PHP GD库调整大小照片 [英] PHP GD library resize photo

问题描述

我正在尝试使用PHP的GD库创建照片的缩略图.

I am attempting to create thumbnails of photos using PHP's GD library.

这是我正在采取的步骤.

Here are the steps I am taking.

1. 创建GD映像资源.
2. 获取图像的高度和宽度
3. 创建一个100像素高，适当宽度的空白gd图像资源
4. 将资源图像复制到空白的gd图像资源并保存两个图像

这是我的代码:

private function getExtension($filename) {
    $position=strrpos($filename, '.');
    $extension = strtolower(substr($filename, $position+1));
    if ($extension == "jpg") {
        $extension = "jpeg";
    }

    return $extension;
}

public function saveImage($parameters) {
    $extension=$this->getExtension($parameters['filename']);
    $createImageFunc="imagecreatefrom".$extension;
    $imgResource=$createImageFunc(SITE_PATH."tmp/{$parameters['filename']}");
    $width=imagesx($imgResource);
    $height=imagesy($imgResource);
    $ratio=$height/$width;
    $thumbnail=imagecreatetruecolor(100, 100*$ratio);

    imagecopyresized($thumbnail, $imgResource, 0, 0, 0, 0, 100*$ratio, 100, $width, $height);

    $imgResult=imagejpeg($imgResource, SITE_PATH."images/{$parameters['galleryName']}/{$parameters['filename']}");
    $thumbResult=imagejpeg($thumbnail, SITE_PATH."images/{$parameters['galleryName']}/thumbnails/{$parameters['filename']}");

}

正在保存图像，但是无法使用副本，缩略图中没有空白.

The images are saving, but the copy is not working, there is empty black space in the thumbnail picture.

这是原始图像:

这是用gd再次保存的图像:

This is the image saved again with gd:

这是缩略图:

我喜欢四倍检查imagecopyresize，据我了解，代码中的所有值都应该正确.

I've like quadruple checked imagecopyresize and from what I understand of it all the values in the code should be correct.

这是php.net提供的值:

Here is what php.net has for the values:

bool imagecopyresized ( resource $dst_image , resource $src_image , int $dst_x , int $dst_y , int $src_x , int $src_y , int $dst_w , int $dst_h , int $src_w , int $src_h )

有人有什么主意吗?

推荐答案

使用PHP/GD可能很乏味，因此我编写了一个库来简化操作:

Working with PHP/GD can be tedious, so I wrote a library to make things much easier: SimpleImage

使用SimpleImage，您可以在两行中创建一个缩略图:

With SimpleImage, you can create a thumbnail in two simple lines:

// Load image from image.jpg
$image = new \claviska\SimpleImage('image.jpg');

// Create a 100x100 thumbnail, convert to PNG, and save to thumb.png
$image->thumbnail(100, 100)->toFile('thumb.png', 'image/png');

如果您仍然想手动执行此操作，请检查您的imagecopyresized参数.为什么将宽度乘以$ratio?

If you're still bent on doing it manually, check your imagecopyresized parameters. Why is the width being multiplied by $ratio?

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