ThemeEditor: Implement a way to simulate color blindness in preview

Implement a mechanism that allows us to alter colors so that they
mimic those a colorblind person would see. From the color we can then
alter the colors for the whole preview so we can simulate everything
in the theme including icons/decorations.

This filter is also available as a Filter in LibGfx so it can be
reused in multiple other places.

The color simulation algorithm is based on this one
https://github.com/MaPePeR/jsColorblindSimulator publicly available.

Userland/Applications/ThemeEditor/PreviewWidget.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021, Antonio Di Stefano <tonio9681@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -20,6 +21,7 @@
 #include <LibGUI/TextEditor.h>
 #include <LibGfx/Bitmap.h>
 #include <LibGfx/WindowTheme.h>
+#include <WindowServer/Compositor.h>
 
 namespace ThemeEditor {
 
@@ -152,6 +154,12 @@ void PreviewWidget::set_theme_from_file(String const& path, int fd)
         on_theme_load_from_file(path);
 }
 
+void PreviewWidget::set_color_filter(OwnPtr<Gfx::ColorBlindnessFilter> color_filter)
+{
+    m_color_filter = move(color_filter);
+    repaint();
+}
+
 void PreviewWidget::paint_event(GUI::PaintEvent& event)
 {
     GUI::Frame::paint_event(event);
@@ -219,6 +227,24 @@ void PreviewWidget::paint_event(GUI::PaintEvent& event)
     paint_window("Active window", active_rect, Gfx::WindowTheme::WindowState::Active, *m_inactive_window_icon);
 }
 
+void PreviewWidget::second_paint_event(GUI::PaintEvent&)
+{
+    if (!m_color_filter)
+        return;
+
+    GUI::Painter painter(*this);
+
+    auto target = painter.target();
+    auto bitmap_clone_or_error = target->clone();
+    if (bitmap_clone_or_error.is_error())
+        return;
+
+    auto clone = bitmap_clone_or_error.release_value();
+    auto rect = target->rect();
+
+    m_color_filter->apply(*target, rect, *clone, rect);
+}
+
 void PreviewWidget::resize_event(GUI::ResizeEvent&)
 {
     m_gallery->set_relative_rect(Gfx::IntRect(0, 0, 320, 240).centered_within(rect()).translated(0, 20));

Userland/Applications/ThemeEditor/PreviewWidget.h

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021, Antonio Di Stefano <tonio9681@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -9,6 +10,7 @@
 
 #include <LibGUI/Frame.h>
 #include <LibGfx/Bitmap.h>
+#include <LibGfx/Filters/ColorBlindnessFilter.h>
 #include <LibGfx/Palette.h>
 
 namespace ThemeEditor {
@@ -25,6 +27,8 @@ public:
     void set_preview_palette(const Gfx::Palette&);
     void set_theme_from_file(String const& path, int fd);
 
+    void set_color_filter(OwnPtr<Gfx::ColorBlindnessFilter>);
+
     Function<void(String const&)> on_theme_load_from_file;
 
 private:
@@ -33,11 +37,14 @@ private:
     void load_theme_bitmaps();
 
     virtual void paint_event(GUI::PaintEvent&) override;
+    virtual void second_paint_event(GUI::PaintEvent&) override;
     virtual void resize_event(GUI::ResizeEvent&) override;
     virtual void drop_event(GUI::DropEvent&) override;
 
     Gfx::Palette m_preview_palette;
 
+    OwnPtr<Gfx::ColorBlindnessFilter> m_color_filter = nullptr;
+
     RefPtr<Gfx::Bitmap> m_active_window_icon;
     RefPtr<Gfx::Bitmap> m_inactive_window_icon;
 

