LibGfx: Move FastBoxBlurFilter to its own .cpp file

3 files changed, 156 insertions, 139 deletions

diff --git a/Userland/Libraries/LibGfx/CMakeLists.txt b/Userland/Libraries/LibGfx/CMakeLists.txt
index 92625cace3..b496921c9a 100644
--- a/Userland/Libraries/LibGfx/CMakeLists.txt
+++ b/Userland/Libraries/LibGfx/CMakeLists.txt
@@ -12,6 +12,7 @@ set(SOURCES
     DDSLoader.cpp
     DisjointRectSet.cpp
     Emoji.cpp
+    Filters/FastBoxBlurFilter.cpp
     FontDatabase.cpp
     GIFLoader.cpp
     ICOLoader.cpp
diff --git a/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.cpp b/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.cpp
new file mode 100644
index 0000000000..23c18b3224
--- /dev/null
+++ b/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.cpp
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibGfx/Filters/FastBoxBlurFilter.h>
+
+namespace Gfx {
+
+ALWAYS_INLINE static constexpr u8 red_value(Color color)
+{
+    return (color.alpha() == 0) ? 0xFF : color.red();
+}
+ALWAYS_INLINE static constexpr u8 green_value(Color color)
+{
+    return (color.alpha() == 0) ? 0xFF : color.green();
+}
+ALWAYS_INLINE static constexpr u8 blue_value(Color color)
+{
+    return (color.alpha() == 0) ? 0xFF : color.blue();
+}
+
+FastBoxBlurFilter::FastBoxBlurFilter(Bitmap& bitmap)
+    : m_bitmap(bitmap)
+{
+}
+
+// Based on the super fast blur algorithm by Quasimondo, explored here: https://stackoverflow.com/questions/21418892/understanding-super-fast-blur-algorithm
+void FastBoxBlurFilter::apply_single_pass(int radius)
+{
+    VERIFY(radius >= 0);
+    VERIFY(m_bitmap.format() == BitmapFormat::BGRA8888);
+
+    int height = m_bitmap.height();
+    int width = m_bitmap.width();
+
+    int div = 2 * radius + 1;
+
+    Vector<u8, 1024> intermediate_red;
+    Vector<u8, 1024> intermediate_green;
+    Vector<u8, 1024> intermediate_blue;
+    Vector<u8, 1024> intermediate_alpha;
+
+    intermediate_red.resize(width * height);
+    intermediate_green.resize(width * height);
+    intermediate_blue.resize(width * height);
+    intermediate_alpha.resize(width * height);
+
+    // First pass: vertical
+    for (int y = 0; y < height; ++y) {
+        size_t sum_red = 0;
+        size_t sum_green = 0;
+        size_t sum_blue = 0;
+        size_t sum_alpha = 0;
+
+        // Setup sliding window
+        for (int i = -radius; i <= radius; ++i) {
+            auto color_at_px = m_bitmap.get_pixel<StorageFormat::BGRA8888>(clamp(i, 0, width - 1), y);
+            sum_red += red_value(color_at_px);
+            sum_green += green_value(color_at_px);
+            sum_blue += blue_value(color_at_px);
+            sum_alpha += color_at_px.alpha();
+        }
+        // Slide horizontally
+        for (int x = 0; x < width; ++x) {
+            intermediate_red[y * width + x] = (sum_red / div);
+            intermediate_green[y * width + x] = (sum_green / div);
+            intermediate_blue[y * width + x] = (sum_blue / div);
+            intermediate_alpha[y * width + x] = (sum_alpha / div);
+
+            auto leftmost_x_coord = max(x - radius, 0);
+            auto rightmost_x_coord = min(x + radius + 1, width - 1);
+
+            auto leftmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(leftmost_x_coord, y);
