From: Soeren Apel <redacted>
Date: Tue, 13 Aug 2019 07:18:46 +0000 (+0200)
Subject: Trace: Use scroll bars for popups with too much content
X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=commitdiff_plain;h=f52ffd9d82b45313836c5e612c7cc48982ced529

Trace: Use scroll bars for popups with too much content

This fixes bug #183.
---

diff --git a/pv/views/trace/trace.cpp b/pv/views/trace/trace.cpp
index 76adf1d1..6d44da2c 100644
--- a/pv/views/trace/trace.cpp
+++ b/pv/views/trace/trace.cpp
@@ -346,13 +346,28 @@ void Trace::create_popup_form()
 	// handled, leaving the parent popup_ time to handle the change.
 	if (popup_form_) {
 		QWidget *suicidal = new QWidget();
-		suicidal->setLayout(popup_form_);
+		suicidal->setLayout(popup_->layout());
 		suicidal->deleteLater();
 	}
 
 	// Repopulate the popup
-	popup_form_ = new QFormLayout(popup_);
-	popup_->setLayout(popup_form_);
+	widgets::QWidthAdjustingScrollArea* scrollarea = new widgets::QWidthAdjustingScrollArea();
+	QWidget* scrollarea_content = new QWidget(scrollarea);
+
+	scrollarea->setWidget(scrollarea_content);
+	scrollarea->setWidgetResizable(true);
+	scrollarea->setContentsMargins(0, 0, 0, 0);
+	scrollarea->setFrameShape(QFrame::NoFrame);
+	scrollarea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+	scrollarea_content->setContentsMargins(0, 0, 0, 0);
+
+	popup_->setLayout(new QVBoxLayout());
+	popup_->layout()->addWidget(scrollarea);
+	popup_->layout()->setContentsMargins(0, 0, 0, 0);
+
+	popup_form_ = new QFormLayout(scrollarea_content);
+	popup_form_->setSizeConstraint(QLayout::SetMinAndMaxSize);
+
 	populate_popup_form(popup_, popup_form_);
 }
 
diff --git a/pv/widgets/popup.cpp b/pv/widgets/popup.cpp
index 13282cda..ec6d29c9 100644
--- a/pv/widgets/popup.cpp
+++ b/pv/widgets/popup.cpp
@@ -23,6 +23,8 @@
 #include <QApplication>
 #include <QDesktopWidget>
 #include <QLineEdit>
+#include <QScrollBar>
+#include <QStyle>
 #include <QtGui>
 
 #include "popup.hpp"
@@ -37,6 +39,33 @@ const unsigned int Popup::ArrowLength = 10;
 const unsigned int Popup::ArrowOverlap = 3;
 const unsigned int Popup::MarginWidth = 6;
 
+
+QWidthAdjustingScrollArea::QWidthAdjustingScrollArea(QWidget* parent) :
+	QScrollArea(parent)
+{
+}
+
+void QWidthAdjustingScrollArea::setWidget(QWidget* w)
+{
+	QScrollArea::setWidget(w);
+	// It happens that QScrollArea already filters widget events,
+	// but that's an implementation detail that we shouldn't rely on.
+	w->installEventFilter(this);
+}
+
+bool QWidthAdjustingScrollArea::eventFilter(QObject* obj, QEvent* ev)
+{
+	if (obj == widget() && ev->type() == QEvent::Resize) {
+		if (widget()->height() > height())
+			setMinimumWidth(widget()->width() + qApp->style()->pixelMetric(QStyle::PM_ScrollBarExtent));
+		else
+			setMinimumWidth(widget()->width());
+	}
+
+	return QScrollArea::eventFilter(obj, ev);
+}
+
+
 Popup::Popup(QWidget *parent) :
 	QWidget(parent, Qt::Popup | Qt::FramelessWindowHint),
 	point_(),
diff --git a/pv/widgets/popup.hpp b/pv/widgets/popup.hpp
index 66f7f06f..736313c7 100644
--- a/pv/widgets/popup.hpp
+++ b/pv/widgets/popup.hpp
@@ -20,11 +20,29 @@
 #ifndef PULSEVIEW_PV_WIDGETS_POPUP_HPP
 #define PULSEVIEW_PV_WIDGETS_POPUP_HPP
 
+#include <QScrollArea>
 #include <QWidget>
 
 namespace pv {
 namespace widgets {
 
+
+// A regular QScrollArea has a fixed size and provides scroll bars when the
+// content can't be shown in its entirety. However, we want no horizontal
+// scroll bar and want the scroll area to adjust its width to fit the content
+// instead.
+// Inspired by https://stackoverflow.com/questions/21253755/qscrollarea-with-dynamically-changing-contents?answertab=votes#tab-top
+class QWidthAdjustingScrollArea : public QScrollArea
+{
+	Q_OBJECT
+
+public:
+	QWidthAdjustingScrollArea(QWidget* parent = 0);
+	void setWidget(QWidget* w);
+	bool eventFilter(QObject* obj, QEvent* ev);
+};
+
+
 class Popup : public QWidget
 {
 	Q_OBJECT