PixelPaint: Add a bunch of spatial filters

This patchset adds a generic convolution matrix spatial filter, and a
few named derivatives such as BoxBlur, Laplacian, Sharpen and
GaussianBlur.

15 files changed, 869 insertions, 1 deletions

diff --git a/Applications/PixelPaint/CMakeLists.txt b/Applications/PixelPaint/CMakeLists.txt
index 52c55e48b0..3fb7752ca8 100644
--- a/Applications/PixelPaint/CMakeLists.txt
+++ b/Applications/PixelPaint/CMakeLists.txt
@@ -3,6 +3,12 @@ set(SOURCES
     CreateNewLayerDialog.cpp
     EllipseTool.cpp
     EraseTool.cpp
+    Filters/BoxBlurFilter.cpp
+    Filters/Filter.cpp
+    Filters/GenericConvolutionFilter.cpp
+    Filters/LaplacianFilter.cpp
+    Filters/SharpenFilter.cpp
+    Filters/SpatialGaussianBlurFilter.cpp
     Image.cpp
     ImageEditor.cpp
     Layer.cpp
diff --git a/Applications/PixelPaint/Filters/BoxBlurFilter.cpp b/Applications/PixelPaint/Filters/BoxBlurFilter.cpp
new file mode 100644
index 0000000000..4da1c1d158
--- /dev/null
+++ b/Applications/PixelPaint/Filters/BoxBlurFilter.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "BoxBlurFilter.h"
+#include <LibGUI/BoxLayout.h>
+#include <LibGUI/Button.h>
+#include <LibGUI/CheckBox.h>
+#include <LibGUI/SpinBox.h>
+
+namespace PixelPaint {
+
+template<size_t N>
+BoxBlurFilter<N>::BoxBlurFilter()
+{
+}
+
+template<size_t N>
+BoxBlurFilter<N>::~BoxBlurFilter()
+{
+}
+
+template<size_t N>
+void BoxBlurFilter<N>::apply(const Filter::Parameters& parameters)
+{
+    GenericConvolutionFilter<N>::apply(parameters);
+}
+
+template<size_t N>
+typename GenericConvolutionFilter<N>::Parameters BoxBlurFilter<N>::get_parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect)
+{
+    Matrix<N, float> kernel;
+
+    for (size_t i = 0; i < N; ++i) {
+        for (size_t j = 0; j < N; ++j) {
+            kernel.elements()[i][j] = 1;
+        }
+    }
+
+    normalize(kernel);
+
+    return { bitmap, rect, kernel };
+}
+
+}
+
+template class PixelPaint::BoxBlurFilter<3>;
+template class PixelPaint::BoxBlurFilter<5>;
diff --git a/Applications/PixelPaint/Filters/BoxBlurFilter.h b/Applications/PixelPaint/Filters/BoxBlurFilter.h
new file mode 100644
index 0000000000..760eb17df9
--- /dev/null
+++ b/Applications/PixelPaint/Filters/BoxBlurFilter.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "GenericConvolutionFilter.h"
+
+namespace PixelPaint {
+
+template<size_t N>
+class BoxBlurFilter : public GenericConvolutionFilter<N> {
+public:
+    BoxBlurFilter();
+    virtual ~BoxBlurFilter();
+
+    virtual const char* class_name() const override { return "BoxBlurFilter"; }
+
+    virtual void apply(const Filter::Parameters&) override;
+
+    typename GenericConvolutionFilter<N>::Parameters get_parameters(Gfx::Bitmap&, const Gfx::IntRect&);
+};
+
+}
diff --git a/Applications/PixelPaint/Filters/Filter.cpp b/Applications/PixelPaint/Filters/Filter.cpp
new file mode 100644
index 0000000000..cd21c604e4
--- /dev/null
+++ b/Applications/PixelPaint/Filters/Filter.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Filter.h"
+
+namespace PixelPaint {
+
+Filter::Filter()
+{
+}
+
+Filter::~Filter()
+{
+}
+
+}
diff --git a/Applications/PixelPaint/Filters/Filter.h b/Applications/PixelPaint/Filters/Filter.h
new file mode 100644
index 0000000000..c2146324b1
--- /dev/null
+++ b/Applications/PixelPaint/Filters/Filter.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibGUI/Event.h>
+#include <LibGUI/Forward.h>
+#include <LibGfx/Forward.h>
+
+namespace PixelPaint {
+
+class Filter {
+public:
