After some INet searches and personal try-and-failures I succeed to rotate PNG images with preserving alpha channel transparency (semi transparency).
<?php
$filename = 'YourFile.png';
$rotang = 20; // Rotation angle
$source = imagecreatefrompng($filename) or die('Error opening file '.$filename);
imagealphablending($source, false);
imagesavealpha($source, true);
$rotation = imagerotate($source, $rotang, imageColorAllocateAlpha($source, 0, 0, 0, 127));
imagealphablending($rotation, false);
imagesavealpha($rotation, true);
header('Content-type: image/png');
imagepng($rotation);
imagedestroy($source);
imagedestroy($rotation);
?>
imagerotate
(PHP 4 >= 4.3.0, PHP 5, PHP 7)
imagerotate — Rotate an image with a given angle
Description
resource imagerotate
( resource
$image
, float $angle
, int $bgd_color
[, int $ignore_transparent = 0
] )
Rotates the image image using the given
angle in degrees.
The center of rotation is the center of the image, and the rotated image may have different dimensions than the original image.
Parameters
-
image -
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
-
angle -
Rotation angle, in degrees. The rotation angle is interpreted as the number of degrees to rotate the image anticlockwise.
-
bgd_color -
Specifies the color of the uncovered zone after the rotation
-
ignore_transparent -
If set and non-zero, transparent colors are ignored (otherwise kept).
Return Values
Returns an image resource for the rotated image, or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.5.0 | This function is now affected by the interpolation method set by the imagesetinterpolation() function. |
| 5.1.0 |
ignore_transparent was added.
|
Examples
Example #1 Rotate an image 180 degrees
This example rotates an image 180 degrees - upside down.
<?php
// File and rotation
$filename = 'test.jpg';
$degrees = 180;
// Content type
header('Content-type: image/jpeg');
// Load
$source = imagecreatefromjpeg($filename);
// Rotate
$rotate = imagerotate($source, $degrees, 0);
// Output
imagejpeg($rotate);
// Free the memory
imagedestroy($source);
imagedestroy($rotate);
?>
The above example will output something similar to:
Notes
Note:
This function is affected by the interpolation method set by imagesetinterpolation().
User Contributed Notes
meisterix at gmx dot com
3 years ago
xarris_ at hotmail dot com
6 months ago
An issue with imagerotate() is it might need more memory than what is available. It was failing in my script so I tried to increase it with ini_set('memory_limit', '256M')
and everything works fine now.
xavtak at gmail dot com
5 years ago
I've benchmarked three methods described here for rotating an image.
I used a 1600 x 1200 jpeg picture that was duplicated ten times on the disk. I looped through them to apply a CW rotation using either method.
First algorithm (the "imagesetpixel" algorithm):
<?php
function CWRotation($image)
{
$w = imagesx($image);
$h = imagesy($image);
$result = @imagecreatetruecolor($h, $w);
if($result)
{
for ($i = 0; $i < $w; $i++)
for ($j = 0; $j < $h; $j++)
{
$ref = imagecolorat($image, $i, $j);
imagesetpixel($result, ($h - 1) - $j, $i, $ref);
}
}
return $result;
}
?>
Second algorithm (the "imagecopy" algorithm):
<?php
function CWRotation($image)
{
$w = imagesx($image);
$h = imagesy($image);
$result = @imagecreatetruecolor($h, $w);
if($result)
{
for ($i = 0; $i < $w; $i++)
for ($j = 0; $j < $h; $j++)
imagecopy($result, $image, ($h - 1) - $j, $i, $i, $j, 1, 1);
}
return $result;
}
?>
Third algorithm (the "imagerotate" algorithm):
<?php
function CWRotation($image)
{
return imagerotate($image, 270, 0);
}
?>
In each step of the loop, the image is loaded, rotated then a copy is written on the disk.
Here are the results:
imagesetpixel algorithm: the 10 pictures were processed in 29 seconds
imagecopy algorithm: the 10 pictures were processed in 26 seconds
imagerotate algorithm: the 10 pictures were processed in 2 seconds (no typo here)
Writing the pictures on the disk allowed me to control the results. Every resulting picture was the same (tested with winmerge).
Conclusion: imagerotate is way faster than other "home-made" algorithms.
I ran the tests several times to see if the difference between imagesetpixel and imagecopy was introduced by my computer's independent activity, but I always got that 10% difference.
Note: the picture I used was taken from a camera, so no transparency was involved.
I ran the tests on Windows XP using PHP Version 5.3.0
henzeberkheij at gmail dot com
4 years ago
Keep in mind this function rotates counterclockwise. if you want to go 90 degrees clockwise, you have to tell imagerotate to go 270 degrees counter-clockwise.
$angle = 360-$angle;
anon at here dot com
6 years ago
I was quite surprised to see that no one had done any working rotate function. And since I needed one for my web hotel, I whipped this one up. Someone might want to expand it so that it matches imagerotate.
Also, does imagerotate really rotate things counter clockwise? Otherwise this should also be changed.
<?php
if(!function_exists("imagerotate")) {
function imagerotate(&$srcImg, $angle, $bgcolor, $ignore_transparent = 0) {
return imagerotateEquivalent(&$srcImg, $angle, $bgcolor, $ignore_transparent);
}
}
/*
Unfinished imagerotate replacement. ignore_transparent is, well, ignored. :)
Also, should have some standard functions for 90, 180 and 270 degrees, since they are quite
easy to implement faster.
*/
function imagerotateEquivalent(&$srcImg, $angle, $bgcolor, $ignore_transparent = 0)
{
function rotateX($x, $y, $theta){
return $x * cos($theta) - $y * sin($theta);
}
function rotateY($x, $y, $theta){
return $x * sin($theta) + $y * cos($theta);
}
$srcw = imagesx($srcImg);
$srch = imagesy($srcImg);
if($angle == 0) return $srcImg;
// Convert the angle to radians
$theta = deg2rad ($angle);
// Calculate the width of the destination image.
$temp = array ( rotateX(0, 0, 0-$theta),
rotateX($srcw, 0, 0-$theta),
rotateX(0, $srch, 0-$theta),
rotateX($srcw, $srch, 0-$theta)
);
$minX = floor(min($temp));
$maxX = ceil(max($temp));
$width = $maxX - $minX;
// Calculate the height of the destination image.
$temp = array ( rotateY(0, 0, 0-$theta),
rotateY($srcw, 0, 0-$theta),
rotateY(0, $srch, 0-$theta),
rotateY($srcw, $srch, 0-$theta)
);
$minY = floor(min($temp));
$maxY = ceil(max($temp));
$height = $maxY - $minY;
$destimg = imagecreatetruecolor($width, $height);
imagefill($destimg, 0, 0, imagecolorallocate($destimg, 0,255, 0));
// sets all pixels in the new image
for($x=$minX;$x<$maxX;$x++) {
for($y=$minY;$y<$maxY;$y++)
{
// fetch corresponding pixel from the source image
$srcX = round(rotateX($x, $y, $theta));
$srcY = round(rotateY($x, $y, $theta));
if($srcX >= 0 && $srcX < $srcw && $srcY >= 0 && $srcY < $srch)
{
$color = imagecolorat($srcImg, $srcX, $srcY );
}
else
{
$color = $bgcolor;
}
imagesetpixel($destimg, $x-$minX, $y-$minY, $color);
}
}
return $destimg;
}
?>
AJenbo
7 years ago
I modified cbl25's function to allow it to rotate an image either clock wise or counter clock wise.
