LibGfx: Add MatrixFilter and convert HueRotateFilter to be one

This moves the apply a matrix operation to each [r,g,b] vector in an
image to a general class.

Userland/Libraries/LibGfx/Filters/HueRotateFilter.h

@@ -6,17 +6,14 @@
 
 #pragma once
 
-#include <AK/Math.h>
-#include <LibGfx/Filters/ColorFilter.h>
-#include <LibGfx/Matrix3x3.h>
+#include <LibGfx/Filters/MatrixFilter.h>
 
 namespace Gfx {
 
-class HueRotateFilter : public ColorFilter {
+class HueRotateFilter : public MatrixFilter {
 public:
     HueRotateFilter(float angle_degrees)
-        : ColorFilter(angle_degrees)
-        , m_operation(calculate_operation_matrix(angle_degrees))
+        : MatrixFilter(calculate_hue_rotate_matrix(angle_degrees))
     {
     }
 
@@ -25,37 +22,12 @@ public:
         return true;
     }
 
-    float angle_degrees() const
-    {
-        return m_amount;
-    }
-
     virtual StringView class_name() const override { return "HueRotateFilter"sv; }
 
-protected:
-    Color convert_color(Color original) override
-    {
-        FloatVector3 rgb = {
-            original.red() / 256.0f,
-            original.green() / 256.0f,
-            original.blue() / 256.0f,
-        };
-        rgb = m_operation * rgb;
-        auto safe_float_to_u8 = [](float value) -> u8 {
-            return static_cast<u8>(AK::clamp(value, 0.0f, 1.0f) * 256);
-        };
-        return Color {
-            safe_float_to_u8(rgb[0]),
-            safe_float_to_u8(rgb[1]),
-            safe_float_to_u8(rgb[2]),
-            original.alpha()
-        };
-    }
-
 private:
-    static FloatMatrix3x3 calculate_operation_matrix(float angle)
+    static FloatMatrix3x3 calculate_hue_rotate_matrix(float angle_degrees)
     {
-        float angle_rads = angle * (AK::Pi<float> / 180);
+        float angle_rads = angle_degrees * (AK::Pi<float> / 180);
         float cos_angle = 0;
         float sin_angle = 0;
         AK::sincos(angle_rads, sin_angle, cos_angle);
@@ -77,8 +49,6 @@ private:
         };
         // clang-format on
     }
-
-    FloatMatrix3x3 m_operation;
 };
 
 }

Userland/Libraries/LibGfx/Filters/MatrixFilter.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Math.h>
+#include <LibGfx/Filters/ColorFilter.h>
+#include <LibGfx/Matrix3x3.h>
+
+namespace Gfx {
+
+class MatrixFilter : public ColorFilter {
+public:
+    MatrixFilter(FloatMatrix3x3 operation, float amount = 1.0f)
+        : ColorFilter(amount)
+        , m_operation(operation)
+    {
+    }
+
+protected:
+    Color convert_color(Color original) override
+    {
+        auto constexpr u8_max = AK::NumericLimits<u8>::max();
+        auto safe_float_to_u8 = [](float value) -> u8 {
+            return AK::clamp(static_cast<int>(value * u8_max), 0, u8_max);
+        };
+        FloatVector3 rgb = {
+            original.red() / float(u8_max),
+            original.green() / float(u8_max),
+            original.blue() / float(u8_max),
+        };
+        rgb = m_operation * rgb;
+        return Color {
+            safe_float_to_u8(rgb[0]),
+            safe_float_to_u8(rgb[1]),
+            safe_float_to_u8(rgb[2]),
+            original.alpha()
+        };
+    }
+
+private:
+    FloatMatrix3x3 const m_operation;
+};
+
+}