Introduce SimpleTextFloat

Introduce the new class SimpleTextFloat which simply shows a text and
that works like a pseudo tool tip with a narrow margin. It was extracted
from TextFloat to adhere to the single responsibility principle.

The new class is used by:
* Fader: display the current volume when moving the fader
* Knob: display the current value when the knob is moved
* PianoRoll: display the current value when setting the note volume and
  panning

Add stylings for the new widget in style.css.

src/gui/CMakeLists.txt

@@ -112,6 +112,7 @@ SET(LMMS_SRCS
 	gui/widgets/NStateButton.cpp
 	gui/widgets/Oscilloscope.cpp
 	gui/widgets/PixmapButton.cpp
+	gui/widgets/SimpleTextFloat.cpp
 	gui/widgets/TabBar.cpp
 	gui/widgets/TabWidget.cpp
 	gui/widgets/TempoSyncKnob.cpp

src/gui/editors/PianoRoll.cpp

@@ -66,6 +66,7 @@
 #include "PatternStore.h"
 #include "PianoView.h"
 #include "PositionLine.h"
+#include "SimpleTextFloat.h"
 #include "SongEditor.h"
 #include "StepRecorderWidget.h"
 #include "TextFloat.h"
@@ -127,7 +128,7 @@ QPixmap * PianoRoll::s_toolMove = nullptr;
 QPixmap * PianoRoll::s_toolOpen = nullptr;
 QPixmap* PianoRoll::s_toolKnife = nullptr;
 
-TextFloat * PianoRoll::s_textFloat = nullptr;
+SimpleTextFloat * PianoRoll::s_textFloat = nullptr;
 
 static std::array<QString, 12> s_noteStrings {"C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"};
 
@@ -290,7 +291,7 @@ PianoRoll::PianoRoll() :
 	// init text-float
 	if( s_textFloat == nullptr )
 	{
-		s_textFloat = new TextFloat;
+		s_textFloat = new SimpleTextFloat;
 	}
 
 	setAttribute( Qt::WA_OpaquePaintEvent, true );

src/gui/widgets/Fader.cpp

@@ -54,13 +54,13 @@
 #include "embed.h"
 #include "CaptionMenu.h"
 #include "ConfigManager.h"
-#include "TextFloat.h"
+#include "SimpleTextFloat.h"
 
 namespace lmms::gui
 {
 
 
-TextFloat * Fader::s_textFloat = nullptr;
+SimpleTextFloat * Fader::s_textFloat = nullptr;
 QPixmap * Fader::s_back = nullptr;
 QPixmap * Fader::s_leds = nullptr;
 QPixmap * Fader::s_knob = nullptr;
@@ -83,7 +83,7 @@ Fader::Fader( FloatModel * _model, const QString & _name, QWidget * _parent ) :
 {
 	if( s_textFloat == nullptr )
 	{
-		s_textFloat = new TextFloat;
+		s_textFloat = new SimpleTextFloat;
 	}
 	if( ! s_back )
 	{
@@ -125,7 +125,7 @@ Fader::Fader( FloatModel * model, const QString & name, QWidget * parent, QPixma
 {
 	if( s_textFloat == nullptr )
 	{
-		s_textFloat = new TextFloat;
+		s_textFloat = new SimpleTextFloat;
 	}
 
 	m_back = back;

src/gui/widgets/Knob.cpp

@@ -45,14 +45,14 @@
 #include "LocaleHelper.h"
 #include "MainWindow.h"
 #include "ProjectJournal.h"
+#include "SimpleTextFloat.h"
 #include "StringPairDrag.h"
-#include "TextFloat.h"
 
 
 namespace lmms::gui
 {
 
-TextFloat * Knob::s_textFloat = nullptr;
+SimpleTextFloat * Knob::s_textFloat = nullptr;
 
 
 
@@ -86,7 +86,7 @@ void Knob::initUi( const QString & _name )
 {
 	if( s_textFloat == nullptr )
 	{
-		s_textFloat = new TextFloat;
+		s_textFloat = new SimpleTextFloat;
 	}
 
 	setWindowTitle( _name );

src/gui/widgets/SimpleTextFloat.cpp

@@ -0,0 +1,62 @@
+/*
+ * TextFloat.cpp - class textFloat, a floating text-label
+ *
+ * Copyright (c) LMMS team
+ *
+ * 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 "SimpleTextFloat.h"
+
+#include <QTimer>
+#include <QStyleOption>
+#include <QHBoxLayout>
+#include <QLabel>
+
+#include "GuiApplication.h"
+#include "MainWindow.h"
+
+namespace lmms::gui
+{
+
+
+SimpleTextFloat::SimpleTextFloat() :
+	QWidget(getGUI()->mainWindow(), Qt::ToolTip)
+{
+	QHBoxLayout * layout = new QHBoxLayout(this);
+	layout->setMargin(3);
+	setLayout(layout);
+
+	m_textLabel = new QLabel(this);
+	layout->addWidget(m_textLabel);
+}
+
+void SimpleTextFloat::setText( const QString & _text )
+{
+	m_textLabel->setText(_text);
+}
+
+
+void SimpleTextFloat::setVisibilityTimeOut( int _msecs )
+{
+	QTimer::singleShot( _msecs, this, SLOT(hide()));
+	show();
+}
+
+} // namespace lmms::gui