diff --git a/src/svg.panzoom.js b/src/svg.panzoom.js
index 2e02dba..cb4d5dc 100644
--- a/src/svg.panzoom.js
+++ b/src/svg.panzoom.js
@@ -84,18 +84,18 @@ extend(Svg, {
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMID ||
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMID ||
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMID) {
-              viewportTopOffset = -offset / 2
-              viewportBottomOffset = offset / 2
+              viewportTopOffset = offset / 2
+              viewportBottomOffset = -offset / 2
             } else if (
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMIN ||
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMIN ||
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMIN) {
-              viewportBottomOffset = offset
+              viewportBottomOffset = -offset
             } else if (
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMAX ||
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMAX ||
               preserveAspectRatio.align === preserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMAX) {
-              viewportTopOffset = -offset
+              viewportTopOffset = offset
             }
           }