imagecolorclosestalpha
(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)
imagecolorclosestalpha — 取得與指定的顏色加透明度最接近的顏色
說明
imagecolorclosestalpha(
resource
int
int
int
int
): int
resource
$image,int
$red,int
$green,int
$blue,int
$alpha): int
返回影象調色板中與指定的 RGB 值以及
alpha 深度最「接近」的顏色。
參數
-
image -
由圖像建立函式(例如imagecreatetruecolor())返回的 GdImage 對象。
-
red -
紅色成分的值。
-
green -
綠色成分的值。
-
blue -
藍色成分的值。
-
alpha -
A value between
0and127.0indicates completely opaque while127indicates completely transparent.
返回值
Returns the index of the closest color in the palette.
範例
示例 #1 Search for a set of colors in an image
<?php
// Start with an image and convert it to a palette-based image
$im = imagecreatefrompng('figures/imagecolorclosest.png');
imagetruecolortopalette($im, false, 255);
// Search colors (RGB)
$colors = array(
array(254, 145, 154, 50),
array(153, 145, 188, 127),
array(153, 90, 145, 0),
array(255, 137, 92, 84)
);
// Loop through each search and find the closest color in the palette.
// Return the search number, the search RGB and the converted RGB match
foreach($colors as $id => $rgb)
{
$result = imagecolorclosestalpha($im, $rgb[0], $rgb[1], $rgb[2], $rgb[3]);
$result = imagecolorsforindex($im, $result);
$result = "({$result['red']}, {$result['green']}, {$result['blue']}, {$result['alpha']})";
echo "#$id: Search ($rgb[0], $rgb[1], $rgb[2], $rgb[3]); Closest match: $result.\n";
}
imagedestroy($im);
?>
以上例程的輸出類似於：
#0: Search (254, 145, 154, 50); Closest match: (252, 150, 148, 0). #1: Search (153, 145, 188, 127); Closest match: (148, 150, 196, 0). #2: Search (153, 90, 145, 0); Closest match: (148, 90, 156, 0). #3: Search (255, 137, 92, 84); Closest match: (252, 150, 92, 0).
註釋
參見
- imagecolorexactalpha() - 取得指定的顏色加透明度的索引值
- imagecolorclosest() - 取得與指定的顏色最接近的顏色的索引值
- imagecolorclosesthwb() - 取得與給定顏色最接近的色度的黑白色的索引