Imagick::sparseColorImage

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

Imagick::sparseColorImageInterpolates 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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User Contributed Notes 1 note

up
3
aehtyb[]gmail.com
6 years ago
For those curious how to use sparseColorImage() directly without the seperate createGradientImage() function.. here is the format of the array used:

Array (
[0]  => 0   // X1 (X coordinate value #1)
[1]  => 0   // Y1 (Y coordinate value #1)
[2]  => 1   // R (red value between 0 and 1)
[3]  => 0   // G (green value between 0 and 1)
[4]  => 0   // B (blue value between 0 and 1)
[5]  => 1   // A (alpha value between 0 and 1)
[6]  => 400 // X2
[7]  => 0   // Y2
[8]  => 0   // R
[9]  => 1   // G
[10] => 0   // B
[11] => 1   // A
[12] => 0   // X3
[13] => 400 // Y3
[14] => 1   // R
[15] => 1   // G
[16] => 0   // B
[17] => 1   // A
[18] => 400 // X4
[19] => 400 // Y4
[20] => 0   // R
[21] => 0   // G
[22] => 1   // B
[23] => 1   // A
)

<?php

$imagick
= new imagick();
$imagick->newImage(400,400,"white");
$imagick->setImageFormat("png");

$array = Array(0,0,1,0,0,1,400,0,0,1,0,1,0,400,1,1,0,1,400,400,0,0,1,1);
$imagick->sparseColorImage(imagick::SPARSECOLORMETHOD_BILINEAR,$array);
   
header("Content-Type: image/png");
echo
$imagick->getImageBlob();

?>
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