GD and Image 函数
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imagesx

(PHP 4, PHP 5)

imagesx — 取得图像宽度

说明

int imagesx ( resource $image )

imagesx() 返回 image 所代表的图像的宽度。

Example #1 使用 imagesx()

<?php

// create a 300*200 image
$img = imagecreatetruecolor(300, 200);

echo imagesx($img); // 300

?>

参见 imagecreatetruecolor()，getimagesize() 和 imagesy()。

GD and Image 函数
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PHP手册
PHP手册 - N: 取得图像宽度

用户评论:

kris (23-Sep-2004 01:49)

You can in fact convert pixels to CM or to whatever measurement you want if you know the DPI and current resolution of the image.  This will of course give you the real life print size of the image and not the actual on screen size of the image. 

This function seems to have been created for such a purpose.  It is for this reason the creator of the function passes the DPI and resolution to his function.

anC (27-Aug-2004 07:38)

You can't convert pixels into centimeters or something else, atleast without knowing the resolution and the size of your screen and the viewrange of it. For example: The pixels on monitor that's resolution is 1024*768 and size is 17' the size of a pixel is smaller than on the monitor that's resolution is 1024*768 too but size is 21'.

leonardo AT saochico DOT com (21-Nov-2003 03:24)

This function convert image size of Pixel to Centimeter

<?
#$imagem - source of image
#$dpi - resolution to convert E.g.: 72dpi or 300dpi

function px2cm($image, $dpi) {
    #Create a new image from file or URL
    $img = ImageCreateFromJpeg($image);

    #Get image width / height
    $x = ImageSX($img);
    $y = ImageSY($img);
   
    #Convert to centimeter
    $h = $x * 2.54 / $dpi;
    $l = $y * 2.54 / $dpi;
   
    #Format a number with grouped thousands
    $h = number_format($h, 2, ',', ' ');
    $l = number_format($l, 2, ',', ' ');
   
    #add size unit
    $px2cm[] = $h."cm";
    $px2cm[] = $l."cm";
   
    #return array w values
    #$px2cm[0] = X
    #$px2cm[1] = Y   
    return $px2cm;
}

$image = "C:\\inetpub\\wwwroot\\lab\\trata_img\\l0gik.jpg";
$dpi = 300;

$result = px2cm($image, $dpi);

print ($result[0]." x ".$result[1]);
?>