ViewMD -> SeeMD

LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Robert Fulton
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

@@ -1,6 +1,7 @@
 CC = gcc
-CFLAGS = -Wall -Wextra -O2 -g `pkg-config --cflags gtk+-3.0`
-LDFLAGS = `pkg-config --libs gtk+-3.0`
+PKGS = gtk+-3.0 webkit2gtk-4.1
+CFLAGS = -Wall -Wextra -O2 -g `pkg-config --cflags $(PKGS)`
+LDFLAGS = `pkg-config --libs $(PKGS)`
 
 SRCDIR = src
 OBJDIR = obj

README.md

@@ -1,18 +1,19 @@
 # ViewMD
 
-A lightweight GTK 3 markdown viewer for desktop Linux. It is ideal as your default app for opening `.md` files. Uses the excellent library [md4c](https://github.com/mity/md4c) for markdown parsing. This project is sort of a companion app/fork of my other markdown project [TrayMD](https://github.com/rabfulton/TrayMD). 
+A lightweight GTK 3 markdown viewer and editor for desktop Linux. It is ideal as your default app for opening `.md` files. Uses the excellent library [md4c](https://github.com/mity/md4c) for markdown parsing and WebKitGTK for GitHub-style preview rendering. This project is a fork of [ViewMD](https://github.com/rabfulton/ViewMD) by NotAlexNoyle.
 
 ![ViewMD](assets/screenshot.png)
 
 ## Features
 
-- **Native GTK viewer** - No webviews
-- **Read-only rendering** - Focused on viewing markdown files
-- **Minimal UI** - Clean toolbar with open and settings buttons
-- **Lightweight** - Pure C, no web technologies, fast startup
+- **GitHub-style preview** - Rendered Markdown and inline HTML are displayed through WebKitGTK with GitHub-like markdown styling
+- **Read-only preview** - Rendered Markdown stays non-editable until source mode is enabled
+- **Source editing mode** - Toggle between rendered preview and editable Markdown
+- **Minimal UI** - Clean toolbar with open, reload, edit, save, and settings buttons
+- **Lightweight** - Pure C with GTK and WebKitGTK, fast startup
 - **Hyperlink support** - Left click opens links and internal anchors
 - **Document search** - `Ctrl+F` with next/previous match navigation
-- **Local image support** - Local images are resized to fit the the document window
+- **Local image support** - Local images keep natural size unless they need to fit the document window
 
 ## Supported Markdown
 
@@ -30,6 +31,7 @@ A lightweight GTK 3 markdown viewer for desktop Linux. It is ideal as your defau
 | `[text](url)` | Link |
 | `~~strike~~` | Strikethrough |
 | `\| table \| row \|` | Markdown tables |
+| `<strong>HTML</strong>` | GitHub-style inline and block HTML rendered in preview mode |
 | `---` | Horizontal rule |
 
 Code blocks currently support a beta version of keyword highlighting for fenced languages `c`, `java`, and `python`.
@@ -62,6 +64,8 @@ Run `viewmd` to start the application.
 
 - **Open button**: Open a markdown document
 - **Reload button**: Reload the currently open document from disk
+- **Edit button**: Toggle editable Markdown source mode (`Ctrl+E`)
+- **Save button**: Save the current Markdown source (`Ctrl+S`)
 - **Settings button**: Adjust theme, fonts, and markdown accent colors
 
 ### Find in Document
@@ -113,17 +117,17 @@ sudo make uninstall
 
 ### Arch Linux
 ```bash
-sudo pacman -S gtk3
+sudo pacman -S gtk3 webkit2gtk-4.1
 ```
 
 ### Ubuntu/Debian
 ```bash
-sudo apt install libgtk-3-dev
+sudo apt install libgtk-3-dev libwebkit2gtk-4.1-dev
 ```
 
 ### Fedora
 ```bash
-sudo dnf install gtk3-devel
+sudo dnf install gtk3-devel webkit2gtk4.1-devel
 ```
 
 ## Packaging Templates
@@ -133,12 +137,4 @@ sudo dnf install gtk3-devel
 - RPM: `packaging/rpm/viewmd.spec.in`
 ## License
 
-MIT License
-
-## Other Useful Projects
-- TrayMD is an app for taking notes in markdown with live editing [TrayMD](https://github.com/rabfulton/TrayMD)
-- Preditor is an image viewer with a similar philosophy to viewmd [preditor](https://github.com/rabfulton/preditor)
-- Try my AI panel plugin for XFCE [XFCE Ask](https://github.com/rabfulton/xfce-ask)
-- For a feature complete AI application try out [ChatGTK](https://github.com/rabfulton/ChatGTK)
-- A lightweight speech to text implementation [Auriscribe](https://github.com/rabfulton/Auriscribe)
-- A lightweight local movie database and browser [ReelVault](https://github.com/rabfulton/ReelVault)
+Released under the [MIT License](LICENSE).

packaging/arch/PKGBUILD

@@ -5,7 +5,7 @@ pkgdesc="Lightweight GTK3 markdown viewer"
 arch=('x86_64')
 url="https://github.com/rabfulton/ViewMD"
 license=('MIT')
-depends=('gtk3')
+depends=('gtk3' 'webkit2gtk-4.1')
 makedepends=('git' 'gcc' 'make' 'pkgconf')
 source=("$pkgname::git+$url.git")
 sha256sums=('SKIP')

packaging/deb/control.in

@@ -4,6 +4,6 @@ Section: utils
 Priority: optional
 Architecture: @ARCH@
 Maintainer: @MAINTAINER@
-Depends: libgtk-3-0
+Depends: libgtk-3-0, libwebkit2gtk-4.1-0
 Description: ViewMD - lightweight GTK3 markdown viewer
- ViewMD is a lightweight native GTK3 markdown viewer.
+ ViewMD is a lightweight GTK3 markdown viewer with GitHub-style WebKit preview rendering.

packaging/rpm/viewmd.spec.in

@@ -11,11 +11,13 @@ BuildRequires:  gcc
 BuildRequires:  make
 BuildRequires:  pkgconfig
 BuildRequires:  gtk3-devel
+BuildRequires:  webkit2gtk4.1-devel
 
 Requires:       gtk3
+Requires:       webkit2gtk4.1
 
 %description
-ViewMD is a lightweight native GTK3 markdown viewer.
+ViewMD is a lightweight GTK3 markdown viewer with GitHub-style WebKit preview rendering.
 
 %prep
 %autosetup -n viewmd-%{version}

src/app.c

@@ -156,6 +156,45 @@ gboolean markyd_app_open_file(MarkydApp *self, const gchar *path) {
   return TRUE;
 }
 
+gboolean markyd_app_save_file(MarkydApp *self, const gchar *path) {
+  gchar *content;
+  GError *error = NULL;
+
+  if (!self || !self->editor || !path || path[0] == '\0') {
+    return FALSE;
+  }
+
+  content = markyd_editor_get_content(self->editor);
+  if (!g_file_set_contents(path, content ? content : "", -1, &error)) {
+    if (error) {
+      g_printerr("Failed to save markdown file '%s': %s\n", path, error->message);
+      g_error_free(error);
+    }
+    g_free(content);
+    return FALSE;
+  }
+  g_free(content);
+
+  g_free(self->current_file_path);
+  self->current_file_path = g_strdup(path);
+  markyd_app_update_window_title(self);
+  return TRUE;
+}
+
+gboolean markyd_app_save_current_file(MarkydApp *self) {
+  gchar *path;
+  gboolean ok;
+
+  if (!self || !self->current_file_path || self->current_file_path[0] == '\0') {
+    return FALSE;
+  }
+
+  path = g_strdup(self->current_file_path);
+  ok = markyd_app_save_file(self, path);
+  g_free(path);
+  return ok;
+}
+
 const gchar *markyd_app_get_current_path(MarkydApp *self) {
   if (!self) {
     return NULL;

src/app.h

@@ -25,6 +25,8 @@ int markyd_app_run(MarkydApp *app, int argc, char **argv);
 
