Alt-modified mousewheel mode and other wheel tweaks #1234
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Sorry for the late response; I thought I could take a break from mintty after the last release :) Also I am having a hard time to get an overview of these changes. I do not seem to understand what the first one actually changes, except for the one line less which is OK. Which interaction is being avoided or is it after all just some refactoring? About the second, it is good to enrich escape sequences by modifiers (although I couldn’t find a test case to reproduce the difference) but why just Alt. Shouldn’t simply all modifiers be considered generically? The third change reverts Alt semantics for the sake of nano if I understood. |
Sorry for a late response from me too. I'd thought I better leave this one until after 3.6.5. :)
It is partly refactoring, which I'm hoping makes the code a bit clearer before the other two changes. But it also does away with my idea of converting line scroll events to page up/down key presses when the number of lines of an event exceeds the number of rows of the terminal. That's unlikely to happen with a real mousewheel, but it can happen with touchpad scroll events, which the OS converts into mousewheel events. For example, when the mousewheel event says scroll 40 lines down on a 25-row terminal, mintty would convert that to 1 page down and 15 cursor down key presses. With the change here, it's just 40 cursor downs. There are a few reasons for that:
A test case is nano, where Alt+Up/Down scrolls, whereas plain Up/Down moves the cursor.
Okay, I can have a go at that. (Although I'm generally not in favour or applications messing with the Windows key.) While looking at that, should I also look into making the currently hardcoded Shift for page-wise scrolling configurable? 'WheelPageMod', defaulting to 'shift'? As for the use of the Ctrl modifier for single-line scrolling, I'm tempted to just do away with that. I can't remember why I implemented it as it's neither standard nor very useful, and Ctrl+wheel normally means zooming anyway.
Sadly nano doesn't allow configuring cursor key combinations, but I think the implicitly added modifier would also be useful in other applications to do scrolling instead of cursor movement (without going full mouse mode or using the mintty-only application mousewheel codes). For example, vim can be configured to scroll on Alt+Up/Down with this: But maybe a 'WheelScrollMod' option configurable to any modifier but defaulting to 'none' would be a better approach than a dynamic switch? |
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Hi, The first, sanitizing of line vs page events, plus the minus-1 page scroll behaviour, is OK. The second, adding Alt+wheel events, obviously adds value e.g. to nano, so yes.
The generalization to other modifiers as I suggested is optional for now. If you've worked out something already, that's fine of course. Yes, the Win key... I tried to compensate for its side effects by some tricky hooks. I might additionally add user-definable keys for the Meta modifier, like for Super and Hyper. This issue is about the effect of modifiers, anyway, not how they are entered.
I think Shift is somewhat intuitive to make an effect stronger, while Ctrl could make it weaker, so I see only a faint use case here.
As said above, Ctrl intuitively makes things smaller for me. The zoom modifier could be made configurable to uncover the single-line scroll variation. Please leave the code in for now. The third change, I see now how that could implement a preference for nano. Generalizing modifiers and making everything configurable, one could in theory apply a linear algebra matrix to transform modifier configuration... just joking.
I imagine a user might have a shell wrapper for nano, switching this on and off (or push/pull) as desired (although, if nano cannot switch this itself, can it spawn other programs or shells as some editors do? that would make switching a bit inconsistent). Anyway, I'd keep the dynamic sequence. An option could set the initial value, too (there are a few other options that can preset DECSET modes). But please change the sequence value to 7765 (65 = ASCII 'A' = Alt). One of my other patches affects the same file, I've waited so far for your changes. |
Don't convert line scrolling events to page scrolling events when they exceed the terminal height, because we don't actually know how many lines correspond to a page as far as the application is concerned, or whether it supports page up/down events in the first place. Also, scroll the scrollback by one line less than the terminal height when scrolling by pages with the mousewheel, to match what we do for PgUp/Dn presses. Drop len argument from send_keys(), and use NUL-terminated strings instead for more flexibility. Put the count argument first.
If the Alt key is pressed, modify mousewheel events sent as cursor/page up/down keycodes or as mintty's application wheel codes accordingly. In nano, Alt+up/down means scrolling the window instead of moving the cursor. (The Shift and Ctrl modifiers are already used for modifying the scroll distance per wheel notch to whole pages or single lines, so don't send those.)
When enabled, this sends Alt-modified cursor up/down keycodes for mousewheel events. If the Alt key is pressed, unmodified keycodes are sent. The mode does not affect page up/down codes. In the nano editor from version 4.0, the Alt+Up/Down keycodes scroll the window instead of moving the cursor. Scrolling straight away is the proper action for the mousewheel, whereas moving the cursor only scrolls once the cursor reaches the top or bottom. Less can be configured to scroll on Alt+Up/Down with this in ~/.lesskey: \e[1;3A back-line \e[1;3B forw-line Similarly, vim can be configured to do so with this in ~/.vimrc: map <M-Up> <C-Y> map <M-Down> <C-E> imap <M-Up> <C-O><C-Y> imap <M-Down> <C-O><C-E>
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Hi Thomas, I're rebased the three commits onto latest master, and amended the third one to use DECSET 7765 instead of 7777, as requested. (I had originally implemented it with 7765, before realising that I could try to claim 7777 with the 'M'odified, but you're right to reserve that.) I'll look into adding support for the other modifiers to bring it up to par with the arrow keys. |
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Danke, Andy. |
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Released 3.7.0. |
Proposing the following three main changes to mousewheel handling. Further details in the individual commit messages.
Avoid mixed line and page mousewheel scrolling
Don't convert line scrolling events to page scrolling events when they exceed the terminal height. This was my idea to start with, but in hindsight I don't think it was a good one because we don't actually know how many lines correspond to a page as far as the application is concerned, or whether it supports page up/down events in the first place. I think this simplifies the code a bit, and helps witht the following changes.
Send Alt modifier with mousewheel events
If the Alt key is pressed, modify mousewheel events sent as cursor/page up/down keycodes or as mintty's application wheel codes accordingly. (Ctrl and Shift are already used for other purposes.)
Add Alt-modified mousewheel mode
When enabled, this sends Alt-modified cursor up/down keycodes for mousewheel events when the Alt key is not pressed. If the Alt key is pressed, unmodified keycodes are sent. The mode does not affect page up/down codes.
In the nano editor from version 4.0, the Alt+Up/Down keycodes scroll the window instead of moving the cursor. Scrolling straight away is the proper action for the mousewheel, whereas moving the cursor only scrolls once the cursor reaches the top or bottom.
Less scrolls with or without the Alt modifier. Vim and mined at least tolerate Alt+Up/Down, apparently handling it the same as unmodified Up/Down, but they have proper mousewheel scrolling support using full mouse reporting mode anyway.