Add appearance="multiline" to parameters of type string

Renders a Gtk::TextView that automatically fills the available
space in the extension's preferences dialog and can be used
to accept longer multi-line strings.

Newlines in the string value will be passed as "\\n" to the
extension script (i.e. literal '\n' with the backspace escaped).

5 files changed, 102 insertions, 13 deletions

diff --git a/src/extension/extension.cpp b/src/extension/extension.cpp
index 7836a8479..b8c3242a5 100644
--- a/src/extension/extension.cpp
+++ b/src/extension/extension.cpp
@@ -722,7 +722,8 @@ public:
     void addWidget(Gtk::Widget *widg, gchar const *tooltip, int indent) {
         if (widg) {
             widg->set_margin_start(indent * InxParameter::GUI_INDENTATION);
-            this->pack_start(*widg, false, false, 0);
+            this->pack_start(*widg, false, true, 0); // fill=true does not have an effect here, but allows the
+                                                     // child to choose to expand by setting hexpand/vexpand
             if (tooltip) {
                 widg->set_tooltip_text(tooltip);
             } else {
diff --git a/src/extension/prefdialog/parameter-notebook.cpp b/src/extension/prefdialog/parameter-notebook.cpp
index a139bd2bd..a90935ca1 100644
--- a/src/extension/prefdialog/parameter-notebook.cpp
+++ b/src/extension/prefdialog/parameter-notebook.cpp
@@ -82,7 +82,8 @@ Gtk::Widget *ParamNotebook::ParamNotebookPage::get_widget(sigc::signal<void> *ch
         if (child_widget) {
             int indent = child->get_indent();
             child_widget->set_margin_start(indent *GUI_INDENTATION);
-            vbox->pack_start(*child_widget, false, false, 0);
+            vbox->pack_start(*child_widget, false, true, 0); // fill=true does not have an effect here, but allows the
+                                                             // child to choose to expand by setting hexpand/vexpand
 
             const char *tooltip = child->get_tooltip();
             if (tooltip) {
diff --git a/src/extension/prefdialog/parameter-string.cpp b/src/extension/prefdialog/parameter-string.cpp
index bf8ad14a3..6cf57c20e 100644
--- a/src/extension/prefdialog/parameter-string.cpp
+++ b/src/extension/prefdialog/parameter-string.cpp
@@ -11,6 +11,9 @@
 
 #include <gtkmm/box.h>
 #include <gtkmm/entry.h>
+#include <gtkmm/scrolledwindow.h>
+#include <gtkmm/textview.h>
+#include <glibmm/regex.h>
 
 #include "xml/node.h"
 #include "extension/extension.h"
@@ -50,6 +53,16 @@ ParamString::ParamString(Inkscape::XML::Node *xml, Inkscape::Extension::Extensio
     if (max_length) {
         _max_length = strtoul(max_length, nullptr, 0);
     }
+
+    // parse appearance
+    if (_appearance) {
+        if (!strcmp(_appearance, "multiline")) {
+            _mode = MULTILINE;
+        } else {
+            g_warning("Invalid value ('%s') for appearance of parameter '%s' in extension '%s'",
+                      _appearance, _name, _extension->get_id());
+        }
+    }
 }
 
 /**
@@ -80,7 +93,8 @@ std::string ParamString::value_to_string() const
 }
 
 
-/** A special type of Gtk::Entry to handle string parameteres. */
+
+/** A special type of Gtk::Entry to handle string parameters. */
 class ParamStringEntry : public Gtk::Entry {
 private:
     ParamString *_pref;
@@ -119,6 +133,54 @@ void ParamStringEntry::changed_text()
     }
 }
 
