LibGfx: Add Bitmap::rotated and Bitmap::flipped

Author: https://github.com/asliturk
Commit: 8e9d031cb3
Pull-request: https://github.com/SerenityOS/serenity/pull/1756
Reviewed-by: https://github.com/awesomekling

Libraries/LibGfx/Bitmap.cpp

@@ -98,6 +98,48 @@ Bitmap::Bitmap(BitmapFormat format, NonnullRefPtr<SharedBuffer>&& shared_buffer,
     ASSERT(format != BitmapFormat::Indexed8);
 }
 
+NonnullRefPtr<Gfx::Bitmap> Bitmap::rotated(Gfx::RotationDirection rotation_direction) const
+{
+    auto w = this->width();
+    auto h = this->height();
+
+    auto new_bitmap = Gfx::Bitmap::create(this->format(), { h, w });
+
+    for (int i = 0; i < w; i++) {
+        for (int j = 0; j < h; j++) {
+            Color color;
+            if (rotation_direction == Gfx::RotationDirection::Left)
+                color = this->get_pixel(w - i - 1, j);
+            else
+                color = this->get_pixel(i, h - j - 1);
+
+            new_bitmap->set_pixel(j, i, color);
+        }
+    }
+
+    return new_bitmap;
+}
+
+NonnullRefPtr<Gfx::Bitmap> Bitmap::flipped(Gfx::Orientation orientation) const
+{
+    auto w = this->width();
+    auto h = this->height();
+
+    auto new_bitmap = Gfx::Bitmap::create(this->format(), { w, h });
+
+    for (int i = 0; i < w; i++) {
+        for (int j = 0; j < h; j++) {
+            Color color = this->get_pixel(i, j);
+            if (orientation == Orientation::Vertical)
+                new_bitmap->set_pixel(i, h - j - 1, color);
+            else
+                new_bitmap->set_pixel(w - i - 1, j, color);
+        }
+    }
+
+    return new_bitmap;
+}
+
 NonnullRefPtr<Bitmap> Bitmap::to_bitmap_backed_by_shared_buffer() const
 {
     if (m_shared_buffer)

Libraries/LibGfx/Bitmap.h

@@ -42,6 +42,11 @@ enum class BitmapFormat {
     Indexed8
 };
 
+enum RotationDirection {
+    Left,
+    Right
+};
+
 class Bitmap : public RefCounted<Bitmap> {
 public:
     static NonnullRefPtr<Bitmap> create(BitmapFormat, const Size&);
@@ -50,6 +55,8 @@ public:
     static RefPtr<Bitmap> load_from_file(const StringView& path);
     static NonnullRefPtr<Bitmap> create_with_shared_buffer(BitmapFormat, NonnullRefPtr<SharedBuffer>&&, const Size&);
 
+    NonnullRefPtr<Gfx::Bitmap> rotated(Gfx::RotationDirection) const;
+    NonnullRefPtr<Gfx::Bitmap> flipped(Gfx::Orientation) const;
     NonnullRefPtr<Bitmap> to_bitmap_backed_by_shared_buffer() const;
 
     ShareableBitmap to_shareable_bitmap(pid_t peer_pid = -1) const;