Add combined slider and text box widget.

This widgets will be used in the new Compresor2 effect but it is
designed for use in other effects as well.

Signed-off-by: Max Maisel <max.maisel@posteo.de>

src/widgets/SliderTextCtrl.cpp

@@ -0,0 +1,167 @@
+/**********************************************************************
+
+   Audacity: A Digital Audio Editor
+
+   SliderTextCtrl.cpp
+
+   Max Maisel
+
+*******************************************************************//**
+
+\class SliderTextCtrl
+\brief A slider with connected text box.
+
+*//*******************************************************************/
+
+
+#include "../Audacity.h"
+#include "audacity/Types.h"
+#include "SliderTextCtrl.h"
+
+#include <wx/defs.h>
+#include <wx/panel.h>
+#include <wx/sizer.h>
+#include <wx/slider.h>
+#include <wx/textctrl.h>
+#include <wx/valnum.h>
+
+wxDEFINE_EVENT(cEVT_SLIDERTEXT, wxCommandEvent);
+
+SliderTextCtrl::SliderTextCtrl(wxWindow *parent, wxWindowID winid,
+   double value, double min, double max, int precision, double scale,
+   const wxPoint& pos, const wxSize& size, long style, double* varValue)
+   : wxPanelWrapper(parent, winid, pos, size, wxWS_EX_VALIDATE_RECURSIVELY)
+{
+   m_log = style & LOG;
+   m_int = style & INT;
+   m_value = value;
+   m_min = min;
+   m_max = max;
+   m_zero = -std::numeric_limits<double>::infinity();
+
+   if(m_int)
+   {
+      precision = 0;
+      m_format = "%d";
+   }
+   else
+      m_format = wxString::Format("%%.%df", precision);
+
+   if(scale == 0)
+      m_scale = pow(10, precision);
+   else
+      m_scale = scale;
+
+   wxFloatingPointValidator<double> validator(precision, varValue);
+
+   if(m_log)
+   {
+      if(min <= 0.0)
+      {
+         m_zero = -double(precision) - 1.0 / m_scale;
+         min = m_zero;
+      }
+      else
+         min = log10(min);
+
+      if(value <= 0.0)
+         value = m_zero;
+      else
+         value = log10(value);
+      max = log10(max);
+   }
+
+   m_sizer = safenew wxBoxSizer(
+      style & HORIZONTAL ? wxHORIZONTAL : wxVERTICAL);
+   m_slider = safenew wxSlider(this, ID_SLIDER,
+      round(value * m_scale), floor(min * m_scale), ceil(max * m_scale),
+      wxDefaultPosition, wxDefaultSize,
+      style & HORIZONTAL ? wxSL_HORIZONTAL : wxSL_VERTICAL);
+   m_textbox = safenew wxTextCtrl(this, ID_TEXTBOX, wxEmptyString,
+      wxDefaultPosition, wxDefaultSize, 0, validator);
+
+   m_textbox->ChangeValue(FormatValue());
+   m_textbox->Bind(wxEVT_KILL_FOCUS, &SliderTextCtrl::OnKillFocus, this);
+
+   m_sizer->Add(m_slider, 1, wxEXPAND);
+   m_sizer->Add(m_textbox, 0, wxEXPAND);
+
+   SetSizer(m_sizer);
+}
+
+void SliderTextCtrl::SetMinTextboxWidth(int width)
+{
+    wxSize size = GetMinSize();
+    size.SetWidth(width);
+    m_textbox->SetMinSize(size);
+}
+
+double SliderTextCtrl::GetValue() const
+{
+   return m_value;
+}
+
+void SliderTextCtrl::SetValue(double value)
+{
+   m_value = value;
+   m_textbox->ChangeValue(FormatValue());
+}
+
+void SliderTextCtrl::OnTextChange(wxCommandEvent& event)
+{
+   double value;
+   m_textbox->GetValue().ToDouble(&value);
+   m_value = std::min(value, m_max);
+   m_value = std::max(m_value, m_min);
+   if(m_log)
+   {
+      if(m_value == 0.0)
+         value = m_zero;
+      else
+         value = log10(m_value);
+   }
+   m_slider->SetValue(round(value * m_scale));
+   event.SetEventType(cEVT_SLIDERTEXT);
+   event.Skip();
+}
+
+void SliderTextCtrl::OnSlider(wxCommandEvent& event)
+{
+   m_value = m_slider->GetValue() / m_scale;
+   if(m_log)
+   {
+      if(m_value <= m_zero)
+         m_value = 0.0;
+      else
+      {
+         m_value = pow(10.0, m_value);
+         m_value = std::max(m_min, m_value);
+         m_value = std::min(m_max, m_value);
+      }
+   }
+   m_textbox->ChangeValue(FormatValue());
+   m_textbox->SetSelection(-1, -1);
+   event.SetEventType(cEVT_SLIDERTEXT);
+   event.Skip();
+}
+
+void SliderTextCtrl::OnKillFocus(wxFocusEvent& _)
+{
+   m_textbox->ChangeValue(FormatValue());
+   wxCommandEvent event(cEVT_SLIDERTEXT, GetId());
+   wxPostEvent(GetParent(), event);
+}
+
+wxString SliderTextCtrl::FormatValue() const
+{
+   int v = m_value;
+   if(m_int)
+       return wxString::Format(m_format, v);
+   else
+       return wxString::Format(m_format, m_value);
+}
+
+BEGIN_EVENT_TABLE(SliderTextCtrl, wxControl)
+   EVT_TEXT(ID_TEXTBOX, SliderTextCtrl::OnTextChange)
+   EVT_SLIDER(ID_SLIDER, SliderTextCtrl::OnSlider)
+END_EVENT_TABLE()