::fmod(HPrime, 2.0) - 1));
+
+  double RGB1[3];
+  int HPrimeInt = static_cast<int>(HPrime);
+  if (HPrimeInt % 2 == 0) {
+    RGB1[(HPrimeInt / 2) % 3] = C;
+    RGB1[(HPrimeInt / 2 + 1) % 3] = X;
+    RGB1[(HPrimeInt / 2 + 2) % 3] = 0.0;
+  } else {
+    RGB1[(HPrimeInt / 2) % 3] = X;
+    RGB1[(HPrimeInt / 2 + 1) % 3] = C;
+    RGB1[(HPrimeInt / 2 + 2) % 3] = 0.0;
+  }
+
+  double Min = V - C;
+  double RGB2[3] = {RGB1[0] + Min, RGB1[1] + Min, RGB1[2] + Min};
+
+  return std::make_tuple(
+    unitIntervalTo8BitChar(RGB2[0]),
+    unitIntervalTo8BitChar(RGB2[1]),
+    unitIntervalTo8BitChar(RGB2[2])
+  );
+}
+
+// The Hue component of the HSV interpolation Routine
+static double interpolateHue(double H0, double H1, double T) {
+  double D = H1 - H0;
+  if (H0 > H1) {
+    std::swap(H0, H1);
+
+    D = -D;
+    T = 1 - T;
+  }
+
+ if (D <= 180) {
+    return H0 + T * (H1 - H0);
+ } else {
+    H0 = H0 + 360;
+    return std::fmod(H0 + T * (H1 - H0) + 720, 360);
+ } 
+}
+
+// Interpolates between two HSV Colors both represented as a tuple of doubles
+// Returns an HSV Color represented as a tuple of doubles
+static std::tuple<double, double, double>
+interpolateHSV(const std::tuple<double, double, double> &C0,
+               const std::tuple<double, double, double> &C1, double T) {
+  double H = interpolateHue(std::get<0>(C0), std::get<0>(C1), T);
+  double S = std::get<1>(C0) + T * (std::get<1>(C1) - std::get<1>(C0));
+  double V = std::get<2>(C0) + T * (std::get<2>(C1) - std::get<2>(C0));
+  return std::make_tuple(H,S,V);
+}
+
+// Get the Color as a tuple of uint8_ts
+std::tuple<uint8_t, uint8_t, uint8_t>
+ColorHelper::getColorTuple(double Point) const {
+  double IntervalWidth = (MaxIn - MinIn);
+  double OffsetP = Point - MinIn;
+  double SectionWidth = IntervalWidth / (ColorMap.size() - 1);
+  int SectionNo = static_cast<int>(OffsetP / SectionWidth);
+  double T = (OffsetP - SectionNo * SectionWidth) / SectionWidth;
+
+  auto &RGBColor0 = ColorMap[SectionNo];
+  auto &RGBColor1 = ColorMap[SectionNo + 1];
+
+  auto HSVColor0 = convertToHSV(RGBColor0);
+  auto HSVColor1 = convertToHSV(RGBColor1);
+
+  auto InterpolatedHSVColor = interpolateHSV(HSVColor0, HSVColor1, T);
+  return convertToRGB(InterpolatedHSVColor);
+}
+
+// A helper method to convert a color represented as tuple of uint8s to a hex
+// string.
+std::string
+ColorHelper::getColorString(std::tuple<uint8_t, uint8_t, uint8_t> t) {
+  return llvm::formatv("#{0:X-2}{1:X-2}{2:X-2}", std::get<0>(t), std::get<1>(t),
+                       std::get<2>(t));
+}
+
+// Gets a color in a gradient given a number in the interval [0,1], it does this
+// by evaluating a polynomial which maps [0, 1] -> [0, 1] for each of the R G
+// and B values in the color. It then converts this [0,1] colors to a 24 bit
+// color as a hex string.
+std::string ColorHelper::getColorString(double Point) const {
+  return getColorString(getColorTuple(Point));
+}
Index: tools/llvm-xray/xray-graph.h
===================================================================
--- tools/llvm-xray/xray-graph.h
+++ tools/llvm-xray/xray-graph.h
@@ -19,6 +19,7 @@
 #include <vector>
 
 #include "func-id-helper.h"
+#include "xray-color-helper.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Errc.h"
@@ -97,7 +98,7 @@
   PerThreadFunctionStackMap PerThreadFunctionStack;
 
   /// Usefull object for getting human readable Symbol Names.
-  FuncIdConversionHelper &FuncIdHelper;
+  const FuncIdConversionHelper &FuncIdHelper;
   bool DeduceSiblingCalls = false;
   TimestampT CurrentMaxTSC = 0;
 
@@ -117,11 +118,15 @@
   /// Normalises latency statistics for each edge and vertex by CycleFrequency;
   void normalizeStatistics(double CycleFrequency);
 
