qt 6.5.1 original

examples/widgets/graphicsview/flowlayout/CMakeLists.txt

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+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.16)
+project(flowlayout LANGUAGES CXX)
+
+if(NOT DEFINED INSTALL_EXAMPLESDIR)
+    set(INSTALL_EXAMPLESDIR "examples")
+endif()
+
+set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/widgets/graphicsview_flowlayout")
+
+find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
+
+qt_standard_project_setup()
+
+qt_add_executable(graphicsview_flowlayout
+    flowlayout.cpp flowlayout.h
+    main.cpp
+    window.cpp window.h
+)
+
+set_target_properties(graphicsview_flowlayout PROPERTIES
+    WIN32_EXECUTABLE TRUE
+    MACOSX_BUNDLE TRUE
+)
+
+target_link_libraries(graphicsview_flowlayout PRIVATE
+    Qt6::Core
+    Qt6::Gui
+    Qt6::Widgets
+)
+
+install(TARGETS graphicsview_flowlayout
+    RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
+    BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
+    LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
+)

examples/widgets/graphicsview/flowlayout/flowlayout.cpp

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "flowlayout.h"
+
+#include <QtMath>
+
+FlowLayout::FlowLayout(QGraphicsLayoutItem *parent) : QGraphicsLayout(parent)
+{
+    QSizePolicy sp = sizePolicy();
+    sp.setHeightForWidth(true);
+    setSizePolicy(sp);
+}
+
+void FlowLayout::insertItem(int index, QGraphicsLayoutItem *item)
+{
+    item->setParentLayoutItem(this);
+    if (index > m_items.count() || index < 0)
+        index = m_items.count();
+    m_items.insert(index, item);
+    invalidate();
+}
+
+int FlowLayout::count() const
+{
+    return m_items.count();
+}
+
+QGraphicsLayoutItem *FlowLayout::itemAt(int index) const
+{
+    return m_items.value(index);
+}
+
+void FlowLayout::removeAt(int index)
+{
+    m_items.removeAt(index);
+    invalidate();
+}
+
+qreal FlowLayout::spacing(Qt::Orientation o) const
+{
+    return m_spacing[int(o) - 1];
+}
+
+void FlowLayout::setSpacing(Qt::Orientations o, qreal spacing)
+{
+    if (o & Qt::Horizontal)
+        m_spacing[0] = spacing;
+    if (o & Qt::Vertical)
+        m_spacing[1] = spacing;
+}
+
+void FlowLayout::setGeometry(const QRectF &geom)
+{
+    QGraphicsLayout::setGeometry(geom);
+    doLayout(geom, true);
+}
+
+qreal FlowLayout::doLayout(const QRectF &geom, bool applyNewGeometry) const
+{
+    qreal left, top, right, bottom;
+    getContentsMargins(&left, &top, &right, &bottom);
+    const qreal maxw = geom.width() - left - right;
+
+    qreal x = 0;
+    qreal y = 0;
+    qreal maxRowHeight = 0;
+    QSizeF pref;
+    for (QGraphicsLayoutItem *item : m_items) {
+        pref = item->effectiveSizeHint(Qt::PreferredSize);
+        maxRowHeight = qMax(maxRowHeight, pref.height());
+
+        qreal next_x;
+        next_x = x + pref.width();
+        if (next_x > maxw) {
+            if (qFuzzyIsNull(x)) {
+                pref.setWidth(maxw);
+            } else {
+                x = 0;
+                next_x = pref.width();
+            }
+            y += maxRowHeight + spacing(Qt::Vertical);
+            maxRowHeight = 0;
+        }
+
+        if (applyNewGeometry)
+            item->setGeometry(QRectF(QPointF(left + x, top + y), pref));
+        x = next_x + spacing(Qt::Horizontal);
+    }
+    maxRowHeight = qMax(maxRowHeight, pref.height());
+    return top + y + maxRowHeight + bottom;
+}
+
+QSizeF FlowLayout::minSize(const QSizeF &constraint) const
+{
+    QSizeF size(0, 0);
+    qreal left, top, right, bottom;
+    getContentsMargins(&left, &top, &right, &bottom);
+    if (constraint.width() >= 0) {   // height for width
+        const qreal height = doLayout(QRectF(QPointF(0,0), constraint), false);
+        size = QSizeF(constraint.width(), height);
+    } else if (constraint.height() >= 0) {  // width for height?
+        // not supported
+    } else {
+        for (const QGraphicsLayoutItem *item : std::as_const(m_items))
+            size = size.expandedTo(item->effectiveSizeHint(Qt::MinimumSize));
+        size += QSizeF(left + right, top + bottom);
+    }
+    return size;
+}
+
+QSizeF FlowLayout::prefSize() const
+{
+    qreal left, right;
+    getContentsMargins(&left, nullptr, &right, nullptr);
+
+    qreal maxh = 0;
+    qreal totalWidth = 0;
+    for (const QGraphicsLayoutItem *item : std::as_const(m_items)) {
+        if (totalWidth > 0)
+            totalWidth += spacing(Qt::Horizontal);
+        QSizeF pref = item->effectiveSizeHint(Qt::PreferredSize);
+        totalWidth += pref.width();
+        maxh = qMax(maxh, pref.height());
+    }
+    maxh += spacing(Qt::Vertical);
+
+    const qreal goldenAspectRatio = 1.61803399;
+    qreal w = qSqrt(totalWidth * maxh * goldenAspectRatio) + left + right;
+
+    return minSize(QSizeF(w, -1));
+}
+
+QSizeF FlowLayout::maxSize() const
+{
+    qreal totalWidth = 0;
+    qreal totalHeight = 0;
+    for (const QGraphicsLayoutItem *item : std::as_const(m_items)) {
+        if (totalWidth > 0)
+            totalWidth += spacing(Qt::Horizontal);
+        if (totalHeight > 0)
+            totalHeight += spacing(Qt::Vertical);
+        QSizeF pref = item->effectiveSizeHint(Qt::PreferredSize);
+        totalWidth += pref.width();
+        totalHeight += pref.height();
+    }
+
+    qreal left, top, right, bottom;
+    getContentsMargins(&left, &top, &right, &bottom);
+    return QSizeF(left + totalWidth + right, top + totalHeight + bottom);
+}
+
+QSizeF FlowLayout::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
+{
+    QSizeF sh = constraint;
+    switch (which) {
+    case Qt::PreferredSize:
+        sh = prefSize();
+        break;
+    case Qt::MinimumSize:
+        sh = minSize(constraint);
+        break;
+    case Qt::MaximumSize:
+        sh = maxSize();
+        break;
+    default:
+        break;
+    }
+    return sh;
+}

examples/widgets/graphicsview/flowlayout/flowlayout.h

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef FLOWLAYOUT_H
+#define FLOWLAYOUT_H
+
+#include <QGraphicsLayout>
+
+class FlowLayout : public QGraphicsLayout
+{
+public:
+    FlowLayout(QGraphicsLayoutItem *parent = nullptr);
+    inline void addItem(QGraphicsLayoutItem *item);
+    void insertItem(int index, QGraphicsLayoutItem *item);
+    void setSpacing(Qt::Orientations o, qreal spacing);
+    qreal spacing(Qt::Orientation o) const;
+
+    // inherited functions
+    void setGeometry(const QRectF &geom) override;
+
+    int count() const override;
+    QGraphicsLayoutItem *itemAt(int index) const override;
+    void removeAt(int index) override;
+
+protected:
+    QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const override;
+
+private:
+    qreal doLayout(const QRectF &geom, bool applyNewGeometry) const;
+    QSizeF minSize(const QSizeF &constraint) const;
+    QSizeF prefSize() const;
+    QSizeF maxSize() const;
+
+    QList<QGraphicsLayoutItem *> m_items;
+    qreal m_spacing[2] = {6, 6};
+};
+
+
+inline void FlowLayout::addItem(QGraphicsLayoutItem *item)
+{
+    insertItem(-1, item);
+}
+
+#endif // FLOWLAYOUT_H

examples/widgets/graphicsview/flowlayout/flowlayout.pro

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+QT += widgets
+
+QMAKE_PROJECT_NAME = flowlayout_graphicsview
+
+HEADERS += flowlayout.h window.h
+SOURCES += flowlayout.cpp main.cpp window.cpp
+
+# install
+target.path = $$[QT_INSTALL_EXAMPLES]/widgets/graphicsview/flowlayout
+INSTALLS += target

examples/widgets/graphicsview/flowlayout/main.cpp

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+//! [1]
+#include "window.h"
+
+#include <QApplication>
+#include <QGraphicsView>
+
+
+int main(int argc, char *argv[])
+{
+    QApplication app(argc, argv);
+
+    QGraphicsScene scene;
+    QGraphicsView view(&scene);
+    Window *w = new Window;
+    scene.addItem(w);
+
+    view.resize(400, 300);
+    view.show();
+
+    return app.exec();
+}
+//! [1]

examples/widgets/graphicsview/flowlayout/window.cpp

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "window.h"
+#include "flowlayout.h"
+
+#include <QGraphicsProxyWidget>
+#include <QLabel>
+
+Window::Window(QGraphicsItem *parent) : QGraphicsWidget(parent, Qt::Window)
+{
+    FlowLayout *lay = new FlowLayout;
+    const QString sentence(QLatin1String("I am not bothered by the fact that I am unknown."
+                                         " I am bothered when I do not know others. (Confucius)"));
+    const QList<QStringView> words = QStringView{ sentence }.split(QLatin1Char(' '), Qt::SkipEmptyParts);
+    for (const QStringView &word : words) {
+        QGraphicsProxyWidget *proxy = new QGraphicsProxyWidget(this);
+        QLabel *label = new QLabel(word.toString());
+        label->setFrameStyle(QFrame::Box | QFrame::Plain);
+        proxy->setWidget(label);
+        lay->addItem(proxy);
+    }
+    setLayout(lay);
+}

examples/widgets/graphicsview/flowlayout/window.h

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef WINDOW_H
+#define WINDOW_H
+
+#include <QGraphicsWidget>
+
+class Window : public QGraphicsWidget
+{
+    Q_OBJECT
+public:
+    Window(QGraphicsItem *parent = nullptr);
+};
+
+#endif // WINDOW_H