experiments to speed up drawing 32bit images into 565

New (legacy style) blitters only coded for shaders (and very restricted blendmodes)

Bug: skia:
See https://buganizer.corp.google.com/issues/64884885

Change-Id: Ie2546093bfe1e670a825dfd9542d252d53732c40
Reviewed-on: https://skia-review.googlesource.com/54103
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Herb Derby <herb@google.com>

1 files changed, 179 insertions, 0 deletions

diff --git a/src/core/SkSpriteBlitter_RGB565.cpp b/src/core/SkSpriteBlitter_RGB565.cpp
new file mode 100644
index 0000000000..8151347ceb
--- /dev/null
+++ b/src/core/SkSpriteBlitter_RGB565.cpp
@@ -0,0 +1,179 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkSpriteBlitter.h"
+#include "SkArenaAlloc.h"
+#include "SkBlitRow.h"
+#include "SkColorFilter.h"
+#include "SkColorData.h"
+#include "SkTemplates.h"
+#include "SkUtils.h"
+#include "SkXfermodePriv.h"
+
+///////////////////////////////////////////////////////////////////////////////
+
+static void S32_src(uint16_t dst[], const SkPMColor src[], int count) {
+    for (int i = 0; i < count; ++i) {
+        dst[i] = SkPixel32ToPixel16(src[i]);
+    }
+}
+
+static void S32_srcover(uint16_t dst[], const SkPMColor src[], int count) {
+    for (int i = 0; i < count; ++i) {
+        dst[i] = SkSrcOver32To16(src[i], dst[i]);
+    }
+}
+
+class Sprite_D16_S32 : public SkSpriteBlitter {
+public:
+    Sprite_D16_S32(const SkPixmap& src, SkBlendMode mode)  : INHERITED(src) {
+        SkASSERT(src.colorType() == kN32_SkColorType);
+        SkASSERT(mode == SkBlendMode::kSrc || mode == SkBlendMode::kSrcOver);
+
+        fUseSrcOver = (mode == SkBlendMode::kSrcOver) && !src.isOpaque();
+    }
+
+    void blitRect(int x, int y, int width, int height) override {
+        SkASSERT(width > 0 && height > 0);
+        uint16_t* SK_RESTRICT dst = fDst.writable_addr16(x, y);
+        const uint32_t* SK_RESTRICT src = fSource.addr32(x - fLeft, y - fTop);
+        size_t dstRB = fDst.rowBytes();
+        size_t srcRB = fSource.rowBytes();
+
+        do {
+            if (fUseSrcOver) {
+                S32_srcover(dst, src, width);
+            } else {
+                S32_src(dst, src, width);
+            }
+
+            dst = (uint16_t* SK_RESTRICT)((char*)dst + dstRB);
+            src = (const uint32_t* SK_RESTRICT)((const char*)src + srcRB);
+        } while (--height != 0);
+    }
+
+private:
+    bool fUseSrcOver;
+
+    typedef SkSpriteBlitter INHERITED;
+};
+
+SkSpriteBlitter* SkSpriteBlitter::ChooseL565(const SkPixmap& source, const SkPaint& paint,
+                                             SkArenaAlloc* allocator) {
+    SkASSERT(allocator != nullptr);
+
+    if (paint.getColorFilter() != nullptr) {
+        return nullptr;
+    }
+    if (paint.getMaskFilter() != nullptr) {
+        return nullptr;
+    }
+
+    U8CPU alpha = paint.getAlpha();
+    if (alpha != 0xFF) {
+        return nullptr;
+    }
+
+    if (source.colorType() == kN32_SkColorType) {
+        switch (paint.getBlendMode()) {
+            case SkBlendMode::kSrc:
+            case SkBlendMode::kSrcOver:
+                return allocator->make<Sprite_D16_S32>(source, paint.getBlendMode());
+            default:
+                break;
+        }
+    }
+    return nullptr;
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////////
+
+static unsigned div255(unsigned a, unsigned b) {
+    return (a * b * 257 + 127) >> 16;
+}
+
+static void S32_src_da8(uint8_t dst[], const SkPMColor src[], int count) {
+    for (int i = 0; i < count; ++i) {
+        dst[i] = SkGetPackedA32(src[i]);
+    }
+}
+
+static void S32_srcover_da8(uint8_t dst[], const SkPMColor src[], int count) {
+    for (int i = 0; i < count; ++i) {
+        SkPMColor c = src[i];
+        if (c) {
+            unsigned a = SkGetPackedA32(c);
+            if (a == 0xFF) {
+                dst[i] = 0xFF;
+            } else {
+                dst[i] = a + div255(255 - a, dst[i]);
+            }
+        }
+    }
+}
+
+class Sprite_D8_S32 : public SkSpriteBlitter {
+public:
+    Sprite_D8_S32(const SkPixmap& src, SkBlendMode mode)  : INHERITED(src) {
+        SkASSERT(src.colorType() == kN32_SkColorType);
+        SkASSERT(mode == SkBlendMode::kSrc || mode == SkBlendMode::kSrcOver);
+
+        fUseSrcOver = (mode == SkBlendMode::kSrcOver) && !src.isOpaque();
+    }
+
+    void blitRect(int x, int y, int width, int height) override {
+        SkASSERT(width > 0 && height > 0);
+        uint8_t* SK_RESTRICT dst = fDst.writable_addr8(x, y);
+        const uint32_t* SK_RESTRICT src = fSource.addr32(x - fLeft, y - fTop);
+        size_t dstRB = fDst.rowBytes();
+        size_t srcRB = fSource.rowBytes();
+
+        do {
+            if (fUseSrcOver) {
+                S32_srcover_da8(dst, src, width);
+            } else {
+                S32_src_da8(dst, src, width);
+            }
+
+            dst = (uint8_t* SK_RESTRICT)((char*)dst + dstRB);
+            src = (const uint32_t* SK_RESTRICT)((const char*)src + srcRB);
+        } while (--height != 0);
+    }
+
+private:
+    bool fUseSrcOver;
+
+    typedef SkSpriteBlitter INHERITED;
+};
+
+SkSpriteBlitter* SkSpriteBlitter::ChooseLA8(const SkPixmap& source, const SkPaint& paint,
+                                            SkArenaAlloc* allocator) {
+    SkASSERT(allocator != nullptr);
+
+    if (paint.getColorFilter() != nullptr) {
+        return nullptr;
+    }
+    if (paint.getMaskFilter() != nullptr) {
+        return nullptr;
+    }
+
+    U8CPU alpha = paint.getAlpha();
+    if (alpha != 0xFF) {
+        return nullptr;
+    }
+
+    if (source.colorType() == kN32_SkColorType) {
+        switch (paint.getBlendMode()) {
+            case SkBlendMode::kSrc:
+            case SkBlendMode::kSrcOver:
+                return allocator->make<Sprite_D8_S32>(source, paint.getBlendMode());
+            default:
+                break;
+        }
+    }
+    return nullptr;
+}