PixelPaint: Add grayscale filter

Add a new Color category to the Filter menu. Add the Grayscale
filter under Filter->Color to turn the selected layer to grey colors.
Created GrayscaleFilter.h. Modify Filter.h to allow filters
without parameters.

2 files changed, 13 insertions, 0 deletions

diff --git a/Userland/Applications/PixelPaint/FilterParams.h b/Userland/Applications/PixelPaint/FilterParams.h
index 906e7d6a42..f923f90853 100644
--- a/Userland/Applications/PixelPaint/FilterParams.h
+++ b/Userland/Applications/PixelPaint/FilterParams.h
@@ -16,6 +16,7 @@
 #include <LibGUI/TextBox.h>
 #include <LibGfx/Filters/BoxBlurFilter.h>
 #include <LibGfx/Filters/GenericConvolutionFilter.h>
+#include <LibGfx/Filters/GrayscaleFilter.h>
 #include <LibGfx/Filters/LaplacianFilter.h>
 #include <LibGfx/Filters/SharpenFilter.h>
 #include <LibGfx/Filters/SpatialGaussianBlurFilter.h>
diff --git a/Userland/Applications/PixelPaint/main.cpp b/Userland/Applications/PixelPaint/main.cpp
index 7b7661b3c4..7ed498e4a5 100644
--- a/Userland/Applications/PixelPaint/main.cpp
+++ b/Userland/Applications/PixelPaint/main.cpp
@@ -660,6 +660,18 @@ int main(int argc, char** argv)
         }
     }));
 
+    auto& color_filters_menu = filter_menu.add_submenu("&Color");
+    color_filters_menu.add_action(GUI::Action::create("Grayscale", [&](auto&) {
+        auto* editor = current_image_editor();
+        if (!editor)
+            return;
+        if (auto* layer = editor->active_layer()) {
+            Gfx::GrayscaleFilter filter;
+            filter.apply(layer->bitmap(), layer->rect(), layer->bitmap(), layer->rect());
+            editor->did_complete_action();
+        }
+    }));
+
     auto& help_menu = window->add_menu("&Help");
     help_menu.add_action(GUI::CommonActions::make_about_action("Pixel Paint", app_icon, window));