Improve button overlay so buttons will not be shown over e.g. spin box buttons

* Unify/streamline code
* Use Qt::SC_ComboBoxEditField/Qt::SC_SpinBoxEditField to determine the edit
  area for better compatibility accorss various styles

CMakeLists.txt

@@ -10,7 +10,7 @@ set(META_APP_DESCRIPTION
     "Common Qt related C++ classes and routines used by my applications such as dialogs, widgets and models")
 set(META_VERSION_MAJOR 6)
 set(META_VERSION_MINOR 0)
-set(META_VERSION_PATCH 6)
+set(META_VERSION_PATCH 7)
 set(META_APP_VERSION ${META_VERSION_MAJOR}.${META_VERSION_MINOR}.${META_VERSION_PATCH})
 
 project(${META_PROJECT_NAME})

widgets/buttonoverlay.cpp

@@ -37,15 +37,7 @@ ButtonOverlay::ButtonOverlay(QWidget *widget)
     , m_clearButton(nullptr)
     , m_infoButton(nullptr)
 {
-    // setup button widget and layout
+    buttonLayout()->setAlignment(Qt::AlignCenter | Qt::AlignRight);
-    const QMargins margins = widget->contentsMargins();
-    QStyleOption opt;
-    opt.initFrom(m_widget);
-    const int frameWidth = widget->style()->pixelMetric(QStyle::PM_DefaultFrameWidth, &opt, m_widget);
-    const int pad = 2;
-    m_buttonLayout->setContentsMargins(
-        margins.left() + frameWidth + pad, margins.top() + frameWidth, margins.right() + frameWidth + pad, margins.bottom() + frameWidth);
-    m_buttonLayout->setAlignment(Qt::AlignCenter | Qt::AlignRight);
     widget->setLayout(m_buttonLayout);
 }
 
@@ -187,4 +179,17 @@ void ButtonOverlay::showInfo()
         QToolTip::showText(QCursor::pos(), m_infoButton->toolTip(), m_infoButton);
     }
 }
+
+/*!
+ * \brief Sets the contents margins of the button layout so the overlay buttons will only be shown over the \a editFieldRect and
+ *        not interfere with e.g. spin box buttons.
+ */
+void ButtonOverlay::setContentsMarginsFromEditFieldRectAndFrameWidth(const QRect &editFieldRect, int frameWidth, int padding)
+{
+    const auto margins = m_widget->contentsMargins();
+    const auto buttonWidth = m_widget->width() - editFieldRect.width();
+    buttonLayout()->setContentsMargins(margins.left() + frameWidth + padding, margins.top() + frameWidth,
+        margins.right() + frameWidth + padding + buttonWidth, margins.bottom() + frameWidth);
+}
+
 } // namespace QtUtilities

widgets/buttonoverlay.h

@@ -9,12 +9,24 @@ QT_FORWARD_DECLARE_CLASS(QWidget)
 QT_FORWARD_DECLARE_CLASS(QHBoxLayout)
 QT_FORWARD_DECLARE_CLASS(QString)
 QT_FORWARD_DECLARE_CLASS(QPixmap)
+QT_FORWARD_DECLARE_CLASS(QMargins)
+QT_FORWARD_DECLARE_CLASS(QRect)
 
 namespace QtUtilities {
 
 class IconButton;
+class ClearComboBox;
+class ClearSpinBox;
+class ClearPlainTextEdit;
+class ClearLineEdit;
 
 class QT_UTILITIES_EXPORT ButtonOverlay {
+    // allow these derived classes to use private helpers provided by ButtonOverlay
+    friend class ClearComboBox;
+    friend class ClearSpinBox;
+    friend class ClearPlainTextEdit;
+    friend class ClearLineEdit;
+
 public:
     explicit ButtonOverlay(QWidget *widget);
     virtual ~ButtonOverlay();
@@ -36,6 +48,7 @@ protected:
 
 private:
     void showInfo();
+    void setContentsMarginsFromEditFieldRectAndFrameWidth(const QRect &editFieldRect, int frameWidth, int padding = 0);
 