<?php
function rotateImage($image, $direction) {
$direction = strtolower($direction);
$degrees = $direction == 'cw' ? 270 : ($direction == 'ccw' ? 90 : NULL);
if(!$degrees)
return $image;
$width = imagesx($image);
$height = imagesy($image);
$side = $width > $height ? $width : $height;
$imageSquare = imagecreatetruecolor($side, $side);
imagecopy($imageSquare, $image, 0, 0, 0, 0, $width, $height);
imagedestroy($image);
$imageSquare = imagerotate($imageSquare, $degrees, 0, -1);
$image = imagecreatetruecolor($height, $width);
$x = $degrees == 90 ? 0 : ($height > $width ? 0 : ($side - $height));
$y = $degrees == 270 ? 0 : ($height < $width ? 0 : ($side - $width));
imagecopy($image, $imageSquare, 0, 0, $x, $y, $height, $width);
imagedestroy($imageSquare);
return $image;
}
//Usage
$image = rotateImage($image, 'cw');
$image = rotateImage($image, 'ccw');
?>
edwins at xs4all dot net
6 years ago
This function apparently contains a memory leak. Because of this, it was kept out of the GD library that comes with Ubuntu (and I assume other OS'es, too).
So, If you are running Ubuntu and wonder why you get "Call to undefined function imagerotate()" even though you seemingly have the correct GD lib installed, this is why. Use the alternative supplied by beau at dragonflydevelopment dot com instead. It works flawlessly (for angles in steps of 90 degrees).
On a side-note, some other GD image functions (unfortunately, the more interesting ones) suffer from the same problem and are kept out of the Ubuntu distribution as well.
kmrohe at letsco dot de
6 years ago
As an alternative to the GD rotateImage() function, this is an easy way to rotate images by 90 degrees ccw *without* loosing transparency:
<?php
function rotateImage($image) {
$width = imagesx($image);
$height = imagesy($image);
$newImage= imagecreatetruecolor($height, $width);
imagealphablending($newImage, false);
imagesavealpha($newImage, true);
for($w=0; $w<$width; $w++)
for($h=0; $h<$height; $h++) {
$ref = imagecolorat($image, $w, $h);
imagesetpixel($newImage, $h, ($width-1)-$w, $ref);
}
return $newImage;
}
?>
dave dot richards at gmail dot com
7 years ago
There is a slight mistake in the previous post by Kae Cyphet.
When setting the pixels of the new image the co-ordinates have to occasionally use the width ($wid) and height ($hei). These values must be reduced by 1 as the co-ordinates start at 0 (Not 1) so they only go up to $wid - 1 and $hei - 1 (Not $wid and $hei).
Here's an example of the first function to show this:
<?php
function rotate_right90($im)
{
$wid = imagesx($im);
$hei = imagesy($im);
$im2 = imagecreatetruecolor($hei,$wid);
for($i = 0;$i < $wid; $i++)
{
for($j = 0;$j < $hei; $j++)
{
$ref = imagecolorat($im,$i,$j);
imagesetpixel($im2,($hei - 1) - $j,$i,$ref);
}
}
return $im2;
}
?>
Other than that very useful functions!
Sam Yong - hellclanner at live dot com
4 years ago
Note that the image resource returned from the imagerotate() function is an entirely different image resource from your original one.
<?php
$res = imagecreatetruecolor(100, 200);
$res2 = imagerotate($res, 90, 0);
var_dump($res, $res2);
?>
This will output:
resource(2, gd)
resource(3, gd)
kraeh at gmx dot net
5 years ago
I had a problem with a png image containing transparent colors, but found a solution that works for me.
So i thought i might share it:
<?php
$angle=45;
$im=imagerotate($im, $angle, -1);
imagealphablending($im, true);
imagesavealpha($im, true);
?>
superzouz at hotmail dot com
5 years ago
If you're having trouble rotating images through this function, please note that you can rotate images through CSS. As imagerotate() seems to remove image transparency, I resorted to CSS rotate. Here is an example of CSS code that should work across most browsers:
img.rotated90 {
/* CSS3 then proprietary code */
rotation: 90deg;
-webkit-transform: rotate(90deg);
-moz-transform: rotate(90deg);
filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=1);
}
beau at dragonflydevelopment dot com
6 years ago
I believe the rotateImage function below is incorrect. The 180 rotation was actually doing a vertical mirror instead of rotating 180 degrees. The change was $i to $width - $i.
<?php
function rotateImage($img, $rotation) {
$width = imagesx($img);
$height = imagesy($img);
switch($rotation) {
case 90: $newimg= @imagecreatetruecolor($height , $width );break;
case 180: $newimg= @imagecreatetruecolor($width , $height );break;
case 270: $newimg= @imagecreatetruecolor($height , $width );break;
case 0: return $img;break;
case 360: return $img;break;
}
if($newimg) {
for($i = 0;$i < $width ; $i++) {
for($j = 0;$j < $height ; $j++) {
$reference = imagecolorat($img,$i,$j);
switch($rotation) {
case 90: if(!@imagesetpixel($newimg, ($height - 1) - $j, $i, $reference )){return false;}break;
case 180: if(!@imagesetpixel($newimg, $width - $i, ($height - 1) - $j, $reference )){return false;}break;
case 270: if(!@imagesetpixel($newimg, $j, $width - $i, $reference )){return false;}break;
}
}
} return $newimg;
}
return false;
}
?>
you can call it this way:
<?php
$img = rotateImage($imagetorotate,"degrees");
?>
sjef at bosman dot fr
6 years ago
I wanted to draw a transparent GIF-image and show it on a page, at an angle specified in the URL:
<img src="image.php?angle=90" type="image/gif">
I used the native imagerotate() but at angles of 90, 180, etc. the old background colour would become non-transparent. Apparently, there's a bug somewhere in GD, and has been for ages.
My solution below:
<?php
$height = 100;
$width = 100;
$lsize= $width/2;
$angle= $_GET["angle"];
// avoid the bug:
if(($angle%90)==0)
$angle+= 0.001;
$image_p = imagecreatetruecolor($width, $height);
$trans = imagecolorallocate($image_p, 254, 0, 0);
imagefill($image_p, 0, 0, $trans);
imagecolortransparent($image_p, $trans);
$black = imagecolorallocate($image_p, 1, 1, 1);
$red = imagecolorallocate($image_p, 255, 0, 0);
$white = imagecolorallocate($image_p, 255, 255, 255);
// draw something here
imageline($image_p, 3, $lsize, $lsize/2, $lsize, $black);
$image_r= imagerotate($image_p, -$angle, $trans, 0);
$w= imagesx($image_r);
$h= imagesy($image_r);
$image_s = imagecreatetruecolor($width, $height);
imagecopyresized($image_s, $image_r, 0, 0, ($w-$width)/2, ($h-$height)/2, $width, $height, $width, $height);
$trans = imagecolorallocate($image_s, 254, 0, 0);
imagecolortransparent($image_s, $trans);
imagegif($image_s);
?>
Mike Knoop
6 years ago
Don't be tricked into thinking this function will rotate the image resource handle in-place. While the documentation currently doesn't specify and return values, I've found the following return values to be true:
"Returns an image resource identifier on success, FALSE on errors. "
Simply make sure you're doing something like...
