问题
The code below crops the image well, which is what i want, but for larger images, it wotn work as well. Is there any way of 'zooming out of the image'
Idealy i would be able to have each image roughly the same size before cropping so that i would get good results each time
Code is
<?php
$image = $_GET['src']; // the image to crop
$dest_image = 'images/cropped_whatever.jpg'; // make sure the directory is writeable
$img = imagecreatetruecolor('200','150');
$org_img = imagecreatefromjpeg($image);
$ims = getimagesize($image);
imagecopy($img,$org_img, 0, 0, 20, 20, 200, 150);
imagejpeg($img,$dest_image,90);
imagedestroy($img);
echo '<img src="'.$dest_image.'" ><p>';
回答1:
If you are trying to generate thumbnails, you must first resize the image using imagecopyresampled();. You must resize the image so that the size of the smaller side of the image is equal to the corresponding side of the thumb.
For example, if your source image is 1280x800px and your thumb is 200x150px, you must resize your image to 240x150px and then crop it to 200x150px. This is so that the aspect ratio of the image won't change.
Here's a general formula for creating thumbnails:
$image = imagecreatefromjpeg($_GET['src']);
$filename = 'images/cropped_whatever.jpg';
$thumb_width = 200;
$thumb_height = 150;
$width = imagesx($image);
$height = imagesy($image);
$original_aspect = $width / $height;
$thumb_aspect = $thumb_width / $thumb_height;
if ( $original_aspect >= $thumb_aspect )
{
// If image is wider than thumbnail (in aspect ratio sense)
$new_height = $thumb_height;
$new_width = $width / ($height / $thumb_height);
}
else
{
// If the thumbnail is wider than the image
$new_width = $thumb_width;
$new_height = $height / ($width / $thumb_width);
}
$thumb = imagecreatetruecolor( $thumb_width, $thumb_height );
// Resize and crop
imagecopyresampled($thumb,
$image,
0 - ($new_width - $thumb_width) / 2, // Center the image horizontally
0 - ($new_height - $thumb_height) / 2, // Center the image vertically
0, 0,
$new_width, $new_height,
$width, $height);
imagejpeg($thumb, $filename, 80);
Haven't tested this but it should work.
EDIT
Now tested and working.
回答2:
imagecopyresampled() will take a rectangular area from $src_image of width $src_w and height $src_h at position ($src_x, $src_y) and place it in a rectangular area of $dst_image of width $dst_w and height $dst_h at position ($dst_x, $dst_y).
If the source and destination coordinates and width and heights differ, appropriate stretching or shrinking of the image fragment will be performed. The coordinates refer to the upper left corner.
This function can be used to copy regions within the same image. But if the regions overlap, the results will be unpredictable.
- Edit -
If $src_w and $src_h are smaller than $dst_w and $dst_h respectively, thumb image will be zoomed in. Otherwise it will be zoomed out.
<?php
$dst_x = 0; // X-coordinate of destination point
$dst_y = 0; // Y-coordinate of destination point
$src_x = 100; // Crop Start X position in original image
$src_y = 100; // Crop Srart Y position in original image
$dst_w = 160; // Thumb width
$dst_h = 120; // Thumb height
$src_w = 260; // Crop end X position in original image
$src_h = 220; // Crop end Y position in original image
// Creating an image with true colors having thumb dimensions (to merge with the original image)
$dst_image = imagecreatetruecolor($dst_w, $dst_h);
// Get original image
$src_image = imagecreatefromjpeg('images/source.jpg');
// Cropping
imagecopyresampled($dst_image, $src_image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
// Saving
imagejpeg($dst_image, 'images/crop.jpg');
?>
回答3:
php 5.5 has an imagecrop function http://php.net/manual/en/function.imagecrop.php
回答4:
Improved Crop image functionality in PHP on the fly.
http://www.example.com/cropimage.php?filename=a.jpg&newxsize=100&newysize=200&constrain=1
Code in cropimage.php
$basefilename = @basename(urldecode($_REQUEST['filename']));
$path = 'images/';
$outPath = 'crop_images/';
$saveOutput = false; // true/false ("true" if you want to save images in out put folder)
$defaultImage = 'no_img.png'; // change it with your default image
$basefilename = $basefilename;
$w = $_REQUEST['newxsize'];
$h = $_REQUEST['newysize'];
if ($basefilename == "") {
$img = $path . $defaultImage;
$percent = 100;
} else {
$img = $path . $basefilename;
$len = strlen($img);
$ext = substr($img, $len - 3, $len);
$img2 = substr($img, 0, $len - 3) . strtoupper($ext);
if (!file_exists($img)) $img = $img2;
if (file_exists($img)) {
$percent = @$_GET['percent'];
$constrain = @$_GET['constrain'];
$w = $w;
$h = $h;
} else if (file_exists($path . $basefilename)) {
$img = $path . $basefilename;
$percent = $_GET['percent'];
$constrain = $_GET['constrain'];
$w = $w;
$h = $h;
} else {
$img = $path . 'no_img.png'; // change with your default image
$percent = @$_GET['percent'];
$constrain = @$_GET['constrain'];
$w = $w;
$h = $h;
}
}
// get image size of img
$x = @getimagesize($img);
// image width
$sw = $x[0];
// image height
$sh = $x[1];
if ($percent > 0) {
// calculate resized height and width if percent is defined
$percent = $percent * 0.01;
$w = $sw * $percent;
$h = $sh * $percent;
} else {
if (isset ($w) AND !isset ($h)) {
// autocompute height if only width is set
$h = (100 / ($sw / $w)) * .01;
$h = @round($sh * $h);
} elseif (isset ($h) AND !isset ($w)) {
// autocompute width if only height is set
$w = (100 / ($sh / $h)) * .01;
$w = @round($sw * $w);
} elseif (isset ($h) AND isset ($w) AND isset ($constrain)) {
// get the smaller resulting image dimension if both height
// and width are set and $constrain is also set
$hx = (100 / ($sw / $w)) * .01;
$hx = @round($sh * $hx);
$wx = (100 / ($sh / $h)) * .01;
$wx = @round($sw * $wx);
if ($hx < $h) {
$h = (100 / ($sw / $w)) * .01;
$h = @round($sh * $h);
} else {
$w = (100 / ($sh / $h)) * .01;
$w = @round($sw * $w);
}
}
}
$im = @ImageCreateFromJPEG($img) or // Read JPEG Image
$im = @ImageCreateFromPNG($img) or // or PNG Image
$im = @ImageCreateFromGIF($img) or // or GIF Image
$im = false; // If image is not JPEG, PNG, or GIF
if (!$im) {
// We get errors from PHP's ImageCreate functions...
// So let's echo back the contents of the actual image.
readfile($img);
} else {
// Create the resized image destination
$thumb = @ImageCreateTrueColor($w, $h);
// Copy from image source, resize it, and paste to image destination
@ImageCopyResampled($thumb, $im, 0, 0, 0, 0, $w, $h, $sw, $sh);
//Other format imagepng()
if ($saveOutput) { //Save image
$save = $outPath . $basefilename;
@ImageJPEG($thumb, $save);
} else { // Output resized image
header("Content-type: image/jpeg");
@ImageJPEG($thumb);
}
}
回答5:
$image = imagecreatefromjpeg($_GET['src']);
Needs to be replaced with this:
$image = imagecreatefromjpeg('images/thumbnails/myimage.jpg');
Because imagecreatefromjpeg() is expecting a string.
This worked for me.
ref:
http://php.net/manual/en/function.imagecreatefromjpeg.php
回答6:
Is there any way of 'zooming out of the image'.
For a lesser server-side/PHP approach, here's a nice jQuery plugin.
One could do all the necessary adjustments - the zooming, and aspect ratio, kind - on the client-side and send the final cropped area positions and size to the server-side for final manipulation and saving. The docs say pretty much enough for you to get rocking.
回答7:
HTML Code:-
enter code here
<!DOCTYPE html>
<html>
<body>
<form action="upload.php" method="post" enctype="multipart/form-data">
Select image to upload:
<input type="file" name="image" id="fileToUpload">
<input type="submit" value="Upload Image" name="submit">
</form>
</body>
</html>
upload.php
enter code here
<?php
$image = $_FILES;
$NewImageName = rand(4,10000)."-". $image['image']['name'];
$destination = realpath('../images/testing').'/';
move_uploaded_file($image['image']['tmp_name'], $destination.$NewImageName);
$image = imagecreatefromjpeg($destination.$NewImageName);
$filename = $destination.$NewImageName;
$thumb_width = 200;
$thumb_height = 150;
$width = imagesx($image);
$height = imagesy($image);
$original_aspect = $width / $height;
$thumb_aspect = $thumb_width / $thumb_height;
if ( $original_aspect >= $thumb_aspect )
{
// If image is wider than thumbnail (in aspect ratio sense)
$new_height = $thumb_height;
$new_width = $width / ($height / $thumb_height);
}
else
{
// If the thumbnail is wider than the image
$new_width = $thumb_width;
$new_height = $height / ($width / $thumb_width);
}
$thumb = imagecreatetruecolor( $thumb_width, $thumb_height );
// Resize and crop
imagecopyresampled($thumb,
$image,
0 - ($new_width - $thumb_width) / 2, // Center the image horizontally
0 - ($new_height - $thumb_height) / 2, // Center the image vertically
0, 0,
$new_width, $new_height,
$width, $height);
imagejpeg($thumb, $filename, 80);
echo "cropped"; die;
?>
回答8:
You can use imagecrop function in (PHP 5 >= 5.5.0, PHP 7)
Example:
<?php
$im = imagecreatefrompng('example.png');
$size = min(imagesx($im), imagesy($im));
$im2 = imagecrop($im, ['x' => 0, 'y' => 0, 'width' => $size, 'height' => $size]);
if ($im2 !== FALSE) {
imagepng($im2, 'example-cropped.png');
imagedestroy($im2);
}
imagedestroy($im);
?>
回答9:
$image = imagecreatefromjpeg($_GET['src']);
$filename = 'images/cropped_whatever.jpg'
Must be replaced with:
$image = imagecreatefromjpeg($_GET['src']);
Then it will work!
来源：https://stackoverflow.com/questions/1855996/crop-image-in-php