imagecolorclosest

说明

int imagecolorclosest ( resource image, int red, int green, int blue )

返回图像调色板中与指定的 RGB 值最“接近”的颜色。

指定的颜色与调色板中的每个颜色的“距离”的计算方法是把 RGB 值当成三维空间中点的坐标。

如果从文件创建了图像，只有图像中使用了的颜色会被辨析。仅出现在调色板中的颜色不会被辨析。

参见 imagecolorexact()。

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MagicalTux at FF dot st
28-Jun-2005 09:22


A way to get each time an answer :



<?php

function imagegetcolor($im, $r, $g, $b) {

        $c=imagecolorexact($im, $r, $g, $b);

        if ($c!=-1) return $c;

        $c=imagecolorallocate($im, $r, $g, $b);

        if ($c!=-1) return $c;

        return imagecolorclosest($im, $r, $g, $b);

}

?>



If the *exact* color is found in the image, it will be returned. If we don't have the exact color, we try to allocate it. If we can't allocate it, we return the closest color in the image.

Vikrant Korde <vakorde at hotmail dot com>
11-Oct-2003 11:10


This functuion is useful when you are dealing with previously present images like .png, .jpg, etc. You can use this function for writing a text on the image.



For me the function imagecolorallocate() was returning the -1 value. after lot of RnD and site search i found a function use of imagecolorclosest(). This solved my problem of writing the text on the image with customised color. 



Actually previously it was writing on the image but the color was not distinct. It was using the same color as of that background image. 



The following code segment was fine with me.



header ("Content-type: image/jpeg"); 

$im = imagecreatefromjpeg("BlankButton.jpg");

$white = imageColorClosest($im, 255,255,255);

// this is for TTF fonts

imagettftext ($im, 20, 0, 16, 30, $white, "/usr/X11R6/lib/X11/fonts/TTF/luximb.ttf", "Vikrant"); 



//this is for notmal font

imagestring($im, 4, 0,0,"Korde", $white);

imagejpeg($im,"",150); 

imagedestroy ($im);

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