<?php
$rotated_img = imagerotate($src_img, 45, $color)
?>
-Mike
krteczek01 at gmail dot com
6 years ago
Hi, I've rewrote function to class with static methods. Advantage of this solution is ability to be called several times during script execution.
<?php
/*
Unfinished imagerotate replacement. ignore_transparent is, well, ignored. :)
Also, should have some standard functions for 90, 180 and 270 degrees, since they are quite
easy to implement faster.
*/
if(!function_exists("imagerotate")) {
function imagerotate(&$srcImg, $angle, $bgcolor, $ignore_transparent = 0) {
return imagerotateEquivalent::rotate(&$srcImg, $angle, $bgcolor, $ignore_transparent);
}
}
class imagerotateEquivalent {
static private function rotateX($x, $y, $theta){
return $x * cos($theta) - $y * sin($theta);
}
static private function rotateY($x, $y, $theta){
return $x * sin($theta) + $y * cos($theta);
}
public static function rotate(&$srcImg, $angle, $bgcolor, $ignore_transparent = 0) {
$srcw = imagesx($srcImg);
$srch = imagesy($srcImg);
if($angle == 0) return $srcImg;
// Convert the angle to radians
$theta = deg2rad ($angle);
// Calculate the width of the destination image.
$temp = array ( self::rotateX(0, 0, 0-$theta),
self::rotateX($srcw, 0, 0-$theta),
self::rotateX(0, $srch, 0-$theta),
self::rotateX($srcw, $srch, 0-$theta)
);
$minX = floor(min($temp));
$maxX = ceil(max($temp));
$width = $maxX - $minX;
// Calculate the height of the destination image.
$temp = array ( self::rotateY(0, 0, 0-$theta),
self::rotateY($srcw, 0, 0-$theta),
self::rotateY(0, $srch, 0-$theta),
self::rotateY($srcw, $srch, 0-$theta)
);
$minY = floor(min($temp));
$maxY = ceil(max($temp));
$height = $maxY - $minY;
$destimg = imagecreatetruecolor($width, $height);
imagefill($destimg, 0, 0, imagecolorallocate($destimg, 0,255, 0));
// sets all pixels in the new image
for($x=$minX;$x<$maxX;$x++) {
for($y=$minY;$y<$maxY;$y++)
{
// fetch corresponding pixel from the source image
$srcX = round(self::rotateX($x, $y, $theta));
$srcY = round(self::rotateY($x, $y, $theta));
if($srcX >= 0 && $srcX < $srcw && $srcY >= 0 && $srcY < $srch)
{
$color = imagecolorat($srcImg, $srcX, $srcY );
}
else
{
$color = $bgcolor;
}
imagesetpixel($destimg, $x-$minX, $y-$minY, $color);
}
}
return $destimg;
}
}
?>
Kae Cyphet
7 years ago
To solve that annoying problem of having to install a pre-compiled version of GD just to get imagerotate working.
here is an open source solution.
uses the standard stuff included in php when you uncomment 'extension=php_gd2.dll' in the php.ini file and there ya go!
Useage:
<?php
$im = imagecreatefromjpeg('test.jpg');
header('Content-type: image/jpg');
imagejpeg(rotate_right90($im));
imagedestroy($im);
?>
'=================================
<?php
function rotate_right90($im)
{
$wid = imagesx($im);
$hei = imagesy($im);
$im2 = imagecreatetruecolor($hei,$wid);
for($i = 0;$i < $wid; $i++)
{
for($j = 0;$j < $hei; $j++)
{
$ref = imagecolorat($im,$i,$j);
imagesetpixel($im2,$hei - $j,$i,$ref);
}
}
return $im2;
}
function rotate_left90($im)
{
$wid = imagesx($im);
$hei = imagesy($im);
$im2 = imagecreatetruecolor($hei,$wid);
for($i = 0;$i < $wid; $i++)
{
for($j = 0;$j < $hei; $j++)
{
$ref = imagecolorat($im,$i,$j);
imagesetpixel($im2,$j, $wid - $i,$ref);
}
}
return $im2;
}
function mirror($im)
{
$wid = imagesx($im);
$hei = imagesy($im);
$im2 = imagecreatetruecolor($wid,$hei);
for($i = 0;$i < $wid; $i++)
{
for($j = 0;$j < $hei; $j++)
{
$ref = imagecolorat($im,$i,$j);
imagesetpixel($im2,$wid - $i,$j,$ref);
}
}
return $im2;
}
function flip($im)
{
$wid = imagesx($im);
$hei = imagesy($im);
$im2 = imagecreatetruecolor($wid,$hei);
for($i = 0;$i < $wid; $i++)
{
for($j = 0;$j < $hei; $j++)
{
$ref = imagecolorat($im,$i,$j);
imagesetpixel($im2,$i,$hei - $j,$ref);
}
}
return $im2;
}
?>
joseluis at pellicer dot org
7 years ago
About that rotating function by david at horizon-nigh not working, I found the bug.
I noticed that the x1 and y1 where not used, so, in the loop through every pixel and transform it, change
$x2 = $x * cos($theta) - $y * sin($theta);
$y2 = $x * sin($theta) + $y * cos($theta);
to:
$x2 = $x1 * cos($theta) - $y1 * sin($theta);
$y2 = $x1 * sin($theta) + $y1 * cos($theta);
fernando_empresarial at ig dot com dot br
7 years ago
<?php
$urlImage = "images/image.png";
$urlNewImage = "images/imageNew.png";
$src_img = imagecreatefrompng($urlImage);
$originalX = imagesx($src_img);
$originalY = imagesy($src_img);
$dst_img = imagecreatetruecolor(640,480);
$imageRotate = imagerotate($src_img,20,-1);
imagepng($imageRotate,$urlNewImage);
imagedestroy($dst_img);
imagedestroy($src_img);
?>
foi02 at cartefoi dot net
7 years ago
For those who are looking for the GD library for Ubuntu, I let a copy on my server: http://www.cartefoi.net/compl_compl_2.php
It was pretty hard to find, somebody gaveme his. Thanks a lot to him (message up).
Bert Vandeghinste
7 years ago
I'm now using david's code with these changes to get a transparent effect.
I exec convert 2 times:
<?php
exec( $imagick . ' -background \'#555555\' -rotate ' . $angle . ' ' . $file1 . ' ' . $file2 );
exec( $imagick . ' -transparent \'#555555\' -transparent-color \'#555555\' ' . $file2 . ' ' . $file3 );
?>
and then use this after I rotated $output:
<?php imagecolortransparent($output, imagecolorallocatealpha($output, 85, 85, 85, 127)); ?>
david at horizon-nigh dot org
7 years ago
I couldn't get the replacements from 'the dot thawk' or 'pilot' to work for some reason, so here's my own replacement. It uses ImageMagick; binary must be installed, and you may need to modify the search path. (I didn't use PHP's ImageMagick support for my own reasons.)
<?php
/**
* imagerotate()
* Debian php5-gd packages do not include imagerotate() due to some convoluted reason.
