resize from the top.

st.c

@@ -1060,12 +1060,25 @@ tresize(int col, int row) {
 	int i;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
+	int slide = term.c.y - row + 1;
 
 	if(col < 1 || row < 1)
 		return;
 
-	/* free uneeded rows */
-	for(i = row; i < term.row; i++) {
+	/* free unneeded rows */
+	i = 0;
+	if(slide > 0) {
+		/* slide screen to keep cursor where we expect it -
+		 * tscrollup would work here, but we can optimize to
+		 * memmove because we're freeing the earlier lines */
+		for(/* i = 0 */; i < slide; i++) {
+			free(term.line[i]);
+			free(term.alt[i]);
+		}
+		memmove(term.line, term.line + slide, row * sizeof(Line));
+		memmove(term.alt, term.alt + slide, row * sizeof(Line));
+	}
+	for(i += row; i < term.row; i++) {
 		free(term.line[i]);
 		free(term.alt[i]);
 	}