window.onload = function(){
draw();
}
function draw(){
var canvas = document.getElementById('mycanvas');
if (!canvas || !canvas.getContext)return false;
var ctx = canvas.getContext('2d');
ctx.fillStyle = "red"
var y = 0;
(function loop(){
ctx.clearRect(0,0,canvas.width, canvas.height);
if (y > canvas.height) y = -50;
y++;
ctx.fillRect(0,y,50,50);
setTimeout(loop,10);
})();
}
Canvasで遊ぼう
ctx.shadowColor = "#ccc"; ctx.shadowOffsetX = 5; ctx.shadowOffsetY = 5; ctx.shadowBlur = 5; ctx.globalAlpha = 0.5; ctx.fillRect(0, 0, 100, 100);
図形の変形
ctx.scale(0.8,0.8); ctx.rotate(30/180*Math.PI); ctx.translate(100, 10); ctx.fillRect(0, 0, 100, 100);
stroke
ctx.beginPath(); ctx.moveTo(20, 20); ctx.lineTo(120,20); ctx.lineTo(120,120); ctx.stroke();
円形・曲線:round,butt,square
ctx.beginPath(); ctx.arc(100,100,50,10/180*Math.PI,210/180*Math.PI); ctx.lineWidth = 15; ctx.lineCap = "round"; ctx.stroke();
テキスト描画
ctx.font = 'bold 20px Verdana';
ctx.textAlign = 'left';
ctx.fillStyle = 'red';
ctx.fillText('Google', 20, 20, 40);
ctx.strokeText('Google', 20, 120, 200);
画像表示
var img = new Image();
img.src = 'baby.jpg';
img.onload = function(){
ctx.drawImage(img, 10, 10);
}
背景パターン
var img = new Image();
img.src = 'google.png';
im.onload = function(){
var patter = ctx.createPattern(img, 'repeat');
ctx.fillStyle = pattern;
ctx.fillRect(20, 20, 100, 100);
}
設定の保存、復元
ctx.fillStyle = "yellow"; ctx.save(); ctx.fillRect(0, 0, 50, 50); ctx.fillStyle= "blue"; ctx.fillRect(100, 0, 50, 50); ctx.restore(); ctx.fillRect(200, 0, 50, 50);
window.onload = function(){
draw();
}
function draw(){
var canvas = document.getElementById('mycanvas');
if (!canvas || !canvas.getContext)return false;
var ctx = canvas.getContext('2d');
ctx.globalAlpha = 0.5;
for (var i = 0; i < 100; i++){
var x = Math.floor(Math.random() * 400);
var y = Math.floor(Math.random() * 200);
var r = Math.floor(Math.random() * 200);
ctx.fillStyle = "rgb("+rgb()+","+rgb()+","+rgb()+")";
ctx.beginPath();
ctx.arc(x,y,r,0,2*Math.PI);
ctx.stroke();
ctx.fill();
}
function rgb(){
return Math.floor(Math.random() * 255);
}
}
Canvas
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="utf-8">
<title>Canvas</title>
</head>
<body>
<h1>Canvas</h1>
<canvas id="mycanvas" width="800" height="800">
対応ブラウザを使用ください。</canvas>
<p>
</p>
<script src="myscript.js"></script>
</body>
</html>
window.onload = function(){
draw();
}
function draw(){
var canvas = document.getElementById('mycanvas');
if (!canvas || !canvas.getContext)return false;
var ctx = canvas.getContext('2d');
//ctx.strokeRect(50, 10, 50, 150);
ctx.fillRect(10, 10, 50, 50);
ctx.clearRect(15, 15, 20, 20);
}
線の塗りやスタイル
ctx.strokeStyle = "rgba(255, 0, 0, 0.5)"; ctx.lineWidth = 15; ctx.lineJoin = "bevel";//"round"; ctx.fillStyle = "rgba(255, 0, 0, 0.5)"; ctx.strokeRect(10, 10, 50, 50); ctx.fillRect(100, 10, 50, 50);
var g = ctx.createLinearGradient(0, 0, 0, 100); g.addColorStop(0.0, "red"); g.addColorStop(0.5, "yellow"); g.addColorStop(1.0, "blue"); ctx.fillStyle = g; ctx.fillRect(0, 0, 100, 100);
円形
var g = ctx.createRadialGradient(50, 50, 0, 50, 50, 80);
日付カウントダウン
setTimeoutは、一定時間後に特定の処理をおこなう（繰り返さずに一度だけ）処理です。setTimeout(function(){
getResult();},200);で、0.2秒ごとに処理を繰り返します。new Date().getTime();から、Date.now()を引いた秒数で表示しています。
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="utf-8">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="https://fonts.googleapis.com/css?family=Bilbo" rel="stylesheet">
<title>Web font</title>
<style>
body {
font-family: 'Bilbo', cursive;
background: #000;
text-align: center;
font-size:36px;
color:red;
}
h1 {
color: #fff;
font-size: 128px;
margin:0;
}
#remainingDays, #remainingTime {
font-size: 64px;
}
</style>
</head>
<body>
<h1>Q</h1>
<p>
<span id="remainingDays"></span>days <span id="remainingTime"></span> to go
</p>
<script>
function getResult(){
var target = new Date(2020, 04, 01, 10, 0, 0).getTime();
