Imagick::sparseColorImage()

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Interpolates colors

说明

publicImagick::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.此方法在Imagick基于ImageMagick 6.4.5以上版本编译时可用。

参数

$SPARSE_METHOD

Refer to this list of sparse method constants

$arguments

An array containing the coordinates. The array is in formatarray(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.缺省为Imagick::CHANNEL_DEFAULT.参考此通道常数列表

返回值

成功时返回TRUE。

错误／异常

错误时抛出 ImagickException。

范例

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;
}
?>

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();
?>