misc fixes to make float buffers work a little better

src/core/SkBitmap.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAtomics.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 545 matching lines @@
                 break;
             default:
                 SkDEBUGFAIL("Can't return addr for config");
                 base = nullptr;
                 break;
         }
     }
     return base;
 }
 
+#include "SkHalf.h"
+
 SkColor SkBitmap::getColor(int x, int y) const {
     SkASSERT((unsigned)x < (unsigned)this->width());
     SkASSERT((unsigned)y < (unsigned)this->height());
 
     switch (this->colorType()) {
         case kGray_8_SkColorType: {
             uint8_t* addr = this->getAddr8(x, y);
             return SkColorSetRGB(*addr, *addr, *addr);
         }
         case kAlpha_8_SkColorType: {
@@ skipping 16 matching lines @@
         case kBGRA_8888_SkColorType: {
             uint32_t* addr = this->getAddr32(x, y);
             SkPMColor c = SkSwizzle_BGRA_to_PMColor(addr[0]);
             return SkUnPreMultiply::PMColorToColor(c);
         }
         case kRGBA_8888_SkColorType: {
             uint32_t* addr = this->getAddr32(x, y);
             SkPMColor c = SkSwizzle_RGBA_to_PMColor(addr[0]);
             return SkUnPreMultiply::PMColorToColor(c);
         }
+        case kRGBA_F16_SkColorType: {
+            const uint64_t* addr = (const uint64_t*)fPixels + y * (fRowBytes >> 3) + x;
+            Sk4f p4 = SkHalfToFloat_01(addr[0]);
+            if (p4[3]) {
+                float inva = 1 / p4[3];
+                p4 = p4 * Sk4f(inva, inva, inva, 1);
+            }
+            SkColor c;
+            SkNx_cast<uint8_t>(p4 * Sk4f(255) + Sk4f(0.5f)).store(&c);
+            // p4 is RGBA, but we want BGRA, so we need to swap next
+            return SkSwizzle_RB(c);
+        }
         default:
             SkASSERT(false);
             return 0;
     }
     SkASSERT(false);  // Not reached.
     return 0;
 }
 
 static bool compute_is_opaque(const SkPixmap& pmap) {
     const int height = pmap.height();
@@ skipping 725 matching lines @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #ifdef SK_DEBUG
 void SkImageInfo::validate() const {
     SkASSERT(fWidth >= 0);
     SkASSERT(fHeight >= 0);
     SkASSERT(SkColorTypeIsValid(fColorType));
     SkASSERT(SkAlphaTypeIsValid(fAlphaType));
 }
 #endif