Adding preview to Nyquist effects as requested by STF

He also added a new Nyquist control header that gives each
effect the ability to control the presentation of the Preview
button.  This will be used by effects are time based and, therefore,
do not produce the same results in preview as they do when applied.

I expect Steve will be committing changes to the effects that can
take advantage of this shortly.

Testing of this can be accomplished by adding:

;preview enabled

to the "tremelo.ny" effect, just after the ";action" line.

Adding that line will cause the "Preview" button to be shown and
you will then be able to preview, adjust, preview, apply...

src/effects/nyquist/Nyquist.cpp

@@ -282,6 +282,13 @@ void EffectNyquist::Parse(wxString line)
       return;
    }
 
+   if (len >= 2 && tokens[0] == wxT("preview")) {
+      if (tokens[1] == wxT("enabled") || tokens[1] == wxT("true")) {
+         mEnablePreview = true;
+      }
+      return;
+   }
+
    if (len >= 6 && tokens[0] == wxT("control")) {
       NyqControl ctrl;
 
@@ -346,6 +353,7 @@ void EffectNyquist::ParseFile()
    mCmd = wxT("");
    SetEffectFlags(PROCESS_EFFECT | PLUGIN_EFFECT);
    mOK = false;
+   mEnablePreview = false;
    mIsSal = false;
    mControls.Clear();
    mDebug = false;
@@ -499,7 +507,7 @@ bool EffectNyquist::TransferParameters( Shuttle & shuttle )
 
 bool EffectNyquist::PromptUser()
 {
-   if (mInteractive) {
+   while (mInteractive) {
       NyquistInputDialog dlog(wxGetTopLevelParent(NULL), -1,
                               _("Nyquist Prompt"),
                               _("Enter Nyquist Command: "),
@@ -563,7 +571,12 @@ bool EffectNyquist::PromptUser()
          }
       }
 
-      return true;
+      if (result != ePreviewID)
+      {
+         return true;
+      }
+
+      Preview();
    }
 
    if (!mExternal) {
@@ -614,7 +627,7 @@ bool EffectNyquist::PromptUser()
       }
    }
 
-   NyquistDialog dlog(mParent, -1, mName, mInfo, &mControls);
+   NyquistDialog dlog(mParent, -1, mName, mInfo, mEnablePreview, this);
    dlog.CentreOnParent();
    int result = dlog.ShowModal();
 
@@ -1156,6 +1169,7 @@ BEGIN_EVENT_TABLE(NyquistDialog, wxDialog)
    EVT_BUTTON(wxID_OK, NyquistDialog::OnOk)
    EVT_BUTTON(wxID_CANCEL, NyquistDialog::OnCancel)
    EVT_BUTTON(eDebugID, NyquistDialog::OnDebug)
+   EVT_BUTTON(ePreviewID, NyquistDialog::OnPreview)
    EVT_COMMAND_RANGE(ID_NYQ_SLIDER, ID_NYQ_SLIDER+99,
                      wxEVT_COMMAND_SLIDER_UPDATED, NyquistDialog::OnSlider)
    EVT_COMMAND_RANGE(ID_NYQ_TEXT, ID_NYQ_TEXT+99,
@@ -1167,10 +1181,12 @@ END_EVENT_TABLE()
 NyquistDialog::NyquistDialog(wxWindow * parent, wxWindowID id,
                              const wxString & title,
                              wxString info,
-                             NyqControlArray *controlArray)
+                             bool preview,
+                             EffectNyquist *effect)
 :   wxDialog(parent, id, title)
 {
-   mControls = controlArray;
+   mEffect = effect;
+   mControls = &mEffect->mControls;
    mInHandler = true; // prevents race condition on MSW
 
    wxBoxSizer *mainSizer = new wxBoxSizer(wxVERTICAL);
@@ -1279,9 +1295,15 @@ NyquistDialog::NyquistDialog(wxWindow * parent, wxWindowID id,
    }
    mainSizer->Add(grid, 0, wxALIGN_CENTRE | wxALL, 5);
 
-   mainSizer->Add(CreateStdButtonSizer(this, eDebugButton | eCancelButton | eOkButton),
+   if (preview) {
-                  0,
+      mainSizer->Add(CreateStdButtonSizer(this, ePreviewButton | eDebugButton | eCancelButton | eOkButton),
-                  wxEXPAND);
+                     0,
+                     wxEXPAND);
+   } else {
+      mainSizer->Add(CreateStdButtonSizer(this, eDebugButton | eCancelButton | eOkButton),
+                     0,
+                     wxEXPAND);
+   }
 
    mInHandler = false;
 
@@ -1420,39 +1442,49 @@ void NyquistDialog::OnDebug(wxCommandEvent & /* event */)
    EndModal(eDebugID);
 }
 
+void NyquistDialog::OnPreview(wxCommandEvent & /* event */)
+{
+   mEffect->Preview();
+}
+
 /**********************************************************/
 
