PHP | imagetruecolortopalette() Function

The imagetruecolortopalette() function is an inbuilt function in PHP which is used to convert a true color image to a palette image.

Syntax:

bool imagetruecolortopalette( $image, $dither, $ncolors )

Parameters: This function accepts three parameters as mentioned above and described below:

• $image: It is returned by one of the image creation functions, such as imagecreatetruecolor(). It is used to create size of image.
• $dither: It is the boolean value which indicate the image is dither. If it is True then dithering will be used which will result in a more speckled image but with better color approximation.
• $ncolors: This parameter contains the set of maximum number of colors that should be retained in the palette.

Return Value: This function returns True on success or False on failure.

Below programs illustrates the imagetruecolortopalette() function in PHP:

Program 1:

<?php

// Create a 400*300 image
$im = imagecreatetruecolor(400, 300);

// Set the background color of image
$background_color = imagecolorallocate($im,  0, 153, 0);

// Fill background with above selected color
imagefill($im, 0, 0, $background_color);

// Convert to palette-based with no dithering and 255 colors
imagetruecolortopalette($im, true, 255);

// Output the picture to the browser
header('Content-type: image/png');

imagepng($im);
?>

Output:

Program 2:

<?php

// Setup the true color and palette images
$im = imagecreatefrompng(
'https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-9.png');

// Convert to palette-based with no dithering and 255 colors
imagetruecolortopalette($im, false, 255);

// Output the picture to the browser
header('Content-type: image/png');

imagepng($im);
?>

Output:

Reference: http://php.net/manual/en/function.imagetruecolortopalette.php