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ImagickDraw::circle

(PECL imagick 2, PECL imagick 3)

ImagickDraw::circle — Draws a circle

说明

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

警告

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。

示例

示例 #1 ImagickDraw::circle() example

<?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();
}

?>

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User Contributed Notes 2 notes

down

SkepticaLee ¶

9 years ago

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.

down

-7

christian dot reinecke at web dot de ¶

14 years ago

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

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