Merge pull request #1519 from bmlpg/patch-1

Account for image resolution units other than pixels per inch

main/SS/Util/ImageUtils.cs

@@ -22,7 +22,8 @@ namespace NPOI.SS.Util
     using NPOI.SS.UserModel;
     using NPOI.Util;
     using SixLabors.ImageSharp;
-
+    using SixLabors.ImageSharp.Metadata;
+    
     /**
      * @author Yegor Kozlov
      */
@@ -103,7 +104,28 @@ namespace NPOI.SS.Util
          */
         public static int[] GetResolution(Image r)
         {
-            return new int[] { (int)r.Metadata.HorizontalResolution, (int)r.Metadata.VerticalResolution };
+            ImageMetadata imageMetadata = r.Metadata;
+
+            double horizontalResolution = 0;
+            double verticalResolution = 0;
+
+            if (imageMetadata.ResolutionUnits == PixelResolutionUnit.PixelsPerMeter)
+            {
+                horizontalResolution = imageMetadata.HorizontalResolution * 0.0254D;
+                verticalResolution = imageMetadata.VerticalResolution * 0.0254D;
+            }
+            else if (imageMetadata.ResolutionUnits == PixelResolutionUnit.PixelsPerCentimeter)
+            {
+                horizontalResolution = imageMetadata.HorizontalResolution * 2.54D;
+                verticalResolution = imageMetadata.VerticalResolution * 2.54D;
+            }
+            else
+            {
+                horizontalResolution = imageMetadata.HorizontalResolution;
+                verticalResolution = imageMetadata.VerticalResolution;
+            }
+
+            return new int[] { (int)Math.Round(horizontalResolution), (int)Math.Round(verticalResolution) };
         }
 
         /**
@@ -296,4 +318,4 @@ namespace NPOI.SS.Util
         }
     }
 
-}
+}