qt-creator/src/libs/utils/layoutbuilder.h

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** Copyright (C) 2020 The Qt Company Ltd.
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** 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
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#pragma once

#include "utils_global.h"

#include <QList>
#include <QString>
#include <QVariant>

QT_BEGIN_NAMESPACE
class QBoxLayout;
class QFormLayout;
class QGridLayout;
class QLayout;
class QWidget;
QT_END_NAMESPACE

namespace Utils {

class BaseAspect;

class QTCREATOR_UTILS_EXPORT LayoutBuilder
{
public:
    enum LayoutType {
        Form,              // Plain QFormLayout, without contentMargins
        Grid,              // Plain QGridLayout, without contentMargins
        HBox,              // Plain QHBoxLayout, without contentMargins
        VBox,              // Plain QVBoxLayout, without contentMargins
        HBoxWithMargins,   // QHBoxLayout with margins
        VBoxWithMargins,   // QVBoxLayout with margins
        // Compat
        FormLayout = Form, // FIXME: Remove
        GridLayout = Grid, // FIXME: Remove
    };
    enum Alignment { DefaultAlignment, AlignAsFormLabel };

    enum class SpecialType {
        NotSpecial,
        Align,
        Space,
        Span,
        Stretch,
        Break,
        Title
    };

    class QTCREATOR_UTILS_EXPORT LayoutItem
    {
    public:
        LayoutItem();
        LayoutItem(QLayout *layout, int span = 1, Alignment align = {});
        LayoutItem(QWidget *widget, int span = 1, Alignment align = {});
        LayoutItem(BaseAspect *aspect, int span = 1, Alignment align = {}); // Remove
        LayoutItem(BaseAspect &aspect, int span = 1, Alignment align = {});
        LayoutItem(const QString &text, int span = 1, Alignment align = {});
        LayoutItem(const LayoutBuilder &builder, int span = 1, Alignment align = {});

        QLayout *layout = nullptr;
        QWidget *widget = nullptr;
        BaseAspect *aspect = nullptr;
        QString text; // FIXME: Use specialValue for that
        int span = 1;
        Alignment align;
        SpecialType specialType = SpecialType::NotSpecial;
        QVariant specialValue;
    };

    using LayoutItems = QList<LayoutItem>;

    explicit LayoutBuilder(QWidget *parent, LayoutType layoutType = Form);
    explicit LayoutBuilder(QLayout *layout); // Adds to existing layout.
    explicit LayoutBuilder(LayoutType layoutType, const LayoutItems &items = {});

    LayoutBuilder(const LayoutBuilder &) = delete;
    LayoutBuilder(LayoutBuilder &&) = default;
    LayoutBuilder &operator=(const LayoutBuilder &) = delete;
    LayoutBuilder &operator=(LayoutBuilder &&) = default;

    ~LayoutBuilder();

    LayoutBuilder &addItem(const LayoutItem &item);
    LayoutBuilder &addItems(const LayoutItems &items);

    LayoutBuilder &finishRow();
    LayoutBuilder &addRow(const LayoutItem &item);
    LayoutBuilder &addRow(const LayoutItems &items);

    QLayout *layout() const;
    QWidget *parentWidget() const;

    void attachTo(QWidget *w, bool stretchAtBottom = true);

    class QTCREATOR_UTILS_EXPORT Space : public LayoutItem
    {
    public:
        explicit Space(int space);
    };

    class QTCREATOR_UTILS_EXPORT Stretch : public LayoutItem
    {
    public:
        explicit Stretch(int stretch = 1);
    };

    class QTCREATOR_UTILS_EXPORT Break : public LayoutItem
    {
    public:
        Break();
    };

    class QTCREATOR_UTILS_EXPORT Title : public LayoutBuilder::LayoutItem
    {
    public:
        explicit Title(const QString &title);
    };

private:
    void flushPendingFormItems();
    void init(QWidget *parent, LayoutType layoutType);

    QFormLayout *m_formLayout = nullptr;
    QGridLayout *m_gridLayout = nullptr;
    QBoxLayout *m_boxLayout = nullptr;
    LayoutItems m_pendingFormItems;
    int m_currentGridRow = 0;
    int m_currentGridColumn = 0;
};

namespace Layouting {

class QTCREATOR_UTILS_EXPORT Group : public LayoutBuilder
{
public:
    Group(std::initializer_list<LayoutBuilder::LayoutItem> items);

    Group &withTitle(const QString &title);
};

class QTCREATOR_UTILS_EXPORT Box : public LayoutBuilder
{
public:
    Box(LayoutType type, const LayoutItems &items);
};

class QTCREATOR_UTILS_EXPORT Column : public Box
{
public:
    Column(std::initializer_list<LayoutItem> items)
        : Box(VBox, items)
    {}
};

class QTCREATOR_UTILS_EXPORT Row : public Box
{
public:
    Row(std::initializer_list<LayoutItem> items)
        : Box(HBox, items)
    {}
};

class QTCREATOR_UTILS_EXPORT Grid : public Box
{
public:
    Grid(std::initializer_list<LayoutItem> items)
        : Box(GridLayout, items)
    {}
};

class QTCREATOR_UTILS_EXPORT Form : public Box
{
public:
    Form(std::initializer_list<LayoutItem> items)
        : Box(FormLayout, items)
    {}
};

using Item = LayoutBuilder::LayoutItem;
using Stretch = LayoutBuilder::Stretch;
using Space = LayoutBuilder::Space;
using Break = LayoutBuilder::Break;
using Title = LayoutBuilder::Title;

}
} // namespace Utils