+  /// An object to color gradients
+  ColorHelper CHelper;
+
 public:
   /// Takes in a reference to a FuncIdHelper in order to have ready access to
   /// Symbol names.
-  explicit GraphRenderer(FuncIdConversionHelper &FuncIdHelper, bool DSC)
-      : FuncIdHelper(FuncIdHelper), DeduceSiblingCalls(DSC) {
+  explicit GraphRenderer(const FuncIdConversionHelper &FuncIdHelper, bool DSC)
+      : FuncIdHelper(FuncIdHelper), DeduceSiblingCalls(DSC),
+        CHelper(ColorHelper::SequentialScheme::OrRd) {
     G[0] = {};
   }
 
Index: tools/llvm-xray/xray-graph.cc
===================================================================
--- tools/llvm-xray/xray-graph.cc
+++ tools/llvm-xray/xray-graph.cc
@@ -373,61 +373,6 @@
   return S.str();
 }
 
-// Evaluates a polynomial given the coefficints provided in an ArrayRef
-// evaluating:
-//
-//    p(x) = a[n-0]*x^0 + a[n-1]*x^1 + ... a[n-n]*x^n
-//
-// at x_0 using Horner's Method for both performance and stability reasons.
-static double polyEval(ArrayRef<double> a, double x_0) {
-  double B = 0;
-  for (const auto &c : a) {
-    B = c + B * x_0;
-  }
-  return B;
-}
-
-// Takes a double precision number, clips it between 0 and 1 and then converts
-// that to an integer between 0x00 and 0xFF with proxpper rounding.
-static uint8_t uintIntervalTo8bitChar(double B) {
-  double n = std::max(std::min(B, 1.0), 0.0);
-  return static_cast<uint8_t>(255 * n + 0.5);
-}
-
-// Gets a color in a gradient given a number in the interval [0,1], it does this
-// by evaluating a polynomial which maps [0, 1] -> [0, 1] for each of the R G
-// and B values in the color. It then converts this [0,1] colors to a 24 bit
-// color.
-//
-// In order to calculate these polynomials,
-//   1. Convert the OrRed9 color scheme from http://colorbrewer2.org/ from sRGB
-//      to LAB color space.
-//   2. Interpolate between the descrete colors in LAB space using a cubic
-//      spline interpolation.
-//   3. Sample this interpolation at 100 points and convert to sRGB.
-//   4. Calculate a polynomial fit for these 100 points for each of R G and B.
-//      We used a polynomial of degree 9 arbitrarily based on a fuzzy goodness
-//      of fit metric (using human judgement);
-//   5. Extract these polynomial coefficients from matlab as a set of constants.
-static std::string getColor(double point) {
-  assert(point >= 0.0 && point <= 1);
-  const static double RedPoly[] = {-38.4295,  239.239, -600.108, 790.544,
-                                   -591.26,   251.304, -58.0983, 6.62999,
-                                   -0.325899, 1.00173};
-  const static double GreenPoly[] = {-603.634,   2338.15, -3606.74, 2786.16,
-                                     -1085.19,   165.15,  11.2584,  -6.11338,
-                                     -0.0091078, 0.965469};
-  const static double BluePoly[] = {-325.686, 947.415,  -699.079, -513.75,
-                                    1127.78,  -732.617, 228.092,  -33.8202,
-                                    0.732108, 0.913916};
-
-  uint8_t r = uintIntervalTo8bitChar(polyEval(RedPoly, point));
-  uint8_t g = uintIntervalTo8bitChar(polyEval(GreenPoly, point));
-  uint8_t b = uintIntervalTo8bitChar(polyEval(BluePoly, point));
-
-  return llvm::formatv("#{0:X-2}{1:X-2}{2:x-2}", r, g, b);
-}
-
 // Returns the quotient between the property T of this and another TimeStat as
 // a double
 double GraphRenderer::TimeStat::compare(StatType T, const TimeStat &O) const {
@@ -491,7 +436,8 @@
     OS << "F" << E.first.first << " -> "
        << "F" << E.first.second << " [label=\"" << S.getAsString(ET) << "\"";
     if (EC != StatType::NONE)
-      OS << " color=\"" << getColor(S.compare(EC, G.GraphEdgeMax)) << "\"";
+      OS << " color=\"" << CHelper.getColorString(S.compare(EC, G.GraphEdgeMax))
+         << "\"";
     OS << "];\n";
   }
 
@@ -507,7 +453,8 @@
     else
       OS << "\"";
     if (VC != StatType::NONE)
-      OS << " color=\"" << getColor(VA.S.compare(VC, G.GraphVertexMax)) << "\"";
+      OS << " color=\"" << CHelper.getColorString(VA.S.compare(VC, G.GraphVertexMax))
+         << "\"";
     OS << "];\n";
   }
   OS << "}\n";