Reverting 26975.

Review URL: http://codereview.chromium.org/222011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@26979 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 146 insertions, 2 deletions

diff --git a/skia/ext/skia_utils.cc b/skia/ext/skia_utils.cc
index c95054d..84a003b 100644
--- a/skia/ext/skia_utils.cc
+++ b/skia/ext/skia_utils.cc
@@ -1,10 +1,9 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "skia/ext/skia_utils.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
-#include "third_party/skia/include/core/SkShader.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 
 namespace skia {
@@ -22,5 +21,150 @@ SkShader* CreateGradientShader(int start_point,
       grad_points, grad_colors, NULL, 2, SkShader::kRepeat_TileMode);
 }
 
+// Helper function for HSLToSKColor.
+static inline double calcHue(double temp1, double temp2, double hueVal) {
+  if (hueVal < 0.0)
+    hueVal++;
+  else if (hueVal > 1.0)
+    hueVal--;
+
+  if (hueVal * 6.0 < 1.0)
+    return temp1 + (temp2 - temp1) * hueVal * 6.0;
+  if (hueVal * 2.0 < 1.0)
+    return temp2;
+  if (hueVal * 3.0 < 2.0)
+    return temp1 + (temp2 - temp1) * (2.0 / 3.0 - hueVal) * 6.0;
+
+  return temp1;
+}
+
+SkColor HSLToSkColor(U8CPU alpha, HSL hsl) {
+  double hue = hsl.h;
+  double saturation = hsl.s;
+  double lightness = hsl.l;
+
+  // If there's no color, we don't care about hue and can do everything based
+  // on brightness.
+  if (!saturation) {
+    U8CPU light;
+
+    if (lightness < 0)
+      light = 0;
+    else if (lightness >= SK_Scalar1)
+      light = 255;
+    else
+      light = SkDoubleToFixed(lightness) >> 8;
+
+    return SkColorSetARGB(alpha, light, light, light);
+  }
+
+  double temp2 = (lightness < 0.5) ?
+      lightness * (1.0 + saturation) :
+      lightness + saturation - (lightness * saturation);
+  double temp1 = 2.0 * lightness - temp2;
+
+  double rh = calcHue(temp1, temp2, hue + 1.0 / 3.0);
+  double gh = calcHue(temp1, temp2, hue);
+  double bh = calcHue(temp1, temp2, hue - 1.0 / 3.0);
+
+  return SkColorSetARGB(alpha,
+      static_cast<int>(rh * 255),
+      static_cast<int>(gh * 255),
+      static_cast<int>(bh * 255));
+}
+
+void SkColorToHSL(SkColor c, HSL& hsl) {
+  double r = SkColorGetR(c) / 255.0;
+  double g = SkColorGetG(c) / 255.0;
+  double b = SkColorGetB(c) / 255.0;
+
+  double h, s, l;
+
+  double vmax = r > g ? r : g;
+  vmax = vmax > b ? vmax : b;
+  double vmin = r < g ? r : g;
+  vmin = vmin < b ? vmin : b;
+  double delta = vmax - vmin;
+
+  l = (vmax + vmin) / 2;
+
+  if (delta == 0) {
+    h = 0;
+    s = 0;
+  } else {
+    if (l < 0.5)
+      s = delta / (vmax + vmin);
+    else
+      s = delta / (2 - vmax - vmin);
+
+    double dr = (((vmax - r) / 6.0) + (delta / 2.0)) / delta;
+    double dg = (((vmax - g) / 6.0) + (delta / 2.0)) / delta;
+    double db = (((vmax - b) / 6.0) + (delta / 2.0)) / delta;
+
+    if (r == vmax)
+      h = db - dg;
+    else if (g == vmax)
+      h = (1.0 / 3.0) + dr - db;
+    else if (b == vmax)
+      h = (2.0 / 3.0) + dg - dr;
+
+    if (h < 0) h += 1;
+    if (h > 1) h -= 1;
+  }
+
+  hsl.h = h;
+  hsl.s = s;
+  hsl.l = l;
+}
+
+SkColor HSLShift(SkColor color, HSL shift) {
+  HSL hsl;
+  int alpha = SkColorGetA(color);
+  SkColorToHSL(color, hsl);
+
+  // Replace the hue with the tint's hue.
+  if (shift.h >= 0)
+    hsl.h = shift.h;
+
+  // Change the saturation.
+  if (shift.s >= 0) {
+    if (shift.s <= 0.5) {
+      hsl.s *= shift.s * 2.0;
+    } else {
+      hsl.s = hsl.s + (1.0 - hsl.s) *
+        ((shift.s - 0.5) * 2.0);
+    }
+  }
+
+  SkColor result = HSLToSkColor(alpha, hsl);
+
+  // Lightness shifts in the style of popular image editors aren't
+  // actually represented in HSL - the L value does have some effect
+  // on saturation.
+  if (shift.l >= 0) {
+    double r = static_cast<double>SkColorGetR(result);
+    double g = static_cast<double>SkColorGetG(result);
+    double b = static_cast<double>SkColorGetB(result);
+
+    if (shift.l <= 0.5) {
+      r *= (shift.l * 2.0);
+      g *= (shift.l * 2.0);
+      b *= (shift.l * 2.0);
+    } else {
+      r = (r + (255.0 - r) * ((shift.l - 0.5) * 2.0));
+      g = (g + (255.0 - g) * ((shift.l - 0.5) * 2.0));
+      b = (b + (255.0 - b) * ((shift.l - 0.5) * 2.0));
+    }
+
+    return SkColorSetARGB(alpha, 
+                          static_cast<int>(r),
+                          static_cast<int>(g),
+                          static_cast<int>(b));
+  } else {
+    return result;
+  }
+}
+
+
 }  // namespace skia