基本上我想上传一个图像（我已经排序）并将其缩小到某些限制，例如最大宽度和高度，但保持原始图像的纵横比。
我没有在服务器上安装 Imagick - 否则这很容易。
一如既往地感谢任何帮助。谢谢。
编辑：我不需要整个代码或任何东西，只要朝着正确的方向推进就会很棒。
问问题
75321 次
10 回答
24
实际上，公认的解决方案不是正确的解决方案。原因很简单：会出现源图像和目标图像的比例不同的情况。任何计算都应反映这种差异。
请注意 PHP.net 网站上给出的示例中的相关行：
$ratio_orig = $width_orig/$height_orig;
if ($width/$height > $ratio_orig) {
$width = $height*$ratio_orig;
} else {
$height = $width/$ratio_orig;
}
完整的例子可以在这里找到：http: //php.net/manual/en/function.imagecopyresampled.php
对于遇到相同问题的类似问题（以不同方式提出的相同问题），stackoverflow 上还有其他答案（带有示例）。
例子：
假设我们有一个 1630 x 2400 像素的图像，我们希望自动调整其大小，保持纵横比为 160 x 240。让我们用公认的解决方案做一些数学运算：
if($old_x < $old_y)
{
$thumb_w = $old_x*($new_width/$old_y);
$thumb_h = $new_height;
}
高度 = 240 宽度 = 1630 * ( 160/2400 ) = 1630 * 0.0666666666666667 = 108.6666666666667 108.6 x 240 这不是正确的解决方案。
提出的下一个解决方案如下：
if($old_x < $old_y)
{
$thumb_w = $old_x/$old_y*$newHeight;
$thumb_h = $newHeight;
}
高度 = 240；width = 1630 / 2400 * 240 = 163 更好（因为它保持纵横比），但它超过了可接受的最大宽度。
两者都失败了。
我们根据 PHP.net 提出的解决方案进行数学运算：width = 160 height = 160/(1630 / 2400) = 160/0.6791666666666667 = 235.5828220858896（else子句）。160 x 236（四舍五入）是正确答案。
于 2014-12-27T22:50:03.337 回答
20
我已经为我完成的另一个项目编写了一段这样的代码。我在下面复制了它，可能需要一些修补！（它确实需要 GD 库）
这些是它需要的参数：
$image_name - Name of the image which is uploaded
$new_width - Width of the resized photo (maximum)
$new_height - Height of the resized photo (maximum)
$uploadDir - Directory of the original image
$moveToDir - Directory to save the resized image
它会将图像缩小或放大到最大宽度或高度
function createThumbnail($image_name,$new_width,$new_height,$uploadDir,$moveToDir)
{
$path = $uploadDir . '/' . $image_name;
$mime = getimagesize($path);
if($mime['mime']=='image/png') {
$src_img = imagecreatefrompng($path);
}
if($mime['mime']=='image/jpg' || $mime['mime']=='image/jpeg' || $mime['mime']=='image/pjpeg') {
$src_img = imagecreatefromjpeg($path);
}
$old_x = imageSX($src_img);
$old_y = imageSY($src_img);
if($old_x > $old_y)
{
$thumb_w = $new_width;
$thumb_h = $old_y*($new_height/$old_x);
}
if($old_x < $old_y)
{
$thumb_w = $old_x*($new_width/$old_y);
$thumb_h = $new_height;
}
if($old_x == $old_y)
{
$thumb_w = $new_width;
$thumb_h = $new_height;
}
$dst_img = ImageCreateTrueColor($thumb_w,$thumb_h);
imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);
// New save location
$new_thumb_loc = $moveToDir . $image_name;
if($mime['mime']=='image/png') {
$result = imagepng($dst_img,$new_thumb_loc,8);
}
if($mime['mime']=='image/jpg' || $mime['mime']=='image/jpeg' || $mime['mime']=='image/pjpeg') {
$result = imagejpeg($dst_img,$new_thumb_loc,80);
}
imagedestroy($dst_img);
imagedestroy($src_img);
return $result;
}
于 2013-05-27T13:47:20.397 回答
6
保持纵横比的公式是错误的。应该是：原始高度/原始宽度x新宽度=新高度
function createThumbnail($imageName,$newWidth,$newHeight,$uploadDir,$moveToDir)
{
$path = $uploadDir . '/' . $imageName;
$mime = getimagesize($path);
if($mime['mime']=='image/png'){ $src_img = imagecreatefrompng($path); }
if($mime['mime']=='image/jpg'){ $src_img = imagecreatefromjpeg($path); }
if($mime['mime']=='image/jpeg'){ $src_img = imagecreatefromjpeg($path); }
