# ImagickKernel::fromBuiltIn

(PECL imagick >= 3.3.0)

ImagickKernel::fromBuiltIn — Create a kernel from a builtin in kernel

### 说明

public static ImagickKernel::fromBuiltin(int `$kernelType`, string `$kernelString`): ImagickKernel

Create a kernel from a builtin in kernel. See http://www.imagemagick.org/Usage/morphology/#kernel for examples. Currently the 'rotation' symbols are not supported. Example: $diamondKernel = ImagickKernel::fromBuiltIn(\Imagick::KERNEL_DIAMOND, "2");

### 参数

`kerneltype`

  The type of kernel to build e.g. \Imagick::KERNEL_DIAMOND

`kernelString`

  A string that describes the parameters e.g. "4,2.5"

### 返回值

### 示例

示例 #1 ImagickKernel::fromBuiltin()

`<?php
function renderKernel(ImagickKernel $imagickKernel) {
$matrix = $imagickKernel->getMatrix();
$imageMargin = 20;
$tileSize = 20;
$tileSpace = 4;
$shadowSigma = 4;
$shadowDropX = 20;
$shadowDropY = 0;
$radius = ($tileSize / 2) * 0.9;
$rows = count($matrix);
$columns = count($matrix[0]);
$imagickDraw = new \ImagickDraw();
$imagickDraw->setFillColor('#afafaf');
$imagickDraw->setStrokeColor('none');
$imagickDraw->translate($imageMargin, $imageMargin);
$imagickDraw->push();
ksort($matrix);
foreach ($matrix as $row) {
ksort($row);
$imagickDraw->push();
foreach ($row as $cell) {
if ($cell !== false) {
$color = intval(255 * $cell);
$colorString = sprintf("rgb(%f, %f, %f)", $color, $color, $color);
$imagickDraw->setFillColor($colorString);
$imagickDraw->rectangle(0, 0, $tileSize, $tileSize);
}
$imagickDraw->translate(($tileSize + $tileSpace), 0);
}
$imagickDraw->pop();
$imagickDraw->translate(0, ($tileSize + $tileSpace));
}
$imagickDraw->pop();
$width = ($columns * $tileSize) + (($columns - 1) * $tileSpace);
$height = ($rows * $tileSize) + (($rows - 1) * $tileSpace);
$imagickDraw->push();
$imagickDraw->translate($width/2 , $height/2);
$imagickDraw->setFillColor('rgba(0, 0, 0, 0)');
$imagickDraw->setStrokeColor('white');
$imagickDraw->circle(0, 0, $radius - 1, 0);
$imagickDraw->setStrokeColor('black');
$imagickDraw->circle(0, 0, $radius, 0);
$imagickDraw->pop();
$canvasWidth = $width + (2 * $imageMargin);
$canvasHeight = $height + (2 * $imageMargin);
$kernel = new \Imagick();
$kernel->newPseudoImage(
$canvasWidth,
$canvasHeight,
'canvas:none'
);
$kernel->setImageFormat('png');
$kernel->drawImage($imagickDraw);
/* create drop shadow on it's own layer */
$canvas = $kernel->clone();
$canvas->setImageBackgroundColor(new \ImagickPixel('rgb(0, 0, 0)'));
$canvas->shadowImage(100, $shadowSigma, $shadowDropX, $shadowDropY);
$canvas->setImagePage($canvasWidth, $canvasHeight, -5, -5);
$canvas->cropImage($canvasWidth, $canvasHeight, 0, 0);
/* composite original text_layer onto shadow_layer */
$canvas->compositeImage($kernel, \Imagick::COMPOSITE_OVER, 0, 0);
$canvas->setImageFormat('png');
return $canvas;
}
function createFromBuiltin($kernelType, $kernelFirstTerm, $kernelSecondTerm, $kernelThirdTerm) {
$string = '';
if ($kernelFirstTerm != false && strlen(trim($kernelFirstTerm)) != 0) {
$string .= $kernelFirstTerm;
if ($kernelSecondTerm != false && strlen(trim($kernelSecondTerm)) != 0) {
$string .= ','.$kernelSecondTerm;
if ($kernelThirdTerm != false && strlen(trim($kernelThirdTerm)) != 0) {
$string .= ','.$kernelThirdTerm;
}
}
}
$kernel = ImagickKernel::fromBuiltIn(
$kernelType,
$string
);
return $kernel;
}
function fromBuiltin($kernelType, $kernelFirstTerm, $kernelSecondTerm, $kernelThirdTerm) {
$diamondKernel = createFromBuiltin($kernelType, $kernelFirstTerm, $kernelSecondTerm, $kernelThirdTerm);
$imagick = renderKernel($diamondKernel);
header("Content-Type: image/png");
echo $imagick->getImageBlob();
}
fromBuiltin(\Imagick::KERNEL_DIAMOND, 2, false, false);
?>`
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