imageflip()

(PHP 5 >= 5.5.0, PHP 7)

Flips an image using a given mode

说明

imageflip(resource $image,int $mode): bool

Flips the$imageimage using the given$mode.

参数

$image

由图象创建函数(例如imagecreatetruecolor())返回的图象资源。

$mode

Flip mode, this can be one of the IMG_FLIP_* constants:

Constant	Meaning
IMG_FLIP_HORIZONTAL	Flips the image horizontally.
IMG_FLIP_VERTICAL	Flips the image vertically.
IMG_FLIP_BOTH	Flips the image both horizontally and vertically.

返回值

成功时返回TRUE，或者在失败时返回FALSE。

范例

Flips an image vertically

This example uses the IMG_FLIP_VERTICAL constant.

<?php
// File
$filename = 'phplogo.png';
// Content type
header('Content-type: image/png');
// Load
$im = imagecreatefrompng($filename);
// Flip it vertically
imageflip($im, IMG_FLIP_VERTICAL);
// Output
imagejpeg($im);
imagedestroy($im);
?>

以上例程的输出类似于：

Flips the image horizontally

This example uses the IMG_FLIP_HORIZONTAL constant.

<?php
// File
$filename = 'phplogo.png';
// Content type
header('Content-type: image/png');
// Load
$im = imagecreatefrompng($filename);
// Flip it horizontally
imageflip($im, IMG_FLIP_HORIZONTAL);
// Output
imagejpeg($im);
imagedestroy($im);
?>

以上例程的输出类似于：

If you're using PHP < 5.5 you can use this code to add the same functionality. If you pass the wrong $mode in it will silently fail. You might want to add your own error handling for this case.
<?php
if (!function_exists('imageflip')) {
 define('IMG_FLIP_HORIZONTAL', 0);
 define('IMG_FLIP_VERTICAL', 1);
 define('IMG_FLIP_BOTH', 2);
 function imageflip($image, $mode) {
  switch ($mode) {
   case IMG_FLIP_HORIZONTAL: {
    $max_x = imagesx($image) - 1;
    $half_x = $max_x / 2;
    $sy = imagesy($image);
    $temp_image = imageistruecolor($image)? imagecreatetruecolor(1, $sy): imagecreate(1, $sy);
    for ($x = 0; $x < $half_x; ++$x) {
     imagecopy($temp_image, $image, 0, 0, $x, 0, 1, $sy);
     imagecopy($image, $image, $x, 0, $max_x - $x, 0, 1, $sy);
     imagecopy($image, $temp_image, $max_x - $x, 0, 0, 0, 1, $sy);
    }
    break;
   }
   case IMG_FLIP_VERTICAL: {
    $sx = imagesx($image);
    $max_y = imagesy($image) - 1;
    $half_y = $max_y / 2;
    $temp_image = imageistruecolor($image)? imagecreatetruecolor($sx, 1): imagecreate($sx, 1);
    for ($y = 0; $y < $half_y; ++$y) {
     imagecopy($temp_image, $image, 0, 0, 0, $y, $sx, 1);
     imagecopy($image, $image, 0, $y, 0, $max_y - $y, $sx, 1);
     imagecopy($image, $temp_image, 0, $max_y - $y, 0, 0, $sx, 1);
    }
    break;
   }
   case IMG_FLIP_BOTH: {
    $sx = imagesx($image);
    $sy = imagesy($image);
    $temp_image = imagerotate($image, 180, 0);
    imagecopy($image, $temp_image, 0, 0, 0, 0, $sx, $sy);
    break;
   }
   default: {
    return;
   }
  }
  imagedestroy($temp_image);
 }
}
?>