Fix resize issues

include/InstrumentTrackWindow.h

@@ -69,8 +69,6 @@ class InstrumentTrackWindow : public QWidget, public ModelView,
 	InstrumentTrackWindow( InstrumentTrackView * _tv );
 	~InstrumentTrackWindow() override;
 
-	void resizeEvent(QResizeEvent* event) override;
-
 
 	// parent for all internal tab-widgets
 	TabWidget * tabWidgetParent()

include/InstrumentView.h

@@ -64,11 +64,16 @@ class LMMS_EXPORT InstrumentView : public PluginView
 //! Instrument view with fixed LMMS-default size
 class LMMS_EXPORT InstrumentViewFixedSize : public InstrumentView
 {
+protected:
 	QSize sizeHint() const override { return QSize(250, 250); }
 	QSize minimumSizeHint() const override { return sizeHint(); }
 
 public:
-	using InstrumentView::InstrumentView;
+	InstrumentViewFixedSize(Instrument* instrument, QWidget* parent)
+		: InstrumentView(instrument, parent)
+	{
+		setFixedSize(sizeHint());
+	}
 	~InstrumentViewFixedSize() override = default;
 } ;
 

include/QtHelpers.h

@@ -0,0 +1,38 @@
+/*
+ * QtHelpers.h - Qt helper functions
+ *
+ * Copyright (c) 2025 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef QTHELPERS_H
+#define QTHELPERS_H
+
+#include <QSize>
+class QWidget;
+
+namespace lmms::gui
+{
+
+void setMinMaxFromChild(QWidget& parent, const QWidget& child, QSize space);
+
+}
+
+#endif // QTHELPERS_H

src/gui/CMakeLists.txt

@@ -32,6 +32,7 @@ SET(LMMS_SRCS
 	gui/PeakControllerDialog.cpp
 	gui/PluginBrowser.cpp
 	gui/ProjectNotes.cpp
+	gui/QtHelpers.cpp
 	gui/RowTableView.cpp
 	gui/SampleLoader.cpp
 	gui/SampleTrackWindow.cpp

src/gui/QtHelpers.cpp

@@ -0,0 +1,55 @@
+/*
+ * QtHelpers.cpp - Qt helper functions
+ *
+ * Copyright (c) 2025 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <QWidget>
+
+#include "QtHelpers.h"
+
+namespace lmms::gui
+{
+
+void setMinMaxFromChild(QWidget& parent, const QWidget& child, QSize space)
+{
+	// If the child has a maximum, we cannot grow larger
+	if(parent.maximumHeight() > child.maximumHeight() + space.height())
+	{
+		parent.setMaximumHeight(child.maximumHeight() + space.height());
+	}
+	if(parent.maximumWidth() > child.maximumWidth() + space.width())
+	{
+		parent.setMaximumWidth(child.maximumWidth() + space.width());
+	}
+	// If the child has a minimum, we cannot shrink smaller
+	if(parent.minimumHeight() < child.minimumHeight() + space.height())
+	{
+		parent.setMinimumHeight(child.minimumHeight() + space.height());
+	}
+	if(parent.minimumWidth() < child.minimumWidth() + space.width())
+	{
+		parent.setMinimumWidth(child.minimumWidth() + space.width());
+	}
+}
+
+} // namespace lmms::gui
+

src/gui/SubWindow.cpp

@@ -37,6 +37,7 @@
 #include <QStyleOption>
 
 #include "embed.h"
+#include "QtHelpers.h"
 
 namespace lmms::gui
 {
@@ -398,6 +399,10 @@ void SubWindow::focusChanged( QMdiSubWindow *subWindow )
  */
 void SubWindow::resizeEvent( QResizeEvent * event )
 {
+	if (widget()) {
+		setMinMaxFromChild(*this, *widget(), QSize(8, m_titleBarHeight + 6));
+	}
+
 	// When the parent QMdiArea gets resized, maximized subwindows also gets resized, if any.
 	// In that case, we should call QMdiSubWindow::resizeEvent first
 	// to ensure we get the correct window state.

