PHP裁剪图像，以固定宽度和高度，而不会损失尺寸比例

Question

即时通讯正在寻找创建尺寸为100px乘100px的缩略图。我已经看过很多文章解释方法，但如果要保持尺寸比例，最终会得到宽度！=高度。

例如，我有一个450 x 350像素的图像。我想裁剪为100px×100px。如果我保持这个比例，我最终会有100px乘77px。当我将这些图像列在行和列中时，这使得它变得丑陋。然而，没有尺寸比的图像看起来也很糟糕。

我已经看到flickr的图像，它们看起来很棒。例如：
缩略图：http://farm1.static.flickr.com/23/32608803_29470dfeeb_s.jpg
介质尺寸：http://farm1.static.flickr.com/23/32608803_29470dfeeb.jpg
大尺寸：http://farm1.static.flickr.com/23/32608803_29470dfeeb_b.jpg

TKS

Answer 1

这是通过仅使用图像作为具有1缩略图的一部分进行：1的纵横比率（主要是图像的中心）。如果仔细观察，您可以在flickr缩略图中看到它。

因为您的问题中有“crop”，我不确定您是否已经知道这一点，但是您想知道什么？

要使用裁剪，这里有一个例子：

//Your Image 
$imgSrc = "image.jpg"; 

//getting the image dimensions 
list($width, $height) = getimagesize($imgSrc); 

//saving the image into memory (for manipulation with GD Library) 
$myImage = imagecreatefromjpeg($imgSrc); 

// calculating the part of the image to use for thumbnail 
if ($width > $height) { 
    $y = 0; 
    $x = ($width - $height)/2; 
    $smallestSide = $height; 
} else { 
    $x = 0; 
    $y = ($height - $width)/2; 
    $smallestSide = $width; 
} 

// copying the part into thumbnail 
$thumbSize = 100; 
$thumb = imagecreatetruecolor($thumbSize, $thumbSize); 
imagecopyresampled($thumb, $myImage, 0, 0, $x, $y, $thumbSize, $thumbSize, $smallestSide, $smallestSide); 

//final output 
header('Content-type: image/jpeg'); 
imagejpeg($thumb); 

Answer 2

我喜欢用GDLib与图像不甘示弱，它飞驰容易也上班。那里有很多博客文章和教程。我建议使用类或类似的类，因为照顾图像中的所有变化可能非常耗时。基于较小的宽度或高度

public function croppThis($target_url) { 

    $this->jpegImgCrop($target_url); 

} 

$ target_url具有正方形

Answer 3

裁剪图像 - 图像是名称。

public function jpegImgCrop($target_url) {//support 



    $image = imagecreatefromjpeg($target_url); 
    $filename = $target_url; 
    $width = imagesx($image); 
    $height = imagesy($image); 
    $image_type = imagetypes($image); //IMG_GIF | IMG_JPG | IMG_PNG | IMG_WBMP | IMG_XPM 

    if($width==$height) { 

    $thumb_width = $width; 
    $thumb_height = $height; 

    } elseif($width<$height) { 

    $thumb_width = $width; 
    $thumb_height = $width; 

    } elseif($width>$height) { 

    $thumb_width = $height; 
    $thumb_height = $height; 

    } else { 
    $thumb_width = 150; 
    $thumb_height = 150; 
    } 

    $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); 

} 

Answer 4

您可以使用此代码。 您需要传递px中的源图像路径和缩略图大小以及可选的目标路径。如果你通过它将保存图像，否则拇指将被显示。

只允许使用jpg，jpeg和png。

function cropImage($sourcePath, $thumbSize, $destination = null) { 

    $parts = explode('.', $sourcePath); 
    $ext = $parts[count($parts) - 1]; 
    if ($ext == 'jpg' || $ext == 'jpeg') { 
    $format = 'jpg'; 
    } else { 
    $format = 'png'; 
    } 

    if ($format == 'jpg') { 
    $sourceImage = imagecreatefromjpeg($sourcePath); 
    } 
    if ($format == 'png') { 
    $sourceImage = imagecreatefrompng($sourcePath); 
    } 

    list($srcWidth, $srcHeight) = getimagesize($sourcePath); 

    // calculating the part of the image to use for thumbnail 
    if ($srcWidth > $srcHeight) { 
    $y = 0; 
    $x = ($srcWidth - $srcHeight)/2; 
    $smallestSide = $srcHeight; 
    } else { 
    $x = 0; 
    $y = ($srcHeight - $srcWidth)/2; 
    $smallestSide = $srcWidth; 
    } 

    $destinationImage = imagecreatetruecolor($thumbSize, $thumbSize); 
    imagecopyresampled($destinationImage, $sourceImage, 0, 0, $x, $y, $thumbSize, $thumbSize, $smallestSide, $smallestSide); 

    if ($destination == null) { 
    header('Content-Type: image/jpeg'); 
    if ($format == 'jpg') { 
     imagejpeg($destinationImage, null, 100); 
    } 
    if ($format == 'png') { 
     imagejpeg($destinationImage); 
    } 
    if ($destination = null) { 
    } 
    } else { 
    if ($format == 'jpg') { 
     imagejpeg($destinationImage, $destination, 100); 
    } 
    if ($format == 'png') { 
     imagepng($destinationImage, $destination); 
    } 
    } 
}