 /* Document management */
 gboolean markyd_app_open_file(MarkydApp *app, const gchar *path);
+gboolean markyd_app_save_file(MarkydApp *app, const gchar *path);
+gboolean markyd_app_save_current_file(MarkydApp *app);
 
 /* Utility */
 const gchar *markyd_app_get_current_path(MarkydApp *app);

src/editor.c

@@ -2,6 +2,7 @@
 #include "app.h"
 #include "markdown.h"
 #include <string.h>
+#include <webkit2/webkit2.h>
 
 static gboolean on_button_release(GtkWidget *widget, GdkEventButton *event,
                                   gpointer user_data);
@@ -18,6 +19,15 @@ static gboolean resolve_image_source_path(MarkydEditor *self, const gchar *src,
                                           gchar **out_path);
 static void on_text_view_size_allocate(GtkWidget *widget, GtkAllocation *allocation,
                                        gpointer user_data);
+static void on_buffer_changed(GtkTextBuffer *buffer, gpointer user_data);
+static void sync_source_from_buffer(MarkydEditor *self);
+static void show_source_buffer(MarkydEditor *self);
+static void render_preview(MarkydEditor *self);
+static gchar *get_preview_base_uri(MarkydEditor *self);
+static gboolean on_preview_decide_policy(WebKitWebView *web_view,
+                                         WebKitPolicyDecision *decision,
+                                         WebKitPolicyDecisionType type,
+                                         gpointer user_data);
 
 static gchar *get_url_from_iter_tags(GtkTextIter *iter) {
   GSList *tags;
@@ -110,24 +120,43 @@ static gboolean scroll_to_markdown_anchor(MarkydEditor *self,
   return TRUE;
 }
 
-static void set_link_cursor(MarkydEditor *self, gboolean active) {
-  GdkWindow *win = gtk_text_view_get_window(GTK_TEXT_VIEW(self->text_view),
-                                            GTK_TEXT_WINDOW_TEXT);
+static void set_editor_mouse_cursor(MarkydEditor *self, gboolean over_link) {
+  GdkWindow *win;
+  GdkDisplay *display;
+  GdkCursor *cursor;
+
+  if (!self || !self->text_view) {
+    return;
+  }
+
+  win = gtk_text_view_get_window(GTK_TEXT_VIEW(self->text_view),
+                                 GTK_TEXT_WINDOW_TEXT);
+
   if (!win) {
     return;
   }
 
-  if (active) {
-    GdkDisplay *display = gdk_window_get_display(win);
-    GdkCursor *cursor = gdk_cursor_new_from_name(display, "pointer");
-    if (!cursor) {
-      cursor = gdk_cursor_new_for_display(display, GDK_HAND2);
-    }
-    gdk_window_set_cursor(win, cursor);
-    if (cursor) {
-      g_object_unref(cursor);
-    }
-  } else {
+  display = gdk_window_get_display(win);
+  cursor = gdk_cursor_new_from_name(display, over_link ? "pointer" : "text");
+  if (!cursor) {
+    cursor = gdk_cursor_new_for_display(display, over_link ? GDK_HAND2 : GDK_XTERM);
+  }
+  gdk_window_set_cursor(win, cursor);
+  if (cursor) {
+    g_object_unref(cursor);
+  }
+}
+
+static void clear_editor_mouse_cursor(MarkydEditor *self) {
+  GdkWindow *win;
+
+  if (!self || !self->text_view) {
+    return;
+  }
+
+  win = gtk_text_view_get_window(GTK_TEXT_VIEW(self->text_view),
+                                 GTK_TEXT_WINDOW_TEXT);
+  if (win) {
     gdk_window_set_cursor(win, NULL);
   }
 }
@@ -136,6 +165,11 @@ static void apply_markdown(MarkydEditor *self) {
   if (!self) {
     return;
   }
+  if (self->edit_mode) {
+    return;
+  }
+
+  render_preview(self);
 
   self->updating_tags = TRUE;
   markdown_apply_tags(self->buffer,
@@ -190,16 +224,66 @@ static gboolean resolve_image_source_path(MarkydEditor *self, const gchar *src,
 
 static gint get_image_max_width(MarkydEditor *self) {
   GtkAllocation alloc;
+  GdkRectangle visible = {0, 0, 0, 0};
+  GtkTextView *view;
   gint width;
 
   if (!self || !self->text_view) {
     return 0;
   }
 
-  gtk_widget_get_allocation(self->text_view, &alloc);
-  width = alloc.width - gtk_text_view_get_left_margin(GTK_TEXT_VIEW(self->text_view)) -
-          gtk_text_view_get_right_margin(GTK_TEXT_VIEW(self->text_view)) - 24;
-  return MAX(width, 64);
+  view = GTK_TEXT_VIEW(self->text_view);
+  gtk_text_view_get_visible_rect(view, &visible);
+  width = visible.width;
+
+  if (width <= 0) {
+    gtk_widget_get_allocation(self->text_view, &alloc);
+    width = alloc.width;
+  }
+
+  width -= gtk_text_view_get_left_margin(view);
+  width -= gtk_text_view_get_right_margin(view);
+  return MAX(width, 0);
+}
+
+static void compute_image_display_size(gint orig_width, gint orig_height,
+                                       gint requested_width,
+                                       gint requested_height, gint max_width,
+                                       gint *out_width, gint *out_height) {
+  gint width = orig_width;
+  gint height = orig_height;
+
+  if (orig_width <= 0 || orig_height <= 0) {
+    width = MAX(requested_width, 1);
+    height = MAX(requested_height, 1);
+  } else if (requested_width > 0 && requested_height > 0) {
+    width = requested_width;
+    height = requested_height;
+  } else if (requested_width > 0) {
+    width = requested_width;
+    height = (gint)(((gdouble)orig_height * (gdouble)width) /
+                    (gdouble)orig_width + 0.5);
+  } else if (requested_height > 0) {
+    height = requested_height;
+    width = (gint)(((gdouble)orig_width * (gdouble)height) /
+                   (gdouble)orig_height + 0.5);
+  }
+
+  width = MAX(width, 1);
+  height = MAX(height, 1);
+
+  if (max_width > 0 && width > max_width) {
+    height = (gint)(((gdouble)height * (gdouble)max_width) /
+                    (gdouble)width + 0.5);
+    width = max_width;
+  }
+
+  if (out_width) {
+    *out_width = MAX(width, 1);
+  }
+  if (out_height) {
+    *out_height = MAX(height, 1);
+  }
 }
 
 static void scale_image_widget(GtkWidget *widget, gint max_width) {
@@ -207,8 +291,12 @@ static void scale_image_widget(GtkWidget *widget, gint max_width) {
   GdkPixbuf *orig;
   gint ow;
   gint oh;
+  gint requested_width;
+  gint requested_height;
+  gint display_width;
+  gint display_height;
 
-  if (!widget || max_width <= 0) {
+  if (!widget) {
     return;
   }
 
@@ -224,16 +312,23 @@ static void scale_image_widget(GtkWidget *widget, gint max_width) {
     return;
   }
 
-  if (ow > max_width) {
-    gint nh = (gint)(((gdouble)oh * (gdouble)max_width) / (gdouble)ow);
-    GdkPixbuf *scaled =
-        gdk_pixbuf_scale_simple(orig, max_width, MAX(nh, 1), GDK_INTERP_BILINEAR);
-    gtk_image_set_from_pixbuf(GTK_IMAGE(image), scaled);
+  requested_width = GPOINTER_TO_INT(
+      g_object_get_data(G_OBJECT(widget), "viewmd-image-requested-width"));
+  requested_height = GPOINTER_TO_INT(
+      g_object_get_data(G_OBJECT(widget), "viewmd-image-requested-height"));
+
+  compute_image_display_size(ow, oh, requested_width, requested_height, max_width,
+                             &display_width, &display_height);
+
+  if (display_width == ow && display_height == oh) {
+    gtk_image_set_from_pixbuf(GTK_IMAGE(image), orig);
+  } else {
+    GdkPixbuf *scaled = gdk_pixbuf_scale_simple(
+        orig, display_width, display_height, GDK_INTERP_BILINEAR);
+    gtk_image_set_from_pixbuf(GTK_IMAGE(image), scaled ? scaled : orig);
     if (scaled) {
       g_object_unref(scaled);
     }
-  } else {
-    gtk_image_set_from_pixbuf(GTK_IMAGE(image), orig);
   }
 }
 
@@ -284,6 +379,10 @@ static void render_image_widgets(MarkydEditor *self) {
             g_object_get_data(G_OBJECT(anchor), VIEWMD_IMAGE_SRC_DATA);
         const gchar *alt =
             g_object_get_data(G_OBJECT(anchor), VIEWMD_IMAGE_ALT_DATA);
+        gint requested_width = GPOINTER_TO_INT(
+            g_object_get_data(G_OBJECT(anchor), VIEWMD_IMAGE_WIDTH_DATA));
+        gint requested_height = GPOINTER_TO_INT(
+            g_object_get_data(G_OBJECT(anchor), VIEWMD_IMAGE_HEIGHT_DATA));
         gchar *path = NULL;
 
         if (resolve_image_source_path(self, src, &path)) {
@@ -299,6 +398,10 @@ static void render_image_widgets(MarkydEditor *self) {
                               image);
             g_object_set_data_full(G_OBJECT(event_box), "viewmd-image-orig-pixbuf",
                                    orig, g_object_unref);
+            g_object_set_data(G_OBJECT(event_box), "viewmd-image-requested-width",
+                              GINT_TO_POINTER(requested_width));
+            g_object_set_data(G_OBJECT(event_box), "viewmd-image-requested-height",
+                              GINT_TO_POINTER(requested_height));
             scale_image_widget(event_box, max_width);
             image_widget = event_box;
           } else if (err) {
@@ -367,20 +470,274 @@ static void schedule_markdown_apply(MarkydEditor *self) {
   if (!self || self->updating_tags || self->markdown_idle_id != 0) {
     return;
   }
+  if (self->edit_mode) {
+    return;
+  }
 
   self->markdown_idle_id =
       g_idle_add_full(G_PRIORITY_LOW, apply_markdown_idle, self, NULL);
 }
 
-void markyd_editor_refresh(MarkydEditor *self) { schedule_markdown_apply(self); }
+static void sync_source_from_buffer(MarkydEditor *self) {
+  GtkTextIter start;
+  GtkTextIter end;
+  gchar *text;
+
+  if (!self || !self->buffer) {
+    return;
+  }
+
+  gtk_text_buffer_get_bounds(self->buffer, &start, &end);
+  text = gtk_text_buffer_get_text(self->buffer, &start, &end, FALSE);
+  g_free(self->source_content);
+  self->source_content = text ? text : g_strdup("");
+}
+
+static void show_source_buffer(MarkydEditor *self) {
+  if (!self || !self->buffer) {
+    return;
+  }
+
+  self->updating_tags = TRUE;
+  gtk_text_buffer_set_text(self->buffer,
+                           self->source_content ? self->source_content : "", -1);
+  self->updating_tags = FALSE;
+}
+
+static void on_buffer_changed(GtkTextBuffer *buffer, gpointer user_data) {
+  MarkydEditor *self = (MarkydEditor *)user_data;
+  (void)buffer;
+
+  if (!self || self->updating_tags || !self->edit_mode) {
+    return;
+  }
+
+  sync_source_from_buffer(self);
+}
+
+static gchar *get_preview_base_uri(MarkydEditor *self) {
+  const gchar *current_path;
+  gchar *dir;
+  GFile *dir_file;
+  gchar *uri;
+  gchar *base_uri;
+
+  current_path = self && self->app ? markyd_app_get_current_path(self->app) : NULL;
+  if (current_path && current_path[0] != '\0') {
+    dir = g_path_get_dirname(current_path);
+  } else {
+    dir = g_get_current_dir();
+  }
+
+  dir_file = g_file_new_for_path(dir);
+  uri = g_file_get_uri(dir_file);
+  base_uri = g_str_has_suffix(uri, "/") ? g_strdup(uri) : g_strconcat(uri, "/", NULL);
+
+  g_free(uri);
+  g_object_unref(dir_file);
+  g_free(dir);
+  return base_uri;
+}
+
+static void render_preview(MarkydEditor *self) {
+  gchar *base_uri;
+  gchar *html;
+
+  if (!self || !self->preview_view) {
+    return;
+  }
+
+  base_uri = get_preview_base_uri(self);
+  html = markdown_render_github_html(self->source_content ? self->source_content : "",
+                                     base_uri);
+
+  g_free(self->preview_base_uri);
+  self->preview_base_uri = g_strdup(base_uri);
+  webkit_web_view_load_html(WEBKIT_WEB_VIEW(self->preview_view), html, base_uri);
+
+  g_free(html);
+  g_free(base_uri);
+}
+
+static gboolean preview_uri_is_same_document(MarkydEditor *self,
+                                             const gchar *uri) {
+  const gchar *fragment;
+
+  if (!uri || uri[0] == '\0') {
+    return TRUE;
+  }
+  if (uri[0] == '#') {
+    return TRUE;
+  }
+  if (g_str_has_prefix(uri, "about:")) {
+    return TRUE;
+  }
+
+  fragment = strchr(uri, '#');
+  if (fragment && self && self->preview_base_uri &&
+      g_str_has_prefix(uri, self->preview_base_uri)) {
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+static gboolean path_is_markdown_file(const gchar *path) {
+  gchar *lower;
+  gboolean result;
+
+  if (!path) {
+    return FALSE;
+  }
+
+  lower = g_ascii_strdown(path, -1);
+  result = g_str_has_suffix(lower, ".md") ||
+           g_str_has_suffix(lower, ".markdown");
+  g_free(lower);
+  return result;
+}
+
+static gboolean open_local_markdown_link(MarkydEditor *self, const gchar *uri) {
+  gchar *path;
+  gchar *fragment;
+  gboolean opened = FALSE;
+
+  if (!self || !self->app || !uri || !g_str_has_prefix(uri, "file://")) {
+    return FALSE;
+  }
+
+  path = g_filename_from_uri(uri, NULL, NULL);
+  if (!path) {
+    return FALSE;
+  }
+
+  fragment = strchr(path, '#');
+  if (fragment) {
+    *fragment = '\0';
+  }
+
+  if (path_is_markdown_file(path) && g_file_test(path, G_FILE_TEST_EXISTS)) {
+    opened = markyd_app_open_file(self->app, path);
+  }
+
+  g_free(path);
+  return opened;
+}
+
+static void open_preview_uri_externally(GtkWidget *widget, const gchar *uri) {
+  GtkWidget *toplevel;
+  GError *error = NULL;
+
+  if (!uri || uri[0] == '\0') {
+    return;
+  }
+
+  toplevel = gtk_widget_get_toplevel(widget);
+  if (!gtk_show_uri_on_window(GTK_IS_WINDOW(toplevel) ? GTK_WINDOW(toplevel)
+                                                      : NULL,
+                              uri, GDK_CURRENT_TIME, &error)) {
+    if (error) {
+      g_printerr("Failed to open link '%s': %s\n", uri, error->message);
+      g_clear_error(&error);
+    }
+  }
+}
+
+static gboolean on_preview_decide_policy(WebKitWebView *web_view,
+                                         WebKitPolicyDecision *decision,
+                                         WebKitPolicyDecisionType type,
+                                         gpointer user_data) {
+  MarkydEditor *self = (MarkydEditor *)user_data;
+  WebKitNavigationPolicyDecision *navigation_decision;
+  WebKitNavigationAction *action;
+  WebKitURIRequest *request;
+  const gchar *uri;
+
+  if (type != WEBKIT_POLICY_DECISION_TYPE_NAVIGATION_ACTION) {
+    return FALSE;
+  }
+
+  navigation_decision = WEBKIT_NAVIGATION_POLICY_DECISION(decision);
+  action = webkit_navigation_policy_decision_get_navigation_action(
+      navigation_decision);
+  if (!action ||
+      webkit_navigation_action_get_navigation_type(action) !=
+          WEBKIT_NAVIGATION_TYPE_LINK_CLICKED) {
+    return FALSE;
+  }
+
+  request = webkit_navigation_action_get_request(action);
+  uri = request ? webkit_uri_request_get_uri(request) : NULL;
+  if (preview_uri_is_same_document(self, uri)) {
+    return FALSE;
+  }
+
+  if (open_local_markdown_link(self, uri)) {
+    webkit_policy_decision_ignore(decision);
+    return TRUE;
+  }
+
+  open_preview_uri_externally(GTK_WIDGET(web_view), uri);
+  webkit_policy_decision_ignore(decision);
+  return TRUE;
+}
+
+void markyd_editor_refresh(MarkydEditor *self) {
+  if (!self) {
+    return;
+  }
+  if (self->edit_mode) {
+    return;
+  }
+  schedule_markdown_apply(self);
+}
+
+void markyd_editor_set_edit_mode(MarkydEditor *self, gboolean edit_mode) {
+  if (!self || self->edit_mode == edit_mode) {
+    return;
+  }
+
+  if (edit_mode) {
+    if (self->markdown_idle_id != 0) {
+      g_source_remove(self->markdown_idle_id);
+      self->markdown_idle_id = 0;
+    }
+    self->edit_mode = TRUE;
+    show_source_buffer(self);
+    gtk_text_view_set_editable(GTK_TEXT_VIEW(self->text_view), TRUE);
+    gtk_text_view_set_cursor_visible(GTK_TEXT_VIEW(self->text_view), TRUE);
+    gtk_stack_set_visible_child_name(GTK_STACK(self->widget), "source");
+    gtk_widget_grab_focus(self->text_view);
+  } else {
+    sync_source_from_buffer(self);
+    self->edit_mode = FALSE;
+    gtk_text_view_set_editable(GTK_TEXT_VIEW(self->text_view), FALSE);
+    gtk_text_view_set_cursor_visible(GTK_TEXT_VIEW(self->text_view), FALSE);
+    gtk_stack_set_visible_child_name(GTK_STACK(self->widget), "preview");
+    schedule_markdown_apply(self);
+  }
+}
+
+gboolean markyd_editor_get_edit_mode(MarkydEditor *self) {
+  return self ? self->edit_mode : FALSE;
+}
 
 MarkydEditor *markyd_editor_new(MarkydApp *app) {
   MarkydEditor *self = g_new0(MarkydEditor, 1);
+  WebKitSettings *settings;
 
   self->app = app;
   self->source_content = g_strdup("");
   self->updating_tags = FALSE;
   self->markdown_idle_id = 0;
+  self->edit_mode = FALSE;
+  self->preview_base_uri = NULL;
+
+  self->widget = gtk_stack_new();
+  gtk_stack_set_transition_type(GTK_STACK(self->widget),
+                                GTK_STACK_TRANSITION_TYPE_NONE);
+  gtk_widget_set_hexpand(self->widget, TRUE);
+  gtk_widget_set_vexpand(self->widget, TRUE);
 
   self->text_view = gtk_text_view_new();
   gtk_text_view_set_wrap_mode(GTK_TEXT_VIEW(self->text_view),
@@ -392,8 +749,28 @@ MarkydEditor *markyd_editor_new(MarkydApp *app) {
   gtk_text_view_set_editable(GTK_TEXT_VIEW(self->text_view), FALSE);
   gtk_text_view_set_cursor_visible(GTK_TEXT_VIEW(self->text_view), FALSE);
 
+  self->source_scroll = gtk_scrolled_window_new(NULL, NULL);
+  gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(self->source_scroll),
+                                 GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
+  gtk_container_add(GTK_CONTAINER(self->source_scroll), self->text_view);
+
+  self->preview_view = webkit_web_view_new();
+  gtk_widget_set_hexpand(self->preview_view, TRUE);
+  gtk_widget_set_vexpand(self->preview_view, TRUE);
+  settings = webkit_web_view_get_settings(WEBKIT_WEB_VIEW(self->preview_view));
+  webkit_settings_set_enable_javascript(settings, TRUE);
+  webkit_settings_set_enable_javascript_markup(settings, FALSE);
+  webkit_settings_set_auto_load_images(settings, TRUE);
+  g_signal_connect(self->preview_view, "decide-policy",
+                   G_CALLBACK(on_preview_decide_policy), self);
+
+  gtk_stack_add_named(GTK_STACK(self->widget), self->preview_view, "preview");
+  gtk_stack_add_named(GTK_STACK(self->widget), self->source_scroll, "source");
+  gtk_stack_set_visible_child_name(GTK_STACK(self->widget), "preview");
+
   self->buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(self->text_view));
   markdown_init_tags(self->buffer);
+  g_signal_connect(self->buffer, "changed", G_CALLBACK(on_buffer_changed), self);
 
   gtk_widget_add_events(self->text_view, GDK_POINTER_MOTION_MASK |
                                             GDK_LEAVE_NOTIFY_MASK |
@@ -427,6 +804,7 @@ void markyd_editor_free(MarkydEditor *self) {
     self->markdown_idle_id = 0;
   }
   g_free(self->source_content);
+  g_free(self->preview_base_uri);
   g_free(self);
 }
 
@@ -437,24 +815,42 @@ void markyd_editor_set_content(MarkydEditor *self, const gchar *content) {
 
   g_free(self->source_content);
   self->source_content = g_strdup(content ? content : "");
-  schedule_markdown_apply(self);
+  if (self->edit_mode) {
+    show_source_buffer(self);
+  } else {
+    schedule_markdown_apply(self);
+  }
 }
 
 gchar *markyd_editor_get_content(MarkydEditor *self) {
   if (!self) {
     return g_strdup("");
   }
+  if (self->edit_mode) {
+    sync_source_from_buffer(self);
+  }
   return g_strdup(self->source_content ? self->source_content : "");
 }
 
 GtkWidget *markyd_editor_get_widget(MarkydEditor *self) {
-  return self->text_view;
+  return self ? self->widget : NULL;
 }
 
 void markyd_editor_focus(MarkydEditor *self) {
   GtkTextMark *insert_mark;
 
-  if (!self || !self->text_view || !self->buffer) {
+  if (!self) {
+    return;
+  }
+
+  if (!self->edit_mode) {
+    if (self->preview_view) {
+      gtk_widget_grab_focus(self->preview_view);
+    }
+    return;
+  }
+
+  if (!self->text_view || !self->buffer) {
     return;
   }
 
@@ -466,6 +862,74 @@ void markyd_editor_focus(MarkydEditor *self) {
   }
 }
 
+void markyd_editor_scroll_top(MarkydEditor *self) {
+  GtkTextIter start;
+
+  if (!self) {
+    return;
+  }
+
+  if (!self->edit_mode && self->preview_view) {
+    webkit_web_view_evaluate_javascript(WEBKIT_WEB_VIEW(self->preview_view),
+                                        "window.scrollTo(0, 0);", -1, NULL,
+                                        NULL, NULL, NULL, NULL);
+    return;
+  }
+
+  if (!self->buffer || !self->text_view) {
+    return;
+  }
+
+  gtk_text_buffer_get_start_iter(self->buffer, &start);
+  gtk_text_buffer_place_cursor(self->buffer, &start);
+  gtk_text_view_scroll_to_iter(GTK_TEXT_VIEW(self->text_view), &start, 0.0,
+                               FALSE, 0.0, 0.0);
+}
+
+void markyd_editor_find(MarkydEditor *self, const gchar *query) {
+  WebKitFindController *controller;
+
+  if (!self || self->edit_mode || !self->preview_view || !query ||
+      query[0] == '\0') {
+    return;
+  }
+
+  controller = webkit_web_view_get_find_controller(
+      WEBKIT_WEB_VIEW(self->preview_view));
+  webkit_find_controller_search(controller, query,
+                                WEBKIT_FIND_OPTIONS_CASE_INSENSITIVE |
+                                    WEBKIT_FIND_OPTIONS_WRAP_AROUND,
+                                G_MAXUINT);
+}
+
+void markyd_editor_find_next(MarkydEditor *self, gboolean previous) {
+  WebKitFindController *controller;
+
+  if (!self || self->edit_mode || !self->preview_view) {
+    return;
+  }
+
+  controller = webkit_web_view_get_find_controller(
+      WEBKIT_WEB_VIEW(self->preview_view));
+  if (previous) {
+    webkit_find_controller_search_previous(controller);
+  } else {
+    webkit_find_controller_search_next(controller);
+  }
+}
+
+void markyd_editor_find_clear(MarkydEditor *self) {
+  WebKitFindController *controller;
+
+  if (!self || !self->preview_view) {
+    return;
+  }
+
+  controller = webkit_web_view_get_find_controller(
+      WEBKIT_WEB_VIEW(self->preview_view));
+  webkit_find_controller_search_finish(controller);
+}
+
 static gboolean on_button_release(GtkWidget *widget, GdkEventButton *event,
                                   gpointer user_data) {
   MarkydEditor *self = (MarkydEditor *)user_data;
@@ -533,7 +997,7 @@ static gboolean on_motion_notify(GtkWidget *widget, GdkEventMotion *event,
                                         (gint)event->y, &bx, &by);
   gtk_text_view_get_iter_at_location(GTK_TEXT_VIEW(widget), &iter, bx, by);
 
-  set_link_cursor(self, get_link_url_at_iter(self->buffer, &iter, &url));
+  set_editor_mouse_cursor(self, get_link_url_at_iter(self->buffer, &iter, &url));
   g_free(url);
   return FALSE;
 }
@@ -543,6 +1007,6 @@ static gboolean on_leave_notify(GtkWidget *widget, GdkEventCrossing *event,
   MarkydEditor *self = (MarkydEditor *)user_data;
   (void)widget;
   (void)event;
-  set_link_cursor(self, FALSE);
+  clear_editor_mouse_cursor(self);
   return FALSE;
 }

src/editor.h

@@ -6,7 +6,10 @@
 typedef struct _MarkydApp MarkydApp;
 
 typedef struct _MarkydEditor {
+  GtkWidget *widget;
+  GtkWidget *source_scroll;
   GtkWidget *text_view;
+  GtkWidget *preview_view;
   GtkTextBuffer *buffer;
   MarkydApp *app;
 
@@ -18,6 +21,11 @@ typedef struct _MarkydEditor {
 
   /* Coalesce markdown re-rendering to idle to avoid invalidating GTK iterators. */
   guint markdown_idle_id;
+
+  /* TRUE when the buffer is showing editable markdown source instead of preview. */
+  gboolean edit_mode;
+
+  gchar *preview_base_uri;
 } MarkydEditor;
 
 /* Lifecycle */
@@ -28,9 +36,19 @@ void markyd_editor_free(MarkydEditor *editor);
 void markyd_editor_set_content(MarkydEditor *editor, const gchar *content);
 gchar *markyd_editor_get_content(MarkydEditor *editor);
 
+/* Source editing mode */
+void markyd_editor_set_edit_mode(MarkydEditor *editor, gboolean edit_mode);
+gboolean markyd_editor_get_edit_mode(MarkydEditor *editor);
+
 /* Widget access */
 GtkWidget *markyd_editor_get_widget(MarkydEditor *editor);
 void markyd_editor_focus(MarkydEditor *editor);
+void markyd_editor_scroll_top(MarkydEditor *editor);
+
+/* Preview search */
+void markyd_editor_find(MarkydEditor *editor, const gchar *query);
+void markyd_editor_find_next(MarkydEditor *editor, gboolean previous);
+void markyd_editor_find_clear(MarkydEditor *editor);
 
 /* Force a refresh of markdown styling/rendering (e.g., after settings change). */
 void markyd_editor_refresh(MarkydEditor *editor);

src/markdown.h

@@ -36,6 +36,8 @@ void markdown_update_accent_tags(GtkTextBuffer *buffer);
 #define VIEWMD_IMAGE_SRC_DATA "viewmd-image-src"
 #define VIEWMD_IMAGE_ALT_DATA "viewmd-image-alt"
 #define VIEWMD_IMAGE_WIDGET_DATA "viewmd-image-widget"
+#define VIEWMD_IMAGE_WIDTH_DATA "viewmd-image-width"
+#define VIEWMD_IMAGE_HEIGHT_DATA "viewmd-image-height"
 
 typedef struct {
   gint row;
@@ -59,6 +61,9 @@ gchar *markdown_anchor_mark_name(const gchar *fragment);
 /* Render markdown source into the buffer and apply markdown styling. */
 void markdown_apply_tags(GtkTextBuffer *buffer, const gchar *source);
 