+            auto rightmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(rightmost_x_coord, y);
+
+            sum_red -= red_value(leftmost_x_color);
+            sum_red += red_value(rightmost_x_color);
+            sum_green -= green_value(leftmost_x_color);
+            sum_green += green_value(rightmost_x_color);
+            sum_blue -= blue_value(leftmost_x_color);
+            sum_blue += blue_value(rightmost_x_color);
+            sum_alpha -= leftmost_x_color.alpha();
+            sum_alpha += rightmost_x_color.alpha();
+        }
+    }
+
+    // Second pass: horizontal
+    for (int x = 0; x < width; ++x) {
+        size_t sum_red = 0;
+        size_t sum_green = 0;
+        size_t sum_blue = 0;
+        size_t sum_alpha = 0;
+
+        // Setup sliding window
+        for (int i = -radius; i <= radius; ++i) {
+            int offset = clamp(i, 0, height - 1) * width + x;
+            sum_red += intermediate_red[offset];
+            sum_green += intermediate_green[offset];
+            sum_blue += intermediate_blue[offset];
+            sum_alpha += intermediate_alpha[offset];
+        }
+
+        for (int y = 0; y < height; ++y) {
+            auto color = Color(
+                sum_red / div,
+                sum_green / div,
+                sum_blue / div,
+                sum_alpha / div);
+
+            m_bitmap.set_pixel<StorageFormat::BGRA8888>(x, y, color);
+
+            auto topmost_y_coord = max(y - radius, 0);
+            auto bottommost_y_coord = min(y + radius + 1, height - 1);
+
+            sum_red += intermediate_red[x + bottommost_y_coord * width];
+            sum_red -= intermediate_red[x + topmost_y_coord * width];
+            sum_green += intermediate_green[x + bottommost_y_coord * width];
+            sum_green -= intermediate_green[x + topmost_y_coord * width];
+            sum_blue += intermediate_blue[x + bottommost_y_coord * width];
+            sum_blue -= intermediate_blue[x + topmost_y_coord * width];
+            sum_alpha += intermediate_alpha[x + bottommost_y_coord * width];
+            sum_alpha -= intermediate_alpha[x + topmost_y_coord * width];
+        }
+    }
+}
+
+// Math from here: http://blog.ivank.net/fastest-gaussian-blur.html
+void FastBoxBlurFilter::apply_three_passes(size_t radius)
+{
+    if (!radius)
+        return;
+
+    constexpr size_t no_of_passes = 3;
+    double w_ideal = sqrt((12 * radius * radius / (double)no_of_passes) + 1);
+    int wl = floor(w_ideal);
+    if (wl % 2 == 0)
+        wl--;
+    int wu = wl - 2;
+    double m_ideal = (12 * radius * radius - no_of_passes * wl * wl - 4 * no_of_passes * wl - 3 * no_of_passes) / (double)(-4 * wl - 4);
+    int m = round(m_ideal);
+
+    for (size_t i = 0; i < no_of_passes; ++i) {
+        int weighted_radius = (int)i < m ? wl : wu;
+        if (weighted_radius < 2)
+            continue;
+        apply_single_pass((weighted_radius - 1) / 2);
+    }
+}
+
+}
diff --git a/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.h b/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.h
index bb1c26b801..5e7fa96126 100644
--- a/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.h
+++ b/Userland/Libraries/LibGfx/Filters/FastBoxBlurFilter.h
@@ -12,148 +12,12 @@ namespace Gfx {
 
