From fa29c3791119d9fafac1509d43e8da22c31cda6d Mon Sep 17 00:00:00 2001
From: "C. McEnroe" <june@causal.agency>
Date: Mon, 17 Feb 2020 11:49:56 -0500
Subject: Scroll the window only once during reflow

ncurses implements scrolling as a memmove of the array of lines
pointers, which happens each time a line is added to the bottom of the
window, causing a scroll. This would get noticeably slow if WindowLines
were increased to just 1024. Should've used a ring buffer, I think.
---
 ui.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'ui.c')

diff --git a/ui.c b/ui.c
index bcb1003..938eda6 100644
--- a/ui.c
+++ b/ui.c
@@ -621,18 +621,21 @@ void uiFormat(
 
 static void reflow(struct Window *window) {
 	werase(window->pad);
-	wmove(window->pad, WindowLines - 1, 0);
+	wmove(window->pad, 0, 0);
+	int flowed = 0;
 	window->unreadLines = 0;
 	for (size_t i = 0; i < BufferCap; ++i) {
 		const char *line = bufferLine(&window->buffer, i);
 		if (!line) continue;
 		waddch(window->pad, '\n');
+		int lines = 1 + wordWrap(window->pad, line);
 		if (i >= (size_t)(BufferCap - window->unreadTotal)) {
-			window->unreadLines += 1 + wordWrap(window->pad, line);
-		} else {
-			wordWrap(window->pad, line);
+			window->unreadLines += lines;
 		}
+		flowed += lines;
 	}
+	wscrl(window->pad, -(WindowLines - 1 - flowed));
+	wmove(window->pad, WindowLines - 1, RIGHT);
 }
 
 static void resize(void) {
-- 
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