Add ability to toggle markdown preview

src/Editor.vala

@@ -108,7 +108,7 @@ namespace Publicate {
 
         public async void load_ppub(File file, bool initial = false) throws Error {
 
-            window.publication = new Ppub.Publication(file.get_path());
+            window.publication = new Ppub.FilePublication(file.get_path());
             publication_file = file;
 
             header_title.title = window.publication.metadata.title ?? "Untitled PPUB";

src/Editors/MarkdownEditor.vala

@@ -6,17 +6,17 @@ namespace Publicate.Editors {
 
     public class MarkdownEditor : Box, EditorWidget, Savable {
 
-        private Paned leaflet;
+        private Paned paned_view;
 
         private Box toolbar;
-        private GtkCommonMark.MarkdownView markdown_view;
+        private GtkCommonMark.MarkdownView? markdown_view = null;
         private GtkSource.View text_view;
         private GtkSource.Buffer source_buffer;
         private GtkSource.LanguageManager language_manager;
         private GtkSource.StyleSchemeManager style_manager;
         
         private ScrolledWindow source_scroller;
-        private ScrolledWindow markdown_scroller;
+        private ScrolledWindow? markdown_scroller = null;
 
         private ViewerWindow window;
         private TabPage page;
@@ -26,6 +26,7 @@ namespace Publicate.Editors {
         private ToggleButton italic_button;
         private Button insert_link;
         private Button insert_image;
+        private ToggleButton preview_button;
 
         private const string STYLE_HEADING_1 = "Heading 1";
         private const string STYLE_HEADING_2 = "Heading 2";
@@ -65,8 +66,7 @@ namespace Publicate.Editors {
             orientation = Orientation.VERTICAL;
 
             source_scroller = new ScrolledWindow ();
-            markdown_scroller = new ScrolledWindow ();
-            leaflet = new Paned(Orientation.HORIZONTAL);
+            paned_view = new Paned(Orientation.HORIZONTAL);
 
             text_view = new GtkSource.View ();
             language_manager = new GtkSource.LanguageManager ();
@@ -83,7 +83,7 @@ namespace Publicate.Editors {
             text_view.bottom_margin = 18;
             text_view.left_margin = 18;
             text_view.right_margin = 18;
-            text_view.buffer.changed.connect (update_preview);
+            text_view.buffer.changed.connect (() => update_preview());
 
             spell_checker = Spelling.Checker.get_default();
             spell_adapter = new Spelling.TextBufferAdapter(source_buffer, spell_checker);
@@ -94,23 +94,13 @@ namespace Publicate.Editors {
 
             source_scroller.set_policy (PolicyType.NEVER, PolicyType.AUTOMATIC);
             source_scroller.vexpand = true;
-            markdown_scroller.set_policy (PolicyType.NEVER, PolicyType.AUTOMATIC);
-            markdown_scroller.vexpand = true;
-
             source_scroller.vadjustment.value_changed.connect(sync_scroll);
-
-            markdown_view = new GtkCommonMark.MarkdownView ();
-            markdown_view.hexpand = true;
-            markdown_view.set_wrap_mode (WrapMode.WORD_CHAR);
-            markdown_view.widget_embedded.connect(widget_embedded);
-
             source_scroller.child = text_view;
-            markdown_scroller.child = markdown_view;
+            
 
             var source_box = new Box(Orientation.VERTICAL, 0);
             source_box.append(source_scroller);
-            leaflet.start_child = source_box;
-            leaflet.end_child = markdown_scroller;
+            paned_view.start_child = source_box;
 