+/* Render markdown source to a complete GitHub-style HTML document. */
+gchar *markdown_render_github_html(const gchar *source, const gchar *base_uri);
+
 /* Build a GTK widget for a table anchor, or NULL if not a table anchor. */
 GtkWidget *markdown_create_table_widget(GtkTextChildAnchor *anchor);
 

src/window.c

@@ -14,10 +14,14 @@ typedef struct {
 
 #define TAG_SEARCH_MATCH "viewmd_search_match"
 #define TAG_SEARCH_CURRENT "viewmd_search_current"
+#define TOOLBAR_LABEL_DATA "viewmd-toolbar-label"
 
 static void on_open_clicked(GtkButton *button, gpointer user_data);
 static void on_refresh_clicked(GtkButton *button, gpointer user_data);
+static void on_edit_clicked(GtkButton *button, gpointer user_data);
+static void on_save_clicked(GtkButton *button, gpointer user_data);
 static void on_settings_clicked(GtkButton *button, gpointer user_data);
+static void on_about_clicked(GtkButton *button, gpointer user_data);
 static void on_search_changed(GtkEditable *editable, gpointer user_data);
 static void on_search_prev_clicked(GtkButton *button, gpointer user_data);
 static void on_search_next_clicked(GtkButton *button, gpointer user_data);
@@ -62,6 +66,13 @@ static gchar *rgba_to_hex(const GdkRGBA *rgba);
 static void init_color_button(GtkColorButton *btn, const gchar *color_str);
 static void on_color_set(GtkColorButton *btn, gpointer user_data);
 static GtkWidget *create_settings_dialog(MarkydApp *app);
+static gboolean prompt_save_as(MarkydWindow *self);
+static void update_edit_button_state(MarkydWindow *self);
+static void set_edit_mode(MarkydWindow *self, gboolean edit_mode);
+static GtkWidget *create_toolbar_button(const gchar *icon_name, const gchar *label,
+                                        const gchar *tooltip);
+static void set_toolbar_button_label(GtkWidget *button, const gchar *label);
+static void restore_editor_focus(MarkydWindow *self);
 
 static gboolean geometry_debug_enabled(void) {
   const gchar *v = g_getenv("VIEWMD_DEBUG_GEOMETRY");
@@ -128,6 +139,8 @@ static void clear_search_matches(MarkydWindow *self) {
     return;
   }
 
+  markyd_editor_find_clear(self->editor);
+
   gtk_text_buffer_get_bounds(self->editor->buffer, &start, &end);
   gtk_text_buffer_remove_tag_by_name(self->editor->buffer, TAG_SEARCH_MATCH,
                                      &start, &end);
@@ -480,6 +493,14 @@ static void update_search_matches(MarkydWindow *self) {
     return;
   }
 
+  if (!markyd_editor_get_edit_mode(self->editor)) {
+    markyd_editor_find(self->editor, query);
+    gtk_widget_set_sensitive(self->btn_search_prev, TRUE);
+    gtk_widget_set_sensitive(self->btn_search_next, TRUE);
+    gtk_label_set_text(GTK_LABEL(self->lbl_search_status), "Preview search");
+    return;
+  }
+
   ensure_search_tags(self);
   gtk_text_buffer_get_start_iter(self->editor->buffer, &iter);
   gtk_text_buffer_get_end_iter(self->editor->buffer, &end);
@@ -548,6 +569,11 @@ static void on_search_prev_clicked(GtkButton *button, gpointer user_data) {
   (void)button;
 
   if (!self || !self->search_matches || self->search_matches->len == 0) {
+    if (self && self->editor && !markyd_editor_get_edit_mode(self->editor) &&
+        self->search_entry &&
+        gtk_entry_get_text_length(GTK_ENTRY(self->search_entry)) > 0) {
+      markyd_editor_find_next(self->editor, TRUE);
+    }
     return;
   }
 
@@ -565,6 +591,11 @@ static void on_search_next_clicked(GtkButton *button, gpointer user_data) {
   (void)button;
 
   if (!self || !self->search_matches || self->search_matches->len == 0) {
+    if (self && self->editor && !markyd_editor_get_edit_mode(self->editor) &&
+        self->search_entry &&
+        gtk_entry_get_text_length(GTK_ENTRY(self->search_entry)) > 0) {
+      markyd_editor_find_next(self->editor, FALSE);
+    }
     return;
   }
 
@@ -624,9 +655,108 @@ static void on_editor_buffer_changed(GtkTextBuffer *buffer, gpointer user_data)
   update_search_matches(self);
 }
 
+static GtkWidget *create_toolbar_button_internal(const gchar *icon_name,
+                                                 const gchar *label,
+                                                 const gchar *tooltip,
+                                                 gboolean toggle) {
+  GtkWidget *button;
+  GtkWidget *box;
+  GtkWidget *image;
+  GtkWidget *label_widget;
+
+  button = toggle ? gtk_toggle_button_new() : gtk_button_new();
+  box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 4);
+  image = gtk_image_new_from_icon_name(icon_name, GTK_ICON_SIZE_BUTTON);
+  label_widget = gtk_label_new(label);
+
+  gtk_widget_set_halign(box, GTK_ALIGN_CENTER);
+  gtk_widget_set_valign(box, GTK_ALIGN_CENTER);
+  gtk_box_pack_start(GTK_BOX(box), image, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(box), label_widget, FALSE, FALSE, 0);
+  gtk_container_add(GTK_CONTAINER(button), box);
+  gtk_widget_set_focus_on_click(button, FALSE);
+
+  if (tooltip) {
+    gtk_widget_set_tooltip_text(button, tooltip);
+  }
+  g_object_set_data(G_OBJECT(button), TOOLBAR_LABEL_DATA, label_widget);
+  return button;
+}
+
+static GtkWidget *create_toolbar_button(const gchar *icon_name, const gchar *label,
+                                        const gchar *tooltip) {
+  return create_toolbar_button_internal(icon_name, label, tooltip, FALSE);
+}
+
+static void set_toolbar_button_label(GtkWidget *button, const gchar *label) {
+  GtkWidget *label_widget;
+
+  if (!button || !label) {
+    return;
+  }
+
+  label_widget = g_object_get_data(G_OBJECT(button), TOOLBAR_LABEL_DATA);
+  if (GTK_IS_LABEL(label_widget)) {
+    gtk_label_set_text(GTK_LABEL(label_widget), label);
+  }
+}
+
+static void restore_editor_focus(MarkydWindow *self) {
+  if (self && self->editor) {
+    markyd_editor_focus(self->editor);
+  }
+}
+
+static void on_about_popover_closed(GtkPopover *popover, gpointer user_data) {
+  MarkydWindow *self = (MarkydWindow *)user_data;
+
+  restore_editor_focus(self);
+  gtk_widget_destroy(GTK_WIDGET(popover));
+}
+
+static void on_about_clicked(GtkButton *button, gpointer user_data) {
+  MarkydWindow *self = (MarkydWindow *)user_data;
+  GtkWidget *popover;
+  GtkWidget *box;
+  GtkWidget *title;
+  GtkWidget *summary;
+  GtkWidget *details;
+
+  popover = gtk_popover_new(GTK_WIDGET(button));
+  gtk_popover_set_position(GTK_POPOVER(popover), GTK_POS_BOTTOM);
+  gtk_container_set_border_width(GTK_CONTAINER(popover), 12);
+  g_signal_connect(popover, "closed", G_CALLBACK(on_about_popover_closed), self);
+
+  box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 8);
+  gtk_widget_set_size_request(box, 300, -1);
+  gtk_container_add(GTK_CONTAINER(popover), box);
+
+  title = gtk_label_new(NULL);
+  gtk_label_set_markup(GTK_LABEL(title), "<b>ViewMD</b>");
+  gtk_label_set_xalign(GTK_LABEL(title), 0.0f);
+  gtk_box_pack_start(GTK_BOX(box), title, FALSE, FALSE, 0);
+
+  summary = gtk_label_new("A lightweight GTK markdown viewer and editor.");
+  gtk_label_set_xalign(GTK_LABEL(summary), 0.0f);
+  gtk_label_set_line_wrap(GTK_LABEL(summary), TRUE);
+  gtk_box_pack_start(GTK_BOX(box), summary, FALSE, FALSE, 0);
+
+  details = gtk_label_new(
+      "This is a fork of ViewMD by NotAlexNoyle, with additional features, "
+      "including GitHub-style preview rendering, HTML-in-Markdown support, "
+      "editing, saving, toolbar labels, and improved image sizing.");
+  gtk_label_set_xalign(GTK_LABEL(details), 0.0f);
+  gtk_label_set_line_wrap(GTK_LABEL(details), TRUE);
+  gtk_label_set_max_width_chars(GTK_LABEL(details), 42);
+  gtk_box_pack_start(GTK_BOX(box), details, FALSE, FALSE, 0);
+
+  gtk_widget_show_all(popover);
+  gtk_popover_popup(GTK_POPOVER(popover));
+}
+
 MarkydWindow *markyd_window_new(MarkydApp *app) {
   MarkydWindow *self = g_new0(MarkydWindow, 1);
-  GtkWidget *left_buttons;
+  GtkWidget *toolbar_buttons;
   GtkWidget *main_box;
   GtkWidget *search_box;
 
