island: corner position helper for the OBS webcam

1 files changed, 8 insertions, 0 deletions

diff --git a/desktop/island/Logic.js b/desktop/island/Logic.js
index 24458cd..e687ac1 100644
--- a/desktop/island/Logic.js
+++ b/desktop/island/Logic.js
@@ -71,3 +71,11 @@ function obsElapsed(ms) {
     const mmss = `${two(Math.floor(s / 60) % 60)}:${two(s % 60)}`;
     return h ? `${h}:${mmss}` : mmss;
 }
+
+// Top-left position for a w x h source on a W x H canvas with margin m, in one
+// of the four corners. Anything unrecognised reads as top-left.
+function cornerPos(corner, W, H, w, h, m) {
+    const right = corner === "tr" || corner === "br";
+    const bottom = corner === "bl" || corner === "br";
+    return { x: right ? W - w - m : m, y: bottom ? H - h - m : m };
+}