             Gtk.Settings.get_default().notify["gtk-application-prefer-dark-theme"].connect(() => configure_tags());
             configure_tags();
@@ -142,22 +132,56 @@ namespace Publicate.Editors {
             insert_image.tooltip_text = "Insert image";
             insert_image.clicked.connect(() => insert_image_clicked());
             toolbar.append(insert_image);
+            preview_button = new ToggleButton();
+            preview_button.child = new Image.from_icon_name("view-dual-symbolic");
+            preview_button.tooltip_text = "Markdown Preview";
+            preview_button.active = true;
+            preview_button.clicked.connect(() => toggle_preview());
+            toolbar.append(preview_button);
             source_box.append(toolbar);
 
             source_buffer.cursor_moved.connect(() => update_toolbar());
             source_buffer.highlight_updated.connect(() => update_toolbar());
-            append(leaflet);
+            append(paned_view);
+            initialise_preview();
 
             page = tab_view.add_page (this, null);
         }
 
+        private void initialise_preview() {
+            markdown_scroller = new ScrolledWindow ();
+            markdown_scroller.set_policy (PolicyType.NEVER, PolicyType.AUTOMATIC);
+            markdown_scroller.vexpand = true;
+
+            markdown_view = new GtkCommonMark.MarkdownView ();
+            markdown_view.hexpand = true;
+            markdown_view.set_wrap_mode (WrapMode.WORD_CHAR);
+            markdown_view.widget_embedded.connect(widget_embedded);
+            
+            markdown_scroller.child = markdown_view;
+            //  markdown_scroller.hadjustment.changed.connect(() => sync_scroll());
+            paned_view.end_child = markdown_scroller;
+            set_leaflet_size();
+            configure_tags();
+        }
+
+        private void destruct_preview() {
+            paned_view.end_child = null;
+            markdown_scroller = null;
+            markdown_view = null;
+        }
+
         public void set_zoom_percentage (int percent) {
-            var scale = (float)percent / 100f;
-            markdown_view.tag_manager.font_scale = scale;
+            if(markdown_view != null) {
+                var scale = (float)percent / 100f;
+                markdown_view.tag_manager.font_scale = scale;
+            }
         }
         
         public async void load_asset (Ppub.Publication publication, Ppub.Asset asset) {
-            markdown_view.buffer.set_text("", 0);
+            if(markdown_view != null) {
+                markdown_view.buffer.set_text("", 0);
+            }
             page.title = asset.name;
             this.asset = asset;
 
@@ -170,7 +194,11 @@ namespace Publicate.Editors {
             text_view.buffer.set_text ((string)text, text.length);
             set_tab_name(false);
 
-            Timeout.add_once(100, () => leaflet.position = int.max(300, leaflet.get_width() / 2));
+            Timeout.add_once(100, () => set_leaflet_size());
+        }
+
+        private void set_leaflet_size() {
+            paned_view.position = int.max(300, paned_view.get_width() / 2);
         }
 
         public void save_asset(Ppub.Builder builder) {
@@ -211,7 +239,9 @@ namespace Publicate.Editors {
 
         private void configure_tags() {
             var link = new LinkButton("");
-            markdown_view.tag_manager.update_link_colour(link.get_color());
+            if(markdown_view != null) {
+                markdown_view.tag_manager.update_link_colour(link.get_color());
+            }
 
             if(Gtk.Settings.get_default().gtk_application_prefer_dark_theme) {
                 source_buffer.style_scheme = style_manager.get_scheme("Adwaita-dark");
@@ -221,11 +251,16 @@ namespace Publicate.Editors {
             }
         }
 
-        private void update_preview() {
+        private void update_preview(bool changes = true) {
+            if(changes) {
+                set_tab_name(true);
+            }
+            if(markdown_view == null) {
+                return;
+            }
             var text = get_text();
             markdown_view.buffer.set_text("", 0);
             markdown_view.load_from_string((string)text);
-            set_tab_name(true);
         }
 
         public string get_text() {
@@ -239,7 +274,9 @@ namespace Publicate.Editors {
         }
 
         private void sync_scroll() {
-            set_scroll_from_frac(markdown_scroller, get_scroll_frac(source_scroller));
+            if(markdown_scroller != null) {
+                set_scroll_from_frac(markdown_scroller, get_scroll_frac(source_scroller));
+            }
         }
 
         private static double get_scroll_frac(ScrolledWindow scroller) {
@@ -566,6 +603,16 @@ namespace Publicate.Editors {
             source_buffer.insert(ref iter, link, link.length);
             source_buffer.end_user_action();
         }
+
+        private void toggle_preview() {
+            if(preview_button.active) {
+                initialise_preview();
+                update_preview(false);
+            }
+            else {
+                destruct_preview();
+            }
+        }
         
     }