A few notes about this function...
This function will only work on images where the palette is 256 colors or less. You also can not use imagetruecolortopalette() to reduce the palette on a true color PNG image that has greater than 256 colors in it's palette, then call this function. If you try to do this imagecolorexact() will report colors not being in the image when they are in the image!
1. works on png(s) 8bit/256 colors or less.
2. works on all gif(s)
3. does not work on any type of jpg/jpeg image.
imagecolorexact
(PHP 4, PHP 5, PHP 7)
imagecolorexact — Get the index of the specified color
설명
int imagecolorexact
( resource
$image
, int $red
, int $green
, int $blue
)Returns the index of the specified color in the palette of the image.
이미지를 파일에서 생성하였을 경우, 이미지에서 사용한 색만 해석됩니다. 팔레트에 존재하는 색은 해석되지 않습니다.
인수
-
image -
imagecreatetruecolor() 등의 이미지 생성 함수에서 반환한 이미지 자원.
-
red -
Red 컴포넌트 값.
-
green -
Green 컴포넌트 값.
-
blue -
Blue 컴포넌트 값.
반환값
Returns the index of the specified color in the palette, or -1 if the color does not exist.
예제
Example #1 Get colors from the GD logo
<?php
// Setup an image
$im = imagecreatefrompng('./gdlogo.png');
$colors = Array();
$colors[] = imagecolorexact($im, 255, 0, 0);
$colors[] = imagecolorexact($im, 0, 0, 0);
$colors[] = imagecolorexact($im, 255, 255, 255);
$colors[] = imagecolorexact($im, 100, 255, 52);
print_r($colors);
// Free from memory
imagedestroy($im);
?>
위 예제의 출력 예시:
Array
(
[0] => 16711680
[1] => 0
[2] => 16777215
[3] => 6618932
)
add a note
User Contributed Notes 3 notes
jbr at ya-right dot com ¶
18 years ago
samtobia at geemail dot com ¶
13 years ago
A script that changes colors depending on get variable
important to note: I had little success with pngs and getting true red
gifs work much better
<?php
//0 is yellow, 1 is red, 2 is blue
$y = 1 - ceil($_GET["c"]/2);
$r = 1 - floor($_GET["c"]/2);
$b = floor($_GET["c"]/2);
$gd = imagecreatefromgif("example.gif");
imagecolorset($gd, imagecolorexact($gd, 255, 0, 0), $r*255, $y*255, $b*255);
imagecolorset($gd, imagecolorexact($gd, 191, 0, 0), $r*191, $y*191, $b*191);
imagecolorset($gd, imagecolorexact($gd, 128, 0, 0), $r*128, $y*128, $b*128);
imagecolorset($gd, imagecolorexact($gd, 255, 0, 0), $r*64, $y*64, $b*64);
header('Content-Type: image/gif');
imagegif($gd);
?>
info at educar dot pro dot br ¶
19 years ago
<?php
$src = "../images/pic.gif";
$red = 9;
$green = 9;
$blue = 4;
$pic0026 = imagecreatefromgif ( $src );
$ind = imagecolorexact ( $pic, $red, $green, $blue );
echo '<img src="../images/pic.gif" border="0" alt="pic" title="View pic" /><br /><br />';
echo "RED ( " . $red . " ) GREEN ( " . $green . " ) BLUE ( " . $blue . " )<br />-> Palette Index = " . $ind;
if ( $ind != -1 )
{
echo "<br />[ The color exists! ]";
}
else
{
echo "<br />[ The color does not exist! ]";
}
imagedestroy ( $pic );
?>