var now = Date.now();
var diff = (target - now) /1000;
var d = Math.floor(diff / 60 / 60/ 24);
diff = diff - 60 * 60 * 24 * d;
var h = Math.floor(diff / 60 / 60);
diff = diff - 60 * 60 * h;
var m = Math.floor(diff / 60);
diff = diff - 60 * m;
var s = Math.floor(diff);
document.getElementById('remainingDays').innerHTML = d;
document.getElementById('remainingTime').innerHTML = padZero(h) + ':' + padZero(m) + ':' + padZero(s);
setTimeout(function(){
getResult();
},200);
}
getResult();
function padZero(n){
return (n < 10) ? '0'+n : n;
}
</script>
</body>
</html>
二次元バーコード生成
jQuery doc
.attr()
Get the value of an attribute for the first element in the set of matched elements or set one or more attributes for every matched element.
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="utf-8">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>二次元バーコード</title>
<style>
body {
}
</style>
</head>
<body>
<h1>二次元バーコード</h1>
<p>
<input type="text" id="msg">
<input type="button" value="変換" id="button">
</p>
<div id="barCode"></div>
<script>
$(function(){
$('#button').click(function(){
var msg = encodeURIComponent($('#msg').val());
var img = $('<img>').attr('src', 'http://chart.apis.google.com/chart?cht=qr&chs=150x150&choe=Shift_JIS&chl='+msg);
$('#barCode').html(img);
});
});
</script>
</body>
</html>
Redisの操作
127.0.0.1:6379> rpush mycolor pink (integer) 1 127.0.0.1:6379> rpush mycolor green (integer) 2 127.0.0.1:6379> rpush mycolor red (integer) 3 127.0.0.1:6379> rpush mycolor yellow (integer) 4 127.0.0.1:6379> rpush mycolor blue (integer) 5 127.0.0.1:6379> rpush myclolor purple (integer) 1 127.0.0.1:6379> lrange mycolor 0 5 1) "pink" 2) "green" 3) "red" 4) "yellow" 5) "blue" 127.0.0.1:6379> lrange mycolor 0 -1 1) "pink" 2) "green" 3) "red" 4) "yellow" 5) "blue"
リスト操作
127.0.0.1:6379> rpop mycolor "blue" 127.0.0.1:6379> lrange mycolor 0 -1 1) "pink" 2) "green" 3) "red" 4) "yellow" 127.0.0.1:6379> lpop mycolor "pink" 127.0.0.1:6379> lrange mycolor 0 -1 1) "green" 2) "red" 3) "yellow" 127.0.0.1:6379> lindex mycolor 2 "yellow" 127.0.0.1:6379> llen mycolor (integer) 3 127.0.0.1:6379> ltrim mycolor 0 2 OK 127.0.0.1:6379> lrange mycolor 0 -1 1) "green" 2) "red" 3) "yellow"
セット型の計算
127.0.0.1:6379> sadd myset1 a (integer) 1 127.0.0.1:6379> sadd myset1 b (integer) 1 127.0.0.1:6379> sadd myset1 c (integer) 1 127.0.0.1:6379> smembers myset1 1) "c" 2) "b" 3) "a" 127.0.0.1:6379> sadd myset1 d (integer) 1 127.0.0.1:6379> smembers myset1 1) "d" 2) "c" 3) "b" 4) "a" 127.0.0.1:6379> srem myset1 d (integer) 1 127.0.0.1:6379> smembers myset1 1) "c" 2) "b" 3) "a" 127.0.0.1:6379> sadd myset2 b (integer) 1 127.0.0.1:6379> sadd myset2 c (integer) 1 127.0.0.1:6379> sadd myset2 e (integer) 1 127.0.0.1:6379> smembers myset1 1) "c" 2) "b" 3) "a" 127.0.0.1:6379> smembers myset2 1) "c" 2) "b" 3) "e" 127.0.0.1:6379> sunion myset1 myset2 1) "b" 2) "c" 3) "e" 4) "a" 127.0.0.1:6379> sinter mysete1 myset2 (empty list or set) 127.0.0.1:6379> sdiff myset1 myset2 1) "a"
ソート済みの集合
127.0.0.1:6379> zadd hs 22 yamada (integer) 1 127.0.0.1:6379> zadd hs 50 tanaka (integer) 1 127.0.0.1:6379> zadd hs 80 yasuda (integer) 1 127.0.0.1:6379> zadd hs 21 okamoto (integer) 1 127.0.0.1:6379> zrange hs 0 -1 1) "okamoto" 2) "yamada" 3) "tanaka" 4) "yasuda" 127.0.0.1:6379> zrevrange hs 0 -1 1) "yasuda" 2) "tanaka" 3) "yamada" 4) "okamoto" 127.0.0.1:6379> zrank hs yamada (integer) 1 127.0.0.1:6379> zrevrank hs yamada (integer) 2
Redis
永続化の機能があるインメモリデータベースです。高速処理用に部分的に使われるなどのケースが多いようです。
インストールして、サーバーを立ち上げます。
[vagrant@localhost redis]$ redis-server
[14193] 12 Nov 04:58:10.521 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
[14193] 12 Nov 04:58:10.522 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
[14193] 12 Nov 04:58:10.522 # Redis can't set maximum open files to 10032 because of OS error: Operation not permitted.