if($mime['mime']=='image/pjpeg'){ $src_img = imagecreatefromjpeg($path); }
$old_x = imageSX($src_img);
$old_y = imageSY($src_img);
if($old_x > $old_y)
{
$thumb_w = $newWidth;
$thumb_h = $old_y/$old_x*$newWidth;
}
if($old_x < $old_y)
{
$thumb_w = $old_x/$old_y*$newHeight;
$thumb_h = $newHeight;
}
if($old_x == $old_y)
{
$thumb_w = $newWidth;
$thumb_h = $newHeight;
}
$dst_img = ImageCreateTrueColor($thumb_w,$thumb_h);
imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);
// New save location
$new_thumb_loc = $moveToDir . $imageName;
if($mime['mime']=='image/png'){ $result = imagepng($dst_img,$new_thumb_loc,8); }
if($mime['mime']=='image/jpg'){ $result = imagejpeg($dst_img,$new_thumb_loc,80); }
if($mime['mime']=='image/jpeg'){ $result = imagejpeg($dst_img,$new_thumb_loc,80); }
if($mime['mime']=='image/pjpeg'){ $result = imagejpeg($dst_img,$new_thumb_loc,80); }
imagedestroy($dst_img);
imagedestroy($src_img);
return $result;
}
于 2014-10-27T11:08:24.123 回答
1
我找到了一种数学方法来完成这项工作
Github 回购 - https://github.com/gayanSandamal/easy-php-image-resizer
现场示例 - https://plugins.nayague.com/easy-php-image-resizer/
<?php
//path for the image
$source_url = '2018-04-01-1522613288.PNG';
//separate the file name and the extention
$source_url_parts = pathinfo($source_url);
$filename = $source_url_parts['filename'];
$extension = $source_url_parts['extension'];
//define the quality from 1 to 100
$quality = 10;
//detect the width and the height of original image
list($width, $height) = getimagesize($source_url);
$width;
$height;
//define any width that you want as the output. mine is 200px.
$after_width = 200;
//resize only when the original image is larger than expected with.
//this helps you to avoid from unwanted resizing.
if ($width > $after_width) {
//get the reduced width
$reduced_width = ($width - $after_width);
//now convert the reduced width to a percentage and round it to 2 decimal places
$reduced_radio = round(($reduced_width / $width) * 100, 2);
//ALL GOOD! let's reduce the same percentage from the height and round it to 2 decimal places
$reduced_height = round(($height / 100) * $reduced_radio, 2);
//reduce the calculated height from the original height
$after_height = $height - $reduced_height;
//Now detect the file extension
//if the file extension is 'jpg', 'jpeg', 'JPG' or 'JPEG'
if ($extension == 'jpg' || $extension == 'jpeg' || $extension == 'JPG' || $extension == 'JPEG') {
//then return the image as a jpeg image for the next step
$img = imagecreatefromjpeg($source_url);
} elseif ($extension == 'png' || $extension == 'PNG') {
//then return the image as a png image for the next step
$img = imagecreatefrompng($source_url);
} else {
//show an error message if the file extension is not available
echo 'image extension is not supporting';
}
//HERE YOU GO :)
//Let's do the resize thing
//imagescale([returned image], [width of the resized image], [height of the resized image], [quality of the resized image]);
$imgResized = imagescale($img, $after_width, $after_height, $quality);
//now save the resized image with a suffix called "-resized" and with its extension.
