Useful Lua libraries for Norns synth to make it easier to create scripts that are user friendly. There are currently two separate library files. You only need to include what you want to actually use. The initial motivation was to help in creating the https://github.com/skibu/nornsLib/taweeet Norns script.
See bottom of this doc on full instructions on how to include the library.
Ever gotten frustrated trying to understand what is in a table because tab.print(tbl) is just way too limited?? Ever want to read or write data in a human readable format so that you can actually understand the data? Well, the JSON extension can really help. Not only does it enable easily converting from table objects to json and visa versa, but you can also print out a table in json format. Handles non-standard JSON values including Infinity, -Infinity, NaN, and null. Also handles function pointers well for encoding, though cannot handle them when decoding.
Returns a table as a JSON string. Great way to see what is inside a complicated table. The indent parameter specifies how much each level should be indented, which makes for much more readable results. Default indent is 2 spaces. Use 0 if you want to minimize file size.
Converts a JSON string into a Lua table.
A great replacement for tab.pring(). This function prints the table in JSON format, and can show all levels. Worth the price of admission!
Writes table object to a file in json format
Reads json file and converts the json into a table object and returns it. If the file doesn't exist then returns nil.
Does a json api call to the specified url and converts the JSON to a Lua table. This is done via a curl call. Allows compressed data to be provided. You can optionally provide custom headers by passing in a table with key/value pairs, as in {["API-KEY"]="827382736"}
The parameter extensions library does several things: 1) prevents overlap for option parameters; 2) makes navigation to parameter setting menu much simpler because user just has to press key1; 3) parameters (mEDIT) screen doesn't highlight separators since they cannot be modified, and better title; and 4) fixed params:bang(id) to optionally take a parameter id.
This feature makes sure that option parameters don't overlap the label and the value, since that makes the text unreadable. To use this feature you only need to include the parameterExtensions library. Everything else is taken care of by changing some of the low-level code. If overlap for an option parameter is found, a narrower font will be used. And if there would still be overlap with the narrower font, then the right portion of the text will be trimmed off. If you happen to ever have overlapping text in a parameter option this provides a great and simple solution.
The default of having the parameter values being right justified makes them look quitei jumbly. But now they can be left aligned. One simply needs to call set_left_align_parameter_values(true) at initialization to do so.
Left alignment of parameter values works especially well if the right sides of the parameter labels are aligned. This can be done by padding the left of the parameter labels by spaces of various widths, until they align. Note: while a normal space char " " is 5 pixels wide, one can use a half space char "\u{2009}" of 3 pixels or and even skinnier hair space "\u{200A}" that is just a single pixel wide.
One of the great thing about a Norns is that the application scripts can have lots of parameters, allowing the user to finely control things. But the default method for getting to the parameters is quite clunky and dissuades users.
The current method is a rather magical sequence of a short key1 press to get to Menus (but a long key press of greater than 0.25 won't work!), then turn encoder1 to get to PARAMETERS menu, then turn encoder2 to select Edit >, and then click on key3 to get to the script's param page, and then use encoder2 to actually get to a param. That is simply too convoluted.
This library makes it so that the user can simply hit key1, with a long or short press, and they will be brought automatically to the script's parameter page and the first parameter will already be selected. And to get back the script page the user can simply hit key1 again with a long or short press. No more wondering why can navigate the menus due to hitting key1 just a bit longer than 0.25 sec!
To enable this functionality the script needs to add parameterExt = require "nornsLib/parameterExt" and call the library function parameterExt.jump_to_edit_params_screen() when the desired key sequence is hit. For example, for your script to have key1, long or short press, jump right to the parameters page one can do something like the following:
parameterExt = require "nornsLib/parameterExt"
function key(n, down)
if n == 1 and down == 0 then
-- Key1 up so jump to edit params directly. Don't require it
-- to be a short press so that it is easier. And use key up
-- event because if used key down then the subsequent key1 up would
-- switch back from edit params menu to the application screen.
parameterExt.jump_to_edit_params_screen()
end
...
end
Parameters (mEDIT) screen doesn't highlight separators since they cannot be modified. Improved the title
Turns out that in lua/core/clock.lua that params:bang("clock_tempo") is called to bang just the single parameter. But the standard bang() function bangs ALL parameters, which is not desired in this situation. So this definition overrides the bang function so that optionally only a single param can be banged. If id not specified then all all banged.
