imagecolorresolve

(PHP 4, PHP 5, PHP 7, PHP 8)

imagecolorresolve取得指定颜色的索引值或有可能得到的最接近的替代值

说明

imagecolorresolve(
    GdImage $image,
    int $red,
    int $green,
    int $blue
): int

本函数可以保证对所请求的颜色返回颜色索引,要么是准确的颜色要么是最接近的颜色。

如果图象由文件创建,只有该图象使用到的颜色会被解析。仅存在于调色板中的颜色不会被解析。

参数

image

由图象创建函数(例如imagecreatetruecolor())返回的 GdImage 对象。

red

红色成分的值。

green

绿色成分的值。

blue

蓝色成分的值。

返回值

返回颜色索引值。

更新日志

版本 说明
8.0.0 image expects a GdImage instance now; previously, a resource was expected.

范例

示例 #1 使用 imagecoloresolve() 从图像中获取颜色

<?php
// Load an image
$im = imagecreatefromgif('phplogo.gif');

// Get closest colors from the image
$colors = array();
$colors[] = imagecolorresolve($im, 255, 255, 255);
$colors[] = imagecolorresolve($im, 0, 0, 200);

// Output
print_r($colors);

imagedestroy($im);
?>

以上例程的输出类似于:

Array
(
    [0] => 89
    [1] => 85
)

参见

add a note

User Contributed Notes 1 note

up
0
ceo at l-i-e dot com
21 years ago
Okay, so sometimes it's really IMPORTANT to get the exact color you want, only it's not *IN* the Image, and ImageColorResolve just isn't "close enough".

The following code is a disgustingly gross hack, rather slow, but it does that.

$colorcount = array();
for ($x = 0; $x < $width; $x++){
    for ($y = 0; $y < $height; $y++){
        $colorindex = imagecolorat($jpg, $x, $y);
        if (!isset($colorcount[$colorindex])){
            $colorcount[$colorindex] = 1;
        }
        else{
            $colorcount[$colorindex]++;
        }
    }
}
asort($colorcount);
reset($colorcount);

$black = imagecolorexact($jpg, 0, 0, 0);
if ($black == -1){
    $goner = key($colorcount);
    $rgb = imagecolorsforindex($jpg, $goner);
    #error_log("Need black: About to kill $goner ($rgb[red], $rgb[green], $rgb[blue]) which was only used in $colorcount[$goner] pixels", 0);
    unset($colorcount[$goner]);
    imagecolordeallocate($jpg, $goner);
    $black = imagecolorallocate($jpg, 0, 0, 0);
}
if ($black == -1){
    $black = imagecolorresolve($jpg, 0, 0, 0);
    #error_log("Damn!  STILL couldn't allocate the color!", 0);
}
To Top