gecko-dev/gfx/2d/ScaledFontBase.cpp

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "ScaledFontBase.h"

#ifdef USE_SKIA
#include "PathSkia.h"
#include "skia/include/core/SkPaint.h"
#endif

#ifdef USE_CAIRO
#include "PathCairo.h"
#include "DrawTargetCairo.h"
#include "HelpersCairo.h"
#endif

#include <vector>
#include <cmath>

using namespace std;

namespace mozilla {
namespace gfx {

ScaledFontBase::~ScaledFontBase()
{
#ifdef USE_SKIA
  SkSafeUnref(mTypeface);
#endif
#ifdef USE_CAIRO_SCALED_FONT
  cairo_scaled_font_destroy(mScaledFont);
#endif
}

ScaledFontBase::ScaledFontBase(Float aSize)
  : mSize(aSize)
{
#ifdef USE_SKIA
  mTypeface = nullptr;
#endif
#ifdef USE_CAIRO_SCALED_FONT
  mScaledFont = nullptr;
#endif
}

#ifdef USE_CAIRO_SCALED_FONT
bool
ScaledFontBase::PopulateCairoScaledFont()
{
  cairo_font_face_t* cairoFontFace = GetCairoFontFace();
  if (!cairoFontFace) {
    return false;
  }

  cairo_matrix_t sizeMatrix;
  cairo_matrix_t identityMatrix;

  cairo_matrix_init_scale(&sizeMatrix, mSize, mSize);
  cairo_matrix_init_identity(&identityMatrix);

  cairo_font_options_t *fontOptions = cairo_font_options_create();

  mScaledFont = cairo_scaled_font_create(cairoFontFace, &sizeMatrix,
    &identityMatrix, fontOptions);

  cairo_font_options_destroy(fontOptions);
  cairo_font_face_destroy(cairoFontFace);

  return (cairo_scaled_font_status(mScaledFont) == CAIRO_STATUS_SUCCESS);
}
#endif

#ifdef USE_SKIA
SkPath
ScaledFontBase::GetSkiaPathForGlyphs(const GlyphBuffer &aBuffer)
{
  SkTypeface *typeFace = GetSkTypeface();
  MOZ_ASSERT(typeFace);

  SkPaint paint;
  paint.setTypeface(sk_ref_sp(typeFace));
  paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
  paint.setTextSize(SkFloatToScalar(mSize));

  std::vector<uint16_t> indices;
  std::vector<SkPoint> offsets;
  indices.resize(aBuffer.mNumGlyphs);
  offsets.resize(aBuffer.mNumGlyphs);

  for (unsigned int i = 0; i < aBuffer.mNumGlyphs; i++) {
    indices[i] = aBuffer.mGlyphs[i].mIndex;
    offsets[i].fX = SkFloatToScalar(aBuffer.mGlyphs[i].mPosition.x);
    offsets[i].fY = SkFloatToScalar(aBuffer.mGlyphs[i].mPosition.y);
  }

  SkPath path;
  paint.getPosTextPath(&indices.front(), aBuffer.mNumGlyphs*2, &offsets.front(), &path);
  return path;
}
#endif

already_AddRefed<Path>
ScaledFontBase::GetPathForGlyphs(const GlyphBuffer &aBuffer, const DrawTarget *aTarget)
{
#ifdef USE_SKIA
  if (aTarget->GetBackendType() == BackendType::SKIA) {
    SkPath path = GetSkiaPathForGlyphs(aBuffer);
    return MakeAndAddRef<PathSkia>(path, FillRule::FILL_WINDING);
  }
#endif
#ifdef USE_CAIRO
  if (aTarget->GetBackendType() == BackendType::CAIRO) {
    MOZ_ASSERT(mScaledFont);

    DrawTarget *dt = const_cast<DrawTarget*>(aTarget);
    cairo_t *ctx = static_cast<cairo_t*>(dt->GetNativeSurface(NativeSurfaceType::CAIRO_CONTEXT));

    bool isNewContext = !ctx;
    if (!ctx) {
      ctx = cairo_create(DrawTargetCairo::GetDummySurface());
      cairo_matrix_t mat;
      GfxMatrixToCairoMatrix(aTarget->GetTransform(), mat);
      cairo_set_matrix(ctx, &mat);
    }

    cairo_set_scaled_font(ctx, mScaledFont);

    // Convert our GlyphBuffer into an array of Cairo glyphs.
    std::vector<cairo_glyph_t> glyphs(aBuffer.mNumGlyphs);
    for (uint32_t i = 0; i < aBuffer.mNumGlyphs; ++i) {
      glyphs[i].index = aBuffer.mGlyphs[i].mIndex;
      glyphs[i].x = aBuffer.mGlyphs[i].mPosition.x;
      glyphs[i].y = aBuffer.mGlyphs[i].mPosition.y;
    }

    cairo_new_path(ctx);

    cairo_glyph_path(ctx, &glyphs[0], aBuffer.mNumGlyphs);