@@ -664,33 +794,52 @@ MarkydWindow *markyd_window_new(MarkydApp *app) {
   gtk_header_bar_set_show_close_button(GTK_HEADER_BAR(self->header_bar), TRUE);
   gtk_window_set_titlebar(GTK_WINDOW(self->window), self->header_bar);
 
-  self->lbl_title = gtk_label_new("ViewMD");
-  gtk_widget_set_halign(self->lbl_title, GTK_ALIGN_CENTER);
-  gtk_header_bar_set_custom_title(GTK_HEADER_BAR(self->header_bar),
-                                  self->lbl_title);
+  self->lbl_title = gtk_button_new_with_label("ViewMD");
+  gtk_button_set_relief(GTK_BUTTON(self->lbl_title), GTK_RELIEF_NONE);
+  gtk_widget_set_focus_on_click(self->lbl_title, FALSE);
+  gtk_widget_set_tooltip_text(self->lbl_title, "About ViewMD");
+  gtk_widget_set_halign(self->lbl_title, GTK_ALIGN_END);
+  gtk_widget_set_margin_start(self->lbl_title, 12);
+  gtk_widget_set_margin_end(self->lbl_title, 12);
+  g_signal_connect(self->lbl_title, "clicked", G_CALLBACK(on_about_clicked),
+                   self);
 
   self->btn_open =
-      gtk_button_new_from_icon_name("document-open-symbolic", GTK_ICON_SIZE_BUTTON);
-  gtk_widget_set_tooltip_text(self->btn_open, "Open Markdown Document");
+      create_toolbar_button("document-open-symbolic", "Open",
+                            "Open Markdown Document");
   g_signal_connect(self->btn_open, "clicked", G_CALLBACK(on_open_clicked), self);
 
   self->btn_refresh =
-      gtk_button_new_from_icon_name("view-refresh-symbolic", GTK_ICON_SIZE_BUTTON);
-  gtk_widget_set_tooltip_text(self->btn_refresh, "Reload Current Document");
+      create_toolbar_button("view-refresh-symbolic", "Reload",
+                            "Reload Current Document");
   g_signal_connect(self->btn_refresh, "clicked", G_CALLBACK(on_refresh_clicked),
                    self);
 
+  self->btn_edit =
+      create_toolbar_button("accessories-text-editor-symbolic", "Edit",
+                            "Edit Markdown Source");
+  g_signal_connect(self->btn_edit, "clicked", G_CALLBACK(on_edit_clicked), self);
+
+  self->btn_save =
+      create_toolbar_button("document-save-symbolic", "Save",
+                            "Save Markdown Document");
+  g_signal_connect(self->btn_save, "clicked", G_CALLBACK(on_save_clicked), self);
+
   self->btn_settings =
-      gtk_button_new_from_icon_name("emblem-system-symbolic", GTK_ICON_SIZE_BUTTON);
-  gtk_widget_set_tooltip_text(self->btn_settings, "Settings");
+      create_toolbar_button("emblem-system-symbolic", "Settings", "Settings");
   g_signal_connect(self->btn_settings, "clicked", G_CALLBACK(on_settings_clicked),
                    self);
 
-  left_buttons = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
-  gtk_box_pack_start(GTK_BOX(left_buttons), self->btn_open, FALSE, FALSE, 0);
-  gtk_box_pack_start(GTK_BOX(left_buttons), self->btn_refresh, FALSE, FALSE, 0);
-  gtk_box_pack_start(GTK_BOX(left_buttons), self->btn_settings, FALSE, FALSE, 0);
-  gtk_header_bar_pack_start(GTK_HEADER_BAR(self->header_bar), left_buttons);
+  toolbar_buttons = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
+  gtk_widget_set_halign(toolbar_buttons, GTK_ALIGN_CENTER);
+  gtk_box_pack_start(GTK_BOX(toolbar_buttons), self->btn_open, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(toolbar_buttons), self->btn_refresh, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(toolbar_buttons), self->btn_edit, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(toolbar_buttons), self->btn_save, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(toolbar_buttons), self->btn_settings, FALSE, FALSE, 0);
+  gtk_header_bar_set_custom_title(GTK_HEADER_BAR(self->header_bar),
+                                  toolbar_buttons);
+  gtk_header_bar_pack_end(GTK_HEADER_BAR(self->header_bar), self->lbl_title);
 
   main_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
   gtk_container_add(GTK_CONTAINER(self->window), main_box);
@@ -737,14 +886,10 @@ MarkydWindow *markyd_window_new(MarkydApp *app) {
   gtk_widget_set_halign(self->lbl_search_status, GTK_ALIGN_END);
   gtk_box_pack_start(GTK_BOX(search_box), self->lbl_search_status, FALSE, FALSE, 0);
 
-  self->scroll = gtk_scrolled_window_new(NULL, NULL);
-  gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(self->scroll),
-                                 GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
-  gtk_box_pack_start(GTK_BOX(main_box), self->scroll, TRUE, TRUE, 0);
-
   self->editor = markyd_editor_new(app);
-  gtk_container_add(GTK_CONTAINER(self->scroll),
-                    markyd_editor_get_widget(self->editor));
+  self->scroll = self->editor->source_scroll;
+  gtk_box_pack_start(GTK_BOX(main_box), markyd_editor_get_widget(self->editor),
+                     TRUE, TRUE, 0);
   self->search_matches = g_array_new(FALSE, FALSE, sizeof(SearchMatch));
   self->search_current_index = -1;
   g_signal_connect(self->editor->buffer, "changed",
@@ -918,6 +1063,94 @@ gboolean markyd_window_is_visible(MarkydWindow *self) {
   return gtk_widget_get_visible(self->window);
 }
 
