Use a custom I-beam mouse cursor for pre-Mojave OS versions

src/MacVim/MMTextViewHelper.m

@@ -1028,6 +1028,38 @@ - (void)dragTimerFired:(NSTimer *)timer
 
 - (void)setCursor
 {
+    static NSCursor *ibeamCursor = nil;
+
+    if (!ibeamCursor) {
+        if (floor(NSAppKitVersionNumber) >= NSAppKitVersionNumber10_14)
+        {
+            // macOS 10.14 (Mojave) introduced dark mode, and seems to have
+            // added a thick white border around the system I-beam cursor,
+            // which makes it legible across bright and dark background. Just
+            // use it.
+            ibeamCursor = [NSCursor IBeamCursor];
+        }
+        else
+        {
+            // Pre-Mojave versions the I-beam cursors doesn't have the strong
+            // white background and is hard to read on dark background. Use a
+            // custom I-beam cursor that has better contrast against dark
+            // backgrounds.
+            NSImage *ibeamImage = [NSImage imageNamed:@"ibeam"];
+            if (ibeamImage) {
+                NSSize size = [ibeamImage size];
+                NSPoint hotSpot = { size.width*.5f, size.height*.5f };
+
+                ibeamCursor = [[NSCursor alloc]
+                               initWithImage:ibeamImage hotSpot:hotSpot];
+            }
+            if (!ibeamCursor) {
+                ASLogWarn(@"Failed to load custom Ibeam cursor");
+                ibeamCursor = [NSCursor IBeamCursor];
+            }
+        }
+    }
+
     // This switch should match mshape_names[] in misc2.c.
     //
     // We don't fill every shape here. Only the ones that make sense and have
@@ -1037,7 +1069,7 @@ - (void)setCursor
             [[NSCursor arrowCursor] set]; break;
         //case 1: // blank
         case 2: // beam
-            [[NSCursor IBeamCursor] set]; break;
+            [ibeamCursor set]; break;
         case 3: // updown
         case 4: // udsizing
             [[NSCursor resizeUpDownCursor] set]; break;

src/MacVim/MacVim.h

@@ -48,6 +48,9 @@
 #ifndef NSAppKitVersionNumber10_13
 # define NSAppKitVersionNumber10_13 1561
 #endif
+#ifndef NSAppKitVersionNumber10_14
+# define NSAppKitVersionNumber10_14 1671
+#endif
 
 #if MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_12
 // Deprecated constants in 10.12 SDK

src/MacVim/MacVim.xcodeproj/project.pbxproj

@@ -53,6 +53,7 @@
 		1DCD00D30E50B2B700460166 /* Undo.png in Resources */ = {isa = PBXBuildFile; fileRef = 1DCD00BE0E50B2B700460166 /* Undo.png */; };
 		1DD04DEC0C529C5E006CDC2B /* Credits.rtf in Resources */ = {isa = PBXBuildFile; fileRef = 1DD04DEB0C529C5E006CDC2B /* Credits.rtf */; };
 		1DD0C20C0C60FFB4008CD84A /* gvimrc in Copy Vim Runtime Files */ = {isa = PBXBuildFile; fileRef = 1DD0C20A0C60FF9A008CD84A /* gvimrc */; };
+		1DD3D51E0D82D4C9006E4320 /* ibeam.png in Resources */ = {isa = PBXBuildFile; fileRef = 1DD3D51D0D82D4C9006E4320 /* ibeam.png */; };
 		1DD66ECE0C803D3600EBDAB3 /* MMApplication.m in Sources */ = {isa = PBXBuildFile; fileRef = 1DD66ECC0C803D3600EBDAB3 /* MMApplication.m */; };
 		1DD9F5E50C85D60500E8D5A5 /* SystemColors.plist in Resources */ = {isa = PBXBuildFile; fileRef = 1DD9F5E40C85D60500E8D5A5 /* SystemColors.plist */; };
 		1DE3F8E70D50F80500052B9E /* Preferences.nib in Resources */ = {isa = PBXBuildFile; fileRef = 1DE3F8E50D50F80500052B9E /* Preferences.nib */; };
@@ -228,6 +229,7 @@
 		1DCD00BE0E50B2B700460166 /* Undo.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; name = Undo.png; path = Toolbar/Undo.png; sourceTree = "<group>"; };
 		1DD04DEB0C529C5E006CDC2B /* Credits.rtf */ = {isa = PBXFileReference; lastKnownFileType = text.rtf; path = Credits.rtf; sourceTree = "<group>"; };
 		1DD0C20A0C60FF9A008CD84A /* gvimrc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = gvimrc; sourceTree = "<group>"; };
+		1DD3D51D0D82D4C9006E4320 /* ibeam.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = ibeam.png; sourceTree = "<group>"; };
 		1DD66ECB0C803D3600EBDAB3 /* MMApplication.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; path = MMApplication.h; sourceTree = "<group>"; };
 		1DD66ECC0C803D3600EBDAB3 /* MMApplication.m */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.objc; path = MMApplication.m; sourceTree = "<group>"; };
 		1DD9F5E40C85D60500E8D5A5 /* SystemColors.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = SystemColors.plist; sourceTree = "<group>"; };
@@ -554,6 +556,7 @@
 				1D8BEA73104992290069B072 /* FindAndReplace.nib */,
 				0395A8A90D72D88B00881434 /* General.png */,
 				1D22374A0E45DF4800E6FFFF /* Advanced.png */,
+				1DD3D51D0D82D4C9006E4320 /* ibeam.png */,
 				1D0F11480D58C77800D5DA09 /* Font */,
 				1DE9726C0C48050600F96A9F /* Toolbar */,
 				1DD9F5E40C85D60500E8D5A5 /* SystemColors.plist */,
@@ -842,6 +845,7 @@
 				1DD9F5E50C85D60500E8D5A5 /* SystemColors.plist in Resources */,
 				1DE3F8E70D50F80500052B9E /* Preferences.nib in Resources */,
 				0395A8AA0D72D88B00881434 /* General.png in Resources */,
+				1DD3D51E0D82D4C9006E4320 /* ibeam.png in Resources */,
 				1D22374B0E45DF4800E6FFFF /* Advanced.png in Resources */,
 				1DCD00BF0E50B2B700460166 /* Attention.png in Resources */,
 				1DCD00C00E50B2B700460166 /* Copy.png in Resources */,