tests/FCITest.cpp

/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkFontArguments.h"
#include "include/core/SkFontMgr.h"
#include "include/core/SkFontScanner.h"
#include "include/core/SkFontStyle.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkStream.h"
#include "include/core/SkString.h"
#include "include/core/SkTypeface.h"
#include "include/core/SkTypes.h"
#include "include/ports/SkFontConfigInterface.h"
#include "include/ports/SkFontMgr_FontConfigInterface.h"
#include "src/ports/SkFontConfigInterface_direct.h"
#include "tests/Test.h"
#include "tools/Resources.h"
#include "tools/fonts/FontToolUtils.h"

#include <fontconfig/fontconfig.h>
#include <memory>
#include <utility>
#include <vector>

namespace {

FcConfig* build_fontconfig_with_fontfile(const char* fontFilename) {
    FcConfig* config = FcConfigCreate();

    // FontConfig may modify the passed path (make absolute or other).
    FcConfigSetSysRoot(config, reinterpret_cast<const FcChar8*>(GetResourcePath("").c_str()));
    // FontConfig will lexically compare paths against its version of the sysroot.
    SkString fontFilePath(reinterpret_cast<const char*>(FcConfigGetSysRoot(config)));
    fontFilePath += fontFilename;
    FcConfigAppFontAddFile(config, reinterpret_cast<const FcChar8*>(fontFilePath.c_str()));

    FcConfigBuildFonts(config);
    return config;
}

bool fontmgr_understands_ft_named_instance_bits() {
    std::unique_ptr<SkStreamAsset> distortable(GetResourceAsStream("fonts/Distortable.ttf"));
    if (!distortable) {
        return false;
    }

    sk_sp<SkFontMgr> fm = ToolUtils::TestFontMgr();
    SkFontArguments params;
    // The first named variation position in Distortable is 'Thin'.
    params.setCollectionIndex(0x00010000);
    sk_sp<SkTypeface> typeface = fm->makeFromStream(std::move(distortable), params);
    return !!typeface;
}

}  // namespace

DEF_TEST(FontConfigInterface_MatchStyleNamedInstance, reporter) {
    if (!fontmgr_understands_ft_named_instance_bits()) {
        return;
    }

    FcConfig* config = build_fontconfig_with_fontfile("/fonts/NotoSansCJK-VF-subset.otf.ttc");
    sk_sp<SkFontConfigInterfaceDirect> fciDirect(new SkFontConfigInterfaceDirect(config));

    static constexpr const char* family_names[]{"Noto Sans CJK JP",
                                                "Noto Sans CJK HK",
                                                "Noto Sans CJK SC",
                                                "Noto Sans CJK TC",
                                                "Noto Sans CJK KR"};
    static constexpr const struct Test {
        int weight;
        bool highBitsExpectation;
    } tests[] {
        {100, false},
        {300, true },
        {350, true },
        {400, true },
        {500, true },
        {700, true },
        {900, true },
    };

    for (auto&& font_name : family_names) {
        for (auto&& [weight, highBitsExpectation] : tests) {
            SkFontStyle fontStyle(weight, SkFontStyle::kNormal_Width, SkFontStyle::kUpright_Slant);

            SkFontConfigInterface::FontIdentity resultIdentity;
            SkFontStyle resultStyle;
            SkString resultFamily;
            const bool r = fciDirect->matchFamilyName(
                    font_name, fontStyle, &resultIdentity, &resultFamily, &resultStyle);

            REPORTER_ASSERT(reporter, r, "Expecting to find a match result.");
            REPORTER_ASSERT(
                    reporter,
                    (resultIdentity.fTTCIndex >> 16 > 0) == highBitsExpectation,
                    "Expected to have the ttcIndex' upper 16 bits refer to a named instance.");

            // Intentionally go through manually creating the typeface so that SkFontStyle is
            // derived from data inside the font, not from the FcPattern that is the FontConfig
            // match result, see skbug.com/40043982
            std::unique_ptr<SkFontScanner> scanner = ToolUtils::TestFontScanner();
            REPORTER_ASSERT(reporter, scanner != nullptr, "Could not create a font scanner.");
            auto mgr = SkFontMgr_New_FCI(fciDirect, std::move(scanner));
            REPORTER_ASSERT(reporter, mgr != nullptr, "Could not create a fci manager.");

            sk_sp<SkTypeface> typeface(fciDirect->makeTypeface(resultIdentity, mgr));
            if (!typeface) {
                ERRORF(reporter, "Could not instantiate typeface, FcVersion: %d", FcGetVersion());
                return;
            }

            SkString family_from_typeface;
            typeface->getFamilyName(&family_from_typeface);

            REPORTER_ASSERT(reporter,
                            family_from_typeface == SkString(font_name),
                            "Matched font's family name should match the request.");