+    class Parameters {
+    public:
+        Parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect)
+            : m_target_bitmap(bitmap)
+            , m_target_rect(rect)
+
+        {
+        }
+
+        Gfx::Bitmap& bitmap() const { return m_target_bitmap; }
+        const Gfx::IntRect& rect() const { return m_target_rect; }
+        virtual bool is_generic_convolution_filter() const { return false; }
+
+    private:
+        Gfx::Bitmap& m_target_bitmap;
+        Gfx::IntRect m_target_rect;
+    };
+    virtual ~Filter();
+
+    virtual const char* class_name() const = 0;
+
+    virtual void apply(const Parameters&) = 0;
+
+protected:
+    Filter();
+};
+
+}
diff --git a/Applications/PixelPaint/Filters/GenericConvolutionFilter.cpp b/Applications/PixelPaint/Filters/GenericConvolutionFilter.cpp
new file mode 100644
index 0000000000..161beef25a
--- /dev/null
+++ b/Applications/PixelPaint/Filters/GenericConvolutionFilter.cpp
@@ -0,0 +1,172 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "GenericConvolutionFilter.h"
+#include <AK/TemporaryChange.h>
+#include <LibGUI/Action.h>
+#include <LibGUI/BoxLayout.h>
+#include <LibGUI/Button.h>
+#include <LibGUI/CheckBox.h>
+#include <LibGUI/Dialog.h>
+#include <LibGUI/Menu.h>
+#include <LibGUI/Painter.h>
+#include <LibGUI/TextBox.h>
+#include <LibGfx/Bitmap.h>
+
+namespace PixelPaint {
+
+template<size_t N>
+GenericConvolutionFilter<N>::GenericConvolutionFilter()
+{
+}
+
+template<size_t N>
+GenericConvolutionFilter<N>::~GenericConvolutionFilter()
+{
+}
+
+template<size_t N>
+void GenericConvolutionFilter<N>::apply(const Filter::Parameters& parameters)
+{
+    ASSERT(parameters.is_generic_convolution_filter());
+
+    auto& gcf_params = static_cast<const GenericConvolutionFilter::Parameters&>(parameters);
+
+    auto& source = gcf_params.bitmap();
+    const auto& source_rect = gcf_params.rect();
+    auto target = Gfx::Bitmap::create(source.format(), parameters.rect().size());
+
+    // FIXME: Help! I am naive!
+    for (auto i_ = 0; i_ < source_rect.width(); ++i_) {
+        auto i = i_ + source_rect.x();
+        for (auto j_ = 0; j_ < source_rect.height(); ++j_) {
+            auto j = j_ + source_rect.y();
+            FloatVector3 value(0, 0, 0);
+            for (auto k = 0; k < 4; ++k) {
+                auto ki = i + k - 2;
+                if (ki < 0 || ki >= source.size().width()) {
+                    if (gcf_params.should_wrap())
+                        ki = (ki + source.size().width()) % source.size().width();
+                    else
+                        continue;
+                }
+
+                for (auto l = 0; l < 4; ++l) {
+                    auto lj = j + l - 2;
+                    if (lj < 0 || lj >= source.size().height()) {
+                        if (gcf_params.should_wrap())
+                            lj = (lj + source.size().height()) % source.size().height();
+                        else
+                            continue;
+                    }
+
+                    auto pixel = source.get_pixel(ki, lj);
+                    FloatVector3 pixel_value(pixel.red(), pixel.green(), pixel.blue());
+
+                    value = value + pixel_value * gcf_params.kernel().elements()[k][l];
+                }
+            }
+
+            // The float->u8 overflow is intentional.
+            target->set_pixel(i_, j_, Color(value.x(), value.y(), value.z(), source.get_pixel(i, j).alpha()));
+        }
+    }
+
+    // FIXME: Substitute for some sort of faster "blit" method.