+
+
+/** A special type of Gtk::TextView to handle multiline string parameters. */
+class ParamMultilineStringEntry : public Gtk::TextView {
+private:
+    ParamString *_pref;
+    sigc::signal<void> *_changeSignal;
+public:
+    /**
+     * Build a string preference for the given parameter.
+     * @param  pref  Where to get the string from, and where to put it
+     *                when it changes.
+     */
+    ParamMultilineStringEntry(ParamString *pref, sigc::signal<void> *changeSignal)
+        : Gtk::TextView()
+        , _pref(pref)
+        , _changeSignal(changeSignal)
+    {
+        // replace literal '\n' with actual newlines for multiline strings
+        Glib::ustring value = Glib::Regex::create("\\\\n")->replace_literal(_pref->get(), 0, "\n", (Glib::RegexMatchFlags)0);
+
+        this->get_buffer()->set_text(value);
+        this->get_buffer()->signal_changed().connect(sigc::mem_fun(this, &ParamMultilineStringEntry::changed_text));
+    };
+    void changed_text();
+};
+
+/**
+ * Respond to the text box changing.
+ *
+ * This function responds to the box changing by grabbing the value
+ * from the text box and putting it in the parameter.
+ */
+void ParamMultilineStringEntry::changed_text()
+{
+    Glib::ustring data = this->get_buffer()->get_text();
+
+    // always store newlines as literal '\n'
+    data = Glib::Regex::create("\n")->replace_literal(data, 0, "\\n", (Glib::RegexMatchFlags)0);
+
+    _pref->set(data.c_str());
+    if (_changeSignal != nullptr) {
+        _changeSignal->emit();
+    }
+}
+
+
+
 /**
  * Creates a text box for the string parameter.
  *
@@ -130,18 +192,36 @@ Gtk::Widget *ParamString::get_widget(sigc::signal<void> *changeSignal)
         return nullptr;
     }
 
-    Gtk::HBox *hbox = Gtk::manage(new Gtk::HBox(false, GUI_PARAM_WIDGETS_SPACING));
+    Gtk::Box *box = Gtk::manage(new Gtk::Box(Gtk::ORIENTATION_HORIZONTAL, GUI_PARAM_WIDGETS_SPACING));
+
     Gtk::Label *label = Gtk::manage(new Gtk::Label(_text, Gtk::ALIGN_START));
     label->show();
-    hbox->pack_start(*label, false, false);
+    box->pack_start(*label, false, false);
+
+    if (_mode == MULTILINE) {
+        box->set_orientation(Gtk::ORIENTATION_VERTICAL);
 
-    ParamStringEntry * textbox = new ParamStringEntry(this, changeSignal);
-    textbox->show();
-    hbox->pack_start(*textbox, true, true);
+        Gtk::ScrolledWindow *textarea = new Gtk::ScrolledWindow();
+        textarea->set_vexpand();
+        textarea->set_shadow_type(Gtk::SHADOW_IN);
+
+        ParamMultilineStringEntry *entry = new ParamMultilineStringEntry(this, changeSignal);
+        entry->show();
+
+        textarea->add(*entry);
+        textarea->show();
+
+        box->pack_start(*textarea, true, true);
+    } else {
+        Gtk::Widget *entry = new ParamStringEntry(this, changeSignal);
+        entry->show();
+
+        box->pack_start(*entry, true, true);
+    }
 
-    hbox->show();
+    box->show();
 
-    return dynamic_cast<Gtk::Widget *>(hbox);
+    return dynamic_cast<Gtk::Widget *>(box);
 }
 
 }  /* namespace Extension */
diff --git a/src/extension/prefdialog/parameter-string.h b/src/extension/prefdialog/parameter-string.h
index ef1d48821..3af83111d 100644
--- a/src/extension/prefdialog/parameter-string.h
+++ b/src/extension/prefdialog/parameter-string.h
@@ -20,6 +20,10 @@ namespace Extension {
 
 class ParamString : public InxParameter {
 public:
+    enum AppearanceMode {
+        DEFAULT, MULTILINE
+    };
+
     ParamString(Inkscape::XML::Node *xml, Inkscape::Extension::Extension *ext);
 
     /** \brief  Returns \c _value, with a \i const to protect it. */
@@ -37,8 +41,10 @@ private:
     /** \brief  Internal value. */
     Glib::ustring _value;
 
-    /** \brief Maximum length of the string in characters (zero meaning unlimited).
-      */
+    /** appearance mode **/
+    AppearanceMode _mode = DEFAULT;
+
+    /** \brief Maximum length of the string in characters (zero meaning unlimited). */
     int _max_length = 0;
 };
 
diff --git a/src/extension/prefdialog/widget-box.cpp b/src/extension/prefdialog/widget-box.cpp
index 2c9d24f4a..9fd75e19a 100644
--- a/src/extension/prefdialog/widget-box.cpp
+++ b/src/extension/prefdialog/widget-box.cpp
@@ -96,7 +96,8 @@ Gtk::Widget *WidgetBox::get_widget(sigc::signal<void> *changeSignal)
         if (child_widget) {
             int indent = child->get_indent();
             child_widget->set_margin_start(indent * GUI_INDENTATION);
-            box->pack_start(*child_widget, false, false, 0);
+            box->pack_start(*child_widget, false, true, 0); // fill=true does not have an effect here, but allows the
+                                                            // child to choose to expand by setting hexpand/vexpand
 
             const char *tooltip = child->get_tooltip();
             if (tooltip) {