Userland/Applications/ThemeEditor/main.cpp

@@ -2,6 +2,7 @@
  * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Jakob-Niklas See <git@nwex.de>
  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021, Antonio Di Stefano <tonio9681@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -12,6 +13,7 @@
 #include <LibCore/ConfigFile.h>
 #include <LibCore/System.h>
 #include <LibFileSystemAccessClient/Client.h>
+#include <LibGUI/ActionGroup.h>
 #include <LibGUI/Application.h>
 #include <LibGUI/BoxLayout.h>
 #include <LibGUI/Button.h>
@@ -26,6 +28,7 @@
 #include <LibGUI/SpinBox.h>
 #include <LibGUI/TextBox.h>
 #include <LibGUI/Window.h>
+#include <LibGfx/Filters/ColorBlindnessFilter.h>
 #include <LibMain/Main.h>
 #include <unistd.h>
 
@@ -316,6 +319,67 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     TRY(file_menu->try_add_separator());
     TRY(file_menu->try_add_action(GUI::CommonActions::make_quit_action([&](auto&) { app->quit(); })));
 
+    auto accessibility_menu = TRY(window->try_add_menu("&Accessibility"));
+
+    auto default_accessibility_action = GUI::Action::create_checkable("Default - non-impaired", { Mod_AltGr, Key_1 }, [&](auto&) {
+        preview_widget.set_color_filter(nullptr);
+    });
+    default_accessibility_action->set_checked(true);
+
+    auto pratanopia_accessibility_action = GUI::Action::create_checkable("Protanopia", { Mod_AltGr, Key_2 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_protanopia());
+    });
+
+    auto pratanomaly_accessibility_action = GUI::Action::create_checkable("Protanomaly", { Mod_AltGr, Key_3 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_protanomaly());
+    });
+
+    auto tritanopia_accessibility_action = GUI::Action::create_checkable("Tritanopia", { Mod_AltGr, Key_4 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_tritanopia());
+    });
+
+    auto tritanomaly_accessibility_action = GUI::Action::create_checkable("Tritanomaly", { Mod_AltGr, Key_5 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_tritanomaly());
+    });
+
+    auto deuteranopia_accessibility_action = GUI::Action::create_checkable("Deuteranopia", { Mod_AltGr, Key_6 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_deuteranopia());
+    });
+
+    auto deuteranomaly_accessibility_action = GUI::Action::create_checkable("Deuteranomaly", { Mod_AltGr, Key_7 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_deuteranomaly());
+    });
+
+    auto achromatopsia_accessibility_action = GUI::Action::create_checkable("Achromatopsia", { Mod_AltGr, Key_8 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_achromatopsia());
+    });
+
+    auto achromatomaly_accessibility_action = GUI::Action::create_checkable("Achromatomaly", { Mod_AltGr, Key_9 }, [&](auto&) {
+        preview_widget.set_color_filter(Gfx::ColorBlindnessFilter::create_achromatomaly());
+    });
+
+    auto preview_type_action_group = make<GUI::ActionGroup>();
+    preview_type_action_group->set_exclusive(true);
+    preview_type_action_group->add_action(*default_accessibility_action);
+    preview_type_action_group->add_action(*pratanopia_accessibility_action);
+    preview_type_action_group->add_action(*pratanomaly_accessibility_action);
+    preview_type_action_group->add_action(*tritanopia_accessibility_action);
+    preview_type_action_group->add_action(*tritanomaly_accessibility_action);
+    preview_type_action_group->add_action(*deuteranopia_accessibility_action);
+    preview_type_action_group->add_action(*deuteranomaly_accessibility_action);
+    preview_type_action_group->add_action(*achromatopsia_accessibility_action);
+    preview_type_action_group->add_action(*achromatomaly_accessibility_action);
+
+    TRY(accessibility_menu->try_add_action(default_accessibility_action));
+    TRY(accessibility_menu->try_add_action(pratanopia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(pratanomaly_accessibility_action));
+    TRY(accessibility_menu->try_add_action(tritanopia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(tritanomaly_accessibility_action));
+    TRY(accessibility_menu->try_add_action(deuteranopia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(deuteranomaly_accessibility_action));
+    TRY(accessibility_menu->try_add_action(achromatopsia_accessibility_action));
+    TRY(accessibility_menu->try_add_action(achromatomaly_accessibility_action));
+
     auto help_menu = TRY(window->try_add_menu("&Help"));
     TRY(help_menu->try_add_action(GUI::CommonActions::make_about_action("Theme Editor", app_icon, window)));