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imageflip

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

imageflipFlips an image using a given mode

Descrizione

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

Flips the image image using the given mode.

Elenco dei parametri

image

Una risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().

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.

Valori restituiti

Restituisce true in caso di successo, false in caso di fallimento.

Log delle modifiche

Versione Descrizione
8.0.0 image expects a GdImage instance now; previously, a valid gd resource was expected.

Esempi

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($im, IMG_FLIP_VERTICAL);

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

Il precedente esempio visualizzerà qualcosa simile a:

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($im, IMG_FLIP_HORIZONTAL);

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

Il precedente esempio visualizzerà qualcosa simile a:

Output of example: Horizontally flipped image

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User Contributed Notes 1 note

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5
Daniel Klein
8 years ago
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);
}
}
?>
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