Improve the text tool's behaviour when pasting without text in the cl…

…ipboard

- Avoid an unhandled exception if the clipboard doesn't have text (e.g. an image). This should be treated as if the clipboard was empty
- When editing, consume the paste event so that it doesn't pull the user out of editing to attempt to paste as an image.

Bug: #2047495

CHANGELOG.md

@@ -35,6 +35,7 @@ Thanks to the following contributors who worked on this release:
 - Fixed a bug where dragging a control point in the Curves dialog could unexpectedly erase other control points ([#1973602](https://bugs.launchpad.net/pinta/+bug/1973602))
 - Improved error handling when loading incompatible add-ins ([#2047274](https://bugs.launchpad.net/pinta/+bug/2047274))
 - The Clone Stamp tool no longer resets the destination offset after each stroke ([#2031257](https://bugs.launchpad.net/pinta/+bug/2031257))
+- Fixed potential errors when pasting in the text tool if the clipboard didn't contain text ([#2047495](https://bugs.launchpad.net/pinta/+bug/2047495))
 
 ## [2.1.1](https://github.com/PintaProject/Pinta/releases/tag/2.1.1) - 2023/02/26
 

Pinta.Core/Classes/Re-editable/Text/TextEngine.cs

@@ -348,8 +348,15 @@ public void PerformCut (Gdk.Clipboard clipboard)
 	/// </summary>
 	public async Task<bool> PerformPaste (Gdk.Clipboard clipboard)
 	{
-		string? txt = await clipboard.ReadTextAsync ();
-		if (String.IsNullOrEmpty (txt))
+		string? txt;
+		try {
+			txt = await clipboard.ReadTextAsync (); 
+		} catch (GLib.GException) {
+			// The clipboard probably contained an image.
+			return false;
+		} 
+
+		if (string.IsNullOrEmpty (txt))
 			return false;
 
 		if (HasSelection ())

Pinta.Tools/Tools/TextTool.cs

@@ -1082,12 +1082,12 @@ protected override async Task<bool> OnHandlePaste (Document document, Clipboard
 		if (!is_editing)
 			return false;
 
-		if (await CurrentTextEngine.PerformPaste (cb)) {
+		if (await CurrentTextEngine.PerformPaste (cb))
 			RedrawText (true, true);
-			return true;
-		}
 
-		return false;
+		// Always consume the paste event when editing, otherwise this will pull the user out
+		// of editing to attempt to paste an image.
+		return true;
 	}
 
 	protected override bool OnHandleCopy (Document document, Clipboard cb)