裁剪前PHP图像调整大小

Question

我希望将图像大小调整为 400 x 300 像素。如果图像的宽度大于 400 像素，我希望先调整其大小，然后再裁剪高度。

图像来自远程网站，因此可以是纵向的，也可以是横向的，但我想要实现的是尽可能减少裁剪量，并尽可能在裁剪前先调整大小。

我正在使用以下代码（老实说，我自己很困惑）。比率和数字不太好。代码来自几个 SO 答案代码。

function makeThumb($imgsrc, $imgtarg, $imgtarg_d) {



    $ext = exif_imagetype($imgsrc);

    if ($ext == false) {
        return;
    }

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

//saving the image into memory (for manipulation with GD Library)

    switch($ext) {
        case 1:
            $myImage = imagecreatefromgif($imgsrc);
            break;
        case 2:
            $myImage = imagecreatefromjpeg($imgsrc);
            break;
        case 3:
            $myImage = imagecreatefrompng($imgsrc);
            break;
    }


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

        if ($width >= 400) {

            $thumbSizeWidth = 400;
            $thumbSizeHeight = 300;

        } else {

            $thumbSizeWidth = $width;
            $thumbSizeHeight = 300;
        }
    } else {
        $x = 0;
        $y = ($height - $width) / 2;
        $smallestSide = $width;

        if ($height >= 300) {
            $thumbSizeHeight = 300;
            $thumbSizeWidth = 400;
        } else {
            $thumbSizeHeight = $height;
            $thumbSizeWidth = 400;
        }


    }

    $thumb = imagecreatetruecolor($thumbSizeWidth, $thumbSizeHeight);

    /*RESIZE FIRST*/
    imagecopyresampled($thumb, $myImage, 0, 0, 0, $y, $thumbSizeWidth, $thumbSizeHeight, $width, $height);

    /*CROP*/
    imagecopyresampled($thumb, $myImage, 0, 0, $x, $y, $thumbSizeWidth, $thumbSizeHeight, $smallestSide, $smallestSide);

//final output

    imagejpeg($thumb, $imgtarg_d . '/' . $imgtarg,80);
    imagedestroy($thumb);

}

图像总是从中心裁剪（如预期的那样），但如果图像宽度超过 400 像素，它不会先调整大小。

imagecopyresampled($thumb, $myImage, 0, 0, 0, $y, $thumbSizeWidth, $thumbSizeHeight, $width, $height);
imagecopyresampled($thumb, $myImage, 0, 0, $x, $y, $thumbSizeWidth, $thumbSizeHeight, $smallestSide, $smallestSide);

Answer 1

试试这个

//resize and crop image by center
function resize_crop_image($max_width, $max_height, $source_file, $dst_dir, $quality = 80){
    $imgsize = getimagesize($source_file);
    $width = $imgsize[0];
    $height = $imgsize[1];
    $mime = $imgsize['mime'];

    switch($mime){
        case 'image/gif':
            $image_create = "imagecreatefromgif";
            $image = "imagegif";
            break;

        case 'image/png':
            $image_create = "imagecreatefrompng";
            $image = "imagepng";
            $quality = 7;
            break;

        case 'image/jpeg':
            $image_create = "imagecreatefromjpeg";
            $image = "imagejpeg";
            $quality = 80;
            break;

        default:
            return false;
            break;
    }

    $dst_img = imagecreatetruecolor($max_width, $max_height);
    $src_img = $image_create($source_file);

    $width_new = $height * $max_width / $max_height;
    $height_new = $width * $max_height / $max_width;
    //if the new width is greater than the actual width of the image, then the height is too large and the rest cut off, or vice versa
    if($width_new > $width){
        //cut point by height
        $h_point = (($height - $height_new) / 2);
        //copy image
        imagecopyresampled($dst_img, $src_img, 0, 0, 0, $h_point, $max_width, $max_height, $width, $height_new);
    }else{
        //cut point by width
        $w_point = (($width - $width_new) / 2);
        imagecopyresampled($dst_img, $src_img, 0, 0, $w_point, 0, $max_width, $max_height, $width_new, $height);
    }

    $image($dst_img, $dst_dir, $quality);

    if($dst_img)imagedestroy($dst_img);
    if($src_img)imagedestroy($src_img);
}
//usage example
resize_crop_image(100, 100, "test.jpg", "test.jpg");

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