PHP / GD - 裁剪和调整图像大小 [英] PHP/GD - Cropping and Resizing Images

问题描述

我编写了一个函数，将图像裁剪为给定的宽高比，最后调整大小并将其输出为JPG：

I've coded a function that crops an image to a given aspect ratio and finally then resizes it and outputs it as JPG:

<?php

function Image($image, $crop = null, $size = null)
{
    $image = ImageCreateFromString(file_get_contents($image));

    if (is_resource($image) === true)
    {
        $x = 0;
        $y = 0;
        $width = imagesx($image);
        $height = imagesy($image);

        /*
        CROP (Aspect Ratio) Section
        */

        if (is_null($crop) === true)
        {
            $crop = array($width, $height);
        }

        else
        {
            $crop = array_filter(explode(':', $crop));

            if (empty($crop) === true)
            {
                $crop = array($width, $height);
            }

            else
            {
                if ((empty($crop[0]) === true) || (is_numeric($crop[0]) === false))
                {
                    $crop[0] = $crop[1];
                }

                else if ((empty($crop[1]) === true) || (is_numeric($crop[1]) === false))
                {
                    $crop[1] = $crop[0];
                }
            }

            $ratio = array
            (
                0 => $width / $height,
                1 => $crop[0] / $crop[1],
            );

            if ($ratio[0] > $ratio[1])
            {
                $width = $height * $ratio[1];
                $x = (imagesx($image) - $width) / 2;
            }

            else if ($ratio[0] < $ratio[1])
            {
                $height = $width / $ratio[1];
                $y = (imagesy($image) - $height) / 2;
            }

            /*
            How can I skip (join) this operation
            with the one in the Resize Section?
            */

            $result = ImageCreateTrueColor($width, $height);

            if (is_resource($result) === true)
            {
                ImageSaveAlpha($result, true);
                ImageAlphaBlending($result, false);
                ImageFill($result, 0, 0, ImageColorAllocateAlpha($result, 255, 255, 255, 127));

                ImageCopyResampled($result, $image, 0, 0, $x, $y, $width, $height, $width, $height);

                $image = $result;
            }
        }

        /*
        Resize Section
        */

        if (is_null($size) === true)
        {
            $size = array(imagesx($image), imagesy($image));
        }

        else
        {
            $size = array_filter(explode('x', $size));

            if (empty($size) === true)
            {
                $size = array(imagesx($image), imagesy($image));
            }

            else
            {
                if ((empty($size[0]) === true) || (is_numeric($size[0]) === false))
                {
                    $size[0] = round($size[1] * imagesx($image) / imagesy($image));
                }

                else if ((empty($size[1]) === true) || (is_numeric($size[1]) === false))
                {
                    $size[1] = round($size[0] * imagesy($image) / imagesx($image));
                }
            }
        }

        $result = ImageCreateTrueColor($size[0], $size[1]);

        if (is_resource($result) === true)
        {
            ImageSaveAlpha($result, true);
            ImageAlphaBlending($result, true);
            ImageFill($result, 0, 0, ImageColorAllocate($result, 255, 255, 255));
            ImageCopyResampled($result, $image, 0, 0, 0, 0, $size[0], $size[1], imagesx($image), imagesy($image));

            header('Content-Type: image/jpeg');

            ImageInterlace($result, true);
            ImageJPEG($result, null, 90);
        }
    }

    return false;
}

?>

该功能按预期工作但我正在创建一个非必需的GD图像资源，我该怎么办？修理它？我已尝试加入两个电话，但我必须做一些错误的估算。

The function works as expected but I'm creating a non-required GD image resource, how can I fix it? I've tried joining both calls but I must be doing some miscalculations.

<?php

/*
Usage Examples
*/

Image('http://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png', '1:1', '600x');
Image('http://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png', '2:1', '600x');
Image('http://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png', '2:', '250x300');

?>

非常感谢任何帮助，谢谢。

Any help is greatly appreciated, thanks.

推荐答案

您必须修改调整大小代码，使其不再基于裁剪后的图像。由于你想一次性进行裁剪和调整大小，你需要独立计算它。

You will have to modify your resizing code not to be based on the cropped image to start with. Since you want to do the cropping and resizing in one go you need to calculate it independently.

<?php
function Image($image, $crop = ':', $size = null) {

    $image = ImageCreateFromString(file_get_contents($image));

    if (is_resource($image)) {

        $x = 0;
        $y = 0;
        $width = imagesx($image);
        $height = imagesy($image);

        // CROP (Aspect Ratio) Section
        $crop = array_filter(explode(':', $crop));

        if (empty($crop)) {

            $crop = [$width, $height];

        } else {

            $crop[0] = $crop[0] ?: $crop[1];
            $crop[1] = $crop[1] ?: $crop[0];

        }

        $ratio = [$width / $height, $crop[0] / $crop[1]];

        if ($ratio[0] > $ratio[1]) {

            $width = $height * $ratio[1];
            $x = (imagesx($image) - $width) / 2;

        } else {

            $height = $width / $ratio[1];
            $y = (imagesy($image) - $height) / 2;

        }


        // Resize Section    
        if (is_null($size)) {

            $size = [$width, $height];

        } else {

            $size = array_filter(explode('x', $size));

            if (empty($size)) {

                $size = [imagesx($image), imagesy($image)];

            } else {

                $size[0] = $size[0] ?: round($size[1] * $width / $height);
                $size[1] = $size[1] ?: round($size[0] * $height / $width);

            }
        }

        $result = ImageCreateTrueColor($size[0], $size[1]);

        if (is_resource($result)) {

            ImageSaveAlpha($result, true);
            ImageAlphaBlending($result, true);
            ImageFill($result, 0, 0, ImageColorAllocate($result, 255, 255, 255));
            ImageCopyResampled($result, $image, 0, 0, $x, $y, $size[0], $size[1], $width, $height);

            ImageInterlace($result, true);
            ImageJPEG($result, null, 90);

        }
    }

    return false;
}

header('Content-Type: image/jpeg');
Image('http://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png', '1:1', '600x');

?>

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