[14193] 12 Nov 04:58:10.522 # Current maximum open files is 1024. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
_._
_.-``__ ''-._
_.-`` `. `_. ''-._ Redis 2.8.12 (00000000/0) 64 bit
.-`` .-```. ```\/ _.,_ ''-._
( ' , .-` | `, ) Running in stand alone mode
|`-._`-...-` __...-.``-._|'` _.-'| Port: 6379
| `-._ `._ / _.-' | PID: 14193
`-._ `-._ `-./ _.-' _.-'
|`-._`-._ `-.__.-' _.-'_.-'|
| `-._`-._ _.-'_.-' | http://redis.io
`-._ `-._`-.__.-'_.-' _.-'
|`-._`-._ `-.__.-' _.-'_.-'|
| `-._`-._ _.-'_.-' |
`-._ `-._`-.__.-'_.-' _.-'
`-._ `-.__.-' _.-'
`-._ _.-'
`-.__.-'
[14193] 12 Nov 04:58:10.524 # Server started, Redis version 2.8.12
[14193] 12 Nov 04:58:10.525 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
[14193] 12 Nov 04:58:10.526 * The server is now ready to accept connections on port 6379
cliからのアクセス, exit, shutdouwn
[vagrant@localhost redis]$ redis-cli
データベースの選択
> select
データの保存
> bgsave
bgsaveでデータベースを保存すると、redis-serverを立ち上げたディレクトリに、dump.rdbが作成されます。
データの設定
127.0.0.1:6379> set name yamada OK 127.0.0.1:6379> get name "yamada" 127.0.0.1:6379> mset email yamada@gmail.com score 120 OK 127.0.0.1:6379> get name email score (error) ERR wrong number of arguments for 'get' command 127.0.0.1:6379> mget name email score 1) "yamada" 2) "yamada@gmail.com" 3) "120"
incr score
127.0.0.1:6379> incr score (integer) 121 127.0.0.1:6379> get score "121" 127.0.0.1:6379> decrby score 10 (integer) 111 127.0.0.1:6379> get score "111"
keyの操作
127.0.0.1:6379> keys * 1) "name" 2) "score" 3) "email" 127.0.0.1:6379> keys *m* 1) "name" 2) "email" 127.0.0.1:6379> exists score (integer) 1 127.0.0.1:6379> exists age (integer) 0 127.0.0.1:6379> set age 14 OK 127.0.0.1:6379> rename age nenrei OK 127.0.0.1:6379> keys * 1) "nenrei" 2) "email" 3) "score" 4) "name" 127.0.0.1:6379> del nenrei (integer) 1 127.0.0.1:6379> keys * 1) "email" 2) "score" 3) "name" 127.0.0.1:6379> set age 14 OK 127.0.0.1:6379> expire age 5 (integer) 1 127.0.0.1:6379> get age (nil)
psql document
Postgresには独自の命令文が多数用意されています。
blogapp=# select name, length(name) from users; name | length --------+-------- yamada | 6 satou | 5 sasaki | 6 yamada | 6 satou | 5 sasaki | 6 yamada | 6 (7 行)
抽選システム
blogapp=# select * from users order by random() limit 1; id | name | score | team ----+--------+-------+------- 6 | sasaki | 7.6 | green (1 行)
更新
blogapp=# update users set score = 5.8 where name = 'yamada'; UPDATE 3
削除
blogapp=# delete from users where id = 7; DELETE 1
テーブルの変更
blogapp=# alter table users add fullname varchar(255); ALTER TABLE blogapp=# select * from users; id | name | score | team | fullname ----+--------+-------+-------+---------- 2 | satou | 4.3 | green | 3 | sasaki | 8.2 | green | 5 | satou | 4.2 | blue | 6 | sasaki | 7.6 | green | 1 | yamada | 5.8 | red | 4 | yamada | 5.8 | red | (6 行) blogapp=# alter table users alter name type varchar(32); ALTER TABLE
複数のユーザを突き合わせ
select users.name, post.title from users, posts wher users.id = posts.id;
複雑なselect文はviewを作成
