1 files changed, 29 insertions, 4 deletions

diff --git a/beamer/viewer/screen/screen.js b/beamer/viewer/screen/screen.js
index 3d95acd..4bebab4 100644
--- a/beamer/viewer/screen/screen.js
+++ b/beamer/viewer/screen/screen.js
@@ -47,9 +47,32 @@ class Screen {
     };
   }
 
+  _getScreenOffsets(secondary, width, height) {
+    if (!secondary) return { xOffset: 0, yOffset: 0 };
+
+    const viewport = this.page.getViewport(1);
+    if (viewport.width > viewport.height)
+      return { xOffset: -width, yOffset: 0 };
+    else
+      return { xOffset: 0, yOffset: -height };
+  }
+
   _getSlideSizeRatio() {
     const viewport = this.page.getViewport(1);
-    return (viewport.width / 2) / viewport.height;
+
+    if (viewport.width > viewport.height)
+      return (viewport.width / 2) / viewport.height;
+    else
+      return viewport.width / (viewport.height / 2);
+  }
+
+  _getScaleFactor(width, height) {
+    const viewport = this.page.getViewport(1);
+
+    if (viewport.width > viewport.height)
+      return height / viewport.height;
+    else
+      return width / viewport.width;
   }
 
   _newCanvas(width, height, xOffset, yOffset) {
@@ -86,9 +109,11 @@ class Screen {
 
     const screenRatio = this._getSlideSizeRatio();
     const { width, height } = this._getScreenSize(screenRatio);
-    const scaleFactor = height / this.page.getViewport(1).height;
-    const xOffset = this.secondary ? -width : 0;
-    const { canvas, context } = this._newCanvas(width, height, xOffset, 0);
+    const scaleFactor = this._getScaleFactor(width, height);
+    const { xOffset, yOffset } =
+      this._getScreenOffsets(this.secondary, width, height);
+    const { canvas, context } =
+      this._newCanvas(width, height, xOffset, yOffset);
     this._render(canvas, context, scaleFactor);
   }
 }