php - 计算宽度和高度以调整图像大小

Question

我想计算调整大小的图像宽度和大小。我觉得可以分为三种情况:

<强>1。图片宽度超过最大宽度限制:然后将图片宽度调整到最大宽度，并根据最大宽度限制计算高度。例如图片宽度为2248，高度为532，宽度超出高度小于。因此，将宽度减少到最大值 1024，并计算高度，大约为 242。

<强>2。图片高度超过最大高度限制:同样，将高度调整为最大高度并相应地计算宽度。

<强>3。高度和宽度均超过最大高度和最大宽度:进一步处理，找出图像是垂直的还是水平的。如果图像是水平的，将宽度调整为最大宽度并据此计算高度。否则，如果图像是垂直的或正方形的，将高度调整为最大并据此计算宽度。

对于这些情况，你能看看我下面的代码，给出你的专家意见，如果它有什么好处？或者可以改进吗？怎么办？

附言。我问了类似question昨天。在我之前的问题中，我不确定逻辑应该是什么，现在我知道它应该是什么(如上所述)，并且想知道它是否有用。感谢您的帮助。

<?
$max_width = 1024;
$max_height = 768;

$img = "t2.jpg";


list($original_width, $original_height) = getimagesize($img);

if (($original_width > $max_width) OR ($original_height > $max_height))
{
//original width exceeds, so reduce the original width to maximum limit.
//calculate the height according to the maximum width.
    if(($original_width > $max_width) AND ($original_height <= $max_height))
    {   
        $percent = $max_width/$original_width;  
        $new_width = $max_width;
        $new_height = round ($original_height * $percent);
    }

    //image height exceeds, recudece the height to maxmimum limit.
    //calculate the width according to the maximum height limit.
    if(($original_width <= $max_width) AND ($original_height > $max_height))
    {
        $percent = $max_height/$original_height;
        $new_height = $max_height;
        $new_width = round ($original_width * $percent);
    }

    //both height and width exceeds.
    //but image can be vertical or horizontal.
    if(($original_width > $max_width) AND ($original_height > $max_height))
    {
        //if image has more width than height
        //resize width to maximum width.
        if ($original_width > $original_height)
        {
            $percent = $max_width/$original_width;
            $new_width = $max_width;
            $new_height = round ($original_height * $percent );
        }

        //image is vertical or square. More height than width.
        //resize height to maximum height.  
        else
        {
        $new_height = $max_height;
        $percent = $max_height/$original_height;
        $new_height = $max_height;
        $new_width = round ($original_width * $percent);
        }
    }
} 
?>

Answer 1

// Usage example to find the proper dimensions to resize an image down to 300x400 pixels maximum: 
list($width, $height) = getimagesize($image); 
$new_dimensions = resize_dimensions(100,100,$width,$height);  


// Calculates restricted dimensions with a maximum of $goal_width by $goal_height 
function resize_dimensions($goal_width,$goal_height,$width,$height) { 
    $return = array('width' => $width, 'height' => $height); 

    // If the ratio > goal ratio and the width > goal width resize down to goal width 
    if ($width/$height > $goal_width/$goal_height && $width > $goal_width) { 
        $return['width'] = $goal_width; 
        $return['height'] = $goal_width/$width * $height; 
    } 
    // Otherwise, if the height > goal, resize down to goal height 
    else if ($height > $goal_height) { 
        $return['width'] = $goal_height/$height * $width; 
        $return['height'] = $goal_height; 
    } 

    return $return; 
}