Enable scaling

Fit screen, keep aspect rate.

Change-Id: Id11a07560fe254712aaab42018bfb4d1d87ad1df
Signed-off-by: Tadao Tanikawa <tanikawa.tadao@jp.panasonic.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/src/util.cpp b/src/util.cpp
index 2ae856f..068e7b8 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -37,3 +37,30 @@ unique_fd::~unique_fd() {
       close(this->fd);
    }
 }
+
+void rectangle::scale(int to_w, int to_h, bool keep_aspect)
+{
+  if (!keep_aspect) {
+    w = to_w;
+    h = to_h;
+    return;
+  }
+
+  int64_t resized_w = int64_t(to_h) * int64_t(w) / int64_t(h);
+
+  if (resized_w <= to_w) {
+    /* use aspect by height */
+    w = resized_w;
+    h = to_h;
+  } else {
+    /* use aspect by width */
+    w = to_h;
+    h = int64_t(to_h) * int64_t(h) / int64_t(w);
+  }
+}
+
+void rectangle::center(int outer_w, int outer_h)
+{
+  x = (outer_w - w) / 2;
+  y = (outer_h - h) / 2;
+}