imagejpeg($imgResized, $filename . '-resized.'.$extension);
//Finally frees any memory associated with image
//**NOTE THAT THIS WONT DELETE THE IMAGE
imagedestroy($img);
imagedestroy($imgResized);
}
?>
于 2018-04-06T20:35:44.070 回答
1
我正在考虑如何实现这一点，我提出了一个非常好的解决方案，在任何情况下都可以使用......假设您想要调整用户上传到您网站的重图像的大小，但您需要它来保持比例。所以我想出了这个：
<?php
// File
$filename = 'test.jpg';
// Get sizes
list($width, $height) = getimagesize($filename);
//obtain ratio
$imageratio = $width/$height;
if($imageratio >= 1){
$newwidth = 600;
$newheight = 600 / $imageratio;
}
else{
$newidth = 400;
$newheight = 400 / $imageratio;
};
// Load
$thumb = imagecreatetruecolor($newwidth, $newheight);
$source = imagecreatefromjpeg($filename);
// Resize
imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width,
$height);
// Output
imagejpeg($thumb, "img/test.jpg");
imagedestroy();
?>
在这种情况下，如果宽度大于高度，我希望宽度为 600 像素，如果高度大于宽度，我希望宽度为 400 像素
于 2018-08-11T05:17:04.487 回答
1
<?php
Class ResizedImage
{
public $imgfile;
public $string = '';
public $new_width = 0;
public $new_height = 0;
public $angle = 0;
public $max_font_size = 1000;
public $cropped = false;//whether crop the original image if h or w > new h or w
public $font = 'fonts/arialbd.ttf';
private $img;
private $trans_colour;
private $orange;
private $white;
private $whitetr;
private $blacktr;
public function PrintAsBase64()
{
$this->SetImage();
ob_start();
imagepng($this->img);
$b64img = ob_get_contents();
ob_clean();
imagedestroy($this->img);
$b64img = base64_encode($b64img);
echo($b64img);
}
public function PrintAsImage()
{
$this->SetImage();
header('Content-type: image/png');
imagepng($this->img);
imagedestroy($this->img);
}
private function SetImage()
{
if ($this->imgfile == '') {$this->imgfile='NoImageAvailable.jpg';}
$this->img = imagecreatefromstring(file_get_contents($this->imgfile));
$this->trans_colour = imagecolorallocatealpha($this->img, 0, 0, 0, 127);
$this->orange = imagecolorallocate($this->img, 220, 210, 60);
$this->white = imagecolorallocate($this->img, 255,255, 255);
$this->whitetr = imagecolorallocatealpha($this->img, 255,255, 255, 95);
$this->blacktr = imagecolorallocatealpha($this->img, 0, 0, 0, 95);
if ((!$this->cropped) && ($this->string !=''))
{$this->watermarkimage();}
if (($this->new_height > 0) && ($this->new_width > 0)) {$this->ResizeImage();};
if (($this->cropped) && ($this->string !=''))
{$this->watermarkimage();}
imageAlphaBlending($this->img, true);
imageSaveAlpha($this->img, true);
}
////
private function ResizeImage()
{
# v_fact and h_fact are the factor by which the original vertical / horizontal
# image sizes should be multiplied to get the image to your target size.
$v_fact = $this->new_height / imagesy($this->img);//target_height / im_height;
$h_fact = $this->new_width / imagesx($this->img);//target_width / im_width;
# you want to resize the image by the same factor in both vertical
# and horizontal direction, so you need to pick the correct factor from
# v_fact / h_fact so that the largest (relative to target) of the new height/width
# equals the target height/width and the smallest is lower than the target.
# this is the lowest of the two factors
if($this->cropped)
{ $im_fact = max($v_fact, $h_fact); }
else
{ $im_fact = min($v_fact, $h_fact); }
$new_height = round(imagesy($this->img) * $im_fact);
$new_width = round(imagesx($this->img) * $im_fact);
$img2 = $this->img;
$this->img = imagecreatetruecolor($new_width, $new_height);
imagecopyresampled($this->img, $img2, 0, 0, 0, 0, $new_width, $new_height, imagesx($img2), imagesy($img2));
$img2 = $this->img;
$this->img = imagecreatetruecolor($this->new_width, $this->new_height);
imagefill($this->img, 0, 0, $this->trans_colour);
$dstx = 0;
$dsty = 0;
if ($this->cropped)
{
if (imagesx($this->img) < imagesx($img2))
{ $dstx = round((imagesx($this->img)-imagesx($img2))/2); }
if (imagesy($this->img) < imagesy($img2))
{ $dsty = round((imagesy($this->img)-imagesy($img2))/2); }
}
else
{
if (imagesx($this->img) > imagesx($img2))
{ $dstx = round((imagesx($this->img)-imagesx($img2))/2); }
if (imagesy($this->img) > imagesy($img2))
{ $dsty = round((imagesy($this->img)-imagesy($img2))/2); }
}
imagecopy ( $this->img, $img2, $dstx, $dsty, 0, 0, imagesx($img2) , imagesy($img2));
imagedestroy($img2);
}
////
private function calculateTextBox($text,$fontFile,$fontSize,$fontAngle)
{
/************
simple function that calculates the *exact* bounding box (single pixel precision).
