Do not reset yscroll and selection on redraw

While here, unify handling of when the selection goes off screen.

pick.c

@@ -303,6 +303,8 @@ selected_choice(void)
 			xscroll = cursor_position - tty_columns + 1;
 		else
 			xscroll = 0;
+		if (selection - yscroll >= choices_lines)
+			yscroll = selection - choices_lines + 1;
 		print_line(&query[xscroll], query_length - xscroll, 0, -1, -1);
 		choices_count = print_choices(yscroll, selection);
 		if (choices_count - yscroll < choices.length
@@ -409,7 +411,6 @@ selected_choice(void)
 			break;
 		case CTRL_L:
 			tty_size();
-			selection = yscroll = 0;
 			break;
 		case CTRL_W:
 			if (cursor_position == 0)
@@ -464,13 +465,10 @@ selected_choice(void)
 				continue;
 			break;
 		case PAGE_DOWN:
-			if (selection + choices_lines < choices_count) {
+			if (selection + choices_lines < choices_count)
 				yscroll = selection += choices_lines;
-			} else {
+			else
 				selection = choices_count - 1;
-				if (selection - yscroll >= choices_lines)
-					yscroll = choices_count - choices_lines;
-			}
 			break;
 		case PAGE_UP:
 			if (selection > choices_lines)
@@ -479,11 +477,8 @@ selected_choice(void)
 				yscroll = selection = 0;
 			break;
 		case END:
-			if (choices_count > 0) {
+			if (choices_count > 0)
 				selection = choices_count - 1;
-				if (selection - yscroll >= choices_lines)
-					yscroll = choices_count - choices_lines;
-			}
 			break;
 		case HOME:
 			yscroll = selection = 0;

tests/57.t

@@ -1,7 +1,7 @@
-description: CTRL-L clears the selection
+description: CTRL-L does not clear the selection
 keys: \016 \014 \n # DOWN CTRL_L ENTER
 stdin:
 a
 b
 stdout:
-a
+b