add kRGBA_F16_SkColorType

tests/Float16Test.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+#include "SkColor.h"
+#include "SkHalf.h"
+#include "SkPixmap.h"
+
+static bool eq_within_half_float(float a, float b) {
+    const float kTolerance = 1.0f / (1 << (8 + 10));
+
+    SkHalf ha = SkFloatToHalf(a);
+    SkHalf hb = SkFloatToHalf(b);
+    float a2 = SkHalfToFloat(ha);
+    float b2 = SkHalfToFloat(hb);
+    return fabsf(a2 - b2) <= kTolerance;
+}
+
+static bool eq_within_half_float(const SkPM4f& a, const SkPM4f& b) {
+    for (int i = 0; i < 4; ++i) {
+        if (!eq_within_half_float(a.fVec[i], b.fVec[i])) {
+            return false;
+        }
+    }
+    return true;
+}
+
+DEF_TEST(color_half_float, reporter) {
+    const int w = 100;
+    const int h = 100;
+
+    SkImageInfo info = SkImageInfo::Make(w, h, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
+
+    SkAutoPixmapStorage pm;
+    pm.alloc(info);
+    REPORTER_ASSERT(reporter, pm.getSafeSize() == SkToSizeT(w * h * sizeof(uint64_t)));
+
+    SkColor4f c4 { 0.5f, 1, 0.5f, 0.25f };
+    pm.erase(c4);
+
+    SkPM4f origpm4 = c4.premul();
+    for (int y = 0; y < pm.height(); ++y) {
+        for (int x = 0; x < pm.width(); ++x) {
+            SkPM4f pm4 = SkPM4f::FromF16(pm.addrF16(x, y));
+            REPORTER_ASSERT(reporter, eq_within_half_float(origpm4, pm4));
+        }
+    }
+}