manual | repository contains the sources for the Mixxx User Manual
kandi X-RAY | manual Summary
kandi X-RAY | manual Summary
The Mixxx Manual
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Top functions reviewed by kandi - BETA
- Resolve a cross - reference
- Generate target strings
- Return a generator of objects
- Generate a list of dictionaries
- Setup Mixinx
- Convert a changelog to rst
- Fetch the changelog for the given branch
manual Key Features
manual Examples and Code Snippets
Community Discussions
Trending Discussions on manual
QUESTION
I'm trying to remove an entry from the Caffeine cache manually. I have two attempts but I suspect that there are some problems with both of them:
This one seems like it could suffer from a race condition.
...ANSWER
Answered 2021-Jun-16 at 00:25You should use cache.asMap().remove(key)
as you suspected. The other call delegates to this, but does not return the value because that is not idiomatic for a cache.
The Cache
interface is opinionated for how one should commonly use a cache, while the asMap()
view is more raw to allow for advanced operations. For example, you generally wouldn't iterate over a cache (e.g. memcached doesn't allow this), but if you need to then the Map provides that support. All calls flow into the same backing structure, so there will be no inconsistency. The APIs merely try to nudge users towards best practices, but strive to not block a developer from getting their work done safely and correctly.
QUESTION
I'm trying to create a Windows form via Powershell and I need to capture the file path and store it in a variable. After the user clicks the 'Select' button and chooses the file, I would like to store the file path in a variable. Can someone please help me with this? The part of the code that shows the file path is the $selectButton.Add_Click() method.
...ANSWER
Answered 2021-Jun-15 at 21:22Following your .ShowDialog()
call, you can simply query the value of your $pathTextBox
text-box object.
QUESTION
We have a multi-module maven project. One of the modules has a bunch of .proto
files, which we compile to java files. Pretty much every other module depends on this module. Most of them use Protobuf 2.4, but one needs to use 2.5.
Is there any nice way to do this? (The not nice way is to edit the pom file to say "2.5", build a jar, manually copy that jar to wherever we need it, and then change the pom file back to 2.4.)
...ANSWER
Answered 2021-Jun-08 at 13:59Never used protobuf, but, as I understand it's a plugin that generate stuff.
So I'm gonna give you generic pointer hoping it will help. I think you should either try to make 2 jar with different classifier from a single module, see https://maven.apache.org/plugins/maven-jar-plugin/examples/attached-jar.html For example classifier proto2.4 and proto2.5 then you can add the classifier when you define the dependency to that module.
Other option I see is having 2 modules, the real one, you have now, and another one for 2.5 Generate a zip from the main one and the second module would be empty but have a dependency on the generated zip, unzip it and then compile with the plugin config for 2.5 Slower at execution, a bit dirtier imho, but can be needed if for example you need more customization than just the version.
QUESTION
GNU grep's basic (BRE) and extended (ERE) syntax is documented at https://www.gnu.org/software/grep/manual/html_node/Regular-Expressions.html and PCRE is summarized at man pcresyntax
, but there is no explicit comparison. What are the differences between GNU grep's basic/extended and PCRE (-P
) regular expressions?
ANSWER
Answered 2021-Jun-15 at 20:55My research of the major syntax and functionality differences from http://www.greenend.org.uk/rjk/tech/regexp.html:
.
in GNU grep does not match null bytes and newlines (but does match newlines when used with--null-data
), while Perl, everything except\n
is matched.[...]
in GNU grep defines POSIX bracket expressions, while Perl uses "character" classes. I'm not sure on the details. See http://www.greenend.org.uk/rjk/tech/regexp.html#bracketexpression- "In basic regular expressions the meta-characters
?
,+
,{
,|
,(
, and)
lose their special meaning; instead use the backslashed versions\?
,\+
,\{
,\|
,\(
, and\)
." From https://www.gnu.org/software/grep/manual/html_node/Basic-vs-Extended.html. ERE matches PCRE syntax. - GNU grep
\w
and\W
are the same as[[:alnum:]]
and[^[:alnum]]
, while Perl uses alphanumeric and underscore. - GNU grep has
\<
and\>
for start and end of word.
Perl supports much more additional functionality:
- "nongreedy {}" with syntax
re{...}?
- additional anchors and character types
\A
,\C
,\d
,\D
,\G
,\p
,\P
,\s
,\S
,\X
.\Z
,\z
. (?#comment)
- shy grouping
(?:re)
, shy grouping + modifiers(?modifiers:re)
- lookahead and negative lookahead
(?=re)
and(?!re)
, lookbehind and negative lookbehind(?<=p)
and(?
- Atomic groups
(?>re)
- Conditional expression
(?(cond)re)
- ... and more, see
man pcresyntax
QUESTION
In C++20, we got the capability to sleep on atomic variables, waiting for their value to change.
