下面的代码很好地裁剪了图像，这正是我想要的，但对于较大的图像，它也无法正常工作。有没有办法“缩小图像”
理想情况下，我可以在裁剪之前使每张图像的大小大致相同，这样我每次都能得到很好的结果
代码是
<?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>';
如果您尝试生成缩略图，您必须首先使用imagecopyresampled();. 您必须调整图像的大小，以使图像较小边的大小等于拇指的相应边。
例如，如果您的源图像是 1280x800 像素，而您的拇指是 200x150 像素，则您必须将图像大小调整为 240x150 像素，然后将其裁剪为 200x150 像素。这是为了使图像的纵横比不会改变。
以下是创建缩略图的通用公式：
$image = imagecreatefromjpeg($_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, $filename, 80);
尚未对此进行测试，但它应该可以工作。
编辑
现在测试和工作。
imagecopyresampled()将从 position 的 width 和 height 的矩形区域中取出一个矩形区域，$src_image并将其放置在 position 的 width$src_w和height的$src_h矩形区域中。($src_x, $src_y)$dst_image$dst_w$dst_h($dst_x, $dst_y)
如果源和目标坐标以及宽度和高度不同，则会对图像片段进行适当的拉伸或收缩。坐标指的是左上角。
此功能可用于复制同一图像内的区域。但是如果区域重叠，结果将是不可预测的。
如果$src_w和$src_h分别小于$dst_w和$dst_h，拇指图像将被放大。否则，它将被缩小。
<?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');
?>
php 5.5 有一个 imagecrop 函数http://php.net/manual/en/function.imagecrop.php
$image = imagecreatefromjpeg($_GET['src']);
需要替换为：
$image = imagecreatefromjpeg('images/thumbnails/myimage.jpg');
因为imagecreatefromjpeg()期待一个字符串。
这对我有用。
参考：
http: //php.net/manual/en/function.imagecreatefromjpeg.php
HTML 代码：-
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>
上传.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;
?>
动态改进了 PHP 中的裁剪图像功能。
http://www.example.com/cropimage.php?filename=a.jpg&newxsize=100&newysize=200&constrain=1
代码在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);
}
}
您可以imagecrop在 (PHP 5 >= 5.5.0, PHP 7) 中使用函数
例子：
<?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);
?>
$image = imagecreatefromjpeg($_GET['src']);
$filename = 'images/cropped_whatever.jpg'
必须替换为：
$image = imagecreatefromjpeg($_GET['src']);
然后它将起作用！