Fix GetTextOrientation by cleanly checking if rotation is divisible by 90 and fix #913

src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs

@@ -1,5 +1,7 @@
 namespace UglyToad.PdfPig.Tests.Integration
 {
+    using Content;
+
     public class GithubIssuesTests
     {
         [Fact]
@@ -22,5 +24,32 @@
                 Assert.StartsWith("Value cannot be null.", ex.Message);
             }
         }
+
+        [Fact]
+        public void Issue913()
+        {
+            var doc = IntegrationHelpers.GetSpecificTestDocumentPath("Rotation 45.pdf");
+
+            using (var document = PdfDocument.Open(doc))
+            {
+                var page1 = document.GetPage(1);
+
+                for (int l = 131; l <= 137; ++l)
+                {
+                    var letter = page1.Letters[l];
+                    Assert.Equal(TextOrientation.Other, letter.TextOrientation);
+                    Assert.Equal(45.0, letter.GlyphRectangle.Rotation, 5);
+                }
+
+                var page2 = document.GetPage(2);
+                Assert.Equal(157, page2.Letters.Count);
+
+                var page3 = document.GetPage(3);
+                Assert.Equal(283, page3.Letters.Count);
+
+                var page4 = document.GetPage(4);
+                Assert.Equal(304, page4.Letters.Count);
+            }
+        }
     }
 }

src/UglyToad.PdfPig/Content/Letter.cs

@@ -175,13 +175,12 @@
         private TextOrientation GetTextOrientationRot()
         {
             double rotation = GlyphRectangle.Rotation;
-            int rotationInt = (int)Math.Round(rotation, MidpointRounding.AwayFromZero);
-
-            if (Math.Abs(rotation - rotationInt) >= 10e-5)
+            if (Math.Abs(rotation % 90) >= 10e-5)
             {
                 return TextOrientation.Other;
-            }
+            }
 
+            int rotationInt = (int)Math.Round(rotation, MidpointRounding.AwayFromZero);
             switch (rotationInt)
             {
                 case 0: