From 6d6f45c1e266ffb3206498301a7a6a1b1b22ec3c Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Tue, 10 Jan 2017 21:03:00 +0100
Subject: Moving up, and bugfixes

- moving up!
- insertion auto-scrolls *correctly*
- moving down can also land *after* the line
---
 buffer.cpp | 42 ++++++++++++++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/buffer.cpp b/buffer.cpp
index 61cb15b..afb1c93 100644
--- a/buffer.cpp
+++ b/buffer.cpp
@@ -36,18 +36,20 @@ void Buffer::handleCommand(const Command &cmd){
 		assert(c!='\n');
 		tb.insert(cursor.line,cursor.x,cmd[1][0]);
 		cursor.x++;
+		relayoutScreen();
 		if(findCursorInScreen().x==-1){
 			screen.erase(screen.begin());
+			relayoutScreen();
 		}
-		relayoutScreen();
 	} else if(cmd[0]=="insert_newline"){
 		tb.insert(cursor.line,cursor.x,'\n');
 		cursor.x=0;
 		cursor.line++;
+		relayoutScreen();
 		if(findCursorInScreen().x==-1){
 			screen.erase(screen.begin());
+			relayoutScreen();
 		}
-		relayoutScreen();
 	} else if(cmd[0]=="delete_backward"){
 		if(cursor.x==0&&cursor.line==0){
 			bel();
@@ -128,7 +130,39 @@ void Buffer::handleCommand(const Command &cmd){
 		}
 		cursor.line=screen[sp.y].line;
 		if(sp.x>=(i64)screen[sp.y].cells.size()){
-			cursor.x=tb.lineLen(cursor.line);
+			if(screen[sp.y].cells.size()==0)cursor.x=0;
+			else {
+				cursor.x=screen[sp.y].cells.back().linex;
+				//Now if we would've landed *after* the end of the line, go there.
+				if(cursor.x==tb.lineLen(cursor.line)-1)cursor.x++;
+			}
+		} else {
+			cursor.x=screen[sp.y].cells[sp.x].linex;
+		}
+	} else if(cmd[0]=="move_upward"){
+		Screenpos sp=findCursorInScreen();
+		if(sp.x==-1){
+			bel();
+			return;
+		}
+		if(sp.y==0){
+			if(screen[sp.y].line==0&&screen[sp.y].part==0){
+				if(cursor.x==0)bel();
+				else cursor.x=0;
+				return;
+			}
+			scrollUp();
+		} else {
+			sp.y--;
+		}
+		cursor.line=screen[sp.y].line;
+		if(sp.x>=(i64)screen[sp.y].cells.size()){
+			if(screen[sp.y].cells.size()==0)cursor.x=0;
+			else {
+				cursor.x=screen[sp.y].cells.back().linex;
+				//Now if we would've landed *after* the end of the line, go there.
+				if(cursor.x==tb.lineLen(cursor.line)-1)cursor.x++;
+			}
 		} else {
 			cursor.x=screen[sp.y].cells[sp.x].linex;
 		}
@@ -150,7 +184,7 @@ static string showChar(char c){
 }
 
 vector<Buffer::ScreenLine> Buffer::layoutLine(const string &line,i64 linenum,i64 width){
-	assert(width>=4);
+	assert(width>=5); //5 == (maximum char repr width) + 1, where the 1 is an extra column on the right
 	if(line.size()==0){
 		return {{linenum,0,0,{}}};
 	}
-- 
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