Info Inspector: Now displays ReplayGain info as tooltip for status text

Base.lproj/InfoInspector.xib

@@ -335,6 +335,7 @@
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                         <connections>
+                            <binding destination="-2" name="toolTip" keyPath="valueToDisplay.gainInfo" id="BUp-Hu-Szq"/>
                             <binding destination="-2" name="value" keyPath="valueToDisplay.gainCorrection" id="JgZ-wN-peX"/>
                         </connections>
                     </textField>

Playlist/PlaylistEntry.h

@@ -153,6 +153,8 @@
 
 @property(readonly) NSString *gainCorrection;
 
+@property(readonly) NSString *gainInfo;
+
 @property double currentPosition;
 
 @property(retain) NSString *endian;

Playlist/PlaylistEntry.m

@@ -137,6 +137,11 @@
     return [NSSet setWithObjects:@"replayGainAlbumGain", @"replayGainAlbumPeak", @"replayGainTrackGain", @"replayGainTrackPeak", @"volume", nil];
 }
 
++ (NSSet *)keyPathsForValuesAffectingGainInfo
+{
+    return [NSSet setWithObjects:@"replayGainAlbumGain", @"replayGainAlbumPeak", @"replayGainTrackGain", @"replayGainTrackPeak", @"volume", nil];
+}
+
 - (NSString *)description
 {
     return [NSString stringWithFormat:@"PlaylistEntry %li:(%@)", self.index, self.URL];
@@ -362,7 +367,7 @@
         else
             return @"Track Gain";
     }
-    else if (volume)
+    else if (volume && volume != 1)
     {
         return @"Volume scale";
     }
@@ -372,6 +377,33 @@
     }
 }
 
+@dynamic gainInfo;
+- (NSString *)gainInfo
+{
+    NSMutableArray * gainItems = [[NSMutableArray alloc] init];
+    if (replayGainAlbumGain)
+    {
+        [gainItems addObject:[NSString stringWithFormat:@"Album Gain: %+.2f dB", replayGainAlbumGain]];
+    }
+    if (replayGainAlbumPeak)
+    {
+        [gainItems addObject:[NSString stringWithFormat:@"Album Peak: %.6f", replayGainAlbumPeak]];
+    }
+    if (replayGainTrackGain)
+    {
+        [gainItems addObject:[NSString stringWithFormat:@"Track Gain: %+.2f dB", replayGainTrackGain]];
+    }
+    if (replayGainTrackPeak)
+    {
+        [gainItems addObject:[NSString stringWithFormat:@"Track Peak: %.6f", replayGainTrackPeak]];
+    }
+    if (volume && volume != 1)
+    {
+        [gainItems addObject:[NSString stringWithFormat:@"Volume Scale: %.2f%C", volume, (unichar)0x00D7]];
+    }
+    return [gainItems componentsJoinedByString:@"\n"];
+}
+
 @dynamic positionText;
 - (NSString *)positionText
 {