1 files changed, 136 insertions, 0 deletions
diff --git a/skia/sgl/SkColor.cpp b/skia/sgl/SkColor.cpp
new file mode 100644
index 0000000..1e7aa70
--- /dev/null
+++ b/skia/sgl/SkColor.cpp
@@ -0,0 +1,136 @@
+/* libs/graphics/sgl/SkColor.cpp
+**
+** Copyright 2006, Google Inc.
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#include "SkColor.h"
+#include "SkColorPriv.h"
+
+SkPMColor SkPreMultiplyARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
+    if (a != 255) {
+#if 0
+        unsigned scale = SkAlpha255To256(a);
+        r = SkAlphaMul(r, scale);
+        g = SkAlphaMul(g, scale);
+        b = SkAlphaMul(b, scale);
+#else
+        r = SkMulDiv255Round(r, a);
+        g = SkMulDiv255Round(g, a);
+        b = SkMulDiv255Round(b, a);
+#endif
+    }
+    return SkPackARGB32(a, r, g, b);
+}
+
+SkPMColor SkPreMultiplyColor(SkColor c) {
+    unsigned a = SkColorGetA(c);
+    unsigned r = SkColorGetR(c);
+    unsigned g = SkColorGetG(c);
+    unsigned b = SkColorGetB(c);
+
+    return SkPreMultiplyARGB(a, r, g, b);
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////
+
+static inline SkScalar ByteToScalar(U8CPU x) {
+    SkASSERT(x <= 255);
+    return SkIntToScalar(x) / 255;
+}
+
+static inline SkScalar ByteDivToScalar(int numer, U8CPU denom) {
+    // cast to keep the answer signed
+    return SkIntToScalar(numer) / (int)denom;
+}
+
+void SkRGBToHSV(U8CPU r, U8CPU g, U8CPU b, SkScalar hsv[3]) {
+    SkASSERT(hsv);
+
+    unsigned min = SkMin32(r, SkMin32(g, b));
+    unsigned max = SkMax32(r, SkMax32(g, b));
+    unsigned delta = max - min;
+
+    SkScalar v = ByteToScalar(max);
+    SkASSERT(v >= 0 && v <= SK_Scalar1);
+
+    if (0 == delta) { // we're a shade of gray
+        hsv[0] = hsv[1] = hsv[2] = v;
+        return;
+    }
+
+    SkScalar s = ByteDivToScalar(delta, max);
+    SkASSERT(s >= 0 && s <= SK_Scalar1);
+
+    SkScalar h;    
+    if (r == max) {
+        h = ByteDivToScalar(g - b, delta);
+    } else if (g == max) {
+        h = SkIntToScalar(2) + ByteDivToScalar(b - r, delta);
+    } else { // b == max
+        h = SkIntToScalar(4) + ByteDivToScalar(r - g, delta);
+    }
+
+    h *= 60;
+    if (h < 0) {
+        h += SkIntToScalar(360);
+    }
+    SkASSERT(h >= 0 && h < SkIntToScalar(360));
+
+    hsv[0] = h;
+    hsv[1] = s;
+    hsv[2] = v;
+}
+
+static inline U8CPU UnitScalarToByte(SkScalar x) {
+    if (x < 0) {
+        return 0;
+    }
+    if (x >= SK_Scalar1) {
+        return 255;
+    }
+    return SkScalarToFixed(x) >> 8;
+}
+
+SkColor SkHSVToColor(U8CPU a, const SkScalar hsv[3]) {
+    SkASSERT(hsv);
+
+    U8CPU s = UnitScalarToByte(hsv[1]);
+    U8CPU v = UnitScalarToByte(hsv[2]);
+
+    if (0 == s) { // shade of gray
+        return SkColorSetARGB(a, v, v, v);
+    }
+    SkFixed hx = (hsv[0] < 0 || hsv[0] >= SkIntToScalar(360)) ? 0 : SkScalarToFixed(hsv[0]/60);
+    SkFixed f = hx & 0xFFFF;
+    
+    unsigned v_scale = SkAlpha255To256(v);
+    unsigned p = SkAlphaMul(255 - s, v_scale);
+    unsigned q = SkAlphaMul(255 - (s * f >> 16), v_scale);
+    unsigned t = SkAlphaMul(255 - (s * (SK_Fixed1 - f) >> 16), v_scale);
+    
+    unsigned r, g, b;
+
+    SkASSERT((unsigned)(hx >> 16) < 6);
+    switch (hx >> 16) {
+        case 0: r = v; g = t; b = p; break;
+        case 1: r = q; g = v; b = p; break;
+        case 2: r = p; g = v; b = t; break;
+        case 3: r = p; g = q; b = v; break;
+        case 4: r = t;  g = p; b = v; break;
+        default: r = v; g = p; b = q; break;
+    }
+    return SkColorSetARGB(a, r, g, b);
+}
+