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// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
#include "qwasmfontdatabase.h"
#include "qwasmintegration.h"
#include <QtCore/qfile.h>
#include <QtCore/private/qstdweb_p.h>
#include <QtGui/private/qguiapplication_p.h>
#include <emscripten.h>
#include <emscripten/val.h>
#include <emscripten/bind.h>
#include <map>
#include <array>
QT_BEGIN_NAMESPACE
using namespace emscripten;
using namespace Qt::StringLiterals;
namespace {
bool isLocalFontsAPISupported()
{
return val::global("window")["queryLocalFonts"].isUndefined() == false;
}
val makeObject(const char *key, const char *value)
{
val obj = val::object();
obj.set(key, std::string(value));
return obj;
}
std::multimap<QString, emscripten::val> makeFontFamilyMap(const QList<val> &fonts)
{
std::multimap<QString, emscripten::val> fontFamilies;
for (auto font : fonts) {
QString family = QString::fromStdString(font["family"].as<std::string>());
fontFamilies.insert(std::make_pair(family, font));
}
return fontFamilies;
}
void printError(val err) {
qCWarning(lcQpaFonts)
<< QString::fromStdString(err["name"].as<std::string>())
<< QString::fromStdString(err["message"].as<std::string>());
}
std::array<const char *, 8> webSafeFontFamilies()
{
return {"Arial", "Verdana", "Tahoma", "Trebuchet", "Times New Roman",
"Georgia", "Garamond", "Courier New"};
}
void checkFontAccessPermitted(std::function<void()> callback)
{
const val permissions = val::global("navigator")["permissions"];
if (permissions.isUndefined())
return;
qstdweb::Promise::make(permissions, "query", {
.thenFunc = [callback](val status) {
if (status["state"].as<std::string>() == "granted")
callback();
}
}, makeObject("name", "local-fonts"));
}
void queryLocalFonts(std::function<void(const QList<val> &)> callback)
{
emscripten::val window = emscripten::val::global("window");
qstdweb::Promise::make(window, "queryLocalFonts", {
.thenFunc = [callback](emscripten::val fontArray) {
QList<val> fonts;
const int count = fontArray["length"].as<int>();
fonts.reserve(count);
for (int i = 0; i < count; ++i)
fonts.append(fontArray.call<emscripten::val>("at", i));
callback(fonts);
},
.catchFunc = printError
});
}
void readBlob(val blob, std::function<void(const QByteArray &)> callback)
{
qstdweb::Promise::make(blob, "arrayBuffer", {
.thenFunc = [callback](emscripten::val fontArrayBuffer) {
QByteArray fontData = qstdweb::Uint8Array(qstdweb::ArrayBuffer(fontArrayBuffer)).copyToQByteArray();
callback(fontData);
},
.catchFunc = printError
});
}
void readFont(val font, std::function<void(const QByteArray &)> callback)
{
qstdweb::Promise::make(font, "blob", {
.thenFunc = [callback](val blob) {
readBlob(blob, [callback](const QByteArray &data) {
callback(data);
});
},
.catchFunc = printError
});
}
} // namespace
void QWasmFontDatabase::populateLocalfonts()
{
if (!isLocalFontsAPISupported())
return;
// Run the font population code if local font access has been
// permitted. This does not request permission, since we are currently
// starting up and should not display a permission request dialog at
// this point.
checkFontAccessPermitted([](){
queryLocalFonts([](const QList<val> &fonts){
auto fontFamilies = makeFontFamilyMap(fonts);
// Populate some font families. We can't populate _all_ fonts as in-memory fonts,
// since that would require several gigabytes of memory. Instead, populate
// a subset of the available fonts.
for (const QString &family: webSafeFontFamilies()) {
auto fontsRange = fontFamilies.equal_range(family);
if (fontsRange.first != fontsRange.second)
QFreeTypeFontDatabase::registerFontFamily(family);
for (auto it = fontsRange.first; it != fontsRange.second; ++it) {
const val font = it->second;
readFont(font, [](const QByteArray &fontData){
QFreeTypeFontDatabase::addTTFile(fontData, QByteArray());
QWasmFontDatabase::notifyFontsChanged();
});
}
}
});
});
}
void QWasmFontDatabase::populateFontDatabase()
{
// Load font file from resources. Currently
// all fonts needs to be bundled with the nexe
// as Qt resources.
const QString fontFileNames[] = {
QStringLiteral(":/fonts/DejaVuSansMono.ttf"),
QStringLiteral(":/fonts/Vera.ttf"),
QStringLiteral(":/fonts/DejaVuSans.ttf"),
};
for (const QString &fontFileName : fontFileNames) {
QFile theFont(fontFileName);
if (!theFont.open(QIODevice::ReadOnly))
break;
QFreeTypeFontDatabase::addTTFile(theFont.readAll(), fontFileName.toLatin1());
}
populateLocalfonts();
}
QFontEngine *QWasmFontDatabase::fontEngine(const QFontDef &fontDef, void *handle)
{
return QFreeTypeFontDatabase::fontEngine(fontDef, handle);
}
QStringList QWasmFontDatabase::fallbacksForFamily(const QString &family, QFont::Style style,
QFont::StyleHint styleHint,
QChar::Script script) const
{
QStringList fallbacks
= QFreeTypeFontDatabase::fallbacksForFamily(family, style, styleHint, script);
// Add the vera.ttf and DejaVuSans.ttf fonts (loaded in populateFontDatabase above) as falback fonts
// to all other fonts (except itself).
static const QString wasmFallbackFonts[] = { "Bitstream Vera Sans", "DejaVu Sans" };
for (auto wasmFallbackFont : wasmFallbackFonts) {
if (family != wasmFallbackFont && !fallbacks.contains(wasmFallbackFont))
fallbacks.append(wasmFallbackFont);
}
return fallbacks;
}
void QWasmFontDatabase::releaseHandle(void *handle)
{
QFreeTypeFontDatabase::releaseHandle(handle);
}
QFont QWasmFontDatabase::defaultFont() const
{
return QFont("Bitstream Vera Sans"_L1);
}
void QWasmFontDatabase::notifyFontsChanged()
{
QFontCache::instance()->clear();
emit qGuiApp->fontDatabaseChanged();
}
QT_END_NAMESPACE
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