From bd3b2b31bbf08e9f8e95d40ecbf2082d229f46e2 Mon Sep 17 00:00:00 2001
From: Markus Gans <guru@server.home.net>
Date: Sat, 29 Dec 2018 19:01:47 +0100
Subject: [PATCH] Adding horizontal and vertical scrollability checks in
 FTextView

---
 ChangeLog                     |  3 +++
 examples/listbox.cpp          | 11 +++++++----
 src/ftextview.cpp             |  6 +++---
 src/include/final/ftextview.h | 12 ++++++++++++
 4 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index a6d2a1ef..ed364116 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+2018-12-28  Markus Gans  <guru.mail@muenster.de>
+	* Text scrolling in FTextView was broken since February 17th!
+
 2018-12-28  Markus Gans  <guru.mail@muenster.de>
 	* Add the assignment operator (=) for FButton to set the button text
 	* Corrected shortening of overlong texts in the title bar of FDialog
diff --git a/examples/listbox.cpp b/examples/listbox.cpp
index 172195dc..13403034 100644
--- a/examples/listbox.cpp
+++ b/examples/listbox.cpp
@@ -30,7 +30,7 @@
 using namespace finalcut;
 
 // Global application object
-static std::shared_ptr<FString> temp_str { nullptr };
+static std::weak_ptr<FString> temp_str;
 
 
 // Function prototypes
@@ -57,13 +57,15 @@ void doubleToItem ( FListBoxItem& item
 // Import converter functions
 FString& doubleToString (std::list<double>::const_iterator iter)
 {
-  return temp_str->setNumber(*iter);
+  auto temp = temp_str.lock();
+  return temp->setNumber(*iter);
 }
 
 FString& mapToString ( std::map<FString
                      , FString>::const_iterator iter )
 {
-  return *temp_str = iter->first + ": " + iter->second;
+  auto temp = temp_str.lock();
+  return *temp = iter->first + ": " + iter->second;
 }
 
 
@@ -106,7 +108,8 @@ class Listbox : public FDialog
 Listbox::Listbox (FWidget* parent)
   : FDialog(parent)
 {
-  temp_str = std::make_shared<FString>();
+  auto temp = std::make_shared<FString>();
+  temp_str = temp;
 
   // listbox 1
   //----------
diff --git a/src/ftextview.cpp b/src/ftextview.cpp
index 87f2989b..dee3a45a 100644
--- a/src/ftextview.cpp
+++ b/src/ftextview.cpp
@@ -143,7 +143,7 @@ void FTextView::scrollTo (int x, int y)
   if ( ! isVisible() || ! (changeX || changeY) )
     return;
 
-  if ( xoffset != x )
+  if ( changeX && isHorizontallyScrollable() )
   {
     int xoffset_end = int(maxLineWidth - getTextWidth());
     xoffset = x;
@@ -151,7 +151,7 @@ void FTextView::scrollTo (int x, int y)
     if ( xoffset < 0 )
       xoffset = 0;
 
-    if ( xoffset > xoffset_end )
+    if ( xoffset > xoffset_end && xoffset_end >= 0 )
       xoffset = xoffset_end;
 
     if ( update_scrollbar )
@@ -161,7 +161,7 @@ void FTextView::scrollTo (int x, int y)
     }
   }
 
-  if ( yoffset != y )
+  if ( changeY && isVerticallyScrollable() )
   {
     int yoffset_end = int(getRows() - getTextHeight());
     yoffset = y;
diff --git a/src/include/final/ftextview.h b/src/include/final/ftextview.h
index 189d17e0..e7248d50 100644
--- a/src/include/final/ftextview.h
+++ b/src/include/final/ftextview.h
@@ -137,6 +137,10 @@ class FTextView : public FWidget
     std::size_t        getTextHeight();
     std::size_t        getTextWidth();
 
+    // Inquiry
+    bool               isHorizontallyScrollable();
+    bool               isVerticallyScrollable();
+
     // Methods
     void               init();
     virtual void       draw();
@@ -191,6 +195,14 @@ inline void FTextView::deleteRange (int from, int to)
 inline void FTextView::deleteLine (int pos)
 { deleteRange (pos, pos); }
 
+//----------------------------------------------------------------------
+inline bool FTextView::isHorizontallyScrollable()
+{ return bool( maxLineWidth > getTextWidth() ); }
+
+//----------------------------------------------------------------------
+inline bool FTextView::isVerticallyScrollable()
+{ return bool( getRows() > getTextHeight() ); }
+
 }  // namespace finalcut
 
 #endif  // FTEXTVIEW_H