 BEGIN_EVENT_TABLE(NyquistInputDialog, wxDialog)
    EVT_BUTTON(wxID_OK, NyquistInputDialog::OnOk)
    EVT_BUTTON(wxID_CANCEL, NyquistInputDialog::OnCancel)
    EVT_BUTTON(eDebugID, NyquistInputDialog::OnDebug)
+   EVT_BUTTON(ePreviewID, NyquistInputDialog::OnPreview)
 END_EVENT_TABLE()
 
 NyquistInputDialog::NyquistInputDialog(wxWindow * parent, wxWindowID id,
                                        const wxString & title,
                                        const wxString & prompt,
                                        wxString initialCommand)
-:  wxDialog(parent, id, title)
+:  wxDialog(parent, id, title, wxDefaultPosition, wxDefaultSize, wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER)
 {
-   wxBoxSizer *mainSizer = new wxBoxSizer(wxVERTICAL);
+   ShuttleGui S(this, eIsCreating);
-   wxControl  *item;
 
-   item = new wxStaticText(this, -1, prompt);
+   S.StartVerticalLay();
-   item->SetName(prompt);  // fix for bug 577 (NVDA/Narrator screen readers do not read static text in dialogs)
+   {
-   mainSizer->Add(item, 0, wxALIGN_LEFT | wxLEFT | wxTOP | wxRIGHT, 10);
+      S.StartHorizontalLay(wxEXPAND, 0);
+      {
+          S.AddVariableText(prompt);
+      }
+      S.EndHorizontalLay();
 
-   mCommandText = new wxTextCtrl(this, -1, initialCommand,
+      S.StartHorizontalLay(wxEXPAND, 1);
-                                 wxDefaultPosition, wxSize(400, 200),
+      {
-                                 wxTE_MULTILINE);
+          mCommandText = S.AddTextWindow(initialCommand);
-   mainSizer->Add(mCommandText, 0, wxALIGN_LEFT | wxALL, 10);
+          mCommandText->SetMinSize(wxSize(500, 200));
+      }
+      S.EndHorizontalLay();
+   }
+   S.EndVerticalLay();
 
    // Debug, OK, & Cancel buttons
-   mainSizer->Add(CreateStdButtonSizer(this, eDebugButton|eCancelButton|eOkButton), 0, wxEXPAND);
+   S.AddStandardButtons(ePreviewButton|eDebugButton|eCancelButton|eOkButton);
 
-   SetAutoLayout(true);
+   GetSizer()->SetSizeHints(this);
-   SetSizer(mainSizer);
-   mainSizer->Fit(this);
-   mainSizer->SetSizeHints(this);
 
    mCommandText->SetFocus();
 }
@@ -1479,6 +1511,11 @@ void NyquistInputDialog::OnDebug(wxCommandEvent & /* event */)
    EndModal(eDebugID);
 }
 
+void NyquistInputDialog::OnPreview(wxCommandEvent & /* event */)
+{
+   EndModal(ePreviewID);
+}
+
 
 /**********************************************************/
 

src/effects/nyquist/Nyquist.h

@@ -172,6 +172,7 @@ class AUDACITY_DLL_API EffectNyquist:public Effect
    wxString          mName;   ///< Name of the Effect
    wxString          mAction;
    wxString          mInfo;
+   bool              mEnablePreview;
    bool              mDebug;
    std::string       mDebugOutput;
 
@@ -196,6 +197,8 @@ class AUDACITY_DLL_API EffectNyquist:public Effect
    WaveTrack         *mOutputTrack[2];
 
    wxArrayString     mCategories;
+
+   friend class NyquistDialog;
 };
 
 class NyquistDialog:public wxDialog
@@ -205,17 +208,20 @@ class NyquistDialog:public wxDialog
    NyquistDialog(wxWindow * parent, wxWindowID id,
                  const wxString & title,
                  wxString info,
-                 NyqControlArray *controlArray);
+                 bool preview,
+                 EffectNyquist *effect);
 
  private:
+   EffectNyquist    *mEffect;
    NyqControlArray  *mControls;
    bool              mInHandler;
 
    void OnText(wxCommandEvent & event);
    void OnSlider(wxCommandEvent & event);
    void OnChoice( wxCommandEvent &event );
-   void OnOk(wxCommandEvent & event);
+   void OnPreview(wxCommandEvent & event);
    void OnDebug(wxCommandEvent & event);
+   void OnOk(wxCommandEvent & event);
    void OnCancel(wxCommandEvent & event);
 
  private:
@@ -237,8 +243,9 @@ class NyquistInputDialog:public wxDialog
    wxTextCtrl *mCommandText;
 
    void OnOk(wxCommandEvent & event);
-   void OnDebug(wxCommandEvent & event);
    void OnCancel(wxCommandEvent & event);
+   void OnDebug(wxCommandEvent & event);
+   void OnPreview(wxCommandEvent & event);
 
  private:
    DECLARE_EVENT_TABLE()