We do so by using the std::atomic::wait
method.
Unfortunately, while wait
has been standardized, wait_for
and wait_until
are not. Meaning that we cannot sleep on an atomic variable with a timeout.
Sleeping on an atomic variable is anyway implemented behind the scenes with WaitOnAddress on Windows and the futex system call on Linux.
Working around the above problem (no way to sleep on an atomic variable with a timeout), I could pass the memory address of an std::atomic
to WaitOnAddress
on Windows and it will (kinda) work with no UB, as the function gets void*
as a parameter, and it's valid to cast std::atomic
to void*
On Linux, it is unclear whether it's ok to mix std::atomic
with futex
. futex
gets either a uint32_t*
or a int32_t*
(depending which manual you read), and casting std::atomic
to u/int*
is UB. On the other hand, the manual says
The uaddr argument points to the futex word. On all platforms, futexes are four-byte integers that must be aligned on a four- byte boundary. The operation to perform on the futex is specified in the futex_op argument; val is a value whose meaning and purpose depends on futex_op.
Hinting that alignas(4) std::atomic
should work, and it doesn't matter which integer type is it is as long as the type has the size of 4 bytes and the alignment of 4.
Also, I have seen many places where this trick of combining atomics and futexes is implemented, including boost and TBB.
So what is the best way to sleep on an atomic variable with a timeout in a non UB way? Do we have to implement our own atomic class with OS primitives to achieve it correctly?
(Solutions like mixing atomics and condition variables exist, but sub-optimal)
...ANSWER
Answered 2021-Jun-15 at 20:48You shouldn't necessarily have to implement a full custom atomic
API, it should actually be safe to simply pull out a pointer to the underlying data from the atomic
and pass it to the system.
Since std::atomic
does not offer some equivalent of native_handle
like other synchronization primitives offer, you're going to be stuck doing some implementation-specific hacks to try to get it to interface with the native API.
For the most part, it's reasonably safe to assume that first member of these types in implementations will be the same as the T
type -- at least for integral values [1]. This is an assurance that will make it possible to extract out this value.
... and casting
std::atomic
tou/int*
is UB
This isn't actually the case.
std::atomic
is guaranteed by the standard to be Standard-Layout Type. One helpful but often esoteric properties of standard layout types is that it is safe to reinterpret_cast
a T
to a value or reference of the first sub-object (e.g. the first member of the std::atomic
).
As long as we can guarantee that the std::atomic
contains only the u/int
as a member (or at least, as its first member), then it's completely safe to extract out the type in this manner:
QUESTION
I'm attempting to write a scraper that will download attachments from an outlook account when I specify the path to folder to download from. I have working code but the folder locations are hardcoded as below:-
...ANSWER
Answered 2021-Jun-15 at 20:37You can do this as a reduction over foldernames
using getattr
to dynamically get the next attribute.
QUESTION
I would like to extract the definitions from the book The Navajo Language: A Grammar and Colloquial Dictionary by Young and Morgan. They look like this (very blurry):
I tried running it through the Google Cloud Vision API, and got decent results, but it doesn't know what to do with these "special" letters with accent marks on them, or the curls and lines on/through them. And because of the blurryness (there are no alternative sources of the PDF), it gets a lot of them wrong. So I'm thinking of doing it from scratch in Tesseract. Note the term is bold and the definition is not bold.
How can I use Node.js and Tesseract to get basically an array of JSON objects sort of like this:
...ANSWER
Answered 2021-Jun-15 at 20:17Tesseract takes a lang
variable that you can expand to include different languages if they're installed. I've used the UB Mannheim (https://github.com/UB-Mannheim/tesseract/wiki) installation which includes a ton of languages supported.
To get better and more accurate results, the best thing to do is to process the image before handing it to Tesseract. Set a white/black threshold so that you have black text on white background with no shading. I'm not sure how to do this in Node, but I've done it with Python's OpenCV library.
If that font doesn't get you decent results with the out of the box, then you'll want to train your own, yes. This blog post walks through the process in great detail: https://towardsdatascience.com/simple-ocr-with-tesseract-a4341e4564b6. It revolves around using the jTessBoxEditor to hand-label the objects detected in the images you're using.
Edit: In brief, the process to train your own:
- Install jTessBoxEditor (https://sourceforge.net/projects/vietocr/files/jTessBoxEditor/). Requires Java Runtime installed as well.
- Collect your training images. They want to be .tiffs. I found I got fairly accurate results with not a whole lot of images that had a good sample of all the characters I wanted to detect. Maybe 30/40 images. It's tedious, so you don't want to do TOO many, but need enough in order to get a good sampling.
