PHP 8.3.4 Released!

imagecolormatch

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

imagecolormatchFaz com que as cores da versão em paleta da imagem fiquem mais próximas da versão em cores verdadeiras

Descrição

imagecolormatch(GdImage $image1, GdImage $image2): bool

Faz com que as cores da versão em paleta da imagem fiquem mais próximas da versão em cores verdadeiras.

Parâmetros

image1

Um objeto de imagem em cores verdadeiras.

image2

Um objeto de imagem em paleta apontando para uma imagem que tenha o mesmo tamanho da image1.

Valor Retornado

Retorna true em caso de sucesso ou false em caso de falha.

Registro de Alterações

Versão Descrição
8.0.0 image1 e image2 agora esperam instâncias de GdImage; anteriormente, resources eram esperados.

Exemplos

Exemplo #1 Exemplo de imagecolormatch()

<?php
// Configura as imagens com cores verdadeiras e com paleta
$im1 = imagecreatefrompng('./gdlogo.png');
$im2 = imagecreate(imagesx($im1), imagesy($im1));

// Adiciona algumas cores a $im2
$colors = Array();
$colors[] = imagecolorallocate($im2, 255, 36, 74);
$colors[] = imagecolorallocate($im2, 40, 0, 240);
$colors[] = imagecolorallocate($im2, 82, 100, 255);
$colors[] = imagecolorallocate($im2, 84, 63, 44);

// Faz correspondência dessas cores com a imagem em cores verdadeiras
imagecolormatch($im1, $im2);

// Libera a memória
imagedestroy($im1);
imagedestroy($im2);
?>

Veja Também

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User Contributed Notes 3 notes

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2
gk at karko dot net
13 years ago
Those that have Ubuntu servers note, that this function is added in PHP's GD library fork and is not available by default in Ubuntu php5-gd package.

Here's how-to install the PHP GD version: http://preview.tinyurl.com/yel4r7t
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1
albriNOght at anSPAMre dot net
18 years ago
This function appears to work by changing the values of the colors of the paletted image -- no good if you're trying to force the resultant image to stick with certain pre-defined color values.
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0
Samantha
20 years ago
This function is a godsend! It works exactly as documented.

I'm working on an application where I need to take a transparent GIF, matte the GIF on a user defined background color, and finally scale the GIF based on a user defined %.

The only way I could get this to work so that the final image was high quality, ie: no jagged edges, and a smooth scale, was to convert the GIF to a JPG, and then copy the JPG into a new GIF image like this:

// open transparent gif
$GIFimg = imagecreatefromgif($file_path);

// create jpg image
$JPGimg = imagecreatetruecolor($width, $height);

// copy GIF to JPG
imagecopy($JPGimg, $GIFimg, 0, 0, 0, 0, $width, $height);

// create a true color image
$JPGscaled = imagecreatetruecolor($n_width, $n_height);

// scale the new JPG using the truecolor image
imagecopyresampled($JPGscaled, $JPGimg, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

// create final GIF image
$GIFfinal = imagecreate($n_width, $n_height);

// copy the scaled JPG back to a GIF
imagecopymerge($GIFfinal, $JPGscaled, 0, 0, 0, 0, $n_width, $n_height, 100);

This worked great except the final step, copying the JPG to a GIF. If the JPG had too many colors, the function would index the colors to make it a palette image. So what would end up happening is the final image contained INCORRECT colors.

Adding this one line at the bottom of the code fixed everything.

imagecolormatch($JPGscaled, $GIFfinal);

I hope this helps anyone who is converting images back and forth and dealing with palette issues and color correction. Also, be aware that the above code is a sample and will not work by copying and pasting.
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