From 3e072dff91978e378e39de8cd7410d93689b2f10 Mon Sep 17 00:00:00 2001 From: Ben Harris Date: Tue, 6 Dec 2022 13:06:36 +0000 Subject: [PATCH] Devel docs: Mention mid-end background clearing --- devel.but | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/devel.but b/devel.but index 4b7988a..5920ca8 100644 --- a/devel.but +++ b/devel.but @@ -1438,7 +1438,9 @@ The very first time this function is called for a new area. Since this often involves drawing visual furniture which is never subsequently altered, it is often simplest to arrange this by having a special \q{first time} flag in the draw state, and -resetting it after the first redraw. +resetting it after the first redraw. This function can assume that +the mid-end has filled the drawing area with colour 0 before the first +call. When this function (or any subfunction) calls the drawing API, it is expected to pass colour indices which were previously defined by the