在php中调整图像大小仅供查看

Question

好吧,我发布这个的原因是因为我不确定要搜索什么.我会尽可能清楚地解释它.

说,我的图像大小为800x600.我为图像分配的盒子是150x150,必须始终满意.我只能允许图像的高度和宽度最大显示为150px.因此,从技术上讲,图像必须缩小到200x150.

现在,问题是:

有没有办法可以裁剪高度,所以它只显示150x150？这仅用于查看目的.我不需要将图像保存为新文件.

一个很好的例子是Twitter中的个人资料页面.它会显示您的个人资料图片被裁剪,但是当您点击它时,您仍会获得最初上传的图像.

[编辑] 这是我想要实现的目标.在像素方面获得较小的一面,将其调整为150px然后隐藏另一侧的溢出部分.再一次,没有涉及到储蓄.只是为了人们的观赏乐趣.

Answer 1

我使用一个简单的PHP类,它有几个调整大小的选项.您可以通过此类轻松存储缩略图.正如@jeroen所说,你只需要做一次就可以缓存它们.它只需要PHP5和GD库.这是用法示例:

// *** Include the class
include("resize-class.php");

// *** 1) Initialise / load image
$resizeObj = new resize('sample.jpg');

// *** 2) Resize image (options: exact, portrait, landscape, auto, crop)
$resizeObj -> resizeImage(150, 150, 'crop');

// *** 3) Save image ('image-name', 'quality [int]')
$resizeObj -> saveImage('sample-resized.jpg', 100);

这就是那个课程:

<?php
        Class resize
        {
            // *** Class variables
            private $image;
            private $width;
            private $height;
            private $imageResized;

            function __construct($fileName)
            {
                // *** Open up the file
                $this->image = $this->openImage($fileName);

                // *** Get width and height
                $this->width  = imagesx($this->image);
                $this->height = imagesy($this->image);
            }

            ## --------------------------------------------------------

            private function openImage($file)
            {
                // *** Get extension
                $extension = strtolower(strrchr($file, '.'));

                switch($extension)
                {
                    case '.jpg':
                    case '.jpeg':
                        $img = @imagecreatefromjpeg($file);
                        break;
                    case '.gif':
                        $img = @imagecreatefromgif($file);
                        break;
                    case '.png':
                        $img = @imagecreatefrompng($file);
                        break;
                    default:
                        $img = false;
                        break;
                }
                return $img;
            }

            ## --------------------------------------------------------

            public function resizeImage($newWidth, $newHeight, $option="auto")
            {
                // *** Get optimal width and height - based on $option
                $optionArray = $this->getDimensions($newWidth, $newHeight, $option);

                $optimalWidth  = $optionArray['optimalWidth'];
                $optimalHeight = $optionArray['optimalHeight'];


                // *** Resample - create image canvas of x, y size
                $this->imageResized = imagecreatetruecolor($optimalWidth, $optimalHeight);
                imagecopyresampled($this->imageResized, $this->image, 0, 0, 0, 0, $optimalWidth, $optimalHeight, $this->width, $this->height);


                // *** if option is 'crop', then crop too
                if ($option == 'crop') {
                    $this->crop($optimalWidth, $optimalHeight, $newWidth, $newHeight);
                }
            }

            ## --------------------------------------------------------

            private function getDimensions($newWidth, $newHeight, $option)
            {

               switch ($option)
                {
                    case 'exact':
                        $optimalWidth = $newWidth;
                        $optimalHeight= $newHeight;
                        break;
                    case 'portrait':
                        $optimalWidth = $this->getSizeByFixedHeight($newHeight);
                        $optimalHeight= $newHeight;
                        break;
                    case 'landscape':
                        $optimalWidth = $newWidth;
                        $optimalHeight= $this->getSizeByFixedWidth($newWidth);
                        break;
                    case 'auto':
                        $optionArray = $this->getSizeByAuto($newWidth, $newHeight);
                        $optimalWidth = $optionArray['optimalWidth'];
                        $optimalHeight = $optionArray['optimalHeight'];
                        break;
                    case 'crop':
                        $optionArray = $this->getOptimalCrop($newWidth, $newHeight);
                        $optimalWidth = $optionArray['optimalWidth'];
                        $optimalHeight = $optionArray['optimalHeight'];
                        break;
                }
                return array('optimalWidth' => $optimalWidth, 'optimalHeight' => $optimalHeight);
            }

            ## --------------------------------------------------------

            private function getSizeByFixedHeight($newHeight)
            {
                $ratio = $this->width / $this->height;
                $newWidth = $newHeight * $ratio;
                return $newWidth;
            }

            private function getSizeByFixedWidth($newWidth)
            {
                $ratio = $this->height / $this->width;
                $newHeight = $newWidth * $ratio;
                return $newHeight;
            }

            private function getSizeByAuto($newWidth, $newHeight)
            {
                if ($this->height < $this->width)
                // *** Image to be resized is wider (landscape)
                {
                    $optimalWidth = $newWidth;
                    $optimalHeight= $this->getSizeByFixedWidth($newWidth);
                }
                elseif ($this->height > $this->width)
                // *** Image to be resized is taller (portrait)
                {
                    $optimalWidth = $this->getSizeByFixedHeight($newHeight);
                    $optimalHeight= $newHeight;
                }
                else
                // *** Image to be resizerd is a square
                {
                    if ($newHeight < $newWidth) {
                        $optimalWidth = $newWidth;
                        $optimalHeight= $this->getSizeByFixedWidth($newWidth);
                    } else if ($newHeight > $newWidth) {
                        $optimalWidth = $this->getSizeByFixedHeight($newHeight);
                        $optimalHeight= $newHeight;
                    } else {
                        // *** Sqaure being resized to a square
                        $optimalWidth = $newWidth;
                        $optimalHeight= $newHeight;
                    }
                }

                return array('optimalWidth' => $optimalWidth, 'optimalHeight' => $optimalHeight);
            }

            ## --------------------------------------------------------

            private function getOptimalCrop($newWidth, $newHeight)
            {

                $heightRatio = $this->height / $newHeight;
                $widthRatio  = $this->width /  $newWidth;

                if ($heightRatio < $widthRatio) {
                    $optimalRatio = $heightRatio;
                } else {
                    $optimalRatio = $widthRatio;
                }

                $optimalHeight = $this->height / $optimalRatio;
                $optimalWidth  = $this->width  / $optimalRatio;

                return array('optimalWidth' => $optimalWidth, 'optimalHeight' => $optimalHeight);
            }

            ## --------------------------------------------------------

            private function crop($optimalWidth, $optimalHeight, $newWidth, $newHeight)
            {
                // *** Find center - this will be used for the crop
                $cropStartX = ( $optimalWidth / 2) - ( $newWