Clean up remaining users of SkPMFloat

src/effects/SkColorMatrixFilter.cpp

Index: src/effects/SkColorMatrixFilter.cpp
diff --git a/src/effects/SkColorMatrixFilter.cpp b/src/effects/SkColorMatrixFilter.cpp
index 92b26ebdf91ec901d1dc8bb44baff073288edb1c..d7f0a742955575aeff5399765c03a5a5e4a2ef46 100644
--- a/src/effects/SkColorMatrixFilter.cpp
+++ b/src/effects/SkColorMatrixFilter.cpp
@@ -8,7 +8,7 @@
 #include "SkColorMatrixFilter.h"
 #include "SkColorMatrix.h"
 #include "SkColorPriv.h"
-#include "SkPMFloat.h"
+#include "SkNx.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkUnPreMultiply.h"
@@ -239,25 +239,27 @@ uint32_t SkColorMatrixFilter::getFlags() const {
     return this->INHERITED::getFlags() | fFlags;
 }
 
-static Sk4f premul(const Sk4f& x) {
-    float scale = SkPMFloat(x).a();
-    Sk4f pm = x * SkPMFloat(1, scale, scale, scale);
+static Sk4f scale_rgb(float scale) {
+    static_assert(SK_A32_SHIFT == 24, "Alpha is lane 3");
+    return Sk4f(scale, scale, scale, 1);
+}
 
-#ifdef SK_DEBUG
-    SkPMFloat pmf(pm);
-    SkASSERT(pmf.isValid());
-#endif
+static Sk4f premul(const Sk4f& x) {
+    return x * scale_rgb(x.kth<SK_A32_SHIFT/8>());
+}
 
-    return pm;
+static Sk4f unpremul(const Sk4f& x) {
+    return x * scale_rgb(1 / x.kth<SK_A32_SHIFT/8>());  // TODO: fast/approx invert?
 }
 
-static Sk4f unpremul(const SkPMFloat& pm) {
-    float scale = 1 / pm.a(); // candidate for fast/approx invert?
-    return pm * SkPMFloat(1, scale, scale, scale);
+static Sk4f clamp_0_1(const Sk4f& x) {
+    return Sk4f::Max(Sk4f::Min(x, Sk4f(1)), Sk4f(0));
 }
 
-static Sk4f clamp_0_1(const Sk4f& value) {
-    return Sk4f::Max(Sk4f::Min(value, Sk4f(1)), Sk4f(0));
+static SkPMColor round(const Sk4f& x) {
+    SkPMColor c;
+    (x * Sk4f(255) + Sk4f(0.5f)).toBytes((uint8_t*)&c);
+    return c;
 }
 
 void SkColorMatrixFilter::filterSpan(const SkPMColor src[], int count, SkPMColor dst[]) const {
@@ -285,7 +287,7 @@ void SkColorMatrixFilter::filterSpan(const SkPMColor src[], int count, SkPMColor
         const Sk4f c4 = Sk4f::Load(fTranspose + 16)*Sk4f(1.0f/255);
 
         // todo: we could cache this in the constructor...
-        SkPMColor matrix_translate_pmcolor = SkPMFloat(premul(clamp_0_1(c4))).round();
+        SkPMColor matrix_translate_pmcolor = round(premul(clamp_0_1(c4)));
 
         for (int i = 0; i < count; i++) {
             const SkPMColor src_c = src[i];
@@ -294,22 +296,22 @@ void SkColorMatrixFilter::filterSpan(const SkPMColor src[], int count, SkPMColor
                 continue;
             }
 
-            SkPMFloat srcf(src_c);
+            Sk4f srcf = Sk4f::FromBytes((const uint8_t*)&src_c) * Sk4f(1.0f/255);
 
             if (0xFF != SkGetPackedA32(src_c)) {
                 srcf = unpremul(srcf);
             }
 
-            Sk4f r4 = Sk4f(srcf.r());
-            Sk4f g4 = Sk4f(srcf.g());
-            Sk4f b4 = Sk4f(srcf.b());
-            Sk4f a4 = Sk4f(srcf.a());
+            Sk4f r4 = Sk4f(srcf.kth<SK_R32_SHIFT/8>());
+            Sk4f g4 = Sk4f(srcf.kth<SK_G32_SHIFT/8>());
+            Sk4f b4 = Sk4f(srcf.kth<SK_B32_SHIFT/8>());
+            Sk4f a4 = Sk4f(srcf.kth<SK_A32_SHIFT/8>());
 
             // apply matrix
             Sk4f dst4 = c0 * r4 + c1 * g4 + c2 * b4 + c3 * a4 + c4;
 
             // clamp, re-premul, and write
-            dst[i] = SkPMFloat(premul(clamp_0_1(dst4))).round();
+            dst[i] = round(premul(clamp_0_1(dst4)));
         }
     } else {
         const State& state = fState;