The function returns an associative array with these keys:
left, top: coordinates you will pass to imagettftext
width, height: dimension of the image you have to create
*************/
$rect = imagettfbbox($fontSize,$fontAngle,$fontFile,$text);
$minX = min(array($rect[0],$rect[2],$rect[4],$rect[6]));
$maxX = max(array($rect[0],$rect[2],$rect[4],$rect[6]));
$minY = min(array($rect[1],$rect[3],$rect[5],$rect[7]));
$maxY = max(array($rect[1],$rect[3],$rect[5],$rect[7]));
return array(
"left" => abs($minX) - 1,
"top" => abs($minY) - 1,
"width" => $maxX - $minX,
"height" => $maxY - $minY,
"box" => $rect );
}
private function watermarkimage($font_size=0)
{
if ($this->string == '')
{die('Watermark function call width empty string!');}
$box = $this->calculateTextBox($this->string, $this->font, $font_size, $this->angle);
while ( ($box['width'] < imagesx($this->img)) && ($box['height'] < imagesy($this->img)) && ($font_size <= $this->max_font_size) )
{
$font_size++;
$box = $this->calculateTextBox($this->string, $this->font, $font_size, $this->angle);
}
$font_size--;
$box = $this->calculateTextBox($this->string, $this->font, $font_size, $this->angle);
$vcenter = round((imagesy($this->img) / 2) + ($box['height'] / 2));
$hcenter = round((imagesx($this->img) - $box['width']) / 2 );
imagettftext($this->img, $font_size, $this->angle, $hcenter, $vcenter, $this->blacktr, $this->font, $this->string);
imagettftext($this->img, $font_size, $this->angle, $hcenter+1, $vcenter-2, $this->whitetr, $this->font, $this->string);
}
}
?>
我也一直在使用公认的答案，但在某些情况下它并没有保持这个比例。我在论坛上找到了一些很好的答案，并将它们放在一起，最后创建了一个调整图像大小的类。作为额外功能，您可以放置水印文本。
您可以看到选择裁剪或不裁剪时会发生什么，如果不是，透明区域将添加到新调整大小的图像中。
这个例子比问的多，但我认为这是一个很好的例子。
于 2016-03-26T12:08:00.770 回答
1
这是我使用 X、Y 或两个轴的保存纵横比缩放图像的功能。
它还将图像缩放为其大小的百分比。
与 PHP 5.4 兼容
/** Use X axis to scale image. */
define('IMAGES_SCALE_AXIS_X', 1);
/** Use Y axis to scale image. */
define('IMAGES_SCALE_AXIS_Y', 2);
/** Use both X and Y axes to calc image scale. */
define('IMAGES_SCALE_AXIS_BOTH', IMAGES_SCALE_AXIS_X ^ IMAGES_SCALE_AXIS_Y);
/** Compression rate for JPEG image format. */
define('JPEG_COMPRESSION_QUALITY', 90);
/** Compression rate for PNG image format. */
define('PNG_COMPRESSION_QUALITY', 9);
/**
* Scales an image with save aspect ration for X, Y or both axes.
*
* @param string $sourceFile Absolute path to source image.
* @param string $destinationFile Absolute path to scaled image.
* @param int|null $toWidth Maximum `width` of scaled image.
* @param int|null $toHeight Maximum `height` of scaled image.
* @param int|null $percent Percent of scale of the source image's size.
* @param int $scaleAxis Determines how of axis will be used to scale image.
*
* May take a value of {@link IMAGES_SCALE_AXIS_X}, {@link IMAGES_SCALE_AXIS_Y} or {@link IMAGES_SCALE_AXIS_BOTH}.
* @return bool True on success or False on failure.