+    for (auto i_ = 0; i_ < source_rect.width(); ++i_) {
+        auto i = i_ + source_rect.x();
+        for (auto j_ = 0; j_ < source_rect.height(); ++j_) {
+            auto j = j_ + source_rect.y();
+            source.set_pixel(i, j, target->get_pixel(i_, j_));
+        }
+    }
+}
+
+template<size_t N>
+typename GenericConvolutionFilter<N>::Parameters GenericConvolutionFilter<N>::get_parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect, GUI::Window* parent_window)
+{
+    auto input = GenericConvolutionFilterInputDialog<N>::construct(parent_window);
+    input->exec();
+
+    return { bitmap, rect, input->matrix(), input->should_wrap() };
+}
+
+template<size_t N>
+GenericConvolutionFilterInputDialog<N>::GenericConvolutionFilterInputDialog(Window* parent_window)
+    : Dialog(parent_window)
+{
+    // FIXME: Help! Make this GUI less ugly.
+    auto& main_widget = set_main_widget<GUI::Frame>();
+    main_widget.set_frame_shape(Gfx::FrameShape::Container);
+    main_widget.set_frame_shadow(Gfx::FrameShadow::Raised);
+    main_widget.set_fill_with_background_color(true);
+    main_widget.template set_layout<GUI::VerticalBoxLayout>();
+
+    size_t index = 0;
+    size_t columns = N;
+    size_t rows = N;
+
+    for (size_t row = 0; row < rows; ++row) {
+        auto& horizontal_container = main_widget.template add<GUI::Widget>();
+        horizontal_container.template set_layout<GUI::HorizontalBoxLayout>();
+        for (size_t column = 0; column < columns; ++column) {
+            if (index < columns * rows) {
+                auto& textbox = horizontal_container.template add<GUI::TextBox>();
+                textbox.set_preferred_size({ 30, 50 });
+                textbox.on_change = [&, row = row, column = column] {
+                    auto& element = m_matrix.elements()[row][column];
+                    char* endptr = nullptr;
+                    auto value = strtof(textbox.text().characters(), &endptr);
+                    if (endptr != nullptr)
+                        element = value;
+                    else
+                        textbox.set_text("");
+                };
+            } else {
+                horizontal_container.template add<GUI::Widget>();
+            }
+        }
+    }
+
+    auto& norm_checkbox = main_widget.template add<GUI::CheckBox>("Normalize");
+    norm_checkbox.set_checked(false);
+
+    auto& wrap_checkbox = main_widget.template add<GUI::CheckBox>("Wrap");
+    wrap_checkbox.set_checked(m_should_wrap);
+
+    auto& button = main_widget.template add<GUI::Button>("Done");
+    button.set_button_style(Gfx::ButtonStyle::CoolBar);
+    button.on_click = [&](auto) {
+        m_should_wrap = wrap_checkbox.is_checked();
+        if (norm_checkbox.is_checked())
+            normalize(m_matrix);
+        done(ExecOK);
+    };
+}
+}
+
+template class PixelPaint::GenericConvolutionFilter<3>;
+template class PixelPaint::GenericConvolutionFilter<5>;
diff --git a/Applications/PixelPaint/Filters/GenericConvolutionFilter.h b/Applications/PixelPaint/Filters/GenericConvolutionFilter.h
new file mode 100644
index 0000000000..e32fd5f417
--- /dev/null
+++ b/Applications/PixelPaint/Filters/GenericConvolutionFilter.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "Filter.h"
+#include <LibGUI/Dialog.h>
+#include <LibGfx/Matrix.h>
+#include <LibGfx/Matrix4x4.h>
+
+namespace PixelPaint {
+
+template<size_t N, typename T>
+inline static constexpr void normalize(Matrix<N, T>& matrix)
+{
+    auto sum = 0.0f;
+    for (size_t i = 0; i < matrix.Size; ++i) {
+        for (size_t j = 0; j < matrix.Size; ++j) {
+            sum += matrix.elements()[i][j];
+        }
+    }
+    for (size_t i = 0; i < matrix.Size; ++i) {
+        for (size_t j = 0; j < matrix.Size; ++j) {
