Add BarModelEditor and improve layouts

Add the new class `BarModelEditor` which is intended to become a new way
to adjust values of float models.

Simplify the layout in `LadspaMatrixControlDialog` by removing some
nested layouts. Remove the "Parameters" column.

Adjust `LadspaMatrixControlView` to implement the following changes:
* Show the name of the control next to toggle buttons (`LedCheckBox`).
* Use the new `BarModelEditor` for integer and float types.
* SHow the name of the control next to time based parameters that use
`TempoSyncKnob`.

The names are shown so that the "Parameters" column can be removed.

Technical details
------------------
The class `LadspaMatrixControlDialog` now creates a widget that contains
the matrix layout with the controls. This widget is then added to a
scroll area. The layout is populated in the new method
`arrangeControls`.

Add some helper methods to `LadspaMatrixControlDialog` which retrieve
the `LadspaControls` instance and the number of channels.

Add the implementation of `BarModelEditor` to `src/gui/CMakeLists.txt`.

TODOs
------
Extract common code out of the `Knob` class so that it can be reused by
`BarModelEditor`.

include/BarModelEditor.h

@@ -0,0 +1,57 @@
+/*
+ * BarModelEditor.h - edit model values using a bar display
+ *
+ * Copyright (c) 2023-now Michael Gregorius
+ *
+ * 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 "AutomatableModelView.h"
+
+#include <QWidget>
+
+namespace lmms::gui
+{
+
+class BarModelEditor : public QWidget, public FloatModelView
+{
+public:
+	BarModelEditor(QString text, FloatModel * floatModel, QWidget * parent = nullptr);
+
+	// Define how the widget will behave in a layout
+	QSizePolicy sizePolicy() const;
+
+	virtual QSize minimumSizeHint() const override;
+
+	virtual QSize sizeHint() const override;
+
+protected:
+	virtual void paintEvent(QPaintEvent *event) override;
+
+	virtual void contextMenuEvent(QContextMenuEvent * me) override;
+	virtual void mouseDoubleClickEvent(QMouseEvent * me) override;
+
+private:
+	void connectToModelSignals();
+
+private:
+	QString const m_text;
+};
+
+}

plugins/LadspaEffect/LadspaMatrixControlDialog.cpp

@@ -29,6 +29,8 @@
 #include <QLabel>
 #include <QScrollArea>
 #include <QScrollBar>
+#include <QSpacerItem>
+
 
 #include "LadspaBase.h"
 #include "LadspaControl.h"
@@ -43,110 +45,153 @@
 namespace lmms::gui
 {
 
-static int const s_linkBaseColumn = 0;
-static int const s_parameterNameBaseColumn = 2;
-static int const s_channelBaseColumn = 4;
-
-
-
-
 LadspaMatrixControlDialog::LadspaMatrixControlDialog(LadspaControls * ladspaControls) :
 	EffectControlDialog(ladspaControls),
-	m_effectGridLayout(nullptr),
+	m_scrollArea(nullptr),
 	m_stereoLink(nullptr)
 {
 	QVBoxLayout * mainLayout = new QVBoxLayout(this);
 
-	m_effectGridLayout = new QGridLayout();
-	mainLayout->addLayout(m_effectGridLayout);
+	m_scrollArea = new QScrollArea(this);
+	m_scrollArea->setWidgetResizable(true);
+	m_scrollArea->setFrameShape(QFrame::NoFrame);
 
+	// Add a scroll area that grows
+	mainLayout->addWidget(m_scrollArea, 1);
+
+	// Populate the parameter matrix and put it into the scroll area
 	updateEffectView(ladspaControls);
 
-	if (ladspaControls->m_processors > 1)
+	// Add button to link all channels if there's more than one channel
+	if (getChannelCount() > 1)
 	{
 		mainLayout->addSpacing(3);
-		QHBoxLayout * center = new QHBoxLayout();
-		mainLayout->addLayout(center);
+
 		m_stereoLink = new LedCheckBox(tr("Link Channels"), this);
 		m_stereoLink->setModel(&ladspaControls->m_stereoLinkModel);
-		center->addWidget(m_stereoLink);
+		mainLayout->addWidget(m_stereoLink, 0, Qt::AlignCenter);
 	}
 }
 
-
-
-
-void LadspaMatrixControlDialog::updateEffectView(LadspaControls * ladspaControls)
+bool LadspaMatrixControlDialog::needsLinkColumn() const
 {
-	for (auto child : findChildren<QWidget *>())
+	LadspaControls * ladspaControls = getLadspaControls();
+
+	ch_cnt_t const channelCount = getChannelCount();
+	for (ch_cnt_t i = 0; i < channelCount; ++i)
 	{
-		delete child;
+		// Create a const reference so that the C++11 based for loop does not detach the Qt container
+		auto const & currentControls = ladspaControls->m_controls[i];
+		for (auto ladspaControl : currentControls)
+		{
+			if (ladspaControl->m_link)
+			{
+				return true;
+			}
+		}
 	}
 
-	m_effectControls = ladspaControls;
+	return false;
+}
 
-	QWidget *widget = new QWidget(this);
-	QGridLayout *gridLayout = new QGridLayout(widget);
-	widget->setLayout(gridLayout);
+void LadspaMatrixControlDialog::arrangeControls(QWidget * parent, QGridLayout* gridLayout)
+{
+	LadspaControls * ladspaControls = getLadspaControls();
 
-	gridLayout->addWidget(new QLabel("<b>" + tr("Parameter")  + "</b>", widget), 0, s_parameterNameBaseColumn, Qt::AlignRight);
+	int const headerRow = 0;
+	int const linkColumn = 0;
 
-	bool linkLabelAdded = false;
-	ch_cnt_t const numberOfChannels = ladspaControls->m_processors;
+	bool const linkColumnNeeded = needsLinkColumn();
+	if (linkColumnNeeded)
+	{
+		gridLayout->addWidget(new QLabel("<b>" + tr("Link") + "</b>", parent), headerRow, linkColumn, Qt::AlignHCenter);
 
-	gridLayout->setColumnMinimumWidth(1, 20);
+		// If there's a link column then it should not stretch
+		gridLayout->setColumnStretch(linkColumn, 0);
+	}
 
+	int const channelStartColumn = linkColumnNeeded ? 1 : 0;
+
+	// The header row should not grow vertically
+	gridLayout->setRowStretch(0, 0);
+
+	// Records the maximum row with parameters so that we can add a vertical spacer after that row
+	int maxRow = 0;
+
+	// Iterate the channels and add widgets for each control
+	ch_cnt_t const numberOfChannels = getChannelCount();
 	for (ch_cnt_t i = 0; i < numberOfChannels; ++i)
 	{
-		QString channelString(tr("Channel %1"));
-		int currentChannelColumn = s_channelBaseColumn + 2*i;
+		int currentChannelColumn = channelStartColumn + i;
+		gridLayout->setColumnStretch(currentChannelColumn, 1);
 
-		gridLayout->addWidget(new QLabel("<b>" + channelString.arg(QString::number(i + 1)) + "</b>", widget), 0, currentChannelColumn, Qt::AlignHCenter);
+		// First add the channel header with the channel number
+		gridLayout->addWidget(new QLabel("<b>" + tr("Channel %1").arg(QString::number(i + 1)) + "</b>", parent), headerRow, currentChannelColumn, Qt::AlignHCenter);
 
