在PHP中裁剪图像

时间:2010-01-05 20:36:41

标签: php gd image crop

我想在PHP中裁剪图像并保存文件。我知道你应该使用GD库,但我不知道如何。有什么想法吗?

由于

6 个答案:

答案 0 :(得分:24)

您可以使用imagecopy裁剪图像的必需部分。命令如下:

imagecopy  ( 
    resource $dst_im - the image object ,
    resource $src_im - destination image ,
    int $dst_x - x coordinate in the destination image (use 0) , 
    int $dst_y - y coordinate in the destination image (use 0) , 
    int $src_x - x coordinate in the source image you want to crop , 
    int $src_y - y coordinate in the source image you want to crop , 
    int $src_w - crop width ,
    int $src_h - crop height 
)

来自PHP.net的代码 - 从源图像中裁剪出80x40像素的图像

<?php
// Create image instances
$src = imagecreatefromgif('php.gif');
$dest = imagecreatetruecolor(80, 40);

// Copy
imagecopy($dest, $src, 0, 0, 20, 13, 80, 40);

// Output and free from memory
header('Content-Type: image/gif');
imagegif($dest);

imagedestroy($dest);
imagedestroy($src);
?>

答案 1 :(得分:3)

此功能将裁剪图像保持图像宽高比:)

 function resize_image_crop($image, $width, $height)
     {

        $w = @imagesx($image); //current width

        $h = @imagesy($image); //current height
        if ((!$w) || (!$h)) { $GLOBALS['errors'][] = 'Image couldn\'t be resized because it wasn\'t a valid image.'; return false; }
        if (($w == $width) && ($h == $height)) { return $image; }  //no resizing needed
        $ratio = $width / $w;       //try max width first...
        $new_w = $width;
        $new_h = $h * $ratio;    
        if ($new_h < $height) {  //if that created an image smaller than what we wanted, try the other way
            $ratio = $height / $h;
            $new_h = $height;
            $new_w = $w * $ratio;
        }
        $image2 = imagecreatetruecolor ($new_w, $new_h);
        imagecopyresampled($image2,$image, 0, 0, 0, 0, $new_w, $new_h, $w, $h);    
        if (($new_h != $height) || ($new_w != $width)) {    //check to see if cropping needs to happen
            $image3 = imagecreatetruecolor ($width, $height);
            if ($new_h > $height) { //crop vertically
                $extra = $new_h - $height;
                $x = 0; //source x
                $y = round($extra / 2); //source y
                imagecopyresampled($image3,$image2, 0, 0, $x, $y, $width, $height, $width, $height);
            } else {
                $extra = $new_w - $width;
                $x = round($extra / 2); //source x
                $y = 0; //source y
                imagecopyresampled($image3,$image2, 0, 0, $x, $y, $width, $height, $width, $height);
            }
            imagedestroy($image2);
            return $image3;
        } else {
            return $image2;
        }
    }

答案 2 :(得分:1)

要使用GD裁剪图像,您需要使用GD方法的组合,如果您在PHP的imagecopyresampled方法文档中查看“示例#1”,它将向您展示如何裁剪和输出你只需要添加一些代码来捕获并将输出写入文件......

http://us2.php.net/manual/en/function.imagecopyresampled.php

还有其他选项,包括Image Magick,如果安装在您的服务器上,可以使用PHP的exec方法(或类似方法)直接访问,或者您可以安装PHP Imagick扩展,可以产生更高质量的图像,在我看来,它更直观,更灵活。

最后,我使用了开源PHPThumb类库,它具有非常简单的界面,可以根据服务器上的内容使用多个选项,包括ImageMagick和GD。

答案 3 :(得分:0)

我在某些项目中使用此脚本,它非常易于使用: http://shiftingpixel.com/2008/03/03/smart-image-resizer/

该脚本需要PHP 5.1.0(自2005-11-24以来已经出来 - 如果还没有在此版本升级的时间)和GD(良好的Web主机很少丢失)。

以下是在HTML中使用它的示例:

<img src="/image.php/coffee-bean.jpg?width=200&amp;height=200&amp;image=/wp-content/uploads/2008/03/coffee-bean.jpg" alt="Coffee Bean" />

答案 4 :(得分:0)

我刚刚创建了这个功能,它可以满足我的需求,创建一个居中和裁剪的缩略图。它是简化的,不需要多次图像复制调用,如webGautam的回答所示。

提供图像路径,最终宽度和高度,以及可选的图像质量。我这样做是为了创建缩略图,因此所有图像都保存为JPG,如果需要,可以编辑它以适应其他图像类型。这里的要点是使用imagecopyresampled生成缩略图的数学和方法。使用相同的名称和图像大小保存图像。

function resize_crop_image($image_path, $end_width, $end_height, $quality = '') {
 if ($end_width < 1) $end_width = 100;
 if ($end_height < 1) $end_height = 100;
 if ($quality < 1 || $quality > 100) $quality = 60;

 $image = false;
 $dot = strrpos($image_path,'.');
 $file = substr($image_path,0,$dot).'-'.$end_width.'x'.$end_height.'.jpg';
 $ext = substr($image_path,$dot+1);

 if ($ext == 'jpg' || $ext == 'jpeg') $image = @imagecreatefromjpeg($image_path);
 elseif($ext == 'gif') $image = @imagecreatefromgif($image_path);
 elseif($ext == 'png') $image = @imagecreatefrompng($image_path);

 if ($image) {
  $width = imagesx($image);
  $height = imagesy($image);
  $scale = max($end_width/$width, $end_height/$height);
  $new_width = floor($scale*$width);
  $new_height = floor($scale*$height);
  $x = ($new_width != $end_width ? ($width - $end_width) / 2 : 0);
  $y = ($new_height != $end_height ? ($height - $end_height) / 2 : 0);
  $new_image = @imagecreatetruecolor($new_width, $new_height);

  imagecopyresampled($new_image,$image,0,0,$x,$y,$new_width,$new_height,$width - $x,$height - $y);
  imagedestroy($image);
  imagejpeg($new_image,$file,$quality);
  imagedestroy($new_image);

  return $file;
 }
 return false;
}

答案 5 :(得分:-1)

您可以使用以下方法裁剪图片,

/*parameters are 
    $image =source image name
    $width = target width
    $height = height of image
    $scale = scale of image*/
    function resizeImage($image,$width,$height,$scale) {
        //generate new image height and width of source image
        $newImageWidth = ceil($width * $scale);
        $newImageHeight = ceil($height * $scale);
        //Create a new true color image
        $newImage = imagecreatetruecolor($newImageWidth,$newImageHeight);
        //Create a new image from file 
        $source = imagecreatefromjpeg($image);
        //Copy and resize part of an image with resampling
        imagecopyresampled($newImage,$source,0,0,0,0,$newImageWidth,$newImageHeight,$width,$height);
        //Output image to file
        imagejpeg($newImage,$image,90);
        //set rights on image file
        chmod($image, 0777);
        //return crop image
        return $image;
    }