ImageViewer: Enable and disable navigation

Before there was dialogs to indicate if
current file is last or first.

So in this commit, I added functionality to enable
and disable forward and backward navigation based
on if the next file is avialable or not and if the
pervious file is avialable or not, respectively.

ImageViewer: Refactor code and init data

Data intialization was not happening properly, now I did
Initializations properly so that navigation can work from
the very first image.

Userland/Applications/ImageViewer/ViewWidget.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2021, Mohsan Ali <mohsan0073@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -60,42 +61,52 @@ void ViewWidget::rotate(Gfx::RotationDirection rotation_direction)
     resize_window();
 }
 
-void ViewWidget::navigate(Directions direction)
+bool ViewWidget::is_next_available() const
 {
-    if (m_path == nullptr)
-        return;
+    if (m_current_index.has_value())
+        return m_current_index.value() + 1 < m_files_in_same_dir.size();
+    return false;
+}
 
-    auto current_dir = LexicalPath(m_path).parent().string();
+bool ViewWidget::is_previous_available() const
+{
+    if (m_current_index.has_value())
+        return m_current_index.value() > 0;
+    return false;
+}
 
-    if (m_files_in_same_dir.is_empty()) {
-        Core::DirIterator iterator(current_dir, Core::DirIterator::Flags::SkipDots);
-        while (iterator.has_next()) {
-            String file = iterator.next_full_path();
-            if (!Gfx::Bitmap::is_path_a_supported_image_format(file))
-                continue;
-            m_files_in_same_dir.append(file);
-        }
+Vector<String> ViewWidget::load_files_from_directory(const String& path) const
+{
+    Vector<String> files_in_directory;
+
+    auto current_dir = LexicalPath(path).parent().string();
+    Core::DirIterator iterator(current_dir, Core::DirIterator::Flags::SkipDots);
+    while (iterator.has_next()) {
+        String file = iterator.next_full_path();
+        if (!Gfx::Bitmap::is_path_a_supported_image_format(file))
+            continue;
+        files_in_directory.append(file);
     }
+    return files_in_directory;
+}
 
-    auto current_index = m_files_in_same_dir.find_first_index(m_path);
-    if (!current_index.has_value()) {
+void ViewWidget::set_path(const String& path)
+{
+    m_path = path;
+    m_files_in_same_dir = load_files_from_directory(path);
+    m_current_index = m_files_in_same_dir.find_first_index(path);
+}
+
+void ViewWidget::navigate(Directions direction)
+{
+    if (!m_current_index.has_value()) {
         return;
     }
 
-    size_t index = current_index.value();
+    auto index = m_current_index.value();
     if (direction == Directions::Back) {
-        if (index == 0) {
-            GUI::MessageBox::show(window(), "This is the first file.", "Cannot open image", GUI::MessageBox::Type::Error);
-            return;
-        }
-
         index--;
     } else if (direction == Directions::Forward) {
-        if (index == m_files_in_same_dir.size() - 1) {
-            GUI::MessageBox::show(window(), "This is the last file.", "Cannot open image", GUI::MessageBox::Type::Error);
-            return;
-        }
-
         index++;
     } else if (direction == Directions::First) {
         index = 0;
@@ -103,6 +114,7 @@ void ViewWidget::navigate(Directions direction)
         index = m_files_in_same_dir.size() - 1;
     }
 
+    m_current_index = index;
     this->load_from_file(m_files_in_same_dir.at(index));
 }
 

Userland/Applications/ImageViewer/ViewWidget.h

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2021, Mohsan Ali <mohsan0073@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -34,8 +35,12 @@ public:
     int toolbar_height() { return m_toolbar_height; }
     bool scaled_for_first_image() { return m_scaled_for_first_image; }
     void set_scaled_for_first_image(bool val) { m_scaled_for_first_image = val; }
+    void set_path(const String& path);
     void resize_window();
 
+    bool is_next_available() const;
+    bool is_previous_available() const;
+
     void clear();
     void flip(Gfx::Orientation);
     void rotate(Gfx::RotationDirection);
@@ -59,10 +64,10 @@ private:
     virtual void drop_event(GUI::DropEvent&) override;
 
     void set_bitmap(const Gfx::Bitmap* bitmap);
-
     void relayout();
     void reset_view();
     void animate();
+    Vector<String> load_files_from_directory(const String& path) const;
 
     String m_path;
     RefPtr<Gfx::Bitmap> m_bitmap;
@@ -80,6 +85,7 @@ private:
     Gfx::IntPoint m_click_position;
     Gfx::FloatPoint m_saved_pan_origin;
     Vector<String> m_files_in_same_dir;
+    Optional<size_t> m_current_index;
 };
 
 }

Userland/Applications/ImageViewer/main.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, Mohsan Ali <mohsan0073@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -77,6 +78,9 @@ int main(int argc, char** argv)
     auto& main_toolbar = toolbar_container.add<GUI::Toolbar>();
 
     auto& widget = root_widget.add<ViewWidget>();
+    if (path) {
+        widget.set_path(path);
+    }
     widget.on_scale_change = [&](int scale) {
         if (!widget.bitmap()) {
             window->set_title("Image Viewer");
@@ -100,7 +104,10 @@ int main(int argc, char** argv)
             return;
 
         window->move_to_front();
-        widget.load_from_file(urls.first().path());
+
+        auto path = urls.first().path();
+        widget.set_path(path);
+        widget.load_from_file(path);
 
         for (size_t i = 1; i < urls.size(); ++i) {
             Desktop::Launcher::open(URL::create_with_file_protocol(urls[i].path().characters()), "/bin/ImageViewer");
@@ -117,6 +124,7 @@ int main(int argc, char** argv)
         [&](auto&) {
             auto path = GUI::FilePicker::get_open_filepath(window, "Open Image");
             if (path.has_value()) {
+                widget.set_path(path.value());
                 widget.load_from_file(path.value());
             }
         });
@@ -231,19 +239,22 @@ int main(int argc, char** argv)
         if (widget.bitmap())
             GUI::Clipboard::the().set_bitmap(*widget.bitmap());
     });
-
     widget.on_image_change = [&](const Gfx::Bitmap* bitmap) {
         bool should_enable_image_actions = (bitmap != nullptr);
+        bool should_enable_forward_actions = (widget.is_next_available() && should_enable_image_actions);
+        bool should_enable_backward_actions = (widget.is_previous_available() && should_enable_image_actions);
         delete_action->set_enabled(should_enable_image_actions);
         rotate_left_action->set_enabled(should_enable_image_actions);
         rotate_right_action->set_enabled(should_enable_image_actions);
         vertical_flip_action->set_enabled(should_enable_image_actions);
         horizontal_flip_action->set_enabled(should_enable_image_actions);
         desktop_wallpaper_action->set_enabled(should_enable_image_actions);
-        go_first_action->set_enabled(should_enable_image_actions);
-        go_back_action->set_enabled(should_enable_image_actions);
-        go_forward_action->set_enabled(should_enable_image_actions);
-        go_last_action->set_enabled(should_enable_image_actions);
+
+        go_first_action->set_enabled(should_enable_backward_actions);
+        go_back_action->set_enabled(should_enable_backward_actions);
+        go_forward_action->set_enabled(should_enable_forward_actions);
+        go_last_action->set_enabled(should_enable_forward_actions);
+
         zoom_in_action->set_enabled(should_enable_image_actions);
         reset_zoom_action->set_enabled(should_enable_image_actions);
         zoom_out_action->set_enabled(should_enable_image_actions);