 		int currentRow = 1;
-		for (auto ladspaControl : ladspaControls->m_controls[i])
+
+		if (i == 0)
 		{
-			if (i == 0)
+			// Configure the current parameter row to not stretch.
+			// Only do this once, i.e. when working with the first channel.
+			gridLayout->setRowStretch(currentRow, 0);
+		}
+
+		// Create a const reference so that the C++11 based for loop does not detach the Qt container
+		auto const & currentControls = ladspaControls->m_controls[i];
+		for (auto ladspaControl : currentControls)
+		{
+			// Only use the first channel to determine if we need to add link controls
+			if (i == 0 && ladspaControl->m_link)
 			{
 				// TODO Assumes that all processors are equal! Change to more general approach, e.g. map from name to row
-
-				// Link
-				if (ladspaControl->m_link)
-				{
-					if (!linkLabelAdded)
-					{
-						gridLayout->addWidget(new QLabel("<b>" + tr("Link") + "</b>", widget), 0, s_linkBaseColumn, Qt::AlignHCenter);
-						linkLabelAdded = true;
-					}
-					LedCheckBox * linkCheckBox = new LedCheckBox("", widget);
-					linkCheckBox->setModel(&ladspaControl->m_linkEnabledModel);
-					linkCheckBox->setToolTip(tr("Link channels"));
-					gridLayout->addWidget(linkCheckBox, currentRow, s_linkBaseColumn, Qt::AlignHCenter);
-				}
-
-				// Parameter name
-				QString portName = ladspaControl->port()->name;
-				QLabel *portNameLabel = new QLabel(portName, widget);
-				gridLayout->addWidget(portNameLabel, currentRow, s_parameterNameBaseColumn, Qt::AlignRight);
+				LedCheckBox * linkCheckBox = new LedCheckBox("", parent);
+				linkCheckBox->setModel(&ladspaControl->m_linkEnabledModel);
+				linkCheckBox->setToolTip(tr("Link channels"));
+				gridLayout->addWidget(linkCheckBox, currentRow, linkColumn, Qt::AlignHCenter);
 			}
 
-			LadspaMatrixControlView *ladspaMatrixControlView = new LadspaMatrixControlView(widget, ladspaControl);
-			gridLayout->addWidget(ladspaMatrixControlView, currentRow, currentChannelColumn, Qt::AlignHCenter);
-			gridLayout->setColumnMinimumWidth(currentChannelColumn - 1, 20);
+			// TODO Use a factory to directly create the widgets? Currently they are wrapped in another layout in LadspaMatrixControlView...
+			LadspaMatrixControlView *ladspaMatrixControlView = new LadspaMatrixControlView(parent, ladspaControl);
+			gridLayout->addWidget(ladspaMatrixControlView, currentRow, currentChannelColumn);
+
+			// Record the maximum row so that we add a vertical spacer after that row
+			maxRow = std::max(maxRow, currentRow);
 
 			++currentRow;
 		}
 	}
 
-	QScrollArea *scrollArea = new QScrollArea(this);
-	scrollArea->setWidgetResizable(true);
-	scrollArea->setWidget(widget);
-	scrollArea->setFrameShape(QFrame::NoFrame);
+	// Add a spacer item after the maximum row
+	QSpacerItem * spacer = new QSpacerItem(0, 0, QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
+	gridLayout->addItem(spacer, maxRow + 1, 0);
+}
 
-	m_effectGridLayout->addWidget(scrollArea, 0, 0);
-	m_effectGridLayout->setMargin(0);
+QWidget * LadspaMatrixControlDialog::createMatrixWidget()
+{
+	QWidget *widget = new QWidget(this);
+	QGridLayout *gridLayout = new QGridLayout(widget);
+	widget->setLayout(gridLayout);
 
-	if (numberOfChannels > 1 && m_stereoLink != nullptr)
+	arrangeControls(widget, gridLayout);
+
+	return widget;
+}
+
+void LadspaMatrixControlDialog::updateEffectView(LadspaControls * ladspaControls)
+{
+	m_effectControls = ladspaControls;
+
+	// No need to delete the existing widget as it's deleted
+	// by the scroll view when we replace it.
+	QWidget * matrixWidget = createMatrixWidget();
+	m_scrollArea->setWidget(matrixWidget);
+
+	// Make sure that the horizontal scroll bar does not show
+	// From: https://forum.qt.io/topic/13374/solved-qscrollarea-vertical-scroll-only/4
+	m_scrollArea->setMinimumWidth(matrixWidget->minimumSizeHint().width() + m_scrollArea->verticalScrollBar()->width());
+
+	if (getChannelCount() > 1 && m_stereoLink != nullptr)
 	{
 		m_stereoLink->setModel(&ladspaControls->m_stereoLinkModel);
 	}
@@ -156,4 +201,14 @@ void LadspaMatrixControlDialog::updateEffectView(LadspaControls * ladspaControls
 				Qt::DirectConnection);
 }
 
