maanoo/blog: November 2015

Friday, November 20, 2015

Techniques: Random art with symmetry

So lets add many circles together:

Thats ok but what if we add some symmetry.

Lets add symmetry from one axis:

From two axis:

Those examples are random but the point is that have something not random, they have structure.

I like the more complex symmetry from the center point (not the math definition):

continue_

Wednesday, November 18, 2015

Monday, November 16, 2015

Friday, November 13, 2015

We can save and load values, permanently, using Shared Preferences.

The shared preferences framework provides an easy way to store values, not only preference related but any kind of values. It's a file based so keep that in mind.

To get the SharedPreferences object we need:

private static final String NAME = "...";
public static SharedPreferences getPreferences(Activity a) {
  return a.getSharedPreferences(NAME , Context.MODE_PRIVATE);
}

To save a values we:

public static void save(Activity a) {
  SharedPreferences.Editor sp = getPreferences(a).edit();

  sp.putString("name1", value1);
  sp.putInt("name2", value2);

  sp.commit();
}

And to load a values we:

public static void load(Activity a) {
  SharedPreferences sp = getPreferences(a);

  value1 = sp.getString("name1", default1);
  value2 = sp.getInt("name2", default2);
}

We can also get a single Preferences for each activity with:

getPreferences(Context.MODE_PRIVATE)

Except MODE_PRIVATE we have MODE_WORLD_READABLE and MODE_WORLD_WRITEABLE which are deprecated, so don't use them.

done_

Wednesday, November 11, 2015

JavaScript: Local and Session storage

To store values to a browser we can use localStorage and sessionStorage just by:

localStorage["name"] = value;

and to get the values we just:

value = localStorage["name"];

The localStorage keeps the values for ever (probably).

The sessionStorage keeps the values until the page session ends.

For each domain our browser has a pair of these objects and not for each page.

To store objects without functions we use JSON:

localStorage["name"] = JSON.stringify(object);

object = JSON.parse(localStorage["name"]);

done_

Monday, November 9, 2015

JavaScript: jQuery selector

If we want to use JQuery ONLY for selecting elements like:

$(".item")

Why use a whole library, just:

document.querySelectorAll(".item")

function q(query) {
  return document.querySelectorAll(query);
}

q(".item")

Note: The only thing we gain from this is self-something.

continue_

Friday, November 6, 2015

PHP: Simple counter

A simple counter using a text file.

The php code:

<?php
  $path = "./counter.txt";
  $count = intval(file_get_contents($path));
  if(isset($_GET["add"])) {
    $count++;
    file_put_contents($path, $count);
  }
  echo $count;
?>

To add one to the counter must be called with GET parameter add.

To get the counter value must be called with no parameters.

done_

Wednesday, November 4, 2015

CSS: Transition all

In CSS if we define transitions, every time a value changes an animation-transition is created and executed.

So if we want to use transitions for all elements and for all values (which is wrong in many ways), we can just write:

*{
  transition: all 0.7s ease-in-out;
}