+            matrix.elements()[i][j] /= sum;
+        }
+    }
+}
+
+template<size_t N>
+class GenericConvolutionFilter : public Filter {
+public:
+    class Parameters : public Filter::Parameters {
+    public:
+        Parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect, Gfx::Matrix<N, float> kernel, bool should_wrap = false)
+            : Filter::Parameters(bitmap, rect)
+            , m_kernel(move(kernel))
+            , m_should_wrap(should_wrap)
+
+        {
+        }
+
+        const Gfx::Matrix<N, float>& kernel() const { return m_kernel; }
+        Gfx::Matrix<N, float>& kernel() { return m_kernel; }
+        bool should_wrap() const { return m_should_wrap; }
+
+    private:
+        virtual bool is_generic_convolution_filter() const override { return true; }
+        Gfx::Matrix<N, float> m_kernel;
+        bool m_should_wrap { false };
+    };
+
+    GenericConvolutionFilter();
+    virtual ~GenericConvolutionFilter();
+
+    virtual const char* class_name() const override { return "GenericConvolutionFilter"; }
+
+    virtual void apply(const Filter::Parameters&) override;
+
+    Parameters get_parameters(Gfx::Bitmap&, const Gfx::IntRect&, GUI::Window* parent_window);
+};
+
+template<size_t N>
+class GenericConvolutionFilterInputDialog : public GUI::Dialog {
+    C_OBJECT(GenericConvolutionFilterInputDialog);
+
+public:
+    const Matrix<N, float>& matrix() const { return m_matrix; }
+    bool should_wrap() const { return m_should_wrap; }
+
+private:
+    explicit GenericConvolutionFilterInputDialog(GUI::Window*);
+    Matrix<N, float> m_matrix {};
+    bool m_should_wrap { false };
+};
+
+}
diff --git a/Applications/PixelPaint/Filters/LaplacianFilter.cpp b/Applications/PixelPaint/Filters/LaplacianFilter.cpp
new file mode 100644
index 0000000000..e71ca17e1e
--- /dev/null
+++ b/Applications/PixelPaint/Filters/LaplacianFilter.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "LaplacianFilter.h"
+
+namespace PixelPaint {
+
+LaplacianFilter::LaplacianFilter()
+{
+}
+
+LaplacianFilter::~LaplacianFilter()
+{
+}
+
+void LaplacianFilter::apply(const Filter::Parameters& parameters)
+{
+    GenericConvolutionFilter::apply(parameters);
+}
+
+GenericConvolutionFilter<3>::Parameters LaplacianFilter::get_parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect, bool diagonal)
+{
+    if (diagonal)
+        return { bitmap, rect, Matrix<3, float>(-1, -1, -1, -1, 8, -1, -1, -1, -1) };
+
+    return { bitmap, rect, Matrix<3, float>(0, -1, 0, -1, 4, -1, 0, -1, 0) };
+}
+
+}
diff --git a/Applications/PixelPaint/Filters/LaplacianFilter.h b/Applications/PixelPaint/Filters/LaplacianFilter.h
new file mode 100644
index 0000000000..0184c47e55
--- /dev/null
+++ b/Applications/PixelPaint/Filters/LaplacianFilter.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "GenericConvolutionFilter.h"
+
+namespace PixelPaint {
+
+class LaplacianFilter : public GenericConvolutionFilter<3> {
+public:
+    LaplacianFilter();
+    virtual ~LaplacianFilter();
+
+    virtual const char* class_name() const override { return "LaplacianFilter"; }
+
+    virtual void apply(const Filter::Parameters&) override;
+
+    GenericConvolutionFilter::Parameters get_parameters(Gfx::Bitmap&, const Gfx::IntRect&, bool diagonal);
+};
+
+}
diff --git a/Applications/PixelPaint/Filters/SharpenFilter.cpp b/Applications/PixelPaint/Filters/SharpenFilter.cpp
new file mode 100644
index 0000000000..4d6f34ed43
--- /dev/null
+++ b/Applications/PixelPaint/Filters/SharpenFilter.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "SharpenFilter.h"
+#include "../ImageEditor.h"
+
+namespace PixelPaint {
+
+SharpenFilter::SharpenFilter()
+{
+}
+
+SharpenFilter::~SharpenFilter()
+{
+}
+