+LadspaControls * LadspaMatrixControlDialog::getLadspaControls() const
+{
+	return dynamic_cast<LadspaControls *>(m_effectControls);
+}
+
+ch_cnt_t LadspaMatrixControlDialog::getChannelCount() const
+{
+	return getLadspaControls()->m_processors;
+}
+
 } // namespace lmms::gui

plugins/LadspaEffect/LadspaMatrixControlDialog.h

@@ -28,8 +28,11 @@
 
 #include "EffectControlDialog.h"
 
+#include "lmms_basics.h"
+
 
 class QGridLayout;
+class QScrollArea;
 
 namespace lmms
 {
@@ -53,9 +56,32 @@ public:
 private slots:
 	void updateEffectView(LadspaControls* ctl);
 
+private:
+	/**
+	 * @brief Checks if a link column is needed for the current effect controls.
+	 * @return true if a link column is needed.
+	 */
+	bool needsLinkColumn() const;
+
+	/**
+	 * @brief Arranges widgets for the current controls in a grid/matrix layout.
+	 * @param parent The parent of all created widgets
+	 * @param gridLayout The layout into which the controls are organized
+	 */
+	void arrangeControls(QWidget * parent, QGridLayout* gridLayout);
+
+	/**
+	 * @brief Creates a widget that holds the widgets of the current controls in a matrix arrangement.
+	 * @param ladspaControls
+	 * @return
+	 */
+	QWidget * createMatrixWidget();
+
+	LadspaControls * getLadspaControls() const;
+	ch_cnt_t getChannelCount() const;
 
 private:
-	QGridLayout* m_effectGridLayout;
+	QScrollArea* m_scrollArea;
 	LedCheckBox* m_stereoLink;
 
 };

src/gui/CMakeLists.txt

@@ -95,6 +95,7 @@ SET(LMMS_SRCS
 
 	gui/widgets/AutomatableButton.cpp
 	gui/widgets/AutomatableSlider.cpp
+	gui/widgets/BarModelEditor.cpp
 	gui/widgets/CPULoadWidget.cpp
 	gui/widgets/CaptionMenu.cpp
 	gui/widgets/ComboBox.cpp

src/gui/LadspaMatrixControlView.cpp

@@ -29,10 +29,12 @@
 #include "LadspaControl.h"
 
 #include "LadspaBase.h"
+#include "BarModelEditor.h"
 #include "LedCheckBox.h"
 #include "TempoSyncKnob.h"
 
 #include <QLayout>
+#include <QLabel>
 
 
 namespace lmms::gui
@@ -51,12 +53,13 @@ LadspaMatrixControlView::LadspaMatrixControlView(QWidget * parent,
 	Knob * knob = nullptr;
 
 	buffer_data_t dataType = m_ladspaControl->port()->data_type;
+	QString const name = m_ladspaControl->port()->name;
 	switch (dataType)
 	{
 		case TOGGLED:
 		{
 			LedCheckBox * toggle = new LedCheckBox(
-				"", this, QString(), LedCheckBox::Green);
+				name, this, QString(), LedCheckBox::Green);
 			toggle->setModel(m_ladspaControl->toggledModel());
 			layout->addWidget(toggle);
 			setFixedSize(toggle->width(), toggle->height());
@@ -65,16 +68,20 @@ LadspaMatrixControlView::LadspaMatrixControlView(QWidget * parent,
 
 		case INTEGER:
 		case FLOATING:
-			knob = new Knob(knobBright_26, this, m_ladspaControl->port()->name);
+			/*knob = new Knob(knobBright_26, this, name);
 			knob->setModel(m_ladspaControl->knobModel());
+			knob->setLabel(name);*/
+			layout->addWidget(new BarModelEditor(name, m_ladspaControl->knobModel(), this));
 			break;
 
