(PHP 5 <= 5.3.0, PECL ming SVN)

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


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

К настоящему времени эта функция еще не была документирована; для ознакомления доступен только список аргументов.

Возвращаемые значения

Эта функция не возвращает значения после выполнения.

Смотрите также

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


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...


= new SWFShape();

2008-07-30 13:03:18
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.


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)
$startAngle fmod($startAngle360);

/* first determine number of segments, 8 at most */
$nSegs + (int)round(* ($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);


$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));


$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$shape$r0360 );


//  Set ming defaults

$movie = new SWFMovie();
$movie->setBackground0xff0xff0xff );

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

// Ming circles (in green)
$shape->movePenTo5050 );
$shape->movePenTo5050 );
$shape->movePenTo5050 );
$shape->movePenTo5050 );
$shape->drawCircle0.5 );

// Drawn with drawCircle function below (in black)
$shape->movePenTo5050 );
$shape->movePenTo5050 );
$shape->movePenTo5050 );
$shape->movePenTo5050 );
drawCircle$shape0.5 );

$d $movie->add($sprite);
$movie->setDimension100100 );
$movie->save"test.swf" );

2008-12-16 13:57:15

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