Improve parsing of a geometry in the MagickGeometry class (#1855)

Author: dlemstra

src/Magick.NET/Enums/GeometryFlags.cs

@@ -6,11 +6,17 @@ namespace ImageMagick;
 internal enum GeometryFlags
 {
     NoValue = 0,
-    PercentValue = 0x1000,      /* '%'  percentage of something */
+    X = 0x0001,
+    Y = 0x0002,
+    Width = 0x0004,
+    Height = 0x0008,
+    Percentage = 0x1000,        /* '%'  percentage of something */
     IgnoreAspectRatio = 0x2000, /* '!'  resize no-aspect - special use flag */
     Less = 0x4000,              /* '<'  resize smaller - special use flag */
     Greater = 0x8000,           /* '>'  resize larger - spacial use flag */
     FillArea = 0x10000,         /* '^'  special handling needed */
     LimitPixels = 0x20000,      /* '@'  resize to area - special use flag */
     AspectRatio = 0x100000,     /* '~'  special handling needed  */
+    WidthHeight = Width | Height,
+    XYWidthHeight = X | Y | Width | Height,
 }