PHP缩略图图像按比例调整大小

Question

简而言之,我目前正在建立一个约会类型的网站.用户可以创建帐户并上传个人资料照片(最多8个).为了在网站的浏览区域中显示这些内容,我正在寻找一种PHP(使用第三方处理器/脚本)的方式来调整上传的所有图像的大小,使其具有符合某些尺寸的缩略图.

作为一个例子,我希望"配置文件"图像(缩略图)不大于120*150px.脚本需要调整上传图像的大小(无论是纵向还是横向,无论比例如何)都要遵守这些尺寸而不会被拉伸.

宽度(例如120像素)应始终保持不变,但高度(例如150px)可以变化以保持图像成比例.如果它是风景照片,我假设脚本需要从图像中间取出一块？

所有要调整大小的图像的原因是,当在网格中显示所有缩略图大小大致相同的配置文件时.

任何投入将不胜感激.

Answer 1

$maxwidth = 120;
$maxheight = 150;

$img = imagecreatefromjpeg($jpgimage); 
//or imagecreatefrompng,imagecreatefromgif,etc. depending on user's uploaded file extension

$width = imagesx($img); //get width and height of original image
$height = imagesy($img);

//determine which side is the longest to use in calculating length of the shorter side, since the longest will be the max size for whichever side is longest.    
if ($height > $width) 
{   
$ratio = $maxheight / $height;  
$newheight = $maxheight;
$newwidth = $width * $ratio; 
}
else 
{
$ratio = $maxwidth / $width;   
$newwidth = $maxwidth;  
$newheight = $height * $ratio;   
}

//create new image resource to hold the resized image
$newimg = imagecreatetruecolor($newwidth,$newheight); 

$palsize = ImageColorsTotal($img);  //Get palette size for original image
for ($i = 0; $i < $palsize; $i++) //Assign color palette to new image
{ 
$colors = ImageColorsForIndex($img, $i);   
ImageColorAllocate($newimg, $colors['red'], $colors['green'], $colors['blue']);
} 

//copy original image into new image at new size.
imagecopyresized($newimg, $img, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);

imagejpeg($newimg,$outputfile); //$output file is the path/filename where you wish to save the file.  
//Have to figure that one out yourself using whatever rules you want.  Can use imagegif() or imagepng() or whatever.

这将根据较长的一侧(宽度或高度)按比例缩小任何图像,以达到最大尺寸.它还会炸掉任何小于最大值的图像,您可以通过检查宽度和高度是否小于最大值来停止.因此,200x300图像将缩小至100x150,300x200图像将缩小至120x80.

嗯,你想要宽度总是120,所以它会改变一点,是的,它必须在像200x300的图像的情况下削减一些东西,因为它会缩小到120x180没有任何失真,或者它会必须将它缩小得更远,并将信箱装箱,但这应该让你开始很好.

Letterboxing这个例子只需要弄清楚在imagecopyresized()函数中开始绘制到新图像的正确x和y是什么.在像100x150这样的情况下,我认为X会是10,所以最终每侧有10px的空白区域为120x150.Letterboxing 120x80 X将为0但Y将为35,因此对于120x150,上下将有35px的空白区域.

你还想用$ maxwidth,$ maxheight而不是$ newwidth,$ newheight制作$ newimg,但是imagecopyresized()仍然会使用两个$ new值.

由于我很无聊而且没有别的事可做,这些改变会做到:

if ($height > $width) 
{   
$ratio = $maxheight / $height;  
$newheight = $maxheight;
$newwidth = $width * $ratio; 
$writex = round(($maxwidth - $newwidth) / 2);
$writey = 0;
{
else 
{
$ratio = $maxwidth / $width;   
$newwidth = $maxwidth;  
$newheight = $height * $ratio;   
$writex = 0;
$writey = round(($maxheight - $newheight) / 2);
}

$newimg = imagecreatetruecolor($maxwidth,$maxheight);

//Since you probably will want to set a color for the letter box do this
//Assign a color for the letterbox to the new image, 
//since this is the first call, for imagecolorallocate, it will set the background color
//in this case, black rgb(0,0,0)
imagecolorallocate($newimg,0,0,0);

//Loop Palette assignment stuff here

imagecopyresized($newimg, $img, $writex, $writey, 0, 0, $newwidth, $newheight, $width, $height);

这应该工作,尚未尝试过.