commit 4650064aa757c217fa72f8819a2cf67c689bcdef
from: Russ Cox <rsc@swtch.com>
date: Mon Mar 30 13:56:50 2020 UTC

acme: scale window bodies on resize, not including tag space

This avoids reopening collapsed windows after a large vertical resize.

commit - 92aa0e13ad8cec37936998a66eb728bfca88d689
commit + 4650064aa757c217fa72f8819a2cf67c689bcdef
blob - 63c33ac11c52dded05cc959bb0f7644ed1610780
blob + 63247a84f081f40440480f2545a7ca6a96fa08bd
--- src/cmd/acme/cols.c
+++ src/cmd/acme/cols.c
@@ -232,7 +232,7 @@ colmousebut(Column *c)
 void
 colresize(Column *c, Rectangle r)
 {
-	int i;
+	int i, old, new;
 	Rectangle r1, r2;
 	Window *w;
 
@@ -245,6 +245,8 @@ colresize(Column *c, Rectangle r)
 	r1.max.y += Border;
 	draw(screen, r1, display->black, nil, ZP);
 	r1.max.y = r.max.y;
+	new = Dy(r) - c->nw*(Border + font->height);
+	old = Dy(c->r) - c->nw*(Border + font->height);
 	for(i=0; i<c->nw; i++){
 		w = c->w[i];
 		w->maxlines = 0;
@@ -252,8 +254,8 @@ colresize(Column *c, Rectangle r)
 			r1.max.y = r.max.y;
 		else{
 			r1.max.y = r1.min.y;
-			if(Dy(c->r) != 0){
-				r1.max.y += (Dy(w->r)+Border)*Dy(r)/Dy(c->r);
+			if(new > 0 && old > 0 && Dy(w->r) > Border+font->height){
+				r1.max.y += (Dy(w->r)-Border-font->height)*new/old + Border + font->height;
 			}
 		}
 		r1.max.y = max(r1.max.y, r1.min.y + Border+font->height);