+void SharpenFilter::apply(const Filter::Parameters& parameters)
+{
+    GenericConvolutionFilter::apply(parameters);
+}
+
+GenericConvolutionFilter<3>::Parameters SharpenFilter::get_parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect)
+{
+    return { bitmap, rect, Matrix<3, float>(0, -1, 0, -1, 5, -1, 0, -1, 0) };
+}
+
+}
diff --git a/Applications/PixelPaint/Filters/SharpenFilter.h b/Applications/PixelPaint/Filters/SharpenFilter.h
new file mode 100644
index 0000000000..2fe26bb3fd
--- /dev/null
+++ b/Applications/PixelPaint/Filters/SharpenFilter.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "GenericConvolutionFilter.h"
+
+namespace PixelPaint {
+
+class SharpenFilter : public GenericConvolutionFilter<3> {
+public:
+    SharpenFilter();
+    virtual ~SharpenFilter();
+
+    virtual const char* class_name() const override { return "SharpenFilter"; }
+
+    virtual void apply(const Filter::Parameters&) override;
+
+    GenericConvolutionFilter::Parameters get_parameters(Gfx::Bitmap&, const Gfx::IntRect&);
+};
+
+}
diff --git a/Applications/PixelPaint/Filters/SpatialGaussianBlurFilter.cpp b/Applications/PixelPaint/Filters/SpatialGaussianBlurFilter.cpp
new file mode 100644
index 0000000000..007df1adaa
--- /dev/null
+++ b/Applications/PixelPaint/Filters/SpatialGaussianBlurFilter.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "SpatialGaussianBlurFilter.h"
+
+namespace PixelPaint {
+
+template<size_t N, typename T>
+SpatialGaussianBlurFilter<N, T>::SpatialGaussianBlurFilter()
+{
+}
+
+template<size_t N, typename T>
+SpatialGaussianBlurFilter<N, T>::~SpatialGaussianBlurFilter()
+{
+}
+
+template<size_t N, typename T>
+void SpatialGaussianBlurFilter<N, T>::apply(const Filter::Parameters& parameters)
+{
+    GenericConvolutionFilter<N>::apply(parameters);
+}
+
+template<size_t N, typename _T>
+typename GenericConvolutionFilter<N>::Parameters SpatialGaussianBlurFilter<N, _T>::get_parameters(Gfx::Bitmap& bitmap, const Gfx::IntRect& rect)
+{
+    Matrix<N, float> kernel;
+    auto sigma = 1.0f;
+    auto s = 2.0f * sigma * sigma;
+
+    for (auto x = -(ssize_t)N / 2; x <= (ssize_t)N / 2; x++) {
+        for (auto y = -(ssize_t)N / 2; y <= (ssize_t)N / 2; y++) {
+            auto r = sqrt(x * x + y * y);
+            kernel.elements()[x + 2][y + 2] = (exp(-(r * r) / s)) / (M_PI * s);
+        }
+    }
+
+    normalize(kernel);
+
+    return { bitmap, rect, kernel };
+}
+
+}
+
+template class PixelPaint::SpatialGaussianBlurFilter<3>;
+template class PixelPaint::SpatialGaussianBlurFilter<5>;
diff --git a/Applications/PixelPaint/Filters/SpatialGaussianBlurFilter.h b/Applications/PixelPaint/Filters/SpatialGaussianBlurFilter.h
new file mode 100644
index 0000000000..38e56d501b
--- /dev/null
+++ b/Applications/PixelPaint/Filters/SpatialGaussianBlurFilter.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "GenericConvolutionFilter.h"
+#include <AK/StdLibExtras.h>
+
+namespace PixelPaint {
+
+template<size_t N, typename = typename AK::EnableIf<N % 2 == 1>::Type>
+class SpatialGaussianBlurFilter : public GenericConvolutionFilter<N> {
+public:
+    SpatialGaussianBlurFilter();
+    virtual ~SpatialGaussianBlurFilter();
+
+    virtual const char* class_name() const override { return "SpatialGaussianBlurFilter"; }
+
+    virtual void apply(const Filter::Parameters&) override;
+
+    typename GenericConvolutionFilter<N>::Parameters get_parameters(Gfx::Bitmap&, const Gfx::IntRect&);
+};
+
+}
diff --git a/Applications/PixelPaint/Layer.h b/Applications/PixelPaint/Layer.h
index a9aeb75c8f..f7ef404a7a 100644
--- a/Applications/PixelPaint/Layer.h
+++ b/Applications/PixelPaint/Layer.h
@@ -61,6 +61,8 @@ public:
     const String& name() const { return m_name; }
     void set_name(const String&);
 