*
* @param int $angle - same as PHP builtin function
* @param $bgd_color - not implemented, apparently always #FFFFFF
*
* @return same as PHP builtin function
*/
if ( !function_exists( 'imagerotate' ) ) {
function imagerotate( $source_image, $angle, $bgd_color ) {
$angle = 360-$angle; // GD rotates CCW, imagick rotates CW
foreach ( array( '/usr/bin', '/usr/local/bin', '/opt/local/bin', '/sw/bin' ) as $path ) {
if ( file_exists( $path . '/convert' ) ) {
$imagick = $path . '/convert';
if ( $path == '/opt/local/bin' ) {
$imagick = 'DYLD_LIBRARY_PATH="" ' . $imagick; // some kind of conflict with MacPorts and MAMP
}
break;
}
}
if ( !isset( $imagick ) ) {
//trigger_error( 'imagerotate(): could not find imagemagick binary, original image returned', E_USER_WARNING );
return $source_image;
}
$file1 = '/tmp/imagick_' . rand( 10000,99999 ) . '.png';
$file2 = '/tmp/imagick_' . rand( 10000,99999 ) . '.png';
if ( @imagepng( $source_image, $file1 ) ) {
exec( $imagick . ' -rotate ' . $angle . ' ' . $file1 . ' ' . $file2 );
if ( file_exists( $file2 ) ) {
$new_image = imagecreatefrompng( $file2 );
unlink( $file1 );
unlink( $file2 );
return $new_image;
} else {
//trigger_error( 'imagerotate(): imagemagick conversion failed, original image returned', E_USER_WARNING );
return $source_image;
}
} else {
//trigger_error( 'imagerotate(): could not write to ' . $file1 . ', original image returned', E_USER_WARNING );
return $source_image;
}
}
}
?>
cbl25
7 years ago
Here is a simple function to rotate a non-square image 90 degrees clockwise.
<?php
function rotateImage($imageResource)
{
$width = imagesx($imageResource);
$height = imagesy($imageResource);
$side = $width > $height ? $width : $height;
$squareImage = imagecreatetruecolor($side, $side);
imagecopy($squareImage,$imageResource,0,0,0,0,$width,$height);
$squareImage = imagerotate($squareImage,270,0,-1);
$imageResource = imagecreatetruecolor($height, $width);
$x = $height > $width ? 0 : $side - $height;
imagecopy($imageResource,$squareImage,0,0,$x,0,$height,$width);
return $imageResource;
}
?>
the dot thawk+phpnet at gmail dot com
7 years ago
In response to pilot at myupb dot com on 31-May-2008 02:23
---
I am not sure why you would be defining your own PI, instead of using the built-in constant, and why you do the degrees to radian conversion manually. There might be a speed issue, however here is the exact same code with that small difference.
<?php
if(!function_exists("imagerotate")) {
function imagerotate(&$srcImg, $angle, $transparentColor = null) {
$srcw = imagesx($srcImg);
$srch = imagesy($srcImg);
if($angle == 0) return $srcImg;
// Convert the angle to radians
$theta = deg2rad ($angle);
// Get the origin (center) of the image
$originx = $srcw / 2;
$originy = $srch / 2;
// The pixels array for the new image
$pixels = array();
$minx = 0;
$maxx = 0;
$miny = 0;
$maxy = 0;
$dstw = 0;
$dsth = 0;
// Loop through every pixel and transform it
for($x=0;$x<$srcw;$x++) {
for($y=0;$y<$srch;$y++) {
list($x1, $y1) = translateCoordinate($originx, $originy, $x, $y, false);
$x2 = $x * cos($theta) - $y * sin($theta);
$y2 = $x * sin($theta) + $y * cos($theta);
// Store the pixel color
$pixels[] = array($x2, $y2, imagecolorat($srcImg, $x, $y));
// Check our boundaries
if($x2 > $maxx) $maxx = $x2;
if($x2 < $minx) $minx = $x2;
if($y2 > $maxy) $maxy = $y2;
if($y2 < $miny) $miny = $y2;
}
}
// Determine the new image size
$dstw = $maxx - $minx + 1;
$dsth = $maxy - $miny + 1;
// Create our new image
$dstImg = imagecreatetruecolor($dstw, $dsth);
// Fill the background with our transparent color
if($transparentColor == null) $transparentColor = imagecolorallocate($dstImg, 1, 2, 3);
imagecolortransparent($dstImg, $transparentColor);
imagefilledrectangle($dstImg, 0, 0, $dstw + 1, $dsth + 1, $transparentColor);
// Get the new origin
$neworiginx = -$minx;
$neworiginy = -$miny;
// Fill in the pixels
foreach($pixels as $data) {
list($x, $y, $color) = $data;
list($newx, $newy) = translateCoordinate($neworiginx, $neworiginy, $x, $y);
imagesetpixel($dstImg, $newx, $newy, $color);
}
return $dstImg;
}
/**
* Translates from mathematical coordinate system to computer coordinate system using
* origin coordinates from the computer system or visa versa
*
* @param int $originx
* @param int $originy
* @param int $x
* @param int $y
* @param bool $toComp
* @return array(int $x, int $y)
*/
function translateCoordinate($originx, $originy, $x, $y, $toComp=true) {
if($toComp) {
$newx = $originx + $x;
$newy = $originy - $y;
} else {
$newx = $x - $originx;
$newy = $originy - $y;
}
return array($newx, $newy);
}
}
?>
pilot at myupb dot com
7 years ago
Shortly after posting I was informed about a very nice algorithm for calculating the new pixel position for a rotation and thought it would be a nice improvement. Hopes this helps anyone needing a full implementation.
Note: I tested the function on a 3Mb photo and it seemed to work perfectly with no quality loss.
<?php
if(!function_exists("imagerotate")) {
function imagerotate(&$srcImg, $angle, $transparentColor = null) {
$srcw = imagesx($srcImg);
$srch = imagesy($srcImg);
if($angle == 0) return $srcImg;
// Convert the angle to radians
$pi = 3.141592654;
$theta = $angle * $pi / 180;
// Get the origin (center) of the image
$originx = $srcw / 2;
$originy = $srch / 2;
// The pixels array for the new image
$pixels = array();
$minx = 0;
$maxx = 0;
$miny = 0;
$maxy = 0;
$dstw = 0;
$dsth = 0;
// Loop through every pixel and transform it
for($x=0;$x<$srcw;$x++) {
for($y=0;$y<$srch;$y++) {
list($x1, $y1) = translateCoordinate($originx, $originy, $x, $y, false);
$x2 = $x * cos($theta) - $y * sin($theta);
$y2 = $x * sin($theta) + $y * cos($theta);
// Store the pixel color
$pixels[] = array($x2, $y2, imagecolorat($srcImg, $x, $y));
// Check our boundaries
if($x2 > $maxx) $maxx = $x2;
if($x2 < $minx) $minx = $x2;
if($y2 > $maxy) $maxy = $y2;
if($y2 < $miny) $miny = $y2;
}
}
// Determine the new image size
$dstw = $maxx - $minx + 1;
$dsth = $maxy - $miny + 1;
// Create our new image
$dstImg = imagecreatetruecolor($dstw, $dsth);
// Fill the background with our transparent color
if($transparentColor == null) $transparentColor = imagecolorallocate($dstImg, 1, 2, 3);
imagecolortransparent($dstImg, $transparentColor);
imagefilledrectangle($dstImg, 0, 0, $dstw + 1, $dsth + 1, $transparentColor);
// Get the new origin
$neworiginx = -$minx;
$neworiginy = -$miny;
// Fill in the pixels
foreach($pixels as $data) {
list($x, $y, $color) = $data;
list($newx, $newy) = translateCoordinate($neworiginx, $neworiginy, $x, $y);
imagesetpixel($dstImg, $newx, $newy, $color);
}
return $dstImg;
}
/**
* Translates from mathematical coordinate system to computer coordinate system using
* origin coordinates from the computer system or visa versa
*
* @param int $originx
* @param int $originy
* @param int $x
* @param int $y
* @param bool $toComp
* @return array(int $x, int $y)
*/
function translateCoordinate($originx, $originy, $x, $y, $toComp=true) {
if($toComp) {
$newx = $originx + $x;
$newy = $originy - $y;
} else {
$newx = $x - $originx;
$newy = $originy - $y;
}
return array($newx, $newy);
}
}
?>
pilot at myupb dot com
7 years ago
Thanks to the people who contributed the code for the 90 180 and 270 rotations. I needed a full implementation however so I wrote one. By no mean do I think this is the best way of doing it, I just whipped this together for myself. Seems to work good for me.
Note: I didn't want the image to be shrunk when rotating so this implementation will keep the size of the original image but just rotate it.
<?php
if(!function_exists("imagerotate")) {
function imagerotate(&$srcImg, $angle, $transparentColor = null) {
$srcw = imagesx($srcImg);
$srch = imagesy($srcImg);
if($angle == 0) return $srcImg;
// Convert the angle to radians
$pi = 3.141592654;
$theta = $angle * $pi / 180;
// Get the origin (center) of the image
$originx = $srcw / 2;
$originy = $srch / 2;
// The pixels array for the new image
$pixels = array();
$minx = 0;
$maxx = 0;
$miny = 0;
$maxy = 0;
$dstw = 0;
$dsth = 0;
// Loop through every pixel and transform it
for($x=0;$x<$srcw;$x++) {
for($y=0;$y<$srch;$y++) {
list($x1, $y1) = translateCoordinate($originx, $originy, $x, $y, false);
$theta1 = 0;
$noTranslate = false;
// Determine the angle of original point
if($x1 > 0 && $y1 > 0) {
// Quadrant 1
$theta1 = atan($y1/$x1);
} elseif($x1 < 0 && $y1 > 0) {
// Quadrant 2
$theta1 = $pi - atan($y1/abs($x1));
} elseif($x1 < 0 && $y1 < 0) {
// Quadrant 3
$theta1 = $pi + atan($y1/$x1);
} elseif($x1 > 0 && $y1 < 0) {
// Quadrant 4
$theta1 = 2 * $pi - atan(abs($y1)/$x1);
} elseif($x1 == 0 && $y1 > 0) {
$theta1 = $pi / 2;
} elseif($x1 == 0 && $y1 < 0) {
$theta1 = 3 * $pi / 2;
} elseif($x1 > 0 && $y1 == 0) {
$theta1 = 0;
} elseif($x1 < 0 && $y1 == 0) {
$theta1 = $pi;
} else {
// Only case left should be $x1 == 0 && $y1 == 0
$noTranslate = true;
}
// Translate the position
if(!$noTranslate) {
// Calculate the new angle
$theta2 = $theta1 + $theta;
// Make sure theta2 is in between 0 - 2pi
while($theta2 < 0) $theta2 += 2 * $pi;
while($theta2 > (2 * $pi)) $theta2 -= 2 * $pi;
$radius = sqrt($x1*$x1 + $y1*$y1);
$x2 = ($radius * cos($theta2));
$y2 = ($radius * sin($theta2));
} else {
$x2 = $x1;
$y2 = $y1;
}
// Store the pixel color
$pixels[] = array($x2, $y2, imagecolorat($srcImg, $x, $y));
// Check our boundaries
if($x2 > $maxx) $maxx = $x2;
if($x2 < $minx) $minx = $x2;
if($y2 > $maxy) $maxy = $y2;
if($y2 < $miny) $miny = $y2;
}
}
// Determine the new image size
$dstw = $maxx - $minx + 1;
$dsth = $maxy - $miny + 1;
// Create our new image
$dstImg = imagecreatetruecolor($dstw, $dsth);
// Fill the background with our transparent color
if($transparentColor == null) $transparentColor = imagecolorallocate($dstImg, 1, 2, 3);
imagecolortransparent($dstImg, $transparentColor);
imagefilledrectangle($dstImg, 0, 0, $dstw + 1, $dsth + 1, $transparentColor);
// Get the new origin
$neworiginx = -$minx;
$neworiginy = -$miny;
// Fill in the pixels
foreach($pixels as $data) {
list($x, $y, $color) = $data;
list($newx, $newy) = translateCoordinate($neworiginx, $neworiginy, $x, $y);
imagesetpixel($dstImg, $newx, $newy, $color);
}
return $dstImg;
}
/**
* Translates from mathematical coordinate system to computer coordinate system using
* origin coordinates from the computer system or visa versa
*
* @param int $originx
* @param int $originy
* @param int $x
* @param int $y
* @param bool $toComp
* @return array(int $x, int $y)
*/
function translateCoordinate($originx, $originy, $x, $y, $toComp=true) {
if($toComp) {
$newx = $originx + $x;
$newy = $originy - $y;
} else {
$newx = $x - $originx;
$newy = $originy - $y;
}
return array($newx, $newy);
}
}
?>
achilles
8 years ago
otimized integration from 23-Feb-2007 04:21
just put it anywhere you like to use imagerotate with 90, 180, 270 degrees.
<?php
if(!function_exists("imagerotate")) {
function imagerotate($src_img, $angle) {
$src_x = imagesx($src_img);
$src_y = imagesy($src_img);
if ($angle == 180) {
$dest_x = $src_x;
$dest_y = $src_y; }
elseif ($src_x <= $src_y) {
$dest_x = $src_y;
$dest_y = $src_x; }
elseif ($src_x >= $src_y) {
$dest_x = $src_y;
$dest_y = $src_x; }
$rotate=imagecreatetruecolor($dest_x,$dest_y);
imagealphablending($rotate, false);
switch ($angle) {
case 270:
for ($y = 0; $y < ($src_y); $y++) {
for ($x = 0; $x < ($src_x); $x++) {
$color = imagecolorat($src_img, $x, $y);
imagesetpixel($rotate, $dest_x - $y - 1, $x, $color); }}
break;
case 90:
for ($y = 0; $y < ($src_y); $y++) {
for ($x = 0; $x < ($src_x); $x++) {
$color = imagecolorat($src_img, $x, $y);
imagesetpixel($rotate, $y, $dest_y - $x - 1, $color); }}
break;
case 180:
for ($y = 0; $y < ($src_y); $y++) {
for ($x = 0; $x < ($src_x); $x++) {
$color = imagecolorat($src_img, $x, $y);
imagesetpixel($rotate, $dest_x - $x - 1, $dest_y - $y - 1, $color); }}
break;
default: $rotate = $src_img; }
return $rotate; }}
?>
qrgames at NOSPAMTYrushyo dot com
8 years ago
imagerotate seems to be very fussy about handling transparency when copymerging onto another image. You can use the GD library's other transparency features to cover up the fact imagerotate gets it wrong HOWEVER it will only work if the top-left corner of the image is transparent at all rotations, so make the image a little bigger than it needs to be. This has been tested with png32 but does not work entirely for png8, as a phenomena creates noise around the rotated image.