            SkFontStyle intrinsic_style = typeface->fontStyle();
            REPORTER_ASSERT(reporter,
                            intrinsic_style.weight() == weight,
                            "Matched font's weight should match request.");
            if (intrinsic_style.weight() != weight) {
                ERRORF(reporter,
                       "Matched font had weight: %d, expected %d, family: %s",
                       intrinsic_style.weight(),
                       weight,
                       family_from_typeface.c_str());
            }

            const size_t numAxes = typeface->getVariationDesignPosition({});
            std::vector<SkFontArguments::VariationPosition::Coordinate> coords(numAxes);
            typeface->getVariationDesignPosition(coords);

            REPORTER_ASSERT(reporter,
                            coords.size() == 1,
                            "The font must only have one axis, the weight axis.");

            REPORTER_ASSERT(reporter,
                            coords[0].axis == SkSetFourByteTag('w', 'g', 'h', 't'),
                            "The weight axis must be present and configured.");

            REPORTER_ASSERT(reporter,
                            static_cast<int>(coords[0].value) == weight,
                            "The weight axis must match the weight from the request.");
        }
  }
}

DEF_TEST(FontConfigInterface_MissingFontRejection, reporter) {
    FcConfig* config = build_fontconfig_with_fontfile("/fonts/NotoSansCJK-VF-subset.otf.ttc");
    sk_sp<SkFontConfigInterfaceDirect> fciDirect(new SkFontConfigInterfaceDirect(config));

    SkFontStyle fontStyle(400, SkFontStyle::kNormal_Width, SkFontStyle::kUpright_Slant);
    SkFontConfigInterface::FontIdentity resultIdentity;
    SkString resultFamily;
    SkFontStyle resultStyle;

    // Requesting a non-existent family name when fallback is NOT allowed (i.e. not "sans", "serif",
    // "monospace") should cleanly return false without crashing, leaking memory, or returning an
    // unwanted default substitute
    const bool r = fciDirect->matchFamilyName("NonExistentFontFamilyThatDoesNotExist",
                                              fontStyle,
                                              &resultIdentity,
                                              &resultFamily,
                                              &resultStyle);
    REPORTER_ASSERT(reporter, !r, "Expecting missing font request to be rejected.");
}

DEF_TEST(FontConfigInterface_GenericFallbackAllowed, reporter) {
    FcConfig* config = build_fontconfig_with_fontfile("/fonts/NotoSansCJK-VF-subset.otf.ttc");
    sk_sp<SkFontConfigInterfaceDirect> fciDirect(new SkFontConfigInterfaceDirect(config));

    SkFontStyle fontStyle(400, SkFontStyle::kNormal_Width, SkFontStyle::kUpright_Slant);
    SkFontConfigInterface::FontIdentity resultIdentity;
    SkString resultFamily;
    SkFontStyle resultStyle;

    // When requesting a generic fallback family like "sans" or "monospace",
    // IsFallbackFontAllowed is true, so matchFamilyName should succeed
    const bool r = fciDirect->matchFamilyName(
            "sans", fontStyle, &resultIdentity, &resultFamily, &resultStyle);
    REPORTER_ASSERT(reporter, r, "Expecting generic fallback 'sans' request to find a font.");
}

DEF_TEST(FontConfigInterface_OnlyCheckFirstValidCandidate, reporter) {
    // NotoSansCJK-VF-subset.otf.ttc contains multiple faces:
    //   face 0: "Noto Sans CJK JP"
    //   face 1: "Noto Sans CJK HK"
    //   face 2: "Noto Sans CJK SC" (in the same SIMHEI equivalence class as "Simhei")
    // Because build_fontconfig_with_fontfile uses an empty FcConfig with no alias rules,
    // requesting "Simhei" ranks face 0 ("Noto Sans CJK JP") first in FcFontMatch / FcFontSort.
    // MatchFont must only check the first valid candidate (face 0) for family acceptability
    // and reject the match, rather than scanning all candidates in font_set and matching
    // "Noto Sans CJK SC" via IsMetricCompatibleReplacement (b/564547803).
    FcConfig* config = build_fontconfig_with_fontfile("/fonts/NotoSansCJK-VF-subset.otf.ttc");
    sk_sp<SkFontConfigInterfaceDirect> fciDirect(new SkFontConfigInterfaceDirect(config));

    SkFontStyle fontStyle(400, SkFontStyle::kNormal_Width, SkFontStyle::kUpright_Slant);
    SkFontConfigInterface::FontIdentity resultIdentity;
    SkString resultFamily;
    SkFontStyle resultStyle;

    const bool r = fciDirect->matchFamilyName(
            "Simhei", fontStyle, &resultIdentity, &resultFamily, &resultStyle);
    REPORTER_ASSERT(reporter,
                    !r,
                    "Expecting 'Simhei' to be rejected when the first valid candidate does not "
                    "match, rather than matching 'Noto Sans CJK SC' later in font_set.");
}