SkShaper: optionally disable harfbuzz

tools/SkShaper.cpp

-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include <hb-ot.h>
-
-#include "SkShaper.h"
-#include "SkStream.h"
-#include "SkTextBlob.h"
-#include "SkTypeface.h"
-
-static const int FONT_SIZE_SCALE = 512;
-
-namespace {
-struct HBFBlobDel {
-    void operator()(hb_blob_t* b) { hb_blob_destroy(b); }
-};
-
-std::unique_ptr<hb_blob_t, HBFBlobDel> stream_to_blob(std::unique_ptr<SkStreamAsset> asset) {
-    size_t size = asset->getLength();
-    std::unique_ptr<hb_blob_t, HBFBlobDel> blob;
-    if (const void* base = asset->getMemoryBase()) {
-        blob.reset(hb_blob_create((char*)base, size,
-                                  HB_MEMORY_MODE_READONLY, asset.release(),
-                                  [](void* p) { delete (SkStreamAsset*)p; }));
-    } else {
-        // SkDebugf("Extra SkStreamAsset copy\n");
-        SkAutoMalloc autoMalloc(size);
-        asset->read(autoMalloc.get(), size);
-        void* ptr = autoMalloc.get();
-        blob.reset(hb_blob_create((char*)autoMalloc.release(), size,
-                                  HB_MEMORY_MODE_READONLY, ptr, sk_free));
-    }
-    SkASSERT(blob);
-    hb_blob_make_immutable(blob.get());
-    return blob;
-}
-}  // namespace
-
-struct SkShaper::Impl {
-    struct HBFontDel {
-        void operator()(hb_font_t* f) { hb_font_destroy(f); }
-    };
-    std::unique_ptr<hb_font_t, HBFontDel> fHarfBuzzFont;
-    struct HBBufDel {
-        void operator()(hb_buffer_t* b) { hb_buffer_destroy(b); }
-    };
-    std::unique_ptr<hb_buffer_t, HBBufDel> fBuffer;
-    sk_sp<SkTypeface> fTypeface;
-};
-
-SkShaper::SkShaper(sk_sp<SkTypeface> tf) : fImpl(new Impl) {
-    fImpl->fTypeface = tf ? std::move(tf) : SkTypeface::MakeDefault();
-    int index;
-    std::unique_ptr<hb_blob_t, HBFBlobDel> blob(
-            stream_to_blob(std::unique_ptr<SkStreamAsset>(
-                                   fImpl->fTypeface->openStream(&index))));
-    struct HBFaceDel {
-        void operator()(hb_face_t* f) { hb_face_destroy(f); }
-    };
-    std::unique_ptr<hb_face_t, HBFaceDel> face(
-            hb_face_create(blob.get(), (unsigned)index));
-    SkASSERT(face);
-    if (!face) {
-        return;
-    }
-    hb_face_set_index(face.get(), (unsigned)index);
-    hb_face_set_upem(face.get(), fImpl->fTypeface->getUnitsPerEm());
-
-    fImpl->fHarfBuzzFont.reset(hb_font_create(face.get()));
-    SkASSERT(fImpl->fHarfBuzzFont);
-    hb_font_set_scale(fImpl->fHarfBuzzFont.get(), FONT_SIZE_SCALE, FONT_SIZE_SCALE);
-    hb_ot_font_set_funcs(fImpl->fHarfBuzzFont.get());
-
-    fImpl->fBuffer.reset(hb_buffer_create());
-}
-
-SkShaper::~SkShaper() {}
-
-bool SkShaper::good() const { return fImpl->fHarfBuzzFont != nullptr; }
-
-SkScalar SkShaper::shape(SkTextBlobBuilder* builder,
-                         const SkPaint& srcPaint,
-                         const char* utf8text,
-                         size_t textBytes,
-                         SkPoint point) const {
-    SkPaint paint(srcPaint);
-    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
-    paint.setTypeface(fImpl->fTypeface);
-
-    SkASSERT(builder);
-    hb_buffer_t* buffer = fImpl->fBuffer.get();
-    hb_buffer_add_utf8(buffer, utf8text, -1, 0, -1);
-    hb_buffer_guess_segment_properties(buffer);
-    hb_shape(fImpl->fHarfBuzzFont.get(), buffer, nullptr, 0);
-    unsigned len = hb_buffer_get_length(buffer);
-    if (len == 0) {
-        hb_buffer_clear_contents(buffer);
-        return 0;
-    }
-
-    hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, NULL);
-    hb_glyph_position_t* pos =
-            hb_buffer_get_glyph_positions(buffer, NULL);
-    auto runBuffer = builder->allocRunPos(paint, len);
-
-    double x = point.x();
-    double y = point.y();
-
-    double textSizeY = paint.getTextSize() / (double)FONT_SIZE_SCALE;
-    double textSizeX = textSizeY * paint.getTextScaleX();
-
-    for (unsigned i = 0; i < len; i++) {
-        runBuffer.glyphs[i] = info[i].codepoint;
-        reinterpret_cast<SkPoint*>(runBuffer.pos)[i] =
-                SkPoint::Make(x + pos[i].x_offset * textSizeX,
-                              y - pos[i].y_offset * textSizeY);
-        x += pos[i].x_advance * textSizeX;
-        y += pos[i].y_advance * textSizeY;
-    }
-    hb_buffer_clear_contents(buffer);
-    return (SkScalar)x;
-}