    RefPtr<PathCairo> newPath = new PathCairo(ctx);
    if (isNewContext) {
      cairo_destroy(ctx);
    }

    return newPath.forget();
  }
#endif
  return nullptr;
}

void
ScaledFontBase::CopyGlyphsToBuilder(const GlyphBuffer &aBuffer, PathBuilder *aBuilder, const Matrix *aTransformHint)
{
  BackendType backendType = aBuilder->GetBackendType();
#ifdef USE_SKIA
  if (backendType == BackendType::SKIA) {
    PathBuilderSkia *builder = static_cast<PathBuilderSkia*>(aBuilder);
    builder->AppendPath(GetSkiaPathForGlyphs(aBuffer));
    return;
  }
#endif
#ifdef USE_CAIRO
  if (backendType == BackendType::CAIRO) {
    MOZ_ASSERT(mScaledFont);

    PathBuilderCairo* builder = static_cast<PathBuilderCairo*>(aBuilder);
    cairo_t *ctx = cairo_create(DrawTargetCairo::GetDummySurface());

    if (aTransformHint) {
      cairo_matrix_t mat;
      GfxMatrixToCairoMatrix(*aTransformHint, mat);
      cairo_set_matrix(ctx, &mat);
    }

    // Convert our GlyphBuffer into an array of Cairo glyphs.
    std::vector<cairo_glyph_t> glyphs(aBuffer.mNumGlyphs);
    for (uint32_t i = 0; i < aBuffer.mNumGlyphs; ++i) {
      glyphs[i].index = aBuffer.mGlyphs[i].mIndex;
      glyphs[i].x = aBuffer.mGlyphs[i].mPosition.x;
      glyphs[i].y = aBuffer.mGlyphs[i].mPosition.y;
    }

    cairo_set_scaled_font(ctx, mScaledFont);
    cairo_glyph_path(ctx, &glyphs[0], aBuffer.mNumGlyphs);

    RefPtr<PathCairo> cairoPath = new PathCairo(ctx);
    cairo_destroy(ctx);

    cairoPath->AppendPathToBuilder(builder);
    return;
  }
#endif
}

void
ScaledFontBase::GetGlyphDesignMetrics(const uint16_t* aGlyphs, uint32_t aNumGlyphs, GlyphMetrics* aGlyphMetrics)
{
#ifdef USE_CAIRO_SCALED_FONT
  if (mScaledFont) {
    for (uint32_t i = 0; i < aNumGlyphs; i++) {
      cairo_glyph_t glyph;
      cairo_text_extents_t extents;
      glyph.index = aGlyphs[i];
      glyph.x = 0;
      glyph.y = 0;

      cairo_scaled_font_glyph_extents(mScaledFont, &glyph, 1, &extents);

      aGlyphMetrics[i].mXBearing = extents.x_bearing;
      aGlyphMetrics[i].mXAdvance = extents.x_advance;
      aGlyphMetrics[i].mYBearing = extents.y_bearing;
      aGlyphMetrics[i].mYAdvance = extents.y_advance;
      aGlyphMetrics[i].mWidth = extents.width;
      aGlyphMetrics[i].mHeight = extents.height;

      cairo_font_options_t *options = cairo_font_options_create();
      cairo_scaled_font_get_font_options(mScaledFont, options);

      if (cairo_font_options_get_antialias(options) != CAIRO_ANTIALIAS_NONE) {
        if (cairo_scaled_font_get_type(mScaledFont) == CAIRO_FONT_TYPE_WIN32) {
          if (aGlyphMetrics[i].mWidth > 0 && aGlyphMetrics[i].mHeight > 0) {
            aGlyphMetrics[i].mWidth -= 3.0f;
            aGlyphMetrics[i].mXBearing += 1.0f;
          }
        }
#if defined(MOZ2D_HAS_MOZ_CAIRO) && defined(CAIRO_HAS_DWRITE_FONT)
        else if (cairo_scaled_font_get_type(mScaledFont) == CAIRO_FONT_TYPE_DWRITE) {
          if (aGlyphMetrics[i].mWidth > 0 && aGlyphMetrics[i].mHeight > 0) {
            aGlyphMetrics[i].mWidth -= 2.0f;
            aGlyphMetrics[i].mXBearing += 1.0f;
          }
        }
#endif
      }
      cairo_font_options_destroy(options);
    }

  }
#endif

  // Don't know how to get the glyph metrics...
  MOZ_CRASH("The specific backend type is not supported for GetGlyphDesignMetrics.");
}


#ifdef USE_CAIRO_SCALED_FONT
void
ScaledFontBase::SetCairoScaledFont(cairo_scaled_font_t* font)
{
  MOZ_ASSERT(!mScaledFont);

  if (font == mScaledFont)
    return;
 
  if (mScaledFont)
    cairo_scaled_font_destroy(mScaledFont);

  mScaledFont = font;
  cairo_scaled_font_reference(mScaledFont);
}
#endif

} // namespace gfx
} // namespace mozilla