From 5b4b437b30b320e2cd7c9a566999a39772e5d431 Mon Sep 17 00:00:00 2001 From: Giuseppe D'Angelo Date: Mon, 10 Jun 2019 15:57:52 +0200 Subject: WebGradients: redo implementation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The previous implementation was *extremely* expensive. It relied on loading a binary JSON file from resources (which involved decompressing it), then extracting information out of it to build a gradient. Already-loaded gradients were kept in a local cache, which had to be mutex protected. Instead, this patch extends the gradient generator to build static arrays filled with the web gradient data, sitting in .rodata. These arrays are used when building QGradient objects with a web gradient. No explicit mutex protection is necessary, since accesses will just read from the arrays. As benefits, this patch removes: * the binary json representation from QtGui's resources (~4KB compressed, ~50KB uncompressed) * the overhead of reading from the JSON for each used web gradient; * the startup costs of registering the webgradients in the resources; * all the overhead of mutex locking when building such gradients; * all the runtime memory allocations to load, parse and cache the web gradients (including the memory + CPU spike on first load due to the uncompression of the JSON data, as well as a couple of deep copies). Change-Id: If5c3d704430df76ce8faf55ee75ebd4639ba09c4 Reviewed-by: Tor Arne Vestbø Reviewed-by: Ulf Hermann Reviewed-by: Qt CI Bot Reviewed-by: Thiago Macieira Reviewed-by: Edward Welbourne --- util/gradientgen/gradientgen.cpp | 299 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 299 insertions(+) create mode 100644 util/gradientgen/gradientgen.cpp (limited to 'util/gradientgen/gradientgen.cpp') diff --git a/util/gradientgen/gradientgen.cpp b/util/gradientgen/gradientgen.cpp new file mode 100644 index 0000000000..5dc0b53b9d --- /dev/null +++ b/util/gradientgen/gradientgen.cpp @@ -0,0 +1,299 @@ +/**************************************************************************** +** +** Copyright (C) 2018 The Qt Company Ltd. +** Copyright (C) 2019 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the utils of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:GPL-EXCEPT$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3 as published by the Free Software +** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +#include + +using namespace std; + +static const char LICENSE_HEADER[] = +R"(/**************************************************************************** +** +** Copyright (C) 2019 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtGui module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/)"; + +class Printer { + Q_DISABLE_COPY_MOVE(Printer) +public: + Printer() = default; + + class Indenter + { + Q_DISABLE_COPY_MOVE(Indenter) + Printer &p; + public: + Indenter(Printer &p) : p(p) { p.indent(); } + ~Indenter() { p.deindent(); } + }; + + ~Printer() + { + cout << flush; + } + + void printLine(const QString &str) const + { + printLine(qPrintable(str)); + } + + void printLine(const char *str = nullptr) const + { + if (str) + cout << m_indentString << str << '\n'; + else + cout << '\n'; + } + + void indent() + { + m_indent += 4; + m_indentString = std::string(m_indent, ' '); + } + + void deindent() + { + m_indent -= 4; + m_indentString = std::string(m_indent, ' '); + } + +private: + int m_indent = 0; + std::string m_indentString; +}; + +// like QGradientStop, but with a plain int as second field +struct GradientStop +{ + double position; + int color; + + static bool sortByPosition(GradientStop s1, GradientStop s2) + { + return s1.position < s2.position; + } +}; + +static void printGradientStops(Printer &p, const QJsonArray &presets) +{ + const QString presetCaseString("case QGradient::%1:"); + const QString presetStopColorString("QColor(%1, %2, %3, %4)"); + const QString presetStopString("QGradientStop(%1, %2), "); + + const auto presetStopToGradientStop = [](const QJsonValue &presetStop) + { + const double position = presetStop[QLatin1String("position")].toDouble(); + const int color = presetStop[QLatin1String("color")].toInt(); + + return GradientStop{position, color}; + }; + + for (const QJsonValue &presetValue : presets) { + if (!presetValue.isObject()) + continue; + + QJsonObject preset = presetValue.toObject(); + + // print the case label + const QString presetName = preset[QLatin1String("name")].toString(); + p.printLine(presetCaseString.arg(presetName)); + + Printer::Indenter i(p); + + // convert the json array of stops to QGradientStop objects + const QJsonArray stops = preset[QLatin1String("stops")].toArray(); + Q_ASSERT(!stops.isEmpty()); + + QVector gradientStops; + gradientStops.reserve(stops.size()); + std::transform(stops.cbegin(), + stops.cend(), + std::back_inserter(gradientStops), + presetStopToGradientStop); + + // stops should be sorted, but just in case... + std::sort(gradientStops.begin(), gradientStops.end(), + &GradientStop::sortByPosition); + + Q_ASSERT(gradientStops.size() == stops.size()); + + // convert to strings + QString result; + result.reserve(result.size() + gradientStops.size() * (presetStopString.size() + 20)); + result += "return Q_ARRAY_LITERAL(QGradientStop, "; + + for (const GradientStop &stop : qAsConst(gradientStops)) { + // gradientgen.js does not output the alpha channel, so hardcode full alpha here + Q_ASSERT(qAlpha(stop.color) == 0); + + const QString colorString = presetStopColorString + .arg(qRed(stop.color)) + .arg(qGreen(stop.color)) + .arg(qBlue(stop.color)) + .arg(255); + result += presetStopString.arg(stop.position).arg(colorString); + } + + result.chop(2); + result += ");"; + p.printLine(result); + } + + // Add an entry for NumPresets, to silence warnings about switches over enumerations + p.printLine(presetCaseString.arg("NumPresets")); + { + Printer::Indenter i(p); + p.printLine("Q_UNREACHABLE();"); + } +} + +static void printGradientData(Printer &p, const QJsonArray &presets) +{ + const QString formatString("{ { %1, %2, %3, %4 } },"); + + for (const QJsonValue &presetValue : presets) { + if (!presetValue.isObject()) { + p.printLine("{ { 0, 0, 0, 0 } },"); + } else { + QJsonObject preset = presetValue.toObject(); + const QJsonValue start = preset[QLatin1String("start")]; + const QJsonValue end = preset[QLatin1String("end")]; + + p.printLine(formatString + .arg(start[QLatin1String("x")].toDouble()) + .arg(start[QLatin1String("y")].toDouble()) + .arg(end[QLatin1String("x")].toDouble()) + .arg(end[QLatin1String("y")].toDouble())); + } + } +} + +int main() +{ + QByteArray json; + while (!cin.eof()) { + char arr[1024]; + cin.read(arr, sizeof(arr)); + json.append(arr, cin.gcount()); + } + + QJsonParseError error; + QJsonDocument jsonDocument = QJsonDocument::fromJson(json, &error); + if (jsonDocument.isNull()) + qFatal("Error: %s at offset %d", qPrintable(error.errorString()), error.offset); + + if (!jsonDocument.isArray()) + qFatal("Error: expected a document with a JSON array"); + + QJsonArray presets = jsonDocument.array(); + + Printer p; + + p.printLine(LICENSE_HEADER); + p.printLine(); + p.printLine("// This file is auto-generated by gradientgen. DO NOT EDIT!"); + p.printLine(); + + p.printLine("static QArrayDataPointerRef qt_preset_gradient_stops(QGradient::Preset preset)"); + p.printLine("{"); + { + Printer::Indenter i(p); + p.printLine("Q_ASSERT(preset < QGradient::NumPresets);"); + p.printLine("switch (preset) {"); + printGradientStops(p, presets); + p.printLine("}"); + p.printLine("Q_UNREACHABLE();"); + p.printLine("return {};"); + } + p.printLine("}"); + p.printLine(); + + p.printLine("static Q_CONSTEXPR QGradient::QGradientData qt_preset_gradient_data[] = {"); + { + Printer::Indenter i(p); + printGradientData(p, presets); + } + p.printLine("};"); + p.printLine(); + + p.printLine("static void *qt_preset_gradient_dummy()"); + p.printLine("{"); + { + Printer::Indenter i(p); + p.printLine("union {void *p; uint i;};"); + p.printLine("p = 0;"); + p.printLine("i |= uint(QGradient::ObjectMode);"); + p.printLine("return p;"); + } + p.printLine("}"); +} -- cgit v1.2.3