SWFShape::drawArc

(PHP 5 < 5.3.0, PECL ming SVN)

SWFShape::drawArc — Draws an arc of radius r centered at the current location, from angle startAngle to angle endAngle measured clockwise from 12 o'clock

说明

SWFShape::drawArc ( float $r , float $startAngle , float $endAngle ) : void

Warning

本函数还未编写文档，仅有参数列表。

返回值

没有返回值。

参见

SWFShape::drawCircle() - Draws a circle of radius r centered at the current location, in a counter-clockwise fashion

add a note

User Contributed Notes 2 notes

down

brad_fisher at gensler dot com ¶

10 years ago


It seems that the ming library up to at least v0.4.2 has some rounding issues with rendering the arc.  This is most evident as the radius of the arc gets smaller (try drawing a circle/arc with radius 1 using ming, better yet, try 0.5).  The following code renders a much more accurate arc at smaller radii.  It also does range checking/normalization on the angles passed in that ming doesn't do.

<?php

function drawArc( $shape, $r, $startAngle, $endAngle  ) {
    // Normalize the angles
    $delta = $endAngle - $startAngle;
    if ( abs($delta) >= 360)
        $delta = 360;
    else if ($delta < 0)
        $delta += 360;
    else if ($delta == 0)
        return;
    $startAngle = fmod($startAngle, 360);

    /* first determine number of segments, 8 at most */
    $nSegs = 1 + (int)round(7 * ($delta / 360));

    /* subangle is half the angle of each segment */
    $subangle = M_PI * $delta / $nSegs / 360;

    $angle = M_PI * $startAngle / 180;

    $x = $r * sin($angle);
    $y = -$r * cos($angle);

    $shape->movePen($x, $y);

    $controlRadius = $r / cos($subangle);

    for ( $i=0; $i<$nSegs; ++$i )
    {
        $angle += $subangle;
        $controlx = $controlRadius * sin($angle);
        $controly = -$controlRadius * cos($angle);
        $angle += $subangle;
        $anchorx = ($r*sin($angle));
        $anchory = (-$r*cos($angle));

        $shape->drawCurve($controlx-$x, $controly-$y,
                           $anchorx-$controlx, $anchory-$controly);

        $x = $anchorx;
        $y = $anchory;
    }
}

// SWFShape->drawCircle has the same issue with accuracy.  It's a simple thing to use the function above to fix this:
function drawCircle( $shape, $r ) {
    drawArc( $shape, $r, 0, 360 );
}

// EXAMPLE USAGE:

//  Set ming defaults
ming_setScale(20);
ming_useswfversion(7);

$movie = new SWFMovie();
$movie->setBackground( 0xff, 0xff, 0xff );
$movie->setRate(31);

$sprite = new SWFSprite();
$shape = new SWFShape();

// Ming circles (in green)
$shape->setLine( 0, 0, 0xff, 0 );
$shape->movePenTo( 50, 50 );
$shape->drawCircle( 5 );
$shape->movePenTo( 50, 50 );
$shape->drawCircle( 3 );
$shape->movePenTo( 50, 50 );
$shape->drawCircle( 1 );
$shape->movePenTo( 50, 50 );
$shape->drawCircle( 0.5 );

// Drawn with drawCircle function below (in black)
$shape->setLine( 0, 0, 0, 0 );
$shape->movePenTo( 50, 50 );
drawCircle( $shape, 5 );
$shape->movePenTo( 50, 50 );
drawCircle( $shape, 3 );
$shape->movePenTo( 50, 50 );
drawCircle( $shape, 1 );
$shape->movePenTo( 50, 50 );
drawCircle( $shape, 0.5 );

$sprite->add($shape);
$sprite->nextFrame();
$d = $movie->add($sprite);
$movie->setDimension( 100, 100 );
$movie->save( "test.swf" );

?>

down

visual77 at gmail dot com ¶

10 years ago


After the arc is drawn, the pen does not return to the original coordinate that the arc started on, which is the center of the circle of which the arc is a part. Instead, the pen will remain at the last spot of the arc.

In the case of a full circle, this means the pen will now be at 12 o'clock on the circle after the arc is drawn.

To revert back to the original position after drawing a circle, you can do this...

<?php

$shape = new SWFShape();
$shape->drawArc(5, 0, 360);
$shape->movePen(0, 5);

?>

add a note

官方地址：https://www.php.net/manual/en/swfshape.drawarc.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络数据库 JAVA 面试 NoSQL C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 PHP 8.1 ADORecordSet对象 adodb手册 opcache预加载 Composer的Packagist资源 array_multisort() 多字段排序 mysql面试题 PHPMailer设置utf8 PHPMailer字符集CharSet PHP json解析（json_decode）页面工具 [原创]诡异的php-fpm超时问题 php中几种注释规范纯php实现DES以及TripleDES加密算法 PHP获取指定函数定义在哪个文件中及行号 php上周一、本周一、下周一日期 [鸟哥]PHP FFI详解 - 一种全新的PHP扩展方式

略微加速

PHP官方手册 - 互联网笔记

SWFShape::drawArc

说明

返回值

参见

User Contributed Notes 2 notes