Index: src/opts/SkSwizzler_opts.h |
diff --git a/src/opts/SkSwizzler_opts.h b/src/opts/SkSwizzler_opts.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..467e5d1940624d6571c7561cafc26e6c8a776fa0 |
--- /dev/null |
+++ b/src/opts/SkSwizzler_opts.h |
@@ -0,0 +1,153 @@ |
+/* |
+ * Copyright 2016 Google Inc. |
+ * |
+ * Use of this source code is governed by a BSD-style license that can be |
+ * found in the LICENSE file. |
+ */ |
+ |
+#ifndef SkSwizzler_opts_DEFINED |
+#define SkSwizzler_opts_DEFINED |
+ |
+#include "SkColorPriv.h" |
+ |
+namespace SK_OPTS_NS { |
+ |
+// These variable names in these functions just pretend the input is BGRA. |
+// They work fine with both RGBA and BGRA. |
+ |
+static void premul_xxxa_portable(uint32_t dst[], const uint32_t src[], int count) { |
+ for (int i = 0; i < count; i++) { |
+ uint8_t a = src[i] >> 24, |
+ r = src[i] >> 16, |
+ g = src[i] >> 8, |
+ b = src[i] >> 0; |
+ r = (r*a+127)/255; |
+ g = (g*a+127)/255; |
+ b = (b*a+127)/255; |
+ dst[i] = (uint32_t)a << 24 |
+ | (uint32_t)r << 16 |
+ | (uint32_t)g << 8 |
+ | (uint32_t)b << 0; |
+ } |
+} |
+ |
+static void premul_swaprb_xxxa_portable(uint32_t dst[], const uint32_t src[], int count) { |
+ for (int i = 0; i < count; i++) { |
+ uint8_t a = src[i] >> 24, |
+ r = src[i] >> 16, |
+ g = src[i] >> 8, |
+ b = src[i] >> 0; |
+ r = (r*a+127)/255; |
+ g = (g*a+127)/255; |
+ b = (b*a+127)/255; |
+ dst[i] = (uint32_t)a << 24 |
+ | (uint32_t)b << 16 |
+ | (uint32_t)g << 8 |
+ | (uint32_t)r << 0; |
+ } |
+} |
+ |
+#if defined(SK_ARM_HAS_NEON) |
+ |
+// Rounded divide by 255, (x + 127) / 255 |
+static uint8x8_t div255_round(uint16x8_t x) { |
+ // result = (x + 127) / 255 |
+ // result = (x + 127) / 256 + error1 |
+ // |
+ // error1 = (x + 127) / (255 * 256) |
+ // error1 = (x + 127) / (256 * 256) + error2 |
+ // |
+ // error2 = (x + 127) / (255 * 256 * 256) |
+ // |
+ // The maximum value of error2 is too small to matter. Thus: |
+ // result = (x + 127) / 256 + (x + 127) / (256 * 256) |
+ // result = ((x + 127) / 256 + x + 127) / 256 |
+ // result = ((x + 127) >> 8 + x + 127) >> 8 |
+ // |
+ // Use >>> to represent "rounded right shift" which, conveniently, |
+ // NEON supports in one instruction. |
+ // result = ((x >>> 8) + x) >>> 8 |
+ // |
+ // Note that the second right shift is actually performed as an |
+ // "add, round, and narrow back to 8-bits" instruction. |
+ return vraddhn_u16(x, vrshrq_n_u16(x, 8)); |
+} |
+ |
+// Scale a byte by another, (x * y + 127) / 255 |
+static uint8x8_t scale(uint8x8_t x, uint8x8_t y) { |
+ return div255_round(vmull_u8(x, y)); |
+} |
+ |
+template <bool kSwapRB> |
+static void premul_xxxa_should_swaprb(uint32_t dst[], const uint32_t src[], int count) { |
+ while (count >= 8) { |
+ // Load 8 pixels. |
+ uint8x8x4_t bgra = vld4_u8((const uint8_t*) src); |
+ |
+ uint8x8_t a = bgra.val[3], |
+ r = bgra.val[2], |
+ g = bgra.val[1], |
+ b = bgra.val[0]; |
+ |
+ // Premultiply. |
+ r = scale(r, a); |
+ g = scale(g, a); |
+ b = scale(b, a); |
+ |
+ // Store 8 premultiplied pixels. |
+ if (kSwapRB) { |
+ bgra.val[2] = b; |
+ bgra.val[1] = g; |
+ bgra.val[0] = r; |
+ } else { |
+ bgra.val[2] = r; |
+ bgra.val[1] = g; |
+ bgra.val[0] = b; |
+ } |
+ vst4_u8((uint8_t*) dst, bgra); |
+ src += 8; |
+ dst += 8; |
+ count -= 8; |
+ } |
+ |
+ // Call portable code to finish up the tail of [0,8) pixels. |
+ auto proc = kSwapRB ? premul_swaprb_xxxa_portable : premul_xxxa_portable; |
+ proc(dst, src, count); |
+} |
+ |
+static void premul_xxxa(uint32_t dst[], const uint32_t src[], int count) { |
+ premul_xxxa_should_swaprb<false>(dst, src, count); |
+} |
+ |
+static void premul_swaprb_xxxa(uint32_t dst[], const uint32_t src[], int count) { |
+ premul_xxxa_should_swaprb<true>(dst, src, count); |
+} |
+ |
+#else |
+ |
+static void premul_xxxa(uint32_t dst[], const uint32_t src[], int count) { |
+ premul_xxxa_portable(dst, src, count); |
+} |
+ |
+static void premul_swaprb_xxxa(uint32_t dst[], const uint32_t src[], int count) { |
+ premul_swaprb_xxxa_portable(dst, src, count); |
+} |
+ |
+#endif |
+ |
+static void swaprb_xxxa(uint32_t dst[], const uint32_t src[], int count) { |
+ for (int i = 0; i < count; i++) { |
+ uint8_t a = src[i] >> 24, |
+ r = src[i] >> 16, |
+ g = src[i] >> 8, |
+ b = src[i] >> 0; |
+ dst[i] = (uint32_t)a << 24 |
+ | (uint32_t)b << 16 |
+ | (uint32_t)g << 8 |
+ | (uint32_t)r << 0; |
+ } |
+} |
+ |
+} |
+ |
+#endif // SkSwizzler_opts_DEFINED |