+    void set_bitmap(Gfx::Bitmap& bitmap) { m_bitmap = bitmap; }
+
     void did_modify_bitmap(Image&);
 
     void set_selected(bool selected) { m_selected = selected; }
diff --git a/Applications/PixelPaint/main.cpp b/Applications/PixelPaint/main.cpp
index d5b39f35f8..d54052f612 100644
--- a/Applications/PixelPaint/main.cpp
+++ b/Applications/PixelPaint/main.cpp
@@ -25,14 +25,19 @@
  */
 
 #include "CreateNewLayerDialog.h"
+#include "Filters/BoxBlurFilter.h"
+#include "Filters/GenericConvolutionFilter.h"
+#include "Filters/LaplacianFilter.h"
+#include "Filters/SharpenFilter.h"
+#include "Filters/SpatialGaussianBlurFilter.h"
 #include "Image.h"
 #include "ImageEditor.h"
 #include "Layer.h"
 #include "LayerListWidget.h"
+#include "LayerPropertiesWidget.h"
 #include "PaletteWidget.h"
 #include "Tool.h"
 #include "ToolboxWidget.h"
-#include "LayerPropertiesWidget.h"
 #include <LibGUI/AboutDialog.h>
 #include <LibGUI/Action.h>
 #include <LibGUI/Application.h>
@@ -45,6 +50,7 @@
 #include <LibGUI/TableView.h>
 #include <LibGUI/Window.h>
 #include <LibGfx/Bitmap.h>
+#include <LibGfx/Matrix4x4.h>
 #include <stdio.h>
 
 int main(int argc, char** argv)
@@ -194,6 +200,62 @@ int main(int argc, char** argv)
         },
         window));
 
+    auto& filter_menu = menubar->add_menu("Filter");
+    auto& spatial_filters_menu = filter_menu.add_submenu("Spatial");
+
+    auto& edge_detect_submenu = spatial_filters_menu.add_submenu("Edge Detect");
+    edge_detect_submenu.add_action(GUI::Action::create("Laplacian (cardinal)", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::LaplacianFilter filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect(), false));
+        }
+    }));
+    edge_detect_submenu.add_action(GUI::Action::create("Laplacian (diagonal)", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::LaplacianFilter filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect(), true));
+        }
+    }));
+    auto& blur_submenu = spatial_filters_menu.add_submenu("Blur and Sharpen");
+    blur_submenu.add_action(GUI::Action::create("Gaussian Blur (3x3)", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::SpatialGaussianBlurFilter<3> filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect()));
+        }
+    }));
+    blur_submenu.add_action(GUI::Action::create("Gaussian Blur (5x5)", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::SpatialGaussianBlurFilter<5> filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect()));
+        }
+    }));
+    blur_submenu.add_action(GUI::Action::create("Box Blur (3x3)", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::BoxBlurFilter<3> filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect()));
+        }
+    }));
+    blur_submenu.add_action(GUI::Action::create("Box Blur (5x5)", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::BoxBlurFilter<5> filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect()));
+        }
+    }));
+    blur_submenu.add_action(GUI::Action::create("Sharpen", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::SharpenFilter filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect()));
+        }
+    }));
+
+    spatial_filters_menu.add_separator();
+    spatial_filters_menu.add_action(GUI::Action::create("Generic 5x5 Convolution", [&](auto&) {
+        if (auto* layer = image_editor.active_layer()) {
+            PixelPaint::GenericConvolutionFilter<5> filter;
+            filter.apply(filter.get_parameters(layer->bitmap(), layer->rect(), window));
+        }
+    }));
+
     auto& help_menu = menubar->add_menu("Help");
     help_menu.add_action(GUI::Action::create("About", [&](auto&) {
         GUI::AboutDialog::show("PixelPaint", app_icon.bitmap_for_size(32), window);