<?php
$imgImage = imagecreatefrompng("image.png");
$colBlack = imagecolorallocate($imgImage, 0, 0, 0);
$imgImage = imagerotate($imgImage, 360 - $intHeading, 0);
imagefill($imgImage, 0, 0, $colBlack);
imagecolortransparent($imgImage, $colBlack);
imagecopymerge($imgOriginalImage , $imgImage, $intX, $intY, 0, 0, $intHeight, $intWidth, 100);
imagedestroy($imgImage);
?>
Note. $intHeading is in degrees clockwise :)
Thomaschaaf
9 years ago
<?php
function rotate($degrees)
{
if(function_exists("imagerotate"))
$this->image = imagerotate($this->image, $degrees, 0);
else
{
function imagerotate($src_img, $angle)
{
$src_x = imagesx($src_img);
$src_y = imagesy($src_img);
if ($angle == 180)
{
$dest_x = $src_x;
$dest_y = $src_y;
}
elseif ($src_x <= $src_y)
{
$dest_x = $src_y;
$dest_y = $src_x;
}
elseif ($src_x >= $src_y)
{
$dest_x = $src_y;
$dest_y = $src_x;
}
$rotate=imagecreatetruecolor($dest_x,$dest_y);
imagealphablending($rotate, false);
switch ($angle)
{
case 270:
for ($y = 0; $y < ($src_y); $y++)
{
for ($x = 0; $x < ($src_x); $x++)
{
$color = imagecolorat($src_img, $x, $y);
imagesetpixel($rotate, $dest_x - $y - 1, $x, $color);
}
}
break;
case 90:
for ($y = 0; $y < ($src_y); $y++)
{
for ($x = 0; $x < ($src_x); $x++)
{
$color = imagecolorat($src_img, $x, $y);
imagesetpixel($rotate, $y, $dest_y - $x - 1, $color);
}
}
break;
case 180:
for ($y = 0; $y < ($src_y); $y++)
{
for ($x = 0; $x < ($src_x); $x++)
{
$color = imagecolorat($src_img, $x, $y);
imagesetpixel($rotate, $dest_x - $x - 1, $dest_y - $y - 1, $color);
}
}
break;
default: $rotate = $src_img;
};
return $rotate;
}
$this->image = imagerotate($this->image, $degrees);
}
}
?>
m dot quinton at gmail dot com
9 years ago
with large file, where imagerotate is missing, you can use, when possible "convert" command from ImageMagick. Here is a sample script.
<?php
error_reporting(E_ALL);
header("Content-type: image/png");
$file = 'images/test/imgp2498.jpg';
image_rotate_with_convert($file, 90);
function image_rotate_with_convert($file, $angle){
passthru("convert -rotate $angle $file -");
}
?>
wulff at fyens dot dk
11 years ago
I liked the rotateImageBicubic function implemented by darren at lucidtone dot com. But it just snipped off the parts of the image that were outside the original image.
I fixed this, even though I admit that my solution is a bit naive. But it might come in handy for somebody.
Also his bicubic implementation was broken on my machine so I left it out, if you need it just copy and paste it from above.
<?php
// $src_img - a GD image resource
// $angle - degrees to rotate clockwise, in degrees
// returns a GD image resource
// USAGE:
// $im = imagecreatefrompng('test.png');
// $im = imagerotate($im, 15);
// header('Content-type: image/png');
// imagepng($im);
function imageRotate($src_img, $angle, $bicubic=false) {
// convert degrees to radians
$angle = $angle + 180;
$angle = deg2rad($angle);
$src_x = imagesx($src_img);
$src_y = imagesy($src_img);
$center_x = floor($src_x/2);
$center_y = floor($src_y/2);
$cosangle = cos($angle);
$sinangle = sin($angle);
$corners=array(array(0,0), array($src_x,0), array($src_x,$src_y), array(0,$src_y));
foreach($corners as $key=>$value) {
$value[0]-=$center_x; //Translate coords to center for rotation
$value[1]-=$center_y;
$temp=array();
$temp[0]=$value[0]*$cosangle+$value[1]*$sinangle;
$temp[1]=$value[1]*$cosangle-$value[0]*$sinangle;
$corners[$key]=$temp;
}
$min_x=1000000000000000;
$max_x=-1000000000000000;
$min_y=1000000000000000;
$max_y=-1000000000000000;
foreach($corners as $key => $value) {
if($value[0]<$min_x)
$min_x=$value[0];
if($value[0]>$max_x)
$max_x=$value[0];
if($value[1]<$min_y)
$min_y=$value[1];
if($value[1]>$max_y)
$max_y=$value[1];
}
$rotate_width=round($max_x-$min_x);
$rotate_height=round($max_y-$min_y);
$rotate=imagecreatetruecolor($rotate_width,$rotate_height);
imagealphablending($rotate, false);
imagesavealpha($rotate, true);
//Reset center to center of our image
$newcenter_x = ($rotate_width)/2;
$newcenter_y = ($rotate_height)/2;
for ($y = 0; $y < ($rotate_height); $y++) {
for ($x = 0; $x < ($rotate_width); $x++) {
// rotate...
$old_x = round((($newcenter_x-$x) * $cosangle + ($newcenter_y-$y) * $sinangle))
+ $center_x;
$old_y = round((($newcenter_y-$y) * $cosangle - ($newcenter_x-$x) * $sinangle))
+ $center_y;
if ( $old_x >= 0 && $old_x < $src_x
&& $old_y >= 0 && $old_y < $src_y ) {
$color = imagecolorat($src_img, $old_x, $old_y);
} else {
// this line sets the background colour
$color = imagecolorallocatealpha($src_img, 255, 255, 255, 127);
}
imagesetpixel($rotate, $x, $y, $color);
}
}
return($rotate);
}
?>
Borszczuk
11 years ago
Here's a function that implements right angle (multiplicity of 90 degs - 90, 180, 270) rotation if you need one but lacks native imagerotate() or you don't want non-square images to be scaled down as with imagerotate(). As you probably noticed it's not self contained function, as 180 rotation is handled by ImageFlip() function to gain the performance. The ImageFlip() function used is published here: http://php.net/imagecopy in the comment of mine placed on 05-Jan-2005 04:30
Please note: that in case of 0 degrees rotation handle to imgSrc is returned which may lead to problems if you imagedestroy() it undonditionaly. To solve that you shall add imagecopy($imgDest, $imgSrc, 0,0, 0,0,$srcX, $srcY) in proper place which I have intentionally ommited to save memory resources
<?php
// $imgSrc - GD image handle of source image
// $angle - angle of rotation. Needs to be positive integer
// angle shall be 0,90,180,270, but if you give other it
// will be rouned to nearest right angle (i.e. 52->90 degs,
// 96->90 degs)
// returns GD image handle of rotated image.
function ImageRotateRightAngle( $imgSrc, $angle )
{
// ensuring we got really RightAngle (if not we choose the closest one)
$angle = min( ( (int)(($angle+45) / 90) * 90), 270 );
// no need to fight
if( $angle == 0 )
return( $imgSrc );
// dimenstion of source image
$srcX = imagesx( $imgSrc );
$srcY = imagesy( $imgSrc );
switch( $angle )
{
case 90:
$imgDest = imagecreatetruecolor( $srcY, $srcX );
for( $x=0; $x<$srcX; $x++ )
for( $y=0; $y<$srcY; $y++ )
imagecopy($imgDest, $imgSrc, $srcY-$y-1, $x, $x, $y, 1, 1);
break;
case 180:
$imgDest = ImageFlip( $imgSrc, IMAGE_FLIP_BOTH );
break;
case 270:
$imgDest = imagecreatetruecolor( $srcY, $srcX );
for( $x=0; $x<$srcX; $x++ )
for( $y=0; $y<$srcY; $y++ )
imagecopy($imgDest, $imgSrc, $y, $srcX-$x-1, $x, $y, 1, 1);
break;
}
return( $imgDest );
}
?>
darren at lucidtone dot com
11 years ago
Here's a neat function for those of us who don't have imagerotate() on our servers. It's based on a comment from ron at korving dot demon dot nl on the manual page for imagecopyresampled.
