Allow configuring showing printing dialog in wxHtmlEasyPrinting

Add wxHtmlEasyPrinting::SetPromptMode() to allow suppressing the
"prompt" shown by wxPrinter::Print() when it's called from this class
code.

Closes https://github.com/wxWidgets/wxWidgets/pull/838

docs/changes.txt

@@ -88,6 +88,7 @@ All (GUI):
 - Fix bug with missing items in overflowing AUI toolbar (Maarten Bent).
 - Revert to left-aligning wxSpinCtrl contents by default.
 - Make wxRibbonButtonBar buttons more customizable (Max Maisel).
+- Add wxHtmlEasyPrinting::SetPromptMode() (pavel-t).
 
 wxGTK:
 

include/wx/html/htmprint.h

@@ -273,6 +273,16 @@ public:
     void SetName(const wxString& name) { m_Name = name; }
             // set the printout name
 
+    // Controls showing the dialog when printing: by default, always shown.
+    enum PromptMode
+    {
+        Prompt_Never,
+        Prompt_Once,
+        Prompt_Always
+    };
+
+    void SetPromptMode(PromptMode promptMode) { m_promptMode = promptMode; }
+
 protected:
     virtual wxHtmlPrintout *CreatePrintout();
     virtual bool DoPreview(wxHtmlPrintout *printout1, wxHtmlPrintout *printout2);
@@ -296,6 +306,8 @@ private:
     wxString m_Headers[2], m_Footers[2];
     wxWindow *m_ParentWindow;
 
+    PromptMode m_promptMode;
+
     wxDECLARE_NO_COPY_CLASS(wxHtmlEasyPrinting);
 };
 

interface/wx/html/htmprint.h

@@ -340,6 +340,32 @@ public:
     */
     void SetParentWindow(wxWindow* window);
 
+    /**
+        Controls when the print dialog should be shown.
+
+        @see SetPromptMode()
+
+        @since 3.1.2
+    */
+    enum PromptMode
+    {
+        Prompt_Never,  //!< Do not show the print dialog.
+        Prompt_Once,   //!< Show the print dialog only the first time.
+        Prompt_Always  //!< Show the print dialog every time (default value).
+    };
+
+    /**
+        Enable or disable showing the dialog before printing.
+
+        The prompt mode determines the value of the @c prompt parameter passed
+        to wxPrinter::Print() when it is called by this class.
+
+        Default prompt mode value is Prompt_Always.
+
+        @since 3.1.2
+    */
+    void SetPromptMode(PromptMode promptMode);
+
 private:
     /**
         Check whether the document fits into the page area.

src/html/htmprint.cpp

@@ -619,6 +619,8 @@ wxHtmlEasyPrinting::wxHtmlEasyPrinting(const wxString& name, wxWindow *parentWin
     m_PageSetupData->SetMarginBottomRight(wxPoint(25, 25));
 
     SetStandardFonts(DEFAULT_PRINT_FONT_SIZE);
+
+    m_promptMode = Prompt_Always;
 }
 
 
@@ -709,7 +711,13 @@ bool wxHtmlEasyPrinting::DoPrint(wxHtmlPrintout *printout)
     wxPrintDialogData printDialogData(*GetPrintData());
     wxPrinter printer(&printDialogData);
 
-    if (!printer.Print(m_ParentWindow, printout, true))
+    const bool prompt = m_promptMode != Prompt_Never;
+    if (m_promptMode == Prompt_Once)
+    {
+        m_promptMode = Prompt_Never;
+    }
+
+    if (!printer.Print(m_ParentWindow, printout, prompt))
     {
         return false;
     }