blogapp=# create view yamada_posts as blogapp-# select users.name, post.title from users, posts wher users.id = posts.id;
beginとcommitで囲むと、トランザクションという処理ができるようになります。変更の取り消しはrollbackです。
psql
条件検索
blogapp=# select * from users where score > 4.0; id | name | score | team ----+--------+-------+-------- 1 | yamada | 6.5 | red 2 | satou | 4.3 | green 3 | sasaki | 8.2 | green 5 | satou | 4.2 | blue 6 | sasaki | 7.6 | green 7 | yamada | 5.7 | yellow (6 行)
blogapp=# select * from users where name = 'yamada'; id | name | score | team ----+--------+-------+-------- 1 | yamada | 6.5 | red 4 | yamada | 3.6 | red 7 | yamada | 5.7 | yellow (3 行)
並び順
blogapp=# select * from users order by score; id | name | score | team ----+--------+-------+-------- 4 | yamada | 3.6 | red 5 | satou | 4.2 | blue 2 | satou | 4.3 | green 7 | yamada | 5.7 | yellow 1 | yamada | 6.5 | red 6 | sasaki | 7.6 | green 3 | sasaki | 8.2 | green (7 行) blogapp=# select * from users order by score desc; id | name | score | team ----+--------+-------+-------- 3 | sasaki | 8.2 | green 6 | sasaki | 7.6 | green 1 | yamada | 6.5 | red 7 | yamada | 5.7 | yellow 2 | satou | 4.3 | green 5 | satou | 4.2 | blue 4 | yamada | 3.6 | red
offset
blogapp=# select * from users limit3 offset 3; id | name | score | team ----+--------+-------+-------- 4 | yamada | 3.6 | red 5 | satou | 4.2 | blue 6 | sasaki | 7.6 | green 7 | yamada | 5.7 | yellow (4 行)
レコード集計
blogapp=# select count(*) from users;
count
-------
7
(1 行)
Postgresの操作
blogapp=# \dt
リレーションの一覧
スキーマ | 名前 | 型 | 所有者
----------+-------+----------+----------
public | posts | テーブル | postgres
(1 行)
blogapp=# \d posts
テーブル "public.posts"
カラム | 型 | 修飾語
--------+------------------------+--------
title | character varying(255) |
body | text |
外部ファイルからコマンド入力も可能です。
blogapp=# \i commands.sql CREATE TABLE
テーブルの削除はdrop table hoge;
sqlコマンド
create table posts ( id serial primary key, title varchar(255) not null, body text check(length(body)> 5), id_draft boolean default TRUE, created timestamp default 'now' );
blogapp=# insert into posts (title, body) values('title1', 'body1111');
INSERT 0 1
blogapp=# select * from posts;
id | title | body | id_draft | created
----+--------+----------+----------+----------------------------
1 | title1 | body1111 | t | 2016-11-12 03:44:59.912257
create table users (
id serial primary key,
name varchar(255),
score real,
team varchar(255)
);
insert into users (name, score, team) values
('yamada', 6.5, 'red'),
('satou', 4.3, 'green'),
('sasaki', 8.2, 'green'),
('yamada', 3.6, 'red'),
('satou', 4.2, 'blue'),
('sasaki', 7.6, 'green'),
('yamada', 5.7, 'yellow');
blogapp=# select * from users; id | name | score | team ----+--------+-------+-------- 1 | yamada | 6.5 | red 2 | satou | 4.3 | green 3 | sasaki | 8.2 | green 4 | yamada | 3.6 | red 5 | satou | 4.2 | blue 6 | sasaki | 7.6 | green 7 | yamada | 5.7 | yellow
blogapp=# select name, score from users; name | score --------+------- yamada | 6.5 satou | 4.3 sasaki | 8.2 yamada | 3.6 satou | 4.2 sasaki | 7.6 yamada | 5.7 (7 行)