1 files changed, 53 insertions, 0 deletions
diff --git a/src/util.cpp b/src/util.cpp
index 19d590e..672b089 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -40,3 +40,56 @@ unique_fd::~unique_fd()
         close(this->fd);
     }
 }
+
+void rectangle::fit(unsigned long to_width, unsigned long to_height)
+{
+    // fit rect within (to_width x to_height)
+
+    if (to_width <= width()) {
+        // scale to fit with
+        set_bottom(top() + (static_cast<long>(to_width) * height() / width()) - 1);
+        set_right(left() + to_width - 1);
+    } else {
+        // scale to fit height
+        set_right(left() + (static_cast<long>(to_height) * width () / height()) - 1);
+        set_bottom(top() + to_height - 1);
+    }
+}
+
+void rectangle::center(unsigned long outer_w, unsigned long outer_h)
+{
+    long inner_w = width();
+    long inner_h = height();
+
+    set_left((outer_w - inner_w) / 2);
+    set_right(left() + inner_w - 1);
+    set_top((outer_h - inner_h) / 2);
+    set_bottom(top() + inner_h - 1);
+}
+
+void rectangle::set_aspect(double ratio)
+{
+    // aspect ratio is width:height (= width/height)
+    // e.g. Landscape of HD's ratio is 16:9 (= 1.777...)
+    //      Portrait of HD's ratio is 9:16 (= 0.5625)
+    //
+    // width / height = ratio
+    // width * height = area
+    //
+    // width = sqrt(ratio * area)
+    // height = width / ratio
+
+    long orig_w = width();
+    long orig_h = height();
+
+    if (ratio >= 1) {
+        // width >= height
+        // try to keep width
+        set_right(left() + orig_w - 1);
+        set_bottom(top() + static_cast<long>(orig_w / ratio + 0.5) - 1);
+    } else {
+        set_bottom(top() + orig_h - 1);
+        set_right(left() + static_cast<long>(orig_h * ratio + 0.5) - 1);
+    }
+}
+