The original PSET (Presets) menu screen has a different UI than other situations. The list of presets is simply not clear. And "pset" is a really confusing term since it stands for "preset", not "parameter set". Therefore with psetExt the presets are provided in a single line, as is done with other parameters. Also, switched from using upper case.
But a truly nice feature is that the parameters menu can be setup so that the user can jump directly from that screen to the preset page.
When setting up the script's parameters can use something like params:set_action("pset", psetExt.jump_to_pset_screen ) to allow the user to jump directly to the preset screen, making navigation much more simple.
The original text entry screen can be a bit cumbersome. By simply including the textentryExt library the UI of the text entry screen is replaced. The text entered is presented in a larger font to make it clear what is happening. And a "_" is added to the end to further clarify where characters are entered.
Additionaly, the list of characters was changed to present the SAVE option, and the backspace "<-" option clearly. Also, instead of presenting the characters in ascii order, which is not intended for a UI, first lower case characters, then upper case characters, then numbers, and then just a few symbols are provided. This seems to make it easier to find desired character. Also, one doesn't have to figure out how to switch focus from the characters line to the DEL / OK line at bottom of screen since those options are now available right in the character list.
Originally included in the library a way to store and restore screen parameters. But it turns out this functionality is already provided via screen.save() and screen.restore(). These functions should simply be documented.
Also, the standard screen.text_extents() function has a notable flaw. It doesn't provide the proper width of a string if the string is padded by spaces. Somewhere the string is inappropriately trimmed. This is a problem even if padding with a half space \u{2009} or a hair space \u{200A}. Could not determine where the string is getting inappropriately trimmed so cannot fix the code directly. Instead, screen.text_untrimmed_extents(str) should be used instead of screen.text_extents(str) if the string might be padded. Don't want to use this for every situation though because this function actually makes two calls to the original screen_text_extents(), which slows things down a bit, especially since they are blocking calls. Therefore this function should only be used when the string in question actually might be padded.
- screen.text_untrimmed_extents(str)
There is also a new function for determining the size of an image buffer called screen.extents(). One can pass in either an existing image buffer or a file name of a PNG file. This function is quite handy for if you want to do something like center a PNG image on the screen. The function is:
- screen.extents(image_buffer) and it returns the
width, heightof the image buffer or PNG file.
Screen.level() was modified to accept an floating point instead of just an integer parameter. This way won't get an error if calculating the screen level and it happens to not be an integer. Most of the other Screen functions accept floating point values. level() should as well.
- screen.level(value)
In addition, screen.clear() is overriden to deal with a bug when writing an image buffer to the screen. In the 240424 there is a bug when writing an image buffer after other drawing events are queue up, like screen.clear(). The screen.display_image(), screen.display_image_region(), and screen.draw_to() calls are not queued and therefore can execute before the screen is fully drawn to, resulting in the image not be displayed correctly or even at all. This is being fixed in a future release of Norns, but if you are using these image functions then you will want to include this library since it is a good temporary fix for the problem. Once everyone is on new version of Norns code this can go away, but that might take a while. Using this code after Norns is fixed will still work.
- screen.display_image()
- screen.display_image_region()
- screen.draw_to()
And, overriding screen.draw_to() so that it can pass arguments to the function that is called. This makes drawing to images, controlled by args, possible. Definitely useful if one is working with image buffers.
- function screen.draw_to(image, func, ...)