 class FastBoxBlurFilter {
 public:
-    FastBoxBlurFilter(Bitmap& bitmap)
-        : m_bitmap(bitmap)
-    {
-    }
+    FastBoxBlurFilter(Bitmap&);
 
-    // Based on the super fast blur algorithm by Quasimondo, explored here: https://stackoverflow.com/questions/21418892/understanding-super-fast-blur-algorithm
-    void apply_single_pass(int radius)
-    {
-        VERIFY(radius >= 0);
-        VERIFY(m_bitmap.format() == BitmapFormat::BGRA8888);
-
-        int height = m_bitmap.height();
-        int width = m_bitmap.width();
-
-        int div = 2 * radius + 1;
-
-        Vector<u8, 1024> intermediate_red;
-        Vector<u8, 1024> intermediate_green;
-        Vector<u8, 1024> intermediate_blue;
-        Vector<u8, 1024> intermediate_alpha;
-
-        intermediate_red.resize(width * height);
-        intermediate_green.resize(width * height);
-        intermediate_blue.resize(width * height);
-        intermediate_alpha.resize(width * height);
-
-        // First pass: vertical
-        for (int y = 0; y < height; ++y) {
-            size_t sum_red = 0;
-            size_t sum_green = 0;
-            size_t sum_blue = 0;
-            size_t sum_alpha = 0;
-
-            // Setup sliding window
-            for (int i = -radius; i <= radius; ++i) {
-                auto color_at_px = m_bitmap.get_pixel<StorageFormat::BGRA8888>(clamp(i, 0, width - 1), y);
-                sum_red += red_value(color_at_px);
-                sum_green += green_value(color_at_px);
-                sum_blue += blue_value(color_at_px);
-                sum_alpha += color_at_px.alpha();
-            }
-            // Slide horizontally
-            for (int x = 0; x < width; ++x) {
-                intermediate_red[y * width + x] = (sum_red / div);
-                intermediate_green[y * width + x] = (sum_green / div);
-                intermediate_blue[y * width + x] = (sum_blue / div);
-                intermediate_alpha[y * width + x] = (sum_alpha / div);
-
-                auto leftmost_x_coord = max(x - radius, 0);
-                auto rightmost_x_coord = min(x + radius + 1, width - 1);
-
-                auto leftmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(leftmost_x_coord, y);
-                auto rightmost_x_color = m_bitmap.get_pixel<StorageFormat::BGRA8888>(rightmost_x_coord, y);
-
-                sum_red -= red_value(leftmost_x_color);
-                sum_red += red_value(rightmost_x_color);
-                sum_green -= green_value(leftmost_x_color);
-                sum_green += green_value(rightmost_x_color);
-                sum_blue -= blue_value(leftmost_x_color);
-                sum_blue += blue_value(rightmost_x_color);
-                sum_alpha -= leftmost_x_color.alpha();
-                sum_alpha += rightmost_x_color.alpha();
-            }
-        }
-
-        // Second pass: horizontal
-        for (int x = 0; x < width; ++x) {
-            size_t sum_red = 0;
-            size_t sum_green = 0;
-            size_t sum_blue = 0;
-            size_t sum_alpha = 0;
-
-            // Setup sliding window
-            for (int i = -radius; i <= radius; ++i) {
-                int offset = clamp(i, 0, height - 1) * width + x;
-                sum_red += intermediate_red[offset];
-                sum_green += intermediate_green[offset];
-                sum_blue += intermediate_blue[offset];
-                sum_alpha += intermediate_alpha[offset];
-            }
-
-            for (int y = 0; y < height; ++y) {
-                auto color = Color(
-                    sum_red / div,
-                    sum_green / div,
-                    sum_blue / div,
-                    sum_alpha / div);
-
-                m_bitmap.set_pixel<StorageFormat::BGRA8888>(x, y, color);
-
-                auto topmost_y_coord = max(y - radius, 0);
-                auto bottommost_y_coord = min(y + radius + 1, height - 1);
-
-                sum_red += intermediate_red[x + bottommost_y_coord * width];
-                sum_red -= intermediate_red[x + topmost_y_coord * width];
-                sum_green += intermediate_green[x + bottommost_y_coord * width];
-                sum_green -= intermediate_green[x + topmost_y_coord * width];
-                sum_blue += intermediate_blue[x + bottommost_y_coord * width];
-                sum_blue -= intermediate_blue[x + topmost_y_coord * width];
-                sum_alpha += intermediate_alpha[x + bottommost_y_coord * width];
-                sum_alpha -= intermediate_alpha[x + topmost_y_coord * width];
-            }
-        }
-    }
-
-    // Math from here: http://blog.ivank.net/fastest-gaussian-blur.html
-    void apply_three_passes(size_t radius)
-    {
-        if (!radius)
-            return;
-
-        constexpr size_t no_of_passes = 3;
-        double w_ideal = sqrt((12 * radius * radius / (double)no_of_passes) + 1);
-        int wl = floor(w_ideal);
-        if (wl % 2 == 0)
-            wl--;
-        int wu = wl - 2;
-        double m_ideal = (12 * radius * radius - no_of_passes * wl * wl - 4 * no_of_passes * wl - 3 * no_of_passes) / (double)(-4 * wl - 4);
-        int m = round(m_ideal);
-
-        for (size_t i = 0; i < no_of_passes; ++i) {
-            int weighted_radius = (int)i < m ? wl : wu;
-            if (weighted_radius < 2)
-                continue;
-            apply_single_pass((weighted_radius - 1) / 2);
-        }
-    }
+    void apply_single_pass(int radius);
+    void apply_three_passes(size_t radius);
 
 private:
-    ALWAYS_INLINE static u8 red_value(Color color)
-    {
-        return (color.alpha() == 0) ? 0xFF : color.red();
-    }
-    ALWAYS_INLINE static u8 green_value(Color color)
-    {
-        return (color.alpha() == 0) ? 0xFF : color.green();
-    }
-    ALWAYS_INLINE static u8 blue_value(Color color)
-    {
-        return (color.alpha() == 0) ? 0xFF : color.blue();
-    }
-
     Bitmap& m_bitmap;
 };