+static void update_edit_button_state(MarkydWindow *self) {
+  gboolean editing;
+
+  if (!self || !self->editor || !self->btn_edit) {
+    return;
+  }
+
+  editing = markyd_editor_get_edit_mode(self->editor);
+  set_toolbar_button_label(self->btn_edit, editing ? "Preview" : "Edit");
+  gtk_widget_set_tooltip_text(self->btn_edit,
+                              editing ? "Preview Markdown" : "Edit Markdown Source");
+}
+
+static void set_edit_mode(MarkydWindow *self, gboolean edit_mode) {
+  if (!self || !self->editor) {
+    return;
+  }
+
+  markyd_editor_set_edit_mode(self->editor, edit_mode);
+  update_edit_button_state(self);
+  markyd_editor_focus(self->editor);
+  if (self->search_revealer &&
+      gtk_revealer_get_reveal_child(GTK_REVEALER(self->search_revealer)) &&
+      self->search_entry &&
+      gtk_entry_get_text_length(GTK_ENTRY(self->search_entry)) > 0) {
+    update_search_matches(self);
+  }
+}
+
+static gboolean prompt_save_as(MarkydWindow *self) {
+  GtkWidget *dialog;
+  GtkFileFilter *md_filter;
+  gint response;
+  gboolean saved = FALSE;
+
+  if (!self || !self->window) {
+    return FALSE;
+  }
+
+  dialog = gtk_file_chooser_dialog_new(
+      "Save Markdown Document", GTK_WINDOW(self->window),
+      GTK_FILE_CHOOSER_ACTION_SAVE, "_Cancel", GTK_RESPONSE_CANCEL, "_Save",
+      GTK_RESPONSE_ACCEPT, NULL);
+  gtk_file_chooser_set_do_overwrite_confirmation(GTK_FILE_CHOOSER(dialog), TRUE);
+
+  md_filter = gtk_file_filter_new();
+  gtk_file_filter_set_name(md_filter, "Markdown files (*.md, *.markdown)");
+  gtk_file_filter_add_pattern(md_filter, "*.md");
+  gtk_file_filter_add_pattern(md_filter, "*.markdown");
+  gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(dialog), md_filter);
+
+  md_filter = gtk_file_filter_new();
+  gtk_file_filter_set_name(md_filter, "All files");
+  gtk_file_filter_add_pattern(md_filter, "*");
+  gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(dialog), md_filter);
+
+  {
+    const gchar *current = markyd_app_get_current_path(self->app);
+    if (current && current[0] != '\0') {
+      gtk_file_chooser_set_filename(GTK_FILE_CHOOSER(dialog), current);
+    } else {
+      gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(dialog), "untitled.md");
+    }
+  }
+
+  response = gtk_dialog_run(GTK_DIALOG(dialog));
+  if (response == GTK_RESPONSE_ACCEPT) {
+    gchar *path = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(dialog));
+    if (path) {
+      saved = markyd_app_save_file(self->app, path);
+      if (!saved) {
+        GtkWidget *error_dialog = gtk_message_dialog_new(
+            GTK_WINDOW(self->window),
+            GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_ERROR,
+            GTK_BUTTONS_CLOSE, "Failed to save document");
+        gtk_message_dialog_format_secondary_text(
+            GTK_MESSAGE_DIALOG(error_dialog), "%s", path);
+        gtk_dialog_run(GTK_DIALOG(error_dialog));
+        gtk_widget_destroy(error_dialog);
+      }
+      g_free(path);
+    }
+  }
+
+  gtk_widget_destroy(dialog);
+  return saved;
+}
+
 static void on_open_clicked(GtkButton *button, gpointer user_data) {
   MarkydWindow *self = (MarkydWindow *)user_data;
   GtkWidget *dialog;
@@ -961,6 +1194,7 @@ static void on_open_clicked(GtkButton *button, gpointer user_data) {
   }
 
   gtk_widget_destroy(dialog);
+  restore_editor_focus(self);
 }
 
 static void on_refresh_clicked(GtkButton *button, gpointer user_data) {
@@ -972,6 +1206,7 @@ static void on_refresh_clicked(GtkButton *button, gpointer user_data) {
 
   current = markyd_app_get_current_path(self->app);
   if (!current || current[0] == '\0') {
+    restore_editor_focus(self);
     return;
   }
 
@@ -987,6 +1222,45 @@ static void on_refresh_clicked(GtkButton *button, gpointer user_data) {
     gtk_widget_destroy(error_dialog);
   }
   g_free(path);
+  restore_editor_focus(self);
+}
+
+static void on_edit_clicked(GtkButton *button, gpointer user_data) {
+  MarkydWindow *self = (MarkydWindow *)user_data;
+  (void)button;
+  if (!self || !self->editor) {
+    return;
+  }
+  set_edit_mode(self, !markyd_editor_get_edit_mode(self->editor));
+}
+
+static void on_save_clicked(GtkButton *button, gpointer user_data) {
+  MarkydWindow *self = (MarkydWindow *)user_data;
+  const gchar *current;
+
+  (void)button;
+
+  if (!self || !self->app) {
+    return;
+  }
+
+  current = markyd_app_get_current_path(self->app);
+  if (!current || current[0] == '\0') {
+    prompt_save_as(self);
+    restore_editor_focus(self);
+    return;
+  }
+
+  if (!markyd_app_save_current_file(self->app)) {
+    GtkWidget *error_dialog = gtk_message_dialog_new(
+        GTK_WINDOW(self->window), GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT,
+        GTK_MESSAGE_ERROR, GTK_BUTTONS_CLOSE, "Failed to save document");
+    gtk_message_dialog_format_secondary_text(GTK_MESSAGE_DIALOG(error_dialog),
+                                             "%s", current);
+    gtk_dialog_run(GTK_DIALOG(error_dialog));
+    gtk_widget_destroy(error_dialog);
+  }
+  restore_editor_focus(self);
 }
 
 static void on_settings_clicked(GtkButton *button, gpointer user_data) {
@@ -1007,6 +1281,7 @@ static void on_settings_clicked(GtkButton *button, gpointer user_data) {
   }
 
   gtk_widget_destroy(dialog);
+  restore_editor_focus(self);
 }
 
 static gboolean on_key_press_event(GtkWidget *widget, GdkEventKey *event,
@@ -1023,6 +1298,18 @@ static gboolean on_key_press_event(GtkWidget *widget, GdkEventKey *event,
     return TRUE;
   }
 
+  if ((event->state & GDK_CONTROL_MASK) != 0 &&
+      (event->keyval == GDK_KEY_e || event->keyval == GDK_KEY_E)) {
+    set_edit_mode(self, !markyd_editor_get_edit_mode(self->editor));
+    return TRUE;
+  }
+
+  if ((event->state & GDK_CONTROL_MASK) != 0 &&
+      (event->keyval == GDK_KEY_s || event->keyval == GDK_KEY_S)) {
+    on_save_clicked(NULL, self);
+    return TRUE;
+  }
+
   if (event->keyval == GDK_KEY_Escape &&
       self->search_revealer &&
       gtk_revealer_get_reveal_child(GTK_REVEALER(self->search_revealer))) {
@@ -1030,12 +1317,23 @@ static gboolean on_key_press_event(GtkWidget *widget, GdkEventKey *event,
     return TRUE;
   }
 
+  if (event->keyval == GDK_KEY_Escape && self->editor &&
+      markyd_editor_get_edit_mode(self->editor)) {
+    set_edit_mode(self, FALSE);
+    return TRUE;
+  }
+
   if (event->keyval == GDK_KEY_Escape) {
     gtk_window_close(GTK_WINDOW(widget));
     return TRUE;
   }
 
   if (event->keyval == GDK_KEY_Home || event->keyval == GDK_KEY_KP_Home) {
+    if (self->editor && !markyd_editor_get_edit_mode(self->editor)) {
+      markyd_editor_scroll_top(self->editor);
+      return TRUE;
+    }
+
     if (self->editor && self->editor->buffer && self->editor->text_view) {
       GtkTextIter start;
       GtkAdjustment *hadj = NULL;

src/window.h

@@ -11,6 +11,8 @@ typedef struct _MarkydWindow {
   GtkWidget *header_bar;
   GtkWidget *btn_open;
   GtkWidget *btn_refresh;
+  GtkWidget *btn_edit;
+  GtkWidget *btn_save;
   GtkWidget *btn_settings;
   GtkWidget *search_revealer;
   GtkWidget *search_entry;