From 99a67d1fdbcc95e5545f734b7f416b23d79bb989 Mon Sep 17 00:00:00 2001
From: maxim <maxim@lazarus-ide.org>
Date: Thu, 22 Nov 2018 22:21:36 +0000
Subject: [PATCH] Merged revision(s) 59584 #e5a2420d88, 59596 #f435a9dc89 from
 trunk: SynEdit: fix caret blinking during code-completion drop down, if
 persistent-caret-is-none-blinking ........ SynEdit: (Win10 issue only) fix
 for "ghost" images of text-caret on Windows 10, in certain conditions where
 part of the editor is outside the physical screen. ........

git-svn-id: branches/fixes_2_0@59629 -
---
 components/synedit/syncompletion.pas | 14 ++++++++----
 components/synedit/synedit.pp        | 33 ++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/components/synedit/syncompletion.pas b/components/synedit/syncompletion.pas
index bb56556fdd..8048f2a53f 100644
--- a/components/synedit/syncompletion.pas
+++ b/components/synedit/syncompletion.pas
@@ -264,7 +264,7 @@ type
   private
     FAutoUseSingleIdent: Boolean;
     Form: TSynBaseCompletionForm;
-    FAddedPersistentCaret: boolean;
+    FAddedPersistentCaret, FChangedNoneBlink: boolean;
     FOnExecute: TNotifyEvent;
     FWidth: Integer;
     function GetCaseSensitive: boolean;
@@ -1458,6 +1458,7 @@ begin
 
   //Todo: This is dangerous, if other plugins also change/changed the flag.
   FAddedPersistentCaret := False;
+  FChangedNoneBlink := False;
 
   CurrentString := s;
   if Assigned(OnExecute) then
@@ -1474,8 +1475,11 @@ begin
   if (Form.CurrentEditor is TCustomSynEdit) then begin
     CurSynEdit:=TCustomSynEdit(Form.CurrentEditor);
     FAddedPersistentCaret := not(eoPersistentCaret in CurSynEdit.Options);
+    FChangedNoneBlink := (eoPersistentCaretStopBlink in CurSynEdit.Options2);
     if FAddedPersistentCaret then
       CurSynEdit.Options:=CurSynEdit.Options+[eoPersistentCaret];
+    if FChangedNoneBlink then
+      CurSynEdit.Options2:=CurSynEdit.Options2-[eoPersistentCaretStopBlink];
   end;
   Form.SetBounds(x,y,Form.Width,Form.Height);
   Form.Show;
@@ -1713,11 +1717,13 @@ procedure TSynBaseCompletion.Deactivate;
 var
   CurSynEdit: TCustomSynEdit;
 begin
-  if FAddedPersistentCaret and
-     (Form<>nil) and (Form.CurrentEditor is TCustomSynEdit)
+  if (Form<>nil) and (Form.CurrentEditor is TCustomSynEdit)
   then begin
     CurSynEdit:=TCustomSynEdit(Form.CurrentEditor);
-    CurSynEdit.Options:=CurSynEdit.Options-[eoPersistentCaret];
+    if FAddedPersistentCaret then
+      CurSynEdit.Options:=CurSynEdit.Options-[eoPersistentCaret];
+    if FChangedNoneBlink then
+      CurSynEdit.Options2:=CurSynEdit.Options2+[eoPersistentCaretStopBlink];
   end;
   if Assigned(Form) then Form.Deactivate;
 end;
diff --git a/components/synedit/synedit.pp b/components/synedit/synedit.pp
index 8b49851372..f28fd549f8 100644
--- a/components/synedit/synedit.pp
+++ b/components/synedit/synedit.pp
@@ -61,6 +61,35 @@ unit SynEdit;
                            // gtk2.12 paints faster directly
 {$ENDIF}
 
+{$IFDEF Windows}
+  (* * On Windows 10 there is an issue, where under certain conditions a "ghost" of the text caret remains visible.
+     That is one or a series of vertical black lines remain on the screen.
+     * This can be reproduced, by moving part (eg bottom) of editor off screen (not just behind the taskbar, but
+     off screen). Then press caret down to scroll. Ghost carets will scroll in with the new text.
+     Similar move caret to a place off-screen, unfocus editor, and refocus by clicking into the editor (move caret
+     while setting focus).
+     To reproduce, the editor must have a visible gutter; and must not have "current line" highlight.
+     * The conditions to cause this:
+     - Caret must be in part of editor that is outside the screen.
+     - Carte must be destroyed (maybe only hidden?), or ScrollWindowEx must affect caret
+     - Caret must be in a part of the editor for which NO call to "invalidate" was made,
+       but which will be repainted.
+       E.g. the gutter, but not the line area received an invalidate, and another line above/below was invalidated
+       (can happen through ScrollWindowEx). -> In this case the paint message receives a rect, that contains the caret,
+       even though the part containing the caret was never explicitly invalidated.
+     If this happens, while the caret is on screen (even if hidden behind another window/taskbar) then all works ok.
+     But if the caret was off screen, a permanent image of the caret will remain (once scrolled/moved into the screen area).
+     It seem that in this case windows does not update the information, that the caret became "invisible" when paint did paint
+     over it. So if the already overpainted caret, is later (by Windows) attempted to be hidden by a final "xor", then it actually
+     is made permanently visible.
+
+     As a solution, in the above conditions, the full line (actually the text part with the caret) must be invalidated too.
+     Since this is hard to track, the workaround will invalidate the full line, in any case that potentially could meet the
+     conditions
+  *)
+  {$DEFINE Windows10GhostCaretIssue}
+{$ENDIF}
+
 interface
 
 { $DEFINE SYNSCROLLDEBUG}
@@ -2823,6 +2852,10 @@ begin
     {$IFDEF VerboseSynEditInvalidate}
     DebugLnEnter(['TCustomSynEdit.InvalidateGutterLines ',DbgSName(self), ' FirstLine=',FirstLine, ' LastLine=',LastLine]);
     {$ENDIF}
+    {$IFDEF Windows10GhostCaretIssue}
+    if (FLeftGutter.Visible or FRightGutter.Visible) and (sfCaretChanged in fStateFlags) then
+      InvalidateLines(FirstLine, LastLine);
+    {$ENDIF}
     if (FirstLine = -1) and (LastLine = -1) then begin
       FPaintArea.InvalidateGutterLines(-1, -1);
     end else begin