Imagick::getImageColors

    (PECL imagick 2, PECL imagick 3)

    Imagick::getImageColors — Gets the number of unique colors in the image

    Descrizione

    public Imagick::getImageColors(): int

    Gets the number of unique colors in the image.

    Elenco dei parametri

    Questa funzione non contiene parametri.

    Valori restituiti

    Returns an int, the number of unique colors in the image.

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    User Contributed Notes 2 notes

    up
    3
    holdoffhunger at gmail dot com
    12 years ago
    I've had difficulty getting this function to return the number of unique colors. Also, I wanted to be able to have an array with each $key value being the RGB of the pixel, and each $value value being the number of times that pixel occurs. Basically, a frequency list. For example, you would have "1 / 0 / 0" for red as a $key value, and "25" for the number of times that pixel color was in the image. So, I wrote some code to do that, using a combination of readImageFile, getImageWidth, getImageHeight, getImagePixelColor, and a simple x/y parser, like so :

    <?php

    // Test File
    // ---------------------------------------------

    // Note: This file was just a picture of a 5x5 red square
    // inside of a gigantic 521x512 black square, and
    // then I did a bunch of random, yellow zigzags.

    $file_to_grab_with_location = "test.bmp";

    $imagick_type = new Imagick();

    // Open File
    // ---------------------------------------------

    $file_handle_for_viewing_image_file = fopen($file_to_grab_with_location, 'a+');
    $imagick_type->readImageFile($file_handle_for_viewing_image_file);

    // Preset Information
    // ---------------------------------------------

    $frequency_list_of_values = array();

    // Parse Pixels
    // ---------------------------------------------

    $image_resolution_width = $imagick_type->getImageWidth();
    $image_resolution_height = $imagick_type->getImageHeight();

    print(    "Image Resolution: Width - $image_resolution_width / Height - $image_resolution_height<br><br>");

    // Parse Image Top-to-Bottom (Y-Variable)
    // ---------------------------------------------

    for($y = 0; $y < $image_resolution_height; $y++)
    {
    // Parse Image Left-to-Right (X-Variable)
    // ---------------------------------------------

    for($x = 0; $x < $image_resolution_width; $x++)
    {

    // Image Pixel Color
    // ---------------------------------------------

    $pixel_to_examine = $imagick_type->getImagePixelColor($x,$y);

    $pixel_to_examine_color_value_red = $pixel_to_examine->getColorValue(imagick::COLOR_RED);
    $pixel_to_examine_color_value_green = $pixel_to_examine->getColorValue(imagick::COLOR_GREEN);
    $pixel_to_examine_color_value_blue = $pixel_to_examine->getColorValue(imagick::COLOR_BLUE);

    // Set Key Value
    // ---------------------------------------------

    $key_value = $pixel_to_examine_color_value_red . " / " .
    $pixel_to_examine_color_value_green . " / " .
    $pixel_to_examine_color_value_blue ;

    // Increment Array Entry for Color
    // ---------------------------------------------

    if(isset($frequency_list_of_values[$key_value]) == TRUE)
    {
    $temp = $frequency_list_of_values[$key_value];
    $temp++;
    $frequency_list_of_values[$key_value] = $temp;
    }
    else
    {
    $frequency_list_of_values[$key_value] = 1;
    }
    }
    }

    // Print Out Array of Values
    // ---------------------------------------------

    print("<pre>");
    print_r($frequency_list_of_values);
    print(    "</pre>");

    /*

    Results:
    ------------------

    Image Resolution: Width - 521 / Height - 512

    Array
    (
    [1 / 0 / 0] => 25
    [0 / 0 / 1] => 264107
    [1 / 1 / 0] => 2620
    )

    */

    ?>
    up
    -4
    amaral dot regis at hotmail dot com
    6 years ago
    O exemplo anterior apresentou números fracionados nas chaves da variável $frequency_list_of_values:

    Array
    (
    [1 / 0 / 1] => 157295
    [0.83529411764706 / 0.87843137254902 / 0.82352941176471] => 1
    [0.80392156862745 / 0.84705882352941 / 0.7843137254902] => 2
    [0.8156862745098 / 0.84705882352941 / 0.78823529411765] => 1
    ...

    Então eu fiz uma alteração que melhora o resultado para quem esta buscando saber quais as cores dominantes na imagem, mostrando a chave com o valor rgb exato:
    <?php

    $file_to_grab_with_location     = $imagepath; //caminho relativo ao arquivo de imagem

    $imagick_type = new \Imagick();

    $file_handle_for_viewing_image_file = fopen($file_to_grab_with_location, 'a+');
    $imagick_type->readImageFile($file_handle_for_viewing_image_file);

    $frequency_list_of_values = array();

    $image_resolution_width = $imagick_type->getImageWidth();
    $image_resolution_height = $imagick_type->getImageHeight();

    print(    "Image Resolution: Width - $image_resolution_width / Height - $image_resolution_height<br><br>");

    for(    $y = 0; $y < $image_resolution_height; $y++)
    {

    for(    $x = 0; $x < $image_resolution_width; $x++)
    {

    $pixel_to_examine = $imagick_type->getImagePixelColor($x,$y);

    if(isset(    $frequency_list_of_values[$pixel_to_examine->getColorAsString()]) == TRUE)
    {
    $temp = $frequency_list_of_values[$pixel_to_examine->getColorAsString()];
    $temp++;
    $frequency_list_of_values[$pixel_to_examine->getColorAsString()] = $temp;
    }
    else
    {
    $frequency_list_of_values[$pixel_to_examine->getColorAsString()] = 1;
    }
    }

    arsort($frequency_list_of_values);
    }

    print(    "<pre>");
    print_r($frequency_list_of_values);
    print(    "</pre>");

    ?>

    Resultado:
    Image Resolution: Width - 1965 / Height - 998

    Array
    (
    [srgba(255,0,255,0)] => 451654
    [srgb(54,52,53)] => 281069
    [srgb(177,51,54)] => 130449
    [srgb(236,50,55)] => 64001
    ...

    O método é demorado para imagens muito grandes, pois ele analisa pixel a pixel.
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