From aae38ddb5f3f6f0316689b7c771fdd55531da65e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gon=C3=A7alo=20Silva?= <goncalossilva@gmail.com>
Date: Sat, 8 Jun 2019 02:32:48 +0100
Subject: [PATCH] Prevent scroll when only one of the text view or preview are
 scrollable

---
 uberwriter/preview_web_view.py   | 13 ++++++++-----
 uberwriter/text_view.py          | 11 +++++++----
 uberwriter/text_view_scroller.py |  4 ++++
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/uberwriter/preview_web_view.py b/uberwriter/preview_web_view.py
index e48e795..7094e54 100644
--- a/uberwriter/preview_web_view.py
+++ b/uberwriter/preview_web_view.py
@@ -59,7 +59,7 @@ if (canScroll && isRendered) {{
         self.connect("size-allocate", self.on_size_allocate)
         self.connect("destroy", self.on_destroy)
 
-        self.scroll_scale = 0.0
+        self.scroll_scale = -1
 
         self.state_loaded = False
         self.state_load_failed = False
@@ -69,6 +69,9 @@ if (canScroll && isRendered) {{
 
         self.timeout_id = None
 
+    def can_scroll(self):
+        return self.scroll_scale != -1
+
     def get_scroll_scale(self):
         return self.scroll_scale
 
@@ -114,11 +117,11 @@ if (canScroll && isRendered) {{
             self.timeout_id = None
 
         # Set scroll scale if specified, and the state is not dirty
-        if not self.state_discard_read and scroll_scale not in (None, -1, self.scroll_scale):
+        if not self.state_discard_read and scroll_scale not in (None, self.scroll_scale):
             self.scroll_scale = scroll_scale
-            self.emit("scroll-scale-changed", self.scroll_scale)
-        else:
-            self.state_discard_read = False
+            if self.scroll_scale != -1:
+                self.emit("scroll-scale-changed", self.scroll_scale)
+        self.state_discard_read = False
 
         # Handle the current state
         if not self.state_loaded or self.state_load_failed or self.state_waiting:
diff --git a/uberwriter/text_view.py b/uberwriter/text_view.py
index ea16989..22baa2b 100644
--- a/uberwriter/text_view.py
+++ b/uberwriter/text_view.py
@@ -124,6 +124,9 @@ class TextView(Gtk.TextView):
         text_buffer = self.get_buffer()
         text_buffer.set_text(text)
 
+    def can_scroll(self):
+        return self.scroller.can_scroll()
+
     def get_scroll_scale(self):
         return self.scroller.get_scroll_scale() if self.scroller else 0
 
@@ -150,8 +153,8 @@ class TextView(Gtk.TextView):
         if parent:
             parent.set_size_request(self.get_min_width(), 500)
             self.scroller = TextViewScroller(self, parent)
-            parent.get_vadjustment().connect("changed", self.on_scroll_scale_changed)
-            parent.get_vadjustment().connect("value-changed", self.on_scroll_scale_changed)
+            parent.get_vadjustment().connect("changed", self.on_vadjustment_changed)
+            parent.get_vadjustment().connect("value-changed", self.on_vadjustment_changed)
         else:
             self.scroller = None
 
@@ -168,10 +171,10 @@ class TextView(Gtk.TextView):
             self.markup.apply()
         return False
 
-    def on_scroll_scale_changed(self, *_):
+    def on_vadjustment_changed(self, *_):
         if self.frozen_scroll_scale is not None:
             self.set_scroll_scale(self.frozen_scroll_scale)
-        else:
+        elif self.can_scroll():
             self.emit("scroll-scale-changed", self.get_scroll_scale())
 
     def unfreeze_scroll_scale(self):
diff --git a/uberwriter/text_view_scroller.py b/uberwriter/text_view_scroller.py
index b483359..1efa2f7 100644
--- a/uberwriter/text_view_scroller.py
+++ b/uberwriter/text_view_scroller.py
@@ -6,6 +6,10 @@ class TextViewScroller:
         self.scrolled_window = scrolled_window
         self.smooth_scroller = None
 
+    def can_scroll(self):
+        vap = self.scrolled_window.get_vadjustment().props
+        return vap.upper > vap.page_size
+
     def get_scroll_scale(self):
         vap = self.scrolled_window.get_vadjustment().props
         if vap.upper > vap.page_size: