PHP - 创建缩略图&保持纵横比 [英] PHP - Create Thumbnail & maintaining aspect ratio

问题描述

我有使用PHP创建了一个缩略图创建者。生成的缩略图应该具有相同的大小。但问题是使用上传具有不同宽高比的图像，如横向或纵向缩略图变得难看。所以我创建了上面的图片以便澄清。无论上传的图像是什么，它都将被放入矩形图像中。因此纵横比不会改变，缩略图的大小也会相同。任何人都可以帮助我或者说一些想法吗？

I have created a thumbnail creator using PHP. The thumbnails generated should be of same size. But the problem is the use uploads images having different aspect ratio like landscape or portrait the thumbnail becomes ugly. So i created the picture above for clarification. Whatever be the uploaded image, it will be put into a rectangle image. So the aspect ratio doesn't change and thumbnails will be of same size. Can anyone pls help me or tell some ideas?

推荐答案

define('THUMBNAIL_IMAGE_MAX_WIDTH', 150);
define('THUMBNAIL_IMAGE_MAX_HEIGHT', 150);

function generate_image_thumbnail($source_image_path, $thumbnail_image_path)
{
    list($source_image_width, $source_image_height, $source_image_type) = getimagesize($source_image_path);
    switch ($source_image_type) {
        case IMAGETYPE_GIF:
            $source_gd_image = imagecreatefromgif($source_image_path);
            break;
        case IMAGETYPE_JPEG:
            $source_gd_image = imagecreatefromjpeg($source_image_path);
            break;
        case IMAGETYPE_PNG:
            $source_gd_image = imagecreatefrompng($source_image_path);
            break;
    }
    if ($source_gd_image === false) {
        return false;
    }
    $source_aspect_ratio = $source_image_width / $source_image_height;
    $thumbnail_aspect_ratio = THUMBNAIL_IMAGE_MAX_WIDTH / THUMBNAIL_IMAGE_MAX_HEIGHT;
    if ($source_image_width <= THUMBNAIL_IMAGE_MAX_WIDTH && $source_image_height <= THUMBNAIL_IMAGE_MAX_HEIGHT) {
        $thumbnail_image_width = $source_image_width;
        $thumbnail_image_height = $source_image_height;
    } elseif ($thumbnail_aspect_ratio > $source_aspect_ratio) {
        $thumbnail_image_width = (int) (THUMBNAIL_IMAGE_MAX_HEIGHT * $source_aspect_ratio);
        $thumbnail_image_height = THUMBNAIL_IMAGE_MAX_HEIGHT;
    } else {
        $thumbnail_image_width = THUMBNAIL_IMAGE_MAX_WIDTH;
        $thumbnail_image_height = (int) (THUMBNAIL_IMAGE_MAX_WIDTH / $source_aspect_ratio);
    }
    $thumbnail_gd_image = imagecreatetruecolor($thumbnail_image_width, $thumbnail_image_height);
    imagecopyresampled($thumbnail_gd_image, $source_gd_image, 0, 0, 0, 0, $thumbnail_image_width, $thumbnail_image_height, $source_image_width, $source_image_height);

    $img_disp = imagecreatetruecolor(THUMBNAIL_IMAGE_MAX_WIDTH,THUMBNAIL_IMAGE_MAX_WIDTH);
    $backcolor = imagecolorallocate($img_disp,0,0,0);
    imagefill($img_disp,0,0,$backcolor);

        imagecopy($img_disp, $thumbnail_gd_image, (imagesx($img_disp)/2)-(imagesx($thumbnail_gd_image)/2), (imagesy($img_disp)/2)-(imagesy($thumbnail_gd_image)/2), 0, 0, imagesx($thumbnail_gd_image), imagesy($thumbnail_gd_image));

    imagejpeg($img_disp, $thumbnail_image_path, 90);
    imagedestroy($source_gd_image);
    imagedestroy($thumbnail_gd_image);
    imagedestroy($img_disp);
    return true;
}

generate_image_thumbnail('original_image.jpg', 'thumb_image.jpg'); //call the function

，您将得到类似于

这篇关于PHP - 创建缩略图&保持纵横比的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！