In less, you can have variables that depend on variables that depend on variables etc. pp., like
#a: #000;
#b: #a;
#c: lighten(#b, 50);
#d: darken(#c, 25);
with the ability to import multiple files it can get quite messy to know which variable depends on which other variables.
Is there a way (e.g. a flag to run lessc with or an external program) to get the dependency tree of a given less variable?
Nope. The closest you're going to get is manually adding explanatory comments. If you need those comments in the compiled CSS, make sure to use /* CSS comments */ (// LESS comments don't make it into the compiled CSS).
If you're looking at front-end things in a browser inspector, you can use sourcemaps to track down what file a given style came from, and then read the comments in that file.
If you're minifying your compiled CSS, either don't remove comments or generate an extra non-production copy that doesn't remove comments.
Your example is colors, but note that if dealing with numbers you'll sometimes be able to use calc() to have source values show up in the final CSS (including in browser inspectors, if that's relevant to what you're doing).
Related
I already using the minify argument when building with dart2js.
I looked at the output and I see that the import 'dart:html causes problems in terms of the output file size (2kb .dart file becomes 182kb .js file). For example it imports SVG package though in my code I never touch any <svg> DOM Elements.
I understand that the compiler doesn't know if I'm going to use svg DOM Elements or not. And I understand that the using of var is one of the reasons of that behavior.
But if I will not use any var keywords, the compiler still doesn't have enough 'power' to strip all unused packages and functions.
Is there any directive I can use to forbid the import of certain packages. I mean built-in packages right now. I'm using IntelliJ IDEA and it doesn't allow me to change anything in the Dart default setup.
UPD: Tried to use
import 'dart:html' show querySelector, Element
to import only that method and class, but file size is still 182kb.
The only solution I see for now is to make a few stripped versions of the default 'dart:html' package. The one without WebGL, SVG and some other features.
Because maybe Dart compiler works good, but there is just some methods and classes that I don't use, but the code uses. Like.. the initial package methods checking if some elements are SVG or something like that.
There is a tool for analyzing the output of a dart2js build, especially for references and dependencies. Just tested and gave a better overview in my case.
https://github.com/dart-lang/dump-info-visualizer
hosted :
https://dart-lang.github.io/dump-info-visualizer/
Build with option --dump-info
https://webdev.dartlang.org/tools/dart2js#options
Even when you don't import anything you will get some minimal output size. Dart provides a lot of features like classes with inheritance and mixins (and a lot more) and dart2js output contains code that implements these features.
This is like adding a JS library like jQuery.
Therefore main() {} will already result in an output size of several dozen kb. Adding another line of code probably will only add a few additional bytes.
pub build by default does tree-shaking and minifications, therefore no additional options are required.
I'm already using uncss with grunt, but stumbled upon purifycss.
I can't seem to find comparisons anywhere.
Can anyone tell me the difference between the two to help me choose the right one?
UnCSS removes unused CSS from your stylesheets.
PurifyCSS does not modify the original CSS files.
I use PurifyCSS and I full recommend.
I hope that simplify the things for you, everyone has a way to do the things. If I were you I would test both and see which one is more helpful for you.
EDIT:
PurifyCSS takes also care about JS-Files which could add CSS classes and IDs.
Here is a more recent comparison, courtesy of another similar project, purgecss: https://www.purgecss.com/comparison.html
Summary
PurifyCSS
Works with any file type, not just HTML or JS
Uses extractors, which takes the content of a file and extracts the list of CSS selectors used in it
UnCSS
Effective at removing unused selectors from web apps due to HTML emulation and JS execution.
This has a performance cost.
Most accurate tool if you don't use server-side rendering.
No extractor for JS files, but developers can create extractors for specific frameworks and file types.
Sorry for the horrible question wording, let me explain.
For a project I'm working on, I'd like to manage various dependencies for my LESS files on the server. Because of the way the project is structured (different components symlinked in different ways), it's much more limiting to just use #import to build dependencies etc.
Ideally I'd like to just spit out a list of required LESS files in the section, e.g.:
<link rel='stylesheet/less' href='/path/to/some/file.less' type='text/css' media='all' />
<link rel='stylesheet/less' href='/path/to/some/other-file.less' type='text/css' media='all' />
Then, for example, if a variable or mixin is defined in file.less, I'd like to be able to use it in other-file.less.
From what I can tell, that doesn't work. Each LESS file seems to exist in its own scope and variables etc in one are not available in the other.
