ST_LAYOUT_DEBUG debugging environment

Author: krzyzanowskim

Sources/STTextViewAppKit/Gutter/STGutterLineNumberCell.swift

@@ -26,6 +26,12 @@ final class STGutterLineNumberCell: NSView {
         super.init(frame: .zero)
         wantsLayer = true
         clipsToBounds = true
+
+        if ProcessInfo().environment["ST_LAYOUT_DEBUG"] == "YES" {
+            layer?.backgroundColor = NSColor.systemOrange.withAlphaComponent(0.05).cgColor
+            layer?.borderColor = NSColor.systemOrange.cgColor
+            layer?.borderWidth = 0.5
+        }
     }
 
     override var isFlipped: Bool {

Sources/STTextViewAppKit/STTextLayoutFragmentView.swift

@@ -26,7 +26,12 @@ final class STTextLayoutFragmentView: NSView {
         super.init(frame: frame)
         wantsLayer = true
         clipsToBounds = false // allow overdraw invisible characters
-        // layer?.backgroundColor = NSColor.red.withAlphaComponent(0.2).cgColor
+
+        if ProcessInfo().environment["ST_LAYOUT_DEBUG"] == "YES" {
+            layer?.backgroundColor = NSColor.systemOrange.withAlphaComponent(0.05).cgColor
+            layer?.borderColor = NSColor.systemOrange.cgColor
+            layer?.borderWidth = 0.5
+        }
 
         needsDisplay = true
     }

TextEdit/TextEdit.xcodeproj/xcshareddata/xcschemes/TextEdit.xcscheme

@@ -62,6 +62,11 @@
             value = "YES"
             isEnabled = "NO">
          </EnvironmentVariable>
+         <EnvironmentVariable
+            key = "ST_LAYOUT_DEBUG"
+            value = "YES"
+            isEnabled = "NO">
+         </EnvironmentVariable>
       </EnvironmentVariables>
    </LaunchAction>
    <ProfileAction