I'm still not 100% on coping with transparency, but this function seems to cope okay. It doesn't resize to fit within bounds, it just rotates and you lose anything outside the image box.
The bicubic mode is slooow.
If you want to be able to change the background colour, pass in a colour and use it where indicated. The line I used just sets it transparent.
<?php
// $src_img - a GD image resource
// $angle - degrees to rotate clockwise, in degrees
// returns a GD image resource
// USAGE:
// $im = imagecreatefrompng('test.png');
// $im = imagerotate($im, 15);
// header('Content-type: image/png');
// imagepng($im);
function imageRotateBicubic($src_img, $angle, $bicubic=false) {
// convert degrees to radians
$angle = $angle + 180;
$angle = deg2rad($angle);
$src_x = imagesx($src_img);
$src_y = imagesy($src_img);
$center_x = floor($src_x/2);
$center_y = floor($src_y/2);
$rotate = imagecreatetruecolor($src_x, $src_y);
imagealphablending($rotate, false);
imagesavealpha($rotate, true);
$cosangle = cos($angle);
$sinangle = sin($angle);
for ($y = 0; $y < $src_y; $y++) {
for ($x = 0; $x < $src_x; $x++) {
// rotate...
$old_x = (($center_x-$x) * $cosangle + ($center_y-$y) * $sinangle)
+ $center_x;
$old_y = (($center_y-$y) * $cosangle - ($center_x-$x) * $sinangle)
+ $center_y;
if ( $old_x >= 0 && $old_x < $src_x
&& $old_y >= 0 && $old_y < $src_y ) {
if ($bicubic == true) {
$sY = $old_y + 1;
$siY = $old_y;
$siY2 = $old_y - 1;
$sX = $old_x + 1;
$siX = $old_x;
$siX2 = $old_x - 1;
$c1 = imagecolorsforindex($src_img, imagecolorat($src_img, $siX, $siY2));
$c2 = imagecolorsforindex($src_img, imagecolorat($src_img, $siX, $siY));
$c3 = imagecolorsforindex($src_img, imagecolorat($src_img, $siX2, $siY2));
$c4 = imagecolorsforindex($src_img, imagecolorat($src_img, $siX2, $siY));
$r = ($c1['red'] + $c2['red'] + $c3['red'] + $c4['red'] ) << 14;
$g = ($c1['green'] + $c2['green'] + $c3['green'] + $c4['green']) << 6;
$b = ($c1['blue'] + $c2['blue'] + $c3['blue'] + $c4['blue'] ) >> 2;
$a = ($c1['alpha'] + $c2['alpha'] + $c3['alpha'] + $c4['alpha'] ) >> 2;
$color = imagecolorallocatealpha($src_img, $r,$g,$b,$a);
} else {
$color = imagecolorat($src_img, $old_x, $old_y);
}
} else {
// this line sets the background colour
$color = imagecolorallocatealpha($src_img, 255, 255, 255, 127);
}
imagesetpixel($rotate, $x, $y, $color);
}
}
return $rotate;
}
?>
jon at driestone dot com
11 years ago
imagerotate does not preserve the alpha channel, so if you want to rotate a PNG you need to get
creative. I don't see any command to retrieve the alpha information from an image (as far as
I could see,) so you'll have to do a bit of manual labor before hand. In my case I created a
second PNG file with the alpha saved as RGB data and manually "copied" the data from source
to destination:
<?php
function alpha_rotate($dst,$src,$rotate,$offsetX,$offsetY){
$top = imagecreatefrompng("image_processing/shadow.png");
$top_alpha = imagecreatefrompng("image_processing/shadow_alpha.png");
imagecopyresampled($top,$src,0,0,0,0,100,100,100,100);
$top = imagerotate($top,$rotate,0x000000);
$top_alpha = imagerotate($top_alpha,$rotate,0x000000);
for ($theX=0;$theX<imagesx($top);$theX++){
for ($theY=0;$theY<imagesy($top);$theY++){
$rgb = imagecolorat($top,$theX,$theY);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
$rgb = imagecolorat($top_alpha,$theX,$theY);
$a = $rgb & 0xFF;
$a = 127-floor($a/2);
$myColor = imagecolorallocatealpha($top,$r,$g,$b,$a);
imagesetpixel($dst,($theX+$offsetX),($theY+$offsetY),$myColor);
}
}
}
?>
christoph (at) raketenbasis (dot) de
11 years ago
The default direction of imageRotate() is counter clockwise. Heres a little function which solves the problem.
<?php
function rotate(&$image_source, $rotate_value, $rotate_clockwise = true) {
if($rotate_clockwise == true) {
$rotate_value = 360 - $rotate_value;
}
$image_source = imageRotate($image_source, $rotate_value, 0);
}
?>
Leo
5 years ago
// angle in degrees, clockwise, allowed values from 0 to 360 degrees
function rotateImage ($image, $angle)
{
if ( ($angle < 0) || ($angle > 360) )
{
exit ("Error, angle passed out of range: [0,360]");
}
$width = imagesx ($image);
$height = imagesy ($image);
$dstImage = imagecreatetruecolor ($width, $height);
if ( ($angle == 0) || ($angle == 360) )
{
// Just copy image to output:
imagecopy ($dstImage, $image, 0, 0, 0, 0, $width, $height);
}
else
{
$centerX = floor ($width / 2);
$centerY = floor ($height / 2);
// Run on all pixels of the destination image and fill them:
for ($dstImageX = 0; $dstImageX < $width; $dstImageX++)
{
for ($dstImageY = 0; $dstImageY < $height; $dstImageY++)
{
// Calculate pixel coordinate in coordinate system centered at the image center:
$x = $dstImageX - $centerX;
$y = $centerY - $dstImageY;
if ( ($x == 0) && ($y == 0) )
{
// We are in the image center, this pixel should be copied as is:
$srcImageX = $x;
$srcImageY = $y;
}
else
{
$r = sqrt ($x * $x + $y * $y); // radius - absolute distance of the current point from image center
$curAngle = asin ($y / $r); // angle of the current point [rad]
if ($x < 0)
{
$curAngle = pi () - $curAngle;
}
$newAngle = $curAngle + $angle * pi () / 180; // new angle [rad]
// Calculate new point coordinates (after rotation) in coordinate system at image center
$newXRel = floor ($r * cos ($newAngle));
$newYRel = floor ($r * sin ($newAngle));
// Convert to image absolute coordinates
$srcImageX = $newXRel + $centerX;
$srcImageY = $centerY - $newYRel;
}
$pixelColor = imagecolorat ($image, $srcImageX, $srcImageY); // get source pixel color
imagesetpixel ($dstImage, $dstImageX, $dstImageY, $pixelColor); // write destination pixel
}
}
}
return $dstImage;
}
c kelley at ca - cycleworks dot com
6 years ago
Note, of the rotate functions below, only beau's worked for me. Not sure if it is because of my source image, but upon rotating, the background became blue.
