Cleanup size calculations in SkGlyph

BUG=skia:7515

Change-Id: Ie9d255a93ecff86ce018f8510332bdb280ec575e
Reviewed-on: https://skia-review.googlesource.com/113863
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/src/core/SkGlyph.cpp b/src/core/SkGlyph.cpp
new file mode 100644
index 0000000000..3b72ac5a96
--- /dev/null
+++ b/src/core/SkGlyph.cpp
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkGlyph.h"
+
+void SkGlyph::initWithGlyphID(SkPackedGlyphID glyph_id) {
+    fID             = glyph_id;
+    fImage          = nullptr;
+    fPathData       = nullptr;
+    fMaskFormat     = MASK_FORMAT_UNKNOWN;
+    fForceBW        = 0;
+}
+
+void SkGlyph::toMask(SkMask* mask) const {
+    SkASSERT(mask);
+
+    mask->fImage = (uint8_t*)fImage;
+    mask->fBounds.set(fLeft, fTop, fLeft + fWidth, fTop + fHeight);
+    mask->fRowBytes = this->rowBytes();
+    mask->fFormat = static_cast<SkMask::Format>(fMaskFormat);
+}
+
+void SkGlyph::zeroMetrics() {
+    fAdvanceX = 0;
+    fAdvanceY = 0;
+    fWidth    = 0;
+    fHeight   = 0;
+    fTop      = 0;
+    fLeft     = 0;
+    fRsbDelta = 0;
+    fLsbDelta = 0;
+}
+
+static size_t bits_to_bytes(size_t bits) {
+    return (bits + 7) >> 3;
+}
+
+static size_t format_rowbytes(int width, SkMask::Format format) {
+    switch (format) {
+        case SkMask::kBW_Format:
+            return bits_to_bytes(width);
+        case SkMask::kA8_Format:
+        case SkMask::k3D_Format:
+            return SkAlign4(width);
+        case SkMask::kARGB32_Format:
+            return width * sizeof(uint32_t);
+        case SkMask::kLCD16_Format:
+            return SkAlign4(width * sizeof(uint16_t));
+        default:
+            SK_ABORT("Unknown mask format.");
+            break;
+    }
+    return 0;
+}
+
+static size_t format_alignment(SkMask::Format format) {
+    switch (format) {
+        case SkMask::kBW_Format:
+        case SkMask::kA8_Format:
+        case SkMask::k3D_Format:
+            return alignof(uint8_t);
+        case SkMask::kARGB32_Format:
+            return alignof(uint32_t);
+        case SkMask::kLCD16_Format:
+            return alignof(uint16_t);
+        default:
+            SK_ABORT("Unknown mask format.");
+            break;
+    }
+    return 0;
+}
+
+size_t SkGlyph::allocImage(SkArenaAlloc* alloc) {
+    auto size = this->computeImageSize();
+    auto format = static_cast<SkMask::Format>(fMaskFormat);
+    fImage = alloc->makeBytesAlignedTo(size, format_alignment(format));
+
+    return size;
+}
+
+size_t SkGlyph::rowBytes() const {
+    return format_rowbytes(fWidth, (SkMask::Format)fMaskFormat);
+}
+
+size_t SkGlyph::rowBytesUsingFormat(SkMask::Format format) const {
+    return format_rowbytes(fWidth, format);
+}
+
+size_t SkGlyph::computeImageSize() const {
+    size_t size = this->rowBytes() * fHeight;
+
+    if (fMaskFormat == SkMask::k3D_Format) {
+        size *= 3;
+    }
+
+    return size;
+}