src/gui/instrument/InstrumentTrackWindow.cpp

@@ -292,15 +292,6 @@ InstrumentTrackWindow::InstrumentTrackWindow( InstrumentTrackView * _itv ) :
 	subWin->hide();
 }
 
-void InstrumentTrackWindow::resizeEvent(QResizeEvent * event) {
-	/* m_instrumentView->resize(QSize(size().width()-1, maxHeight)); */
-	adjustTabSize(m_instrumentView);
-	adjustTabSize(m_instrumentFunctionsView);
-	adjustTabSize(m_ssView);
-	adjustTabSize(m_effectView);
-	adjustTabSize(m_midiView);
-	adjustTabSize(m_tuningView);
-}
 
 
 
@@ -468,16 +459,21 @@ void InstrumentTrackWindow::updateInstrumentView()
 
 		modelChanged(); 		// Get the instrument window to refresh
 		m_track->dataChanged(); // Get the text on the trackButton to change
-
 		adjustTabSize(m_instrumentView);
+
 		m_pianoView->setVisible(m_track->m_instrument->hasNoteInput());
 		// adjust window size
 		layout()->invalidate();
 		resize(sizeHint());
-		if (parentWidget())
+
+		if(m_tabWidget->minimumSize() == m_tabWidget->maximumSize())
 		{
-			parentWidget()->resize(parentWidget()->sizeHint());
+			setFixedSize(sizeHint());
+			setSizePolicy(QSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed));
 		}
+		else
+			resize(sizeHint());
+
 		update();
 		m_instrumentView->update();
 	}

src/gui/widgets/TabWidget.cpp

@@ -34,6 +34,7 @@
 #include "DeprecationHelper.h"
 #include "embed.h"
 #include "FontHelper.h"
+#include "QtHelpers.h"
 
 namespace lmms::gui
 {
@@ -68,12 +69,15 @@ TabWidget::TabWidget(const QString& caption, QWidget* parent, bool usePixmap,
 
 }
 
+
+
+
 void TabWidget::addTab(QWidget* w, const QString& name, const char* pixmap, int idx)
 {
 	// Append tab when position is not given
-	if (idx < 0/* || m_widgets.contains(idx) == true*/)
+	if (idx < 0/* || m_widgets.contains(idx)*/)
 	{
-		while(m_widgets.contains(++idx) == true)
+		while(m_widgets.contains(++idx))
 		{
 		}
 	}
@@ -85,9 +89,21 @@ void TabWidget::addTab(QWidget* w, const QString& name, const char* pixmap, int
 	widgetDesc d = {w, pixmap, name, tab_width};
 	m_widgets[idx] = d;
 
-	// Position tab's window
-	if (!m_resizable)
+	// Position tab's window and update size
+	if (m_resizable)
+	{
+		// If the child has a maximum, we cannot grow larger
+		setMinMaxFromChild(*this, *w, QSize(4, m_tabbarHeight));
+
+		// Now that the size might have changed: resize all widgets
+		for (const auto& widget : m_widgets)
+		{
+			widget.w->resize(width() - 4, height() - m_tabbarHeight);
+		}
+	}
+	else
 	{
+		// Tab widget is fixed -> child must be fixed
 		w->setFixedSize(width() - 4, height() - m_tabbarHeight);
 	}
 	w->move(2, m_tabbarHeight - 1);
@@ -197,9 +213,17 @@ void TabWidget::mousePressEvent(QMouseEvent* me)
 
 
 
-void TabWidget::resizeEvent(QResizeEvent*)
+void TabWidget::resizeEvent(QResizeEvent* ev)
 {
-	if (!m_resizable)
+	if (m_resizable)
+	{
+		for (const auto& widget : m_widgets)
+		{
+			widget.w->resize(width() - 4, height() - m_tabbarHeight);
+		}
+		QWidget::resizeEvent(ev);
+	}
+	else
 	{
 		for (const auto& widget : m_widgets)
 		{