The code snippet below is what I used to prepare UPS shipping labels. The UPS xml api will return a base64 encoded gif, but it is sideways, so as to print on the top half of a 8.5x11 "letter" page. We are saving it in a database and sending it to a label printer, so needed it rotated...
The other code further down didn't make the background blue, however it did make the image leave the canvas by about 50%. Additionally, the imagecolorallocate() function has an example describing how to set the background color. That didn't work for me. Even though the blue BG is #0000ff, using that code didn't work, I had to use the transparent trick below.
The GD image functions may be in their infancy, however are a great reminder to me how powerful php is! Also, ubuntu apache users will need to apt-get install php5-gd to get the gd functions.
<?php
$image=imagecreatefromgif( 'data://text/plain;base64,'.$this->shipmentLabelGraphicImage );
$image=$this->rotateImage($image, 90); // Note: rotateImage turns our background to blue!
$blue = imagecolorallocate($image, 0, 0, 255);
imagecolortransparent($image, $blue); // make blue transparent, so image isn't goofy
imagepng($image,$this->shipmentTrackingNumber.".png");
echo '<P><img src="'.$this->shipmentTrackingNumber.'.png"></P>';
imagedestroy($image);
?>
ewald at dutchvisual dot nl
6 years ago
This function will rotate the image. The image will be resampled completely.
<?php
function rotateImage($img, $rotation) {
$width = imagesx($img);
$height = imagesy($img);
switch($rotation) {
case 90: $newimg= @imagecreatetruecolor($height , $width );break;
case 180: $newimg= @imagecreatetruecolor($width , $height );break;
case 270: $newimg= @imagecreatetruecolor($height , $width );break;
case 0: return $img;break;
case 360: return $img;break;
}
if($newimg) {
for($i = 0;$i < $width ; $i++) {
for($j = 0;$j < $height ; $j++) {
$reference = imagecolorat($img,$i,$j);
switch($rotation) {
case 90: if(!@imagesetpixel($newimg, ($height - 1) - $j, $i, $reference )){return false;}break;
case 180: if(!@imagesetpixel($newimg, $i, ($height - 1) - $j, $reference )){return false;}break;
case 270: if(!@imagesetpixel($newimg, $j, $width - $i, $reference )){return false;}break;
}
}
} return $newimg;
}
return false;
}
?>
you can call it this way:
<?php
$img = rotateImage($imagetorotate,"degrees");
?>
dev at imglib dot endofinternet dot net
6 years ago
And you can add a transparent background to you png image by change the
<?php
if ($ignore_transparent == 0) {
imagefill($destimg, 0, 0, imagecolorallocatealpha($destimg, 255,255, 255, 127));
imagesavealpha($destimg, true);
}
?>
to
<?php
if ($ignore_transparent == 0) {
$temp = imagecolorallocatealpha($destimg, 255,255, 255, 127);
imagefill($destimg, 0, 0, $temp);
//if set the default color or white or magic pink then use transparent color
if ( ($bgcolor == 0) || ($bgcolor == 16777215) || ($bgcolor == 16711935) ) {
$bgcolor = $temp;
}
imagesavealpha($destimg, true);
}
?>
gglockner AT NOSPAMdwaffler DOT com
6 years ago
If you're going to do a rotation by hand instead of using the imagerotate function, you can use the imagecopy function to copy a single pixel instead of determining the pixel color and setting the pixel. Not only is this shorter and cleaner, but it also works with images that are not truecolor (on my system, imagecolorat fails with an image that is not truecolor).
jeprubio
6 years ago
hi,
if you have a image with transparent color in previous function "function rotateImage($img1, $rec)"
just before "return $img2;" you have to do:
imagecolortransparent($img2, imagecolorallocate($img2, 0, 0, 0));
Best regards
Anonymous
6 years ago
Sorry, the previous class contains an error, the original image after the rotation 1px move on and get the unwanted "border".
After a careful reading of the local debate, I am using the tip from Dave Richards wrote a new function. With its images can be rotated only 90 ° (default), 180 ° and 270 °, but one rarely needs more ...
The function returns False, or rotated image
<?php
if(!function_exists("imagerotate")) {
function imagerotate($srcImg, $angle, $bgcolor, $ignore_transparent = 0) {
return rotateImage($srcImg, $angle);
}
}
function rotateImage($img1, $rec) {
$wid = imagesx($img1);
$hei = imagesy($img1);
switch($rec) {
case 270:
$img2 = @imagecreatetruecolor($hei, $wid);
break;
case 180:
$img2 = @imagecreatetruecolor($wid, $hei);
break;
default :
$img2 = @imagecreatetruecolor($hei, $wid);
}
if($img2) {
for($i = 0;$i < $wid; $i++) {
for($j = 0;$j < $hei; $j++) {
$ref = imagecolorat($img1,$i,$j);
switch($rec) {
case 270:
if(!@imagesetpixel($img2, ($hei - 1) - $j, $i, $ref)){
return false;
}
break;
case 180:
if(!@imagesetpixel($img2, $i, ($hei - 1) - $j, $ref)) {
return false;
}
break;
default:
if(!@imagesetpixel($img2, $j, ($wid - 1) - $i, $ref)) {
return false;
}
}
}
}
return $img2;
}
return false;
}
?>
Petr
simon_nuttall at hotmail dot com
10 years ago
The following is potentially useful. It extracts the central largest circle of an image into a square of specified size, and optionally rotates it. The rest of the square is made transparent, so useful for drawing over other images. I've named it after binocular effect because on some old TV shows whenever they show someone looking through binoculars the screen shows a big circular image with black edges.
<?php
function image_binocular_effect($src, $bearing, $out_square) {
// the source image is resampled to fit within the specified square, and rotated clockwise by bearing.
// the largest circle within the image is retained, the rest made transparent.
$out = imagecreatetruecolor($out_square, $out_square);
$width=imagesx($src);
$height=imagesy($src);
$square=min($width, $height);
imagecopyresampled($out, $src, 0, 0, ($width - $square)/2 , ($height - $square)/2, $out_square, $out_square, $square, $square);
$mask = imagecreatetruecolor($out_square, $out_square);
$black = ImageColorAllocate ($mask, 0, 0, 0);
$white = ImageColorAllocate ($mask, 255, 255, 255);
imagefilledrectangle($mask , 0, 0, $out_square, $out_square, $white);
$centrexy=$out_square / 2;
imagefilledellipse($mask, $centrexy, $centrexy, $out_square, $out_square, $black);
ImageColorTransparent($mask, $black);
imagecopymerge($out, $mask, 0, 0, 0, 0, $out_square, $out_square, 100);
if ($bearing != 0) {
$rotated_img=imagerotate($out , 360-$bearing, $white);
// take off only the rotated width
$rotated_map_width = imagesx($rotated_img);
$rotated_map_height = imagesy($rotated_img);
imagecopy($out, $rotated_img, 0, 0, ($rotated_map_width - $out_square) / 2, ($rotated_map_height - $out_square) / 2, $out_square, $out_square);
}
ImageColorTransparent($out, $white);
return $out;
}
// Create a sample image to demonstrate the effect, but looks much better on real photos.
$src = imagecreatetruecolor(200, 50);
imagefilledrectangle($src, 0, 0, 200, 50, imagecolorallocate($src, 255, 255, 255));
ImageString($src, 3, 10, 10, "This is a sample image to illustrate the binocular effect", imagecolorallocate($im, 192, 0, 0));
$img=image_binocular_effect($src, 72, 50);
ImagePNG($img,"test.png");
?>
