From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23924 invoked by alias); 23 Jun 2016 12:30:10 -0000 Mailing-List: contact zsh-workers-help@zsh.org; run by ezmlm Precedence: bulk X-No-Archive: yes List-Id: Zsh Workers List List-Post: List-Help: X-Seq: 38755 Received: (qmail 25787 invoked from network); 23 Jun 2016 12:30:09 -0000 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on f.primenet.com.au X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.1 X-AuditID: cbfec7f5-f792a6d000001302-59-576bd3f2fe5a Date: Thu, 23 Jun 2016 13:19:59 +0100 From: Peter Stephenson To: Zsh workers Subject: Re: unwanted scrolling of the terminal Message-id: <20160623131959.03fef86b@pwslap01u.europe.root.pri> In-reply-to: <30660.1466683131@thecus.kiddle.eu> References: <30660.1466683131@thecus.kiddle.eu> Organization: Samsung Cambridge Solution Centre X-Mailer: Claws Mail 3.7.9 (GTK+ 2.22.0; i386-redhat-linux-gnu) MIME-version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrALMWRmVeSWpSXmKPExsVy+t/xK7qfLmeHGyxcJmxxsPkhkwOjx6qD H5gCGKO4bFJSczLLUov07RK4Mlo3v2AseMVZ8e5ATgPjQfYuRk4OCQETiRs9x5ggbDGJC/fW s3UxcnEICSxllGif9ZIdwpnBJHHv7AuozDlGiWmPdzBBOGcZJTZ+62IF6WcRUJW48WYN2Cw2 AUOJqZtmM4LYIkDxOSdOgdUIC+hLrJh9hg3E5hWwlzj96jVYPaeAgcTGowuZQWwhoJq5M36C 1fAD2Vf/foK6z15i5pUzjBC9ghI/Jt9jAbGZBbQkNm9rYoWw5SU2r3kLNUdd4sbd3ewTGIVn IWmZhaRlFpKWBYzMqxhFU0uTC4qT0nON9IoTc4tL89L1kvNzNzFCwvnrDsalx6wOMQpwMCrx 8GYcywoXYk0sK67MPcQowcGsJMJbfSk7XIg3JbGyKrUoP76oNCe1+BCjNAeLkjjvzF3vQ4QE 0hNLUrNTUwtSi2CyTBycUg2Mc6ZJ75x92UvydfM7jr++Mpu6HjxW3bqp+pnFrbVi/c5sh45V bSg5f+9qHZ/DNwPxuRIb8jaYH28XyWNapn5t1reOxcdi5q1Pulhc+vdEkkP7Ol/hrV2HhdnY apP6eEvqTSR8K0xiPmy5pHetN+qO7o0qgx9FywxcDwZxTpmgsP3s+a4TweHCSizFGYmGWsxF xYkADdIUEmMCAAA= On Thu, 23 Jun 2016 13:58:51 +0200 Oliver Kiddle wrote: > Looking at the output in a script log for an 84 char width terminal, I get: > x > \e[39m - colour > \e[K - clear to eol > \r > \e[8@ - insert 8 characters > \e[34m > eight spaces > \e[75C - cursor right 75 chars > \e[39m > two spaces > \r > > So why the two spaces? The second of those is what caused the scrolling. > The first one is printed from line 1958 in zle_refresh.c > The second is from line 2175 in the moveto function It appears to be specific to terminals with automatic margins (hasam). I *think* that code is supposed to have the effect of ensuring if we subsequently more the cursor right without printing then it knows that the new line is actually a logical continuation of the previous one --- hence the subsequent carriage return to get back from there. So I would guess this hasn't been thought through in the case where you're at the end of the screen and don't really want to go right unless you have to. This code is all originally 1990s --- I have no idea if modern terminals even respond to these tricks. I think automatic margin problems were much more trendy twenty years ago. pws