*/
function scaleImage($sourceFile, $destinationFile, $toWidth = null, $toHeight = null, $percent = null, $scaleAxis = IMAGES_SCALE_AXIS_BOTH) {
$toWidth = (int)$toWidth;
$toHeight = (int)$toHeight;
$percent = (int)$percent;
$result = false;
if (($toWidth | $toHeight | $percent)
&& file_exists($sourceFile)
&& (file_exists(dirname($destinationFile)) || mkdir(dirname($destinationFile), 0777, true))) {
$mime = getimagesize($sourceFile);
if (in_array($mime['mime'], ['image/jpg', 'image/jpeg', 'image/pjpeg'])) {
$src_img = imagecreatefromjpeg($sourceFile);
} elseif ($mime['mime'] == 'image/png') {
$src_img = imagecreatefrompng($sourceFile);
}
$original_width = imagesx($src_img);
$original_height = imagesy($src_img);
if ($scaleAxis == IMAGES_SCALE_AXIS_BOTH) {
if (!($toWidth | $percent)) {
$scaleAxis = IMAGES_SCALE_AXIS_Y;
} elseif (!($toHeight | $percent)) {
$scaleAxis = IMAGES_SCALE_AXIS_X;
}
}
if ($scaleAxis == IMAGES_SCALE_AXIS_X && $toWidth) {
$scale_ratio = $original_width / $toWidth;
} elseif ($scaleAxis == IMAGES_SCALE_AXIS_Y && $toHeight) {
$scale_ratio = $original_height / $toHeight;
} elseif ($percent) {
$scale_ratio = 100 / $percent;
} else {
$scale_ratio_width = $original_width / $toWidth;
$scale_ratio_height = $original_height / $toHeight;
if ($original_width / $scale_ratio_width < $toWidth && $original_height / $scale_ratio_height < $toHeight) {
$scale_ratio = min($scale_ratio_width, $scale_ratio_height);
} else {
$scale_ratio = max($scale_ratio_width, $scale_ratio_height);
}
}
$scale_width = $original_width / $scale_ratio;
$scale_height = $original_height / $scale_ratio;
$dst_img = imagecreatetruecolor($scale_width, $scale_height);
imagecopyresampled($dst_img, $src_img, 0, 0, 0, 0, $scale_width, $scale_height, $original_width, $original_height);
if (in_array($mime['mime'], ['image/jpg', 'image/jpeg', 'image/pjpeg'])) {
$result = imagejpeg($dst_img, $destinationFile, JPEG_COMPRESSION_QUALITY);
} elseif ($mime['mime'] == 'image/png') {
$result = imagepng($dst_img, $destinationFile, PNG_COMPRESSION_QUALITY);
}
imagedestroy($dst_img);
imagedestroy($src_img);
}
return $result;
}
测试：
$sourceFile = '/source/file.jpg'; // Original size: 672x100
$destinationPath = '/destination/path/';
scaleImage($sourceFile, $destinationPath . 'file_original_size.jpg', 672, 100);
// Result: Image 672x100
scaleImage($sourceFile, $destinationPath . 'file_scaled_75_PERCENT.jpg', null, null, 75);
// Result: Image 504x75
scaleImage($sourceFile, $destinationPath . 'file_scaled_336_X.jpg', 336, null, null, IMAGES_SCALE_AXIS_X);
// Result: Image 336x50
scaleImage($sourceFile, $destinationPath . 'file_scaled_50_Y.jpg', null, 50, null, IMAGES_SCALE_AXIS_Y);
// Result: Image 336x50
scaleImage($sourceFile, $destinationPath . 'file_scaled_500x70_BOTH.jpg', 500, 70, null, IMAGES_SCALE_AXIS_BOTH);
// Result: Image 470x70
scaleImage($sourceFile, $destinationPath . 'file_scaled_450x70_BOTH.jpg', 450, 70, null, IMAGES_SCALE_AXIS_BOTH);
// Result: Image 450x66
scaleImage($sourceFile, $destinationPath . 'file_scaled_500x70_40_PERCENT_BOTH.jpg', 500, 70, 40, IMAGES_SCALE_AXIS_BOTH);
// Result: Image 268x40
于 2019-07-19T09:07:04.117 回答
0
这是一个综合性的应用程序，我努力研究它，包括最常见的操作，如放大和缩小、缩略图、保留纵横比、转换文件类型、更改质量/文件大小等等......
<?php
//##// Resize (and convert) image (Scale up & scale down, thumbnail, preserve aspect ratio) //##//
///////////////////////////////////////////////
///////////////// Begin.Setup /////////////////
// Source File:
$src_file = "/your/server/path/to/file.png";// png or jpg files only
// Resize Dimensions:
// leave blank for no size change (convert only)
// if you specify one dimension, the other dimension will be calculated according to the aspect ratio
// if you specify both dimensions system will take care of it depending on the actual image size
// $newWidth = 2000;
// $newHeight = 1500;
// Destination Path: (optional, if none: download image)
$dst_path = "/your/server/path/new/";
// Destination File Name: (Leave blank for same file name)
// $dst_name = 'image_name_only_no_extension';
// Destination File Type: (Leave blank for same file extension)
// $dst_type = 'png';
$dst_type = 'jpg';
// Reduce to 8bit - 256 colors (Very low quality but very small file & transparent PNG. Only for thumbnails!)
