Interpolates colors

# Imagick::sparseColorImage

(PECL imagick 2 >= 2.3.0, PECL imagick 3)

Imagick::sparseColorImage — Interpolates colors

### Description

public Imagick::sparseColorImage(int `$SPARSE_METHOD`, array `$arguments`, int `$channel` = Imagick::CHANNEL_DEFAULT): bool

Given the arguments array containing numeric values this method interpolates the colors found at those coordinates across the whole image using `sparse_method`. This method is available if Imagick has been compiled against ImageMagick version 6.4.5 or newer.

### Parameters

`SPARSE_METHOD`

  Refer to this list of sparse method constants

`arguments`

  An array containing the coordinates. The array is in format `array(1,1, 2,45)`

`channel`

  Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channel constants using bitwise operators. Defaults to `Imagick::CHANNEL_DEFAULT`. Refer to this list of channel constants

### Return Values

Returns `true` on success.

### Errors/Exceptions

Throws ImagickException on error.

### Examples

Example #1 SPARSECOLORMETHOD_BARYCENTRIC Imagick::sparseColorImage()

`<?php
function renderImageBarycentric2() {
$points = [
[0.30, 0.10, 'red'],
[0.10, 0.80, 'blue'],
[0.70, 0.60, 'lime'],
[0.80, 0.20, 'yellow'],
];
$imagick = createGradientImage(
400, 400,
$points,
\Imagick::SPARSECOLORMETHOD_BARYCENTRIC
);
header("Content-Type: image/png");
echo $imagick->getImageBlob();
}
?>`

Example #2 SPARSECOLORMETHOD_BILINEAR Imagick::sparseColorImage()

`<?php
function renderImageBilinear() {
$points = [[0.30, 0.10, 'red'], [0.10, 0.80, 'blue'], [0.70, 0.60, 'lime'], [0.80, 0.20, 'yellow'],];
$imagick = createGradientImage(500, 500, $points, \Imagick::SPARSECOLORMETHOD_BILINEAR);
header("Content-Type: image/png");
echo $imagick->getImageBlob();
}
?>`

Example #3 SPARSECOLORMETHOD_SPEPARDS Imagick::sparseColorImage()

`<?php
function renderImageShepards() {
$points = [
[0.30, 0.10, 'red'],
[0.10, 0.80, 'blue'],
[0.70, 0.60, 'lime'],
[0.80, 0.20, 'yellow'],
];
$imagick = createGradientImage(600, 600, $points, \Imagick::SPARSECOLORMETHOD_SPEPARDS);
header("Content-Type: image/png");
echo $imagick->getImageBlob();
}
?>`

Example #4 SPARSECOLORMETHOD_VORONOI Imagick::sparseColorImage()

`<?php
function renderImageVoronoi() {
$points = [
[0.30, 0.10, 'red'],
[0.10, 0.80, 'blue'],
[0.70, 0.60, 'lime'],
[0.80, 0.20, 'yellow'],
];
$imagick = createGradientImage(500, 500, $points, \Imagick::SPARSECOLORMETHOD_VORONOI);
header("Content-Type: image/png");
echo $imagick->getImageBlob();
}
?>`

Example #5 SPARSECOLORMETHOD_BARYCENTRIC Imagick::sparseColorImage()

`<?php
function renderImageBarycentric() {
$points = [
[0, 0, 'skyblue'],
[-1, 1, 'skyblue'],
[1, 1, 'black'],
];
$imagick = createGradientImage(600, 200, $points, \Imagick::SPARSECOLORMETHOD_BARYCENTRIC);
header("Content-Type: image/png");
echo $imagick->getImageBlob();
}
?>`

Example #6 createGradientImage is used by other examples. Imagick::sparseColorImage()

`<?php
function createGradientImage($width, $height, $colorPoints, $sparseMethod, $absolute = false) {
$imagick = new \Imagick();
$imagick->newImage($width, $height, "white");
$imagick->setImageFormat("png");
$barycentricPoints = array();
foreach ($colorPoints as $colorPoint) {
if ($absolute == true) {
$barycentricPoints[] = $colorPoint[0];
$barycentricPoints[] = $colorPoint[1];
}
else {
$barycentricPoints[] = $colorPoint[0] * $width;
$barycentricPoints[] = $colorPoint[1] * $height;
}
if (is_string($colorPoint[2])) {
$imagickPixel = new \ImagickPixel($colorPoint[2]);
}
else if ($colorPoint[2] instanceof \ImagickPixel) {
$imagickPixel = $colorPoint[2];
}
else{
$errorMessage = sprintf(
"Value %s is neither a string nor an ImagickPixel class. Cannot use as a color.",
$colorPoint[2]
);
throw new \InvalidArgumentException(
$errorMessage
);
}
$red = $imagickPixel->getColorValue(\Imagick::COLOR_RED);
$green = $imagickPixel->getColorValue(\Imagick::COLOR_GREEN);
$blue = $imagickPixel->getColorValue(\Imagick::COLOR_BLUE);
$alpha = $imagickPixel->getColorValue(\Imagick::COLOR_ALPHA);
$barycentricPoints[] = $red;
$barycentricPoints[] = $green;
$barycentricPoints[] = $blue;
$barycentricPoints[] = $alpha;
}
$imagick->sparseColorImage($sparseMethod, $barycentricPoints);
return $imagick;
}
?>`
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