From b8dd68f59f6b9930e3cc1d30aed8ae4059874821 Mon Sep 17 00:00:00 2001
From: William Morgan <wmorgan-sup@masanjin.net>
Date: Thu, 3 Sep 2009 13:08:29 -0400
Subject: [PATCH] rejigger alignment of messages when using 'n' and 'p'

minimize horizontal movement. 'z' can be used to force alignment of
current message with left column.
---
 lib/sup/modes/thread-index-mode.rb |  2 +-
 lib/sup/modes/thread-view-mode.rb  | 57 ++++++++++++++----------------
 2 files changed, 27 insertions(+), 32 deletions(-)

diff --git a/lib/sup/modes/thread-index-mode.rb b/lib/sup/modes/thread-index-mode.rb
index fb6b2ce..bc5625c 100644
--- a/lib/sup/modes/thread-index-mode.rb
+++ b/lib/sup/modes/thread-index-mode.rb
@@ -111,7 +111,7 @@ EOS
       mode = ThreadViewMode.new t, @hidden_labels, self
       BufferManager.spawn t.subj, mode
       BufferManager.draw_screen
-      mode.jump_to_first_open true
+      mode.jump_to_first_open
       BufferManager.draw_screen # lame TODO: make this unnecessary
       ## the first draw_screen is needed before topline and botline
       ## are set, and the second to show the cursor having moved
diff --git a/lib/sup/modes/thread-view-mode.rb b/lib/sup/modes/thread-view-mode.rb
index 639ae66..27132de 100644
--- a/lib/sup/modes/thread-view-mode.rb
+++ b/lib/sup/modes/thread-view-mode.rb
@@ -357,16 +357,16 @@ EOS
     end
   end
 
-  def jump_to_first_open loose_alignment=false
+  def jump_to_first_open
     m = @message_lines[0] or return
     if @layout[m].state != :closed
-      jump_to_message m, loose_alignment
+      jump_to_message m#, true
     else
-      jump_to_next_open loose_alignment
+      jump_to_next_open #true
     end
   end
 
-  def jump_to_next_open loose_alignment=false
+  def jump_to_next_open force_alignment=nil
     return continue_search_in_buffer if in_search? # hack: allow 'n' to apply to both operations
     m = (curpos ... @message_lines.length).argfind { |i| @message_lines[i] }
     return unless m
@@ -374,15 +374,15 @@ EOS
       break if @layout[nextm].state != :closed
       m = nextm
     end
-    jump_to_message nextm, loose_alignment if nextm
+    jump_to_message nextm, force_alignment if nextm
   end
 
   def align_current_message
     m = @message_lines[curpos] or return
-    jump_to_message m
+    jump_to_message m, true
   end
 
-  def jump_to_prev_open loose_alignment=false
+  def jump_to_prev_open
     m = (0 .. curpos).to_a.reverse.argfind { |i| @message_lines[i] } # bah, .to_a
     return unless m
     ## jump to the top of the current message if we're in the body;
@@ -394,38 +394,33 @@ EOS
         break if @layout[prevm].state != :closed
         m = prevm
       end
-      jump_to_message prevm, loose_alignment if prevm
+      jump_to_message prevm if prevm
     else
-      jump_to_message m, loose_alignment
+      jump_to_message m
     end
   end
 
-  IDEAL_TOP_CONTEXT = 3 # try and give 3 rows of top context
-  IDEAL_LEFT_CONTEXT = 4 # try and give 4 columns of left context
-  def jump_to_message m, loose_alignment=false
+  def jump_to_message m, force_alignment=false
     l = @layout[m]
-    left = l.depth * INDENT_SPACES
-    right = left + l.width
 
-    ## jump to the top line
-    if loose_alignment
-      jump_to_line [l.top - IDEAL_TOP_CONTEXT, 0].max # give 3 lines of top context
-    else
-      jump_to_line l.top
-    end
-
-    ## jump to the left column
-    ideal_left = left +
-      if loose_alignment
-        -IDEAL_LEFT_CONTEXT + (l.width - buffer.content_width + IDEAL_LEFT_CONTEXT + 1).clamp(0, IDEAL_LEFT_CONTEXT)
-      else
-        0
-      end
+    ## boundaries of the message
+    message_left = l.depth * INDENT_SPACES
+    message_right = message_left + l.width
 
-    jump_to_col [ideal_left, 0].max
+    ## calculate leftmost colum
+    left = if force_alignment # force mode: align exactly
+      message_left
+    else # regular: minimize cursor movement
+      ## leftmost and rightmost are boundaries of all valid left-column
+      ## alignments.
+      leftmost = [message_left, message_right - buffer.content_width + 1].min
+      rightmost = message_left
+      leftcol.clamp(leftmost, rightmost)
+    end
 
-    ## either way, move the cursor to the first line
-    set_cursor_pos l.top
+    jump_to_line l.top    # move vertically
+    jump_to_col left      # move horizontally
+    set_cursor_pos l.top  # set cursor pos
   end
 
   def expand_all_messages
-- 
2.43.0