Is this correct? Is the scope entirely limited to a single file and any #imports therein? I'm reasonably sure that it is, but not entirely.
For now, my workaround is more complex than I'd like: I'm building dependencies server side, and then munging them into a giant, single development.less file on the fly. (Note that for production purposes, I have a build process that compiles and minifies my less so that I serve straight up CSS).
I've looked at browser.js in the LESS source code for clues but thought I'd ask here first if this was possible or even desirable. I was a bit surprised at this behavior since it's not how multiple javascript files and inline code work.
Why It Doesn't Work
Each <link> of a LESS file preprocesses that file and resolves it to just a plain CSS output. No variables or anything are left in the "scope" of the html itself, so there is nothing for the second <link> to be able to use. That is why one cannot read the other.
A Possible Help
With LESS 1.5 an #import can be made to just be a reference (and thus not compile direct output into the file). So your other-file.less could do this:
#import (reference) file.less;
To gain the dependencies needed for it.
I am still struggling to find a good naming convention for assets like images, js and css files used in my web projects.
So, my current would be:
CSS: style-{name}.css
examples: style-main.css, style-no_flash.css, style-print.css etc.
JS:
script-{name}.js
examples: script-main.js, script-nav.js etc.
Images: {imageType}-{name}.{imageExtension}
{imageType} is any of these
icon (e. g. question mark icon for help content)
img (e. g. a header image inserted via <img /> element)
button (e. g. a graphical submit button)
bg (image is used as a background image in css)
sprite (image is used as a background image in css and contains multiple "versions")
Example-names would be: icon-help.gif, img-logo.gif, sprite-main_headlines.jpg, bg-gradient.gif etc.
So, what do you think and what is your naming convention?
I've noticed a lot of frontend developers are moving away from css and js in favor of styles and scripts because there is generally other stuff in there, such as .less, .styl, and .sass as well as, for some, .coffee. Fact is, using specific technology selections in your choice of folder organization is a bad idea even if everyone does it. I'll continue to use the standard I see from these highly respected developers:
src/html
src/images
src/styles
src/styles/fonts
src/scripts
And their destination build equivalents, which are sometimes prefixed with dest depending on what they are building:
./
images
styles
styles/fonts
scripts
This allows those that want to put all files together (rather than breaking out a src directory) to keep that and keeps things clearly associated for those that do break out.
I actually go a bit futher and add
scripts/before
scripts/after
Which get smooshed into two main-before.min.js and main-after.min.js scripts, one for the header (with essential elements of normalize and modernizr that have to run early, for example) and after for last thing in the body since that javascript can wait. These are not intended for reading, much like Google's main page.
If there are scripts and style sheets that make sense to minify and leave linked alone because of a particular cache management approach that is taken care of in the build rules.
These days, if you are not using a build process of some kind, like gulp or grunt, you likely are not reaching most of the mobile-centric performance goals you should probably be considering.
I place CSS files in a folder css, Javascript in js, images in images, ... Add subfolders as you see fit. No need for any naming convention on the level of individual files.
/Assets/
/Css
/Images
/Javascript (or Script)
/Minified
/Source
Is the best structure I've seen and the one I prefer. With folders you don't really need to prefix your CSS etc. with descriptive names.
For large sites where css might define a lot of background images, a file naming convention for those assets comes in really handy for making changes later on.
For example:
[component].[function-description].[filetype]
footer.bkg-image.png
footer.copyright-gradient.png
We have also discussed adding in the element type, but im not sure how helpful that is and could possibly be misleading for future required changes:
[component].[element]-[function-description].[filetype]
footer.div-bkg-image.png
footer.p-copyright-gradient.png
You can name it like this:
/assets/css/ - For CSS files
/assets/font/ - For Font files. (Mostly you can just go to google fonts to search for usable fonts.)
/assets/images/ - For Images files.
/assets/scripts/ or /assets/js/ - For JavaScript files.
/assets/media/ - For video and misc. files.
You can also replace "assets" with "resource" or "files" folder name and keep the name of it's subfolders. Well having an order folder structure like this isn't very important the only important is you just have to arrange your files by it's format. like creating a folder "/css/" for CSS files or "/images/" for Image files.
First, I divide into folders: css, js, img.
Within css and js, I prefix files with the project name because your site may include js and css files which are components, this makes it clear where files are specific for your site, or relating to plugins.
css/mysite.main.css css/mysite.main.js
Other files might be like
js/jquery-1.6.1.js
js/jquery.validate.js
Finally images are divided by their use.
img/btn/submit.png a button
img/lgo/mysite-logo.png a logo
img/bkg/header.gif a background
img/dcl/top-left-widget.jpg a decal element
img/con/portait-of-something.jpg a content image
It's important to keep images organized since there can be over 100 and can easily get totally mixed together and confusingly-named.
I tend to avoid anything generic, such as what smdrager suggested. "mysite.main.css" doesn't mean anything at all.
What is "mysite"?? This one I'm working on? If so then obvious really, but it already has me thinking what it might be and if it is this obvious!
What is "Main"? The word "Main" has no definition outside the coders knowledge of what is within that css file.
While ok in certain scenarios, avoid names like "top" or "left" too: "top-nav.css" or "top-main-logo.png".
You might end up wanting to use the same thing elsewhere, and putting an image in a footer or within the main page content called "top-banner.png" is very confusing!
I don't see any issue with having a good number of stylesheets to allow for a decent naming convention to portray what css is within the given file.
How many depends entirely on the size of the site and what it's function(s) are, and how many different blocks are on the site.
I don't think you need to state "CSS" or "STYLE" in the css filenames at all, as the fact it's in "css" or "styles" folder and has an extension of .css and mainly as these files are only ever called in the <head> area, I know pretty clearly what they are.
That said, I do this with library, JS and config (etc) files. eg libSomeLibrary.php, or JSSomeScript.php. As PHP and JS files are included or used in various areas within other files, and having info of what the file's main purpose is within the name is useful.
eg: Seeing the filename require('libContactFormValidation.php'); is useful. I know it's a library file (lib) and from the name what it does.
For image folders, I usually have images/content-images/ and images/style-images/. I don't think there needs to be any further separation, but again it depends on the project.
Then each image will be named accordingly to what it is, and again I don't think there's any need for defining the file is an image within the file name. Sizes can be useful, especially for when images have different sizes.
site-logo-150x150.png
site-logo-35x35.png
shop-checkout-button-40x40.png
shop-remove-item-20x20.png
etc
A good rule to follow is: if a new developer came to the files, would they sit scratching their head for hours, or would they likely understand what things do and only need a little time researching (which is unavoidable)?
As anything like this, however, one of the most important rules to follow is simply constancy!
Make sure you follow the same logic and patterns thoughout all your naming conventions!
From simple css file names, to PHP library files to database table and column names.
This is an old question, but still valid.
My current recommendation is to go with something in this lines:
assets (or assets-web or assets-www); this one is intended for static content used by the client (browser)
data; some xml files and other stuff
fonts
images
media
styles
scripts
lib (or 3rd-party); this one is intended for code you don't make or modify, the libraries as you get them
lib-modded (or 3rd-party-modified); this one is intended for code you weren't expected to modify, but had to, like applying a workaround/fix in the meantime the library provider releases it
inc (or assets-server or assets-local); this one is intended for content used server side, not to be used by the client, like libraries in languages like PHP or server scripts, like bash files
fonts
lib
lib-modded
I marked in bold the usual ones, the others are not usual content.
The reason for the main division, is in the future you can decide to server the web assets from a CDN or restrict client access to server assets, for security reasons.
Inside the lib directories i use to be descriptive about the libraries, for example
lib
jquery.com
jQuery
vX.Y.Z
github
[path]
[library/project name]
vX.Y.Z (version)
so you can replace the library with a new one, without breaking the code, also allowing future code maintainers, including yourself, to find the library and update it or get support.
Also, feel free to organize the content inside according to its usage, so images/logos and images/icons are expected directories in some projects.
As a side note, the assets name is meaningful, not only meaning we have resources in there, but meaning the resources in there must be of value for the project and not dead weight.
The BBC have tons of standards relating web development.
Their standard is fairly simple for CSS files:
http://www.bbc.co.uk/guidelines/futuremedia/technical/css.shtml
You might be able to find something useful on their main site:
http://www.bbc.co.uk/guidelines/futuremedia/
I'm producing a hex file to run on an ARM processor which I want to keep below 32K. It's currently a lot larger than that and I wondered if someone might have some advice on what's the best approach to slim it down?
Here's what I've done so far
So I've run 'size' on it to determine how big the hex file is.
Then 'size' again to see how big each of the object files are that link to create the hex files. It seems the majority of the size comes from external libraries.
Then I used 'readelf' to see which functions take up the most memory.
I searched through the code to see if I could eliminate calls to those functions.
Here's where I get stuck, there's some functions which I don't call directly (e.g. _vfprintf) and I can't find what calls it so I can remove the call (as I think I don't need it).
So what are the next steps?
Response to answers:
As I can see there are functions being called which take up a lot of memory. I cannot however find what is calling it.
I want to omit those functions (if possible) but I can't find what's calling them! Could be called from any number of library functions I guess.
The linker is working as desired, I think, it only includes the relevant library files. How do you know if only the relevant functions are being included? Can you set a flag or something for that?
I'm using GCC
General list:
Make sure that you have the compiler and linker debug options disabled
Compile and link with all size options turned on (-Os in gcc)
Run strip on the executable
Generate a map file and check your function sizes. You can either get your linker to generate your map file (-M when using ld), or you can use objdump on the final executable (note that this will only work on an unstripped executable!) This won't actually fix the problem, but it will let you know of the worst offenders.
Use nm to investigate the symbols that are called from each of your object files. This should help in finding who's calling functions that you don't want called.
In the original question was a sub-question about including only relevant functions. gcc will include all functions within every object file that is used. To put that another way, if you have an object file that contains 10 functions, all 10 functions are included in your executable even if one 1 is actually called.
The standard libraries (eg. libc) will split functions into many separate object files, which are then archived. The executable is then linked against the archive.
By splitting into many object files the linker is able to include only the functions that are actually called. (this assumes that you're statically linking)
There is no reason why you can't do the same trick. Of course, you could argue that if the functions aren't called the you can probably remove them yourself.
If you're statically linking against other libraries you can run the tools listed above over them too to make sure that they're following similar rules.
Another optimization that might save you work is -ffunction-sections, -Wl,--gc-sections, assuming you're using GCC. A good toolchain will not need to be told that, though.
Explanation: GNU ld links sections, and GCC emits one section per translation unit unless you tell it otherwise. But in C++, the nodes in the dependecy graph are objects and functions.
On deeply embedded projects I always try to avoid using any standard library functions. Even simple functions like "strtol()" blow up the binary size. If possible just simply avoid those calls.
In most deeply embedded projects you don't need a versatile "printf()" or dynamic memory allocation (many controllers have 32kb or less RAM).
Instead of just using "printf()" I use a very simple custom "printf()", this function can only print numbers in hexadecimal or decimal format not more. Most data structures are preallocated at compile time.
Andrew EdgeCombe has a great list, but if you really want to scrape every last byte, sstrip is a good tool that is missing from the list and and can shave off a few more kB.
For example, when run on strip itself, it can shave off ~2kB.
From an old README (see the comments at the top of this indirect source file):
sstrip is a small utility that removes the contents at the end of an
ELF file that are not part of the program's memory image.
Most ELF executables are built with both a program header table and a
section header table. However, only the former is required in order
for the OS to load, link and execute a program. sstrip attempts to
extract the ELF header, the program header table, and its contents,
leaving everything else in the bit bucket. It can only remove parts of
the file that occur at the end, after the parts to be saved. However,
this almost always includes the section header table, and occasionally
a few random sections that are not used when running a program.
Note that due to some of the information that it removes, a sstrip'd executable is rumoured to have issues with some tools. This is discussed more in the comments of the source.
Also... for an entertaining/crazy read on how to make the smallest possible executable, this article is worth a read.
Just to double-check and document for future reference, but do you use Thumb instructions? They're 16 bit versions of the normal instructions. Sometimes you might need 2 16 bit instructions, so it won't save 50% in code space.
A decent linker should take just the functions needed. However, you might need compiler & linke settings to package functions for individual linking.
Ok so in the end I just reduced the project to it's simplest form, then slowly added files one by one until the function that I wanted to remove appeared in the 'readelf' file. Then when I had the file I commented everything out and slowly add things back in until the function popped up again. So in the end I found out what called it and removed all those calls...Now it works as desired...sweet!
Must be a better way to do it though.
To answer this specific need:
•I want to omit those functions (if possible) but I can't find what's
calling them!! Could be called from any number of library functions I
guess.
If you want to analyze your code base to see who calls what, by whom a given function is being called and things like that, there is a great tool out there called "Understand C" provided by SciTools.
https://scitools.com/
I have used it very often in the past to perform static code analysis. It can really help to determine library dependency tree. It allows to easily browse up and down the calling tree among other things.
They provide a limited time evaluation, then you must purchase a license.
You could look at something like executable compression.