// $palette_8bit = true;
///////////////// End.Setup /////////////////
///////////////////////////////////////////////
if (!$dst_name){$dst_name = strtolower(pathinfo($src_file, PATHINFO_FILENAME));}
if (!$dst_type){$dst_type = strtolower(pathinfo($src_file, PATHINFO_EXTENSION));}
if ($palette_8bit){$dst_type = 'png';}
if ($dst_path){$dst_file = $dst_path . $dst_name . '.' . $dst_type;}
$mime = getimagesize($src_file);// Get image dimensions and type
// Destination File Parameters:
if ($dst_type == 'png'){
$dst_content = 'image/png';
$quality = 9;// All same quality! 0 too big file // 0(no comp.)-9 (php default: 6)
} elseif ($dst_type == 'jpg'){
$dst_content = 'image/jpg';
$quality = 85;// 30 Min. 60 Mid. 85 Cool. 90 Max. (100 Full) // 0-100 (php default: 75)
} else {
exit('Unknown Destination File Type');
}
// Source File Parameters:
if ($mime['mime']=='image/png'){$src_img = imagecreatefrompng($src_file);}
elseif ($mime['mime']=='image/jpg'){$src_img = imagecreatefromjpeg($src_file);}
elseif ($mime['mime']=='image/jpeg'){$src_img = imagecreatefromjpeg($src_file);}
elseif ($mime['mime']=='image/pjpeg'){$src_img = imagecreatefromjpeg($src_file);}
else {exit('Unknown Source File Type');}
// Define Dimensions:
$old_x = imageSX($src_img);
$old_y = imageSY($src_img);
if ($newWidth AND $newHeight){
if($old_x > $old_y){
$new_x = $newWidth;
$new_y = $old_y / $old_x * $newWidth;
} elseif($old_x < $old_y){
$new_y = $newHeight;
$new_x = $old_x / $old_y * $newHeight;
} elseif($old_x == $old_y){
$new_x = $newWidth;
$new_y = $newHeight;
}
} elseif ($newWidth){
$new_x = $newWidth;
$new_y = $old_y / $old_x * $newWidth;
} elseif ($newHeight){
$new_y = $newHeight;
$new_x = $old_x / $old_y * $newHeight;
} else {
$new_x = $old_x;
$new_y = $old_y;
}
$dst_img = ImageCreateTrueColor($new_x, $new_y);
if ($palette_8bit){//////// Reduce to 8bit - 256 colors ////////
$transparent = imagecolorallocatealpha($dst_img, 255, 255, 255, 127);
imagecolortransparent($dst_img, $transparent);
imagefill($dst_img, 0, 0, $transparent);
imagecopyresampled($dst_img,$src_img,0,0,0,0,$new_x,$new_y,$old_x,$old_y);// Great quality resize.
imagetruecolortopalette($dst_img, false, 255);
imagesavealpha($dst_img, true);
} else {
// Check image and set transparent for png or white background for jpg
if ($dst_type == 'png'){
imagealphablending($dst_img, false);
imagesavealpha($dst_img, true);
$transparent = imagecolorallocatealpha($dst_img, 255, 255, 255, 127);
imagefilledrectangle($dst_img, 0, 0, $new_x, $new_y, $transparent);
} elseif ($dst_type == 'jpg'){
$white = imagecolorallocate($dst_img, 255, 255, 255);
imagefilledrectangle($dst_img, 0, 0, $new_x, $new_y, $white);
}
imagecopyresampled($dst_img,$src_img,0,0,0,0,$new_x,$new_y,$old_x,$old_y);// Great quality resize.
}
// Skip the save to parameter using NULL, then set the quality; imagejpeg($dst_img);=> Default quality
if ($dst_file){
if ($dst_type == 'png'){
imagepng($dst_img, $dst_file, $quality);
} elseif ($dst_type == 'jpg'){
imagejpeg($dst_img, $dst_file, $quality);
}
} else {
header('Content-Disposition: Attachment;filename=' . $dst_name . '.' . $dst_type);// comment this line to show image in browser instead of download
header('Content-type: ' . $dst_content);
if ($dst_type == 'png'){
imagepng($dst_img, NULL, $quality);
} elseif ($dst_type == 'jpg'){
imagejpeg($dst_img, NULL, $quality);
}
}
imagedestroy($src_img);
imagedestroy($dst_img);
//##// END : Resize image (Scale Up & Down) (thumbnail, bigger image, preserve aspect ratio) END //##//
于 2016-10-09T16:28:25.743 回答
0
非常适合我
static function getThumpnail($file){
$THUMBNAIL_IMAGE_MAX_WIDTH = 150; # exmpl.
