ImagickDraw::circle

(PECL imagick 2.0.0)

ImagickDraw::circle — Draws a circle

说明

bool ImagickDraw::circle ( float $ox , float $oy , float $px , float $py )

Warning

本函数还未编写文档，仅有参数列表。

Draws a circle on the image.

参数

ox: origin x coordinate
oy: origin y coordinate
px: perimeter x coordinate
py: perimeter y coordinate

返回值

没有返回值。

范例

Example #1 ImagickDraw::circle()

  <?php
 function  circle ( $strokeColor ,  $fillColor ,  $backgroundColor ,  $originX ,  $originY ,  $endX ,  $endY ) {

     //Create a ImagickDraw object to draw into.
     $draw  = new \ ImagickDraw ();

     $strokeColor  = new \ ImagickPixel ( $strokeColor );
     $fillColor  = new \ ImagickPixel ( $fillColor );

     $draw -> setStrokeOpacity ( 1 );
     $draw -> setStrokeColor ( $strokeColor );
     $draw -> setFillColor ( $fillColor );

     $draw -> setStrokeWidth ( 2 );
     $draw -> setFontSize ( 72 );

     $draw -> circle ( $originX ,  $originY ,  $endX ,  $endY );

     $imagick  = new \ Imagick ();
     $imagick -> newImage ( 500 ,  500 ,  $backgroundColor );
     $imagick -> setImageFormat ( "png" );
     $imagick -> drawImage ( $draw );

     header ( "Content-Type: image/png" );
    echo  $imagick -> getImageBlob ();
}

 ?>

用户评论:

[#1] SkepticaLee [2014-01-27 21:26:08]

The four values required here are a bit confusing. After all, a circle is defined by three values: the x, y coordinates of the centre, and the radius, r.

The fourth value is redundant, but has to be given, otherwise the function fails. One way of coping with this redundancy is:

<?php $draw = new ImagickDraw (); //given that $x and $y are the coordinates of the centre, and $r the radius: $draw->circle ($x, $y, $x + $r, $y); ?>

There are any number of actions which are synonymous with the last, including:
<?php $draw->circle ($x, $y, $x, $y + $r); $draw->circle ($x, $y, $x - $r, $y); $draw->circle ($x, $y, $x, $y - $r); // etc, etc. ?>

Hope this helps.

[#2] christian dot reinecke at web dot de [2009-06-23 06:31:47]

This example creates a circle, one part green, one part red using kind of masks for transparency, which you might know from Photoshop. drawImage() is a quick helper for debug output (see code comments) to help you reproduce the process.

<?php function drawImage(Imagick $im) { $im->setCompressionQuality(100); $im->setImageFormat("jpg"); header("Content-Type: image/" . $im->getImageFormat()); echo $im; exit; } // define red/green layer $layer1 = new Imagick(); $layer1->newImage(100, 100, "none"); $red = new ImagickDraw(); $red->setFillColor("#FF0000"); $red->rectangle(0, 0, 50, 100); $green = new ImagickDraw(); $green->setFillColor("#00FF00"); $green->rectangle(50, 0, 100, 100); $layer1->drawImage($red); $layer1->drawImage($green); # debug output: two rectangles # drawImage($layer1); // define circle mask $layer2 = new Imagick(); $layer2->newImage(100, 100, "none"); $circle = new ImagickDraw(); $circle->setFillColor("#FFFFFF"); $circle->circle(50, 50, 48, 98); $layer2->drawImage($circle); # debug output: the mask # drawImage($layer2); // use mask $layer1->compositeImage($layer2, Imagick::COMPOSITE_DSTIN, 0, 0); # debug output: the result of our mask usage # drawImage($layer1); // define background $layer3 = new Imagick(); $layer3->newImage(100, 100, "none"); $layer3->compositeImage($layer1, Imagick::COMPOSITE_DEFAULT, 0, 0); // define ring as background $layer4 = new Imagick(); $layer4->newImage(100, 100, "white"); // this is our background $ring1 = new ImagickDraw(); $ring1->setFillColor("black"); $ring1->circle(50, 50, 50, 99); $layer4->drawImage($ring1); # debug output: this is a black circle (not our mask, which is similar, but a little bit smaller) # drawImage($layer4); // use black circle as background (this creates our circle border) $layer4->compositeImage($layer3, Imagick::COMPOSITE_DEFAULT, 0, 0); # debug output: here we go with our circle border # drawImage($layer4); // draw separator between red and green rectangle (now semi circles) $line = new ImagickDraw(); $line->setStrokeWidth(1); $line->setStrokeColor("black"); $line->line(50, 1, 50, 99); // add our separator line $layer4->drawImage($line); drawImage($layer4); ?>

To understand how the COMPOSITE_* constants effect the image merging process, see here:
http://www.imagemagick.org/Usage/compose/#duff-porter