- Use jTessBoxEditor to merge all the images into a single .tiff
- Create a training label file (.box)j. This is done with Tesseract itself.
tesseract your_language.font.exp0.tif your_language.font.exp0 makebox
- Now you can open the box file in jTessBoxEditor and you'll see how/where it detected the characters. Bounding boxes and what character it saw. The tedious part: Hand fix all the bounding boxes and characters to accurately represent what is in the images. Not joking, it's tedious. Slap some tv episodes up and just churn through it.
- Train the tesseract model itself
- save a file:
font_properties
who's content isfont 0 0 0 0 0
- run the following commands:
tesseract num.font.exp0.tif font_name.font.exp0 nobatch box.train
unicharset_extractor font_name.font.exp0.box
shapeclustering -F font_properties -U unicharset -O font_name.unicharset font_name.font.exp0.tr
mftraining -F font_properties -U unicharset -O font_name.unicharset font_name.font.exp0.tr
cntraining font_name.font.exp0.tr
You should, in there close to the end see some output that looks like this:
Master shape_table:Number of shapes = 10 max unichars = 1 number with multiple unichars = 0
That number of shapes should roughly be the number of characters present in all the image files you've provided.
If it went well, you should have 4 files created: inttemp
normproto
pffmtable
shapetable
. Rename them all with the prefix of your_language
from before. So e.g. your_language.inttemp
etc.
Then run:
combine_tessdata your_language
The file: your_language.traineddata
is the model. Copy that into your Tesseract's data folder. On Windows, it'll be like: C:\Program Files x86\tesseract\4.0\tessdata
and on Linux it's probably something like /usr/shared/tesseract/4.0/tessdata
.
Then when you run Tesseract, you'll pass the lang=your_language
. I found best results when I still passed an existing language as well, so like for my stuff it was still English I was grabbing, just funny fonts. So I still wanted the English as well, so I'd pass: lang=your_language+eng
.
QUESTION
I have a dataset with various "chunks" of columns with different prefixes, but the same suffix:
ID A034 B034 C034 D034 A099 B099 A123 B123 ... 1 NA 1 NA NA NA 3 1 NA ... 2 2 NA NA NA 2 NA NA 2 ... 3 NA NA 2 NA NA 2 1 NA ...The number of columns within each "chunk" also varies. Is there any way (other than manually, which is what I have been painstakingly doing with coalesce(!!! select(., contains("XXX")))
) to automatically coalesce by chunk based on the shared suffix? That is, the result should resemble
I'm not sure how to begin doing something like this, so any suggestions would be very helpful.
...ANSWER
Answered 2021-Jun-15 at 20:10We reshape the data into 'long' format with pivot_longer
, then we group by 'ID' and loop across
the other columns, apply the na.omit
to remove the NA elements (we assume that there is only one non-NA per each column by group)
QUESTION
I'm following a tutorial about RecyclerView, but I can't write ct:
the way he did. I typed in manually, but it does not work. I'm not sure how he typed it. He typed in this
, then android studio writes ct:
automatically. What do I need to type to do that?
MyAdapter is a class I created for RecyclerView. Here is the code for that class:
...ANSWER
Answered 2021-Jun-15 at 19:45The little lighter colored "ct" prompt is just a visual aid and it does not always show up. When you provide a raw value as an argument, it will show the prompt (like this, 1, or "foo"). When you provide a variable for the argument like ctx, foo, etc, it does not show up. This goes for all functions that take arguments.
The moral of the story is, it is not important and can be ignored.
QUESTION
I need to get token to connect to API. Tried with python this:
...ANSWER
Answered 2021-Jun-12 at 17:16First note that a token must be obtained from the server ! A token is required to make some API calls due to security concerns. There are usually at least two types of tokens:
- Access token: You use it to make API calls (as in the Authorization header above). But this token usually expires after a short period of time.
- Refresh token: Use this token to refresh the access token after it has expired.
You should use requests-oauthlib in addition with requests.
https://pypi.org/project/requests-oauthlib/
But first, read the available token acquisition workflows:
https://requests-oauthlib.readthedocs.io/en/latest/oauth2_workflow.html#available-workflows
and choose the right workflow that suits your purposes. (The most frequently used is Web App workflow)
Then, implement the workflow in your code to obtain the token. Once a valid token is obtained you can use it to make various API calls.
As a side note: be sure to refresh token if required.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
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Install manual
Install Sphinx, the documentation generator.
Install Graphviz, graph visualization software (used to draw some diagrams)
On Mac, install MacTeX (Basic TeX).
On Debian-based systems, install texlive-fonts-recommended and texlive-latex-extra.
Edit .rst files in source/
Run make html to build an HTML version of the manual
Open the file build/html/index.html in your Web browser to view the results
Note: it's good practice to clean your build directory first:.
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