Merge pull request #4 from aliozertekin/contribute

Bitmap rotation handling

Author: baderouaich

README.md

@@ -236,6 +236,57 @@ int main(void) {
 ![modified-penguin](images/modified-penguin.bmp)
 
 
+<br><br>
+<strong>Rotate, Flip The Penguin</strong>
+<br>
+
+```cpp
+#include "BitmapPlusPlus.hpp"
+#include <iostream>
+
+int main(void) {
+    try {
+        bmp::Bitmap image;
+
+        // Load the original bitmap
+        image.load(std::filesystem::path(ROOT_DIR) / "images" / "penguin.bmp");
+
+        // Test vertical flip
+        bmp::Bitmap flipped_v = image.flip_v();
+        flipped_v.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_flipped_v.bmp");
+        std::cout << "Vertical flip saved as penguin_flipped_v.bmp" << std::endl;
+
+        // Test horizontal flip
+        bmp::Bitmap flipped_h = image.flip_h();
+        flipped_h.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_flipped_h.bmp");
+        std::cout << "Horizontal flip saved as penguin_flipped_h.bmp" << std::endl;
+
+        // Test rotate 90 degrees to the right
+        bmp::Bitmap rotated_right = image.rotate_90_right();
+        rotated_right.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_rotated_right.bmp");
+        std::cout << "Rotated 90 degrees right saved as penguin_rotated_right.bmp" << std::endl;
+
+        // Test rotate 90 degrees to the left
+        bmp::Bitmap rotated_left = image.rotate_90_left();
+        rotated_left.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_rotated_left.bmp");
+        std::cout << "Rotated 90 degrees left saved as penguin_rotated_left.bmp" << std::endl;
+
+        return EXIT_SUCCESS;
+    }
+    catch (const bmp::Exception& e) {
+        std::cerr << "Error: " << e.what() << std::endl;
+        return EXIT_FAILURE;
+    }
+}
+
+```
+![penguin](images/penguin.bmp)
+![penguin_flipped_v](images/rotated/penguin_flipped_v.bmp)
+![penguin_flipped_h](images/rotated/penguin_flipped_h.bmp)
+![penguin_rotated_right](images/rotated/penguin_rotated_right.bmp)
+![penguin_rotated_left](images/rotated/penguin_rotated_left.bmp)
+
+
 <br><br>
 
 <strong>Chess Board</strong>

examples/rotation.cpp

@@ -0,0 +1,38 @@
+#include "BitmapPlusPlus.hpp"
+#include <iostream>
+
+int main(void) {
+    try {
+        bmp::Bitmap image;
+
+        // Load the original bitmap
+        image.load(std::filesystem::path(ROOT_DIR) / "images" / "penguin.bmp");
+
+        // Test vertical flip
+        bmp::Bitmap flipped_v = image.flip_v();
+        flipped_v.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_flipped_v.bmp");
+        std::cout << "Vertical flip saved as penguin_flipped_v.bmp" << std::endl;
+
+        // Test horizontal flip
+        bmp::Bitmap flipped_h = image.flip_h();
+        flipped_h.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_flipped_h.bmp");
+        std::cout << "Horizontal flip saved as penguin_flipped_h.bmp" << std::endl;
+
+        // Test rotate 90 degrees to the right
+        bmp::Bitmap rotated_right = image.rotate_90_right();
+        rotated_right.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_rotated_right.bmp");
+        std::cout << "Rotated 90 degrees right saved as penguin_rotated_right.bmp" << std::endl;
+
+        // Test rotate 90 degrees to the left
+        bmp::Bitmap rotated_left = image.rotate_90_left();
+        rotated_left.save(std::filesystem::path(ROOT_DIR) / "images" / "rotated" / "penguin_rotated_left.bmp");
+        std::cout << "Rotated 90 degrees left saved as penguin_rotated_left.bmp" << std::endl;
+
+        return EXIT_SUCCESS;
+    }
+    catch (const bmp::Exception& e) {
+        std::cerr << "Error: " << e.what() << std::endl;
+        return EXIT_FAILURE;
+    }
+}
+

images/rotated/penguin_flipped_h.bmp

@@ -466,6 +466,70 @@ namespace bmp {
       m_pixels[IX(x, y)] = color;
     }
 
+
+    /**
+    *	Vertically flips the bitmap and returns the flipped version
+    *
+    */
+    Bitmap flip_v() {
+        Bitmap finished(m_width, m_height);
+        for (std::int32_t x = 0; x < m_width; ++x) {
+            for (std::int32_t y = 0; y < m_height; ++y) {
+                // Calculate the reverse y-index
+                finished.m_pixels[IX(x, y)] = m_pixels[IX(x, m_height - 1 - y)];
+            }
+        }
+        return finished;
+    }
+
+    /**
+    *	Horizontally flips the bitmap and returns the flipped version
+    *
+    */
+    Bitmap flip_h() {
+        Bitmap finished(m_width, m_height);
+        for (std::int32_t y = 0; y < m_height; ++y) {
+            for (std::int32_t x = 0; x < m_width; ++x) {
+                // Calculate the reverse x-index
+                finished.m_pixels[IX(x, y)] = m_pixels[IX(m_width - 1 - x, y)];
+            }
+        }
+        return finished;
+    }
+
+    /**
+    *	Rotates the bitmap to the right and returns the rotated version
+    *
+    */
+    Bitmap rotate_90_left() {
+        Bitmap finished(m_height, m_width); // Swap dimensions
+
+        for (std::int32_t y = 0; y < m_height; ++y) {
+            std::int32_t y_offset = y * m_width; // Precompute row start index
+            for (std::int32_t x = 0; x < m_width; ++x) {
+                // Original pixel at (x, y) moves to (y, m_width - 1 - x)
+                finished.m_pixels[(m_width - 1 - x) * m_height + y] = m_pixels[y_offset + x];
+            }
+        }
+
+        return finished;
+    }
+
+    /**
+    *	Rotates the bitmap to the left and returns the rotated version
+    *
+    */
+    Bitmap rotate_90_right() {
+        Bitmap finished(m_height, m_width); // Swap dimensions
+        for (std::int32_t y = 0; y < m_height; ++y) {
+            std::int32_t y_offset = y * m_width; // Precompute row start index
+            for (std::int32_t x = 0; x < m_width; ++x) {
+                finished.m_pixels[x * m_height + (m_height - 1 - y)] = m_pixels[y_offset + x];
+            }
+        }
+
+        return finished;
+    }
     /**
      *	Saves Bitmap pixels into a file
      *   @throws bmp::Exception on error
@@ -584,7 +648,12 @@ namespace bmp {
     [[nodiscard]] constexpr std::size_t IX(const std::int32_t x, const std::int32_t y) const noexcept {
       return static_cast<std::size_t>(x) + static_cast<std::size_t>(m_width) * static_cast<std::size_t>(y);
     }
-
+    /**
+    *	Converts 2D x,y coords into 1D index, with changed width
+    */
+    [[nodiscard]] constexpr std::size_t IX(const std::int32_t x, const std::int32_t y, const std::int32_t width) const noexcept {
+        return static_cast<std::size_t>(x) + static_cast<std::size_t>(m_width) * static_cast<std::size_t>(y);
+    }
     /**
      *	Returns true if x,y coords are within boundaries
      */