     QWidget *m_widget;
     QWidget *m_buttonWidget;

widgets/clearcombobox.cpp

@@ -18,14 +18,11 @@ ClearComboBox::ClearComboBox(QWidget *parent)
     : QComboBox(parent)
     , ButtonOverlay(this)
 {
-    const QMargins margins = contentsMargins();
+    const QStyle *const s = style();
     QStyleOptionComboBox opt;
     opt.initFrom(this);
-    const int frameWidth = style()->pixelMetric(QStyle::PM_ComboBoxFrameWidth, &opt, this);
+    setContentsMarginsFromEditFieldRectAndFrameWidth(
-    const int pad = 2;
+        s->subControlRect(QStyle::CC_ComboBox, &opt, QStyle::SC_ComboBoxEditField, this), s->pixelMetric(QStyle::PM_ComboBoxFrameWidth, &opt, this));
-    const int buttonWidth = style()->subControlRect(QStyle::CC_ComboBox, &opt, QStyle::SC_ComboBoxArrow, this).width();
-    buttonLayout()->setContentsMargins(margins.left() + frameWidth + pad, margins.top() + frameWidth,
-        margins.right() + frameWidth + pad + buttonWidth, margins.bottom() + frameWidth);
     setClearButtonEnabled(isEditable());
     connect(this, &ClearComboBox::currentTextChanged, this, &ClearComboBox::handleTextChanged);
 }

widgets/clearlineedit.cpp

@@ -1,5 +1,8 @@
 #include "./clearlineedit.h"
 
+#include <QStyle>
+#include <QStyleOptionFrame>
+
 namespace QtUtilities {
 
 /*!
@@ -14,6 +17,11 @@ ClearLineEdit::ClearLineEdit(QWidget *parent)
     : QLineEdit(parent)
     , ButtonOverlay(this)
 {
+    const QStyle *const s = style();
+    QStyleOptionFrame opt;
+    opt.initFrom(this);
+    setContentsMarginsFromEditFieldRectAndFrameWidth(s->subElementRect(QStyle::SE_LineEditContents, &opt, this),
+        s->pixelMetric(QStyle::PM_DefaultFrameWidth, &opt, m_widget), s->pixelMetric(QStyle::PM_LayoutVerticalSpacing, &opt, m_widget));
     ButtonOverlay::setClearButtonEnabled(true);
     connect(this, &ClearLineEdit::textChanged, this, &ClearLineEdit::handleTextChanged);
 }

widgets/clearplaintextedit.cpp

@@ -2,6 +2,8 @@
 
 #include <QHBoxLayout>
 #include <QScrollBar>
+#include <QStyle>
+#include <QStyleOptionFrame>
 
 using namespace std;
 
@@ -21,6 +23,11 @@ ClearPlainTextEdit::ClearPlainTextEdit(QWidget *parent)
 {
     // set alignment to show buttons in the bottom right corner
     ButtonOverlay::buttonLayout()->setAlignment(Qt::AlignBottom | Qt::AlignRight);
+    const QStyle *const s = style();
+    QStyleOptionFrame opt;
+    opt.initFrom(this);
+    setContentsMarginsFromEditFieldRectAndFrameWidth(s->subElementRect(QStyle::SE_FrameContents, &opt, this),
+        s->pixelMetric(QStyle::PM_DefaultFrameWidth, &opt, m_widget), s->pixelMetric(QStyle::PM_LayoutVerticalSpacing, &opt, m_widget));
     ButtonOverlay::setClearButtonEnabled(true);
     connect(this, &QPlainTextEdit::textChanged, this, &ClearPlainTextEdit::handleTextChanged);
     // ensure button layout is realigned when scrolling

widgets/clearspinbox.cpp

@@ -21,14 +21,11 @@ ClearSpinBox::ClearSpinBox(QWidget *parent)
     , ButtonOverlay(this)
     , m_minimumHidden(false)
 {
-    const QMargins margins = contentsMargins();
+    const QStyle *const s = style();
-    QStyleOptionComboBox opt;
+    QStyleOptionSpinBox opt;
     opt.initFrom(this);
-    const int frameWidth = style()->pixelMetric(QStyle::PM_SpinBoxFrameWidth, &opt, this);
+    setContentsMarginsFromEditFieldRectAndFrameWidth(
-    const int pad = 5;
+        s->subControlRect(QStyle::CC_SpinBox, &opt, QStyle::SC_SpinBoxEditField, this), s->pixelMetric(QStyle::PM_SpinBoxFrameWidth, &opt, this));
-    const int buttonWidth = style()->subControlRect(QStyle::CC_SpinBox, &opt, QStyle::SC_SpinBoxUp, this).width() + 10;
-    buttonLayout()->setContentsMargins(margins.left() + frameWidth + pad, margins.top() + frameWidth,
-        margins.right() + frameWidth + pad + buttonWidth, margins.bottom() + frameWidth);
     setClearButtonEnabled(true);
     connect(this, static_cast<void (ClearSpinBox::*)(int)>(&ClearSpinBox::valueChanged), this, &ClearSpinBox::handleValueChanged);
 }