imageflip

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

imageflipFlips an image using a given mode

说明

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

Flips the image image 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

更新日志

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

范例

Example #1 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($imIMG_FLIP_VERTICAL);

// Output
imagejpeg($im);
imagedestroy($im);
?>

以上例程的输出类似于:

Output of example: Vertically flipped image

Example #2 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($imIMG_FLIP_HORIZONTAL);

// Output
imagejpeg($im);
imagedestroy($im);
?>

以上例程的输出类似于:

Output of example: Horizontally flipped image

User Contributed Notes

Daniel Klein 04-Feb-2016 01:26
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);
  }
}
?>