feat: space as pagedown in read-only (#47)

Similar shift-space as pageup, as in browsers, command line

Author: gerhardol

Project/Src/Actions/MiscActions.cs

@@ -655,6 +655,36 @@ public override void Execute(TextArea textArea)
         }
     }
 
+    public class Space : AbstractEditAction
+    {
+        /// <remarks>
+        ///     Executes this edit action
+        /// </remarks>
+        /// <param name="textArea">The <see cref="ItextArea" /> which is used for callback purposes</param>
+        public override void Execute(TextArea textArea)
+        {
+            if (!textArea.Document.ReadOnly)
+                return;
+
+            (new MovePageDown()).Execute(textArea);
+        }
+    }
+
+    public class ShiftSpace : AbstractEditAction
+    {
+        /// <remarks>
+        ///     Executes this edit action
+        /// </remarks>
+        /// <param name="textArea">The <see cref="ItextArea" /> which is used for callback purposes</param>
+        public override void Execute(TextArea textArea)
+        {
+            if (!textArea.Document.ReadOnly)
+                return;
+
+            (new MovePageUp()).Execute(textArea);
+        }
+    }
+
     public class Return : AbstractEditAction
     {
         /// <remarks>

Project/Src/Gui/TextArea.cs

@@ -803,7 +803,7 @@ public bool ExecuteDialogKey(Keys keyData)
                 return true;
 
             // if not (or the process was 'silent', use the standard edit actions
-            var action = MotherTextEditorControl?.GetEditAction(keyData);
+            var action = MotherTextEditorControl?.GetEditAction(keyData, Document.ReadOnly);
             AutoClearSelection = true;
             if (action != null)
             {

Project/Src/Gui/TextEditorControlBase.cs

@@ -37,6 +37,12 @@ public abstract class TextEditorControlBase : UserControl
         /// </summary>
         protected Dictionary<Keys, IEditAction> editactions = new Dictionary<Keys, IEditAction>();
 
+        /// <summary>
+        ///    Key combinations for actions only available in read-only mode.
+        ///    In read-write these keys are ignored.
+        /// </summary>
+        protected HashSet<Keys> readonlyactions = new();
+
         private Encoding encoding;
         private int updateLevel;
 
@@ -183,14 +189,14 @@ protected virtual void OnReloadHighlighting(object sender, EventArgs e)
             }
         }
 
-        public bool IsEditAction(Keys keyData)
+        public bool IsEditAction(Keys keyData, bool readOnly)
         {
-            return editactions.ContainsKey(keyData);
+            return editactions.ContainsKey(keyData) && (readOnly || !readonlyactions.Contains(keyData));
         }
 
-        internal IEditAction GetEditAction(Keys keyData)
+        internal IEditAction GetEditAction(Keys keyData, bool readOnly)
         {
-            if (!IsEditAction(keyData))
+            if (!IsEditAction(keyData, readOnly))
                 return null;
             return editactions[keyData];
         }
@@ -231,6 +237,10 @@ private void GenerateDefaultActions()
             editactions[Keys.PageUp | Keys.Shift] = new ShiftMovePageUp();
             editactions[Keys.PageDown] = new MovePageDown();
             editactions[Keys.PageDown | Keys.Shift] = new ShiftMovePageDown();
+            editactions[Keys.Space] = new Space();
+            readonlyactions.Add(Keys.Space);
+            editactions[Keys.Space | Keys.Shift] = new ShiftSpace();
+            readonlyactions.Add(Keys.Space | Keys.Shift);
 
             editactions[Keys.Return] = new Return();
             editactions[Keys.Tab] = new Tab();