And lastly, addresses a very obscure problem with screen.blend_mode(index) where if used an index of 3-Multiply or later that was getting the wrong mode because 3-Saturate was inadvertantly left out of the list in screen.lua . Therefore NornsLib screen extension fixes Screen.BLEND_MODES
- screen.blend_mode(index) - fixes Screen.BLEND_MODES
Note: originally also provided a screen.free(image) for freeing image buffer. But this was removed because image buffers are automatically garbage collected when done with them. If one ever runs out of memory due to creating large number of images, should intersperse calls to collectGarbage() so that they are garbage collected in time.
Returns size of table. Intended to be used for arrays that are sparse, where every index isn't defined. For such tables #tbl only returns number of elements until a nil is found, which of course won't return the true number of elements if it is only sparsely populated.
Sleeps specified fraction number of seconds. Implemented by doing a system call. Note that this will lock out the UI for the specified amount of time, so should be used judiciously.
Retuns epoch time string with with nanosecond precision, by doing a system call. Note that because the number of characters one cannot just convert this to a number via tonumber() because would then loose resolution. And yes, it is doubtful that nono second resolution will be useful since doing a system call, which takes a while. Therefore util.time() will usually be sufficient.
For getting just the filename from full directory path. Returns what is after the last slash of the full filename. If full filename doesn't have any slashes then full_filename is returned.
For finding the directory of a file. Useful for creating file in a directory that doesn't already exist
If dir doesn't already exist, creates directory for a file that is about
to be written. Different from util.make_dir() in that util.make_dir_for_file()
can take in file name and determine the directory from it.
For encoding a url that has special characters.
For decoding a url with special characters
Like os.execute() but returns the result string from the command. And different from util.os_capture() by having a more clear name, and by only filtering out last character if a newline. This means it works well for both shell commands like 'date' and also accessing APIs that can provide binary data, such as using curl to get an binary file.
For logging statements. Each statement is prepended with timestamp so can easily determine what is taking so long to process. They are also written to file at dust/data/<app>/logfile.txt . Debug statements can be enabled or disabled, and contain useful debugging info such as function name, source code, and line number where called from.
Like print(), but puts the epoch time in front. Really nice for understanding what parts of your code are taking a long time to execute and need to be optimized. The time is shortened to only show 4 digits to left of decimal point, and 6 digits to the right. Showing more would just be kind of ugly. Nano seconds are just truncated instead of rounded because that level of precision is not actually useful for print statements.
Uses log.print(), but preceeds the text with "ERROR: "
This function needs to be called if want log.debug() functions to actually output info. To enable, call log.enable_debug(true) or simply log.enable_debug(). To disable use log.enable_debug(false). This is like a condensed traceback.
If enabled via log.enable_debug(value), outputs the object using log.print(), prefixed by "DEBUG: ", and with a second line that shows the context of function name, source code file name, and line number. Great for debugging!
The NornsLib library can easily be included in your script. Since nornsLib is a separate repo from your script you need to make sure that the nornsLib files are not just included, but that the whole library is cloned to the user's Norns device. To make this simple you can just copy and paste the following Lua file into your script repo.
You can copy and paste the script below or do a wget https://raw.githubusercontent.com/skibu/nornsLib/main/fullNornsLibInclude.lua. And then just include this nornsLib script from your application script using something like include "appLib/fullNornsLibInclude". And of course feel free to make needed changes to your copy of this file. For example, you might want to include just particular nornsLib extension files, e.g. include "nornsLib/utilExt" instead of all the extensions via include "nornsLib/includeAllExt"
-- This file shows how nornsLib can be included. It is recommended that the
-- application developer copy this file to their application, modify as needed,
-- and then include it.
-- If nornsLib doesn't exist on user's Norns device then clone it from GitHub
if not util.file_exists(_path.code.."nornsLib") then
os.execute("git clone https://github.com/skibu/nornsLib.git ".._path.code.."nornsLib")
end
-- Include this file if app should auto update nornsLib to pick up the latest
-- greatest version. Now that we know that at least an old verison nornsLib
-- already installed we can include it from the nornsLib directory.
include "nornsLib/updateLib"
-- Include the appropriate nornsLib extensions. Or more easily, just load all of them
-- at once using includeAllExt.
include "nornsLib/includeAllExt"