 		case TIME:
-			knob = new TempoSyncKnob(knobBright_26, this, m_ladspaControl->port()->name);
+			knob = new TempoSyncKnob(knobBright_26, this, name);
 			knob->setModel(m_ladspaControl->tempoSyncKnobModel());
+			knob->setLabel(name);
 			break;
 
 		default:
+			layout->addWidget(new QLabel(tr("%1 (unsupported)").arg(name), this));
 			break;
 	}
 

src/gui/widgets/BarModelEditor.cpp

@@ -0,0 +1,115 @@
+#include <BarModelEditor.h>
+
+#include "CaptionMenu.h"
+
+#include <QPainter>
+#include <QInputDialog>
+
+
+namespace lmms::gui
+{
+
+BarModelEditor::BarModelEditor(QString text, FloatModel * floatModel, QWidget * parent) :
+	QWidget(parent),
+	FloatModelView( floatModel, this ),
+	m_text(text)
+{
+	connectToModelSignals();
+}
+
+QSizePolicy BarModelEditor::sizePolicy() const
+{
+	return QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
+}
+
+QSize BarModelEditor::minimumSizeHint() const
+{
+	auto const fm = fontMetrics();
+	return QSize(200, fm.height() * 1.3);
+}
+
+QSize BarModelEditor::sizeHint() const
+{
+	return minimumSizeHint();
+}
+
+void BarModelEditor::paintEvent(QPaintEvent *event)
+{
+	QWidget::paintEvent(event);
+
+	QColor const background(30, 40, 51);
+	QColor const foreground(3, 94, 97);
+	QColor const textColor(14, 192, 198);
+
+	auto const * mod = model();
+	auto const minValue = mod->minValue();
+	auto const maxValue = mod->maxValue();
+	auto const range = maxValue - minValue;
+
+	QRect const r = rect();
+
+	QPainter painter(this);
+	painter.setPen(background);
+	painter.setBrush(background);
+	painter.drawRect(r);
+
+	// Compute the percentage
+	// min + x * (max - min) = v <=> x = (v - min) / (max - min)
+	auto const percentage = range == 0 ? 1. : (mod->value() - minValue) / range;
+
+	int const margin = 2;
+	QMargins const margins(margin, margin, margin, margin);
+	QRect const valueRect = r.marginsRemoved(margins);
+
+	painter.setPen(foreground);
+	painter.setBrush(foreground);
+	painter.drawRect(QRect(valueRect.topLeft(), QPoint(valueRect.width() * percentage, valueRect.height())));
+
+	// Draw text
+	QRect const textRect = valueRect.marginsRemoved(margins);
+	painter.setPen(textColor);
+	painter.drawText(textRect, m_text);
+}
+
+void BarModelEditor::contextMenuEvent(QContextMenuEvent * me)
+{
+	CaptionMenu contextMenu(model()->displayName(), this);
+
+	addDefaultActions(&contextMenu);
+
+	contextMenu.addSeparator();
+	contextMenu.exec(QCursor::pos());
+}
+
+void BarModelEditor::mouseDoubleClickEvent(QMouseEvent * me)
+{
+	bool ok;
+
+	float new_val = QInputDialog::getDouble(
+		this, tr("Set value"),
+		tr("Please enter a new value between "
+		   "%1 and %2:").
+		arg(model()->minValue()).
+		arg(model()->maxValue()),
+		model()->getRoundedValue(),
+		model()->minValue(),
+		model()->maxValue(), model()->getDigitCount(), &ok);
+
+	if (ok)
+	{
+		model()->setValue(new_val);
+	}
+}
+
+void BarModelEditor::connectToModelSignals()
+{
+	auto * m = model();
+	if(m)
+	{
+		// TODO The first connection does a "friendly" update in Knob. Do we also have to do this?
+		QObject::connect(m, SIGNAL(dataChanged()), this, SLOT(update()));
+		QObject::connect(m ,SIGNAL(propertiesChanged()), this, SLOT(update()));
+	}
+}
+
+}