Implemented Crop method, and added tests

Test/CMakeLists.txt

@@ -30,6 +30,7 @@ add_executable(Test
         SwapChannels.cpp
         Rotate.cpp
         ConvertColormode.cpp
+        Crop.cpp
 )
 
 # Move test images to build dir

Test/Crop.cpp

@@ -0,0 +1,100 @@
+#include <Bmp.h>
+#include <stdexcept>
+#include "Catch2.h"
+
+using namespace Leonetienne::BmpPP;
+using namespace Eule;
+
+// Tests that cropping produces the correct result
+TEST_CASE(__FILE__"/HappyPath", "[Cropping]")
+{
+    SECTION("RGB") {
+        // Read an image
+        BMP bmp("base_hachi.bmp");
+
+        // Crop it
+        bmp = bmp.Crop(
+            Vector2i(95, 83),
+            Vector2i(149, 239)
+        );
+
+        // Read reference image
+        const BMP reference("base_hachi_cropped.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    SECTION("RGBA") {
+        // Read an image
+        BMP bmp("basea_hachi.bmp");
+
+        // Crop it
+        bmp = bmp.Crop(
+            Vector2i(95, 83),
+            Vector2i(149, 239)
+        );
+
+        // Read reference image
+        const BMP reference("basea_hachi_cropped.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    return;
+}
+
+// Tests that cropping with extreme points works (like, 0,0, widht, height)
+TEST_CASE(__FILE__"/ExtremePoints", "[Cropping]")
+{
+    SECTION("Crop includes {0,0}") {
+        // Read an image
+        BMP bmp("base_hachi.bmp");
+
+        // Crop it
+        bmp = bmp.Crop(
+            Vector2i(0, 0),
+            Vector2i(252, 337)
+        );
+
+        // Read reference image
+        const BMP reference("base_hachi_cropped_extreme_topleft.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    SECTION("Crop includes {width, height}") {
+        // Read an image
+        BMP bmp("base_hachi.bmp");
+
+        // Crop it
+        bmp = bmp.Crop(
+            Vector2i(96, 54),
+            bmp.GetDimensions() - Vector2i(96, 54) // As far-right as we can get
+        );
+
+        // Read reference image
+        const BMP reference("base_hachi_cropped_extreme_bottomright.bmp");
+
+        // Assert that they are equal
+        REQUIRE(bmp == reference);
+    }
+
+    SECTION("Crop includes {0, 0, width, height}") {
+        // Read an image
+        BMP bmp("base_hachi.bmp");
+
+        // Crop it (without taking away anything, lol)
+        BMP cropped = bmp.Crop(
+            Vector2i(0, 0),
+            bmp.GetDimensions() // As far-right as we can get
+        );
+
+        // Assert that the cropped image remains the same (as we cropped from 0,0 to width,height)
+        REQUIRE(bmp == cropped);
+    }
+
+    return;
+}