$THUMBNAIL_IMAGE_MAX_HEIGHT = 150;
$src_size = filesize($file);
$filename = basename($file);
list($src_width, $src_height, $src_type) = getimagesize($file);
$src_im = false;
switch ($src_type) {
case IMAGETYPE_GIF : $src_im = imageCreateFromGif($file); break;
case IMAGETYPE_JPEG : $src_im = imageCreateFromJpeg($file); break;
case IMAGETYPE_PNG : $src_im = imageCreateFromPng($file); break;
case IMAGETYPE_WBMP : $src_im = imagecreatefromwbmp($file); break;
}
if ($src_im === false) { return false; }
$src_aspect_ratio = $src_width / $src_height;
$thu_aspect_ratio = $THUMBNAIL_IMAGE_MAX_WIDTH / $THUMBNAIL_IMAGE_MAX_HEIGHT;
if ($src_width <= $THUMBNAIL_IMAGE_MAX_WIDTH && $src_height <= $THUMBNAIL_IMAGE_MAX_HEIGHT) {
$thu_width = $src_width;
$thu_height = $src_height;
} elseif ($thu_aspect_ratio > $src_aspect_ratio) {
$thu_width = (int) ($THUMBNAIL_IMAGE_MAX_HEIGHT * $src_aspect_ratio);
$thu_height = $THUMBNAIL_IMAGE_MAX_HEIGHT;
} else {
$thu_width = $THUMBNAIL_IMAGE_MAX_WIDTH;
$thu_height = (int) ($THUMBNAIL_IMAGE_MAX_WIDTH / $src_aspect_ratio);
}
$thu_im = imagecreatetruecolor($thu_width, $thu_height);
imagecopyresampled($thu_im, $src_im, 0, 0, 0, 0, $thu_width, $thu_height, $src_width, $src_height);
$dst_im = imagecreatetruecolor($THUMBNAIL_IMAGE_MAX_WIDTH,$THUMBNAIL_IMAGE_MAX_WIDTH);
$backcolor = imagecolorallocate($dst_im,192,192,192);
imagefill($dst_im,0,0,$backcolor);
imagecopy($dst_im, $thu_im, (imagesx($dst_im)/2)-(imagesx($thu_im)/2), (imagesy($dst_im)/2)-(imagesy($thu_im)/2), 0, 0, imagesx($thu_im), imagesy($thu_im));
imagedestroy($src_im);
imagedestroy($thu_im);
}
于 2018-11-02T13:27:39.647 回答
0
我知道您正在寻找一个允许按比例调整图像大小的除数。检查这个演示
如何在数学上得到我们的除数
假设我们的原始图像具有宽度 x 和高度 y；x=300 和 y = 700
最大高度和最大宽度为200；
首先，我们将检查图像的哪个维度大于另一个。我们的高度（y）大于宽度（x）
其次，我们检查我们的高度是否大于我们的最大高度。对于我们的例子，我们的高度大于最大高度。在小于最大高度的情况下，我们将新高度设置为原始高度。
最后，我们寻找我们的除数，如下所示
if y is set to maximum height 200 and max-y=200;
y=max-y, that is
if y=max-y
what about
x=?
that is,
if 700 is resized to 200
what about 300?
700=200
300=?
new width = (200 (new height) * 300(width)) / 700 (height)
so our divisor is
divisor= new height (300) / height(700)
new width = divisor * width or width / (1/divisor)
如果宽度大于高度，反之亦然
if ($width > $height) {
if($width < $max_width)
$newwidth = $width;
else
$newwidth = $max_width;
$divisor = $width / $newwidth;
$newheight = floor( $height / $divisor);
}
else {
if($height < $max_height)
$newheight = $height;
else
$newheight = $max_height;
$divisor = $height / $newheight;
$newwidth = floor( $width / $divisor );
}
查看完整示例并使用工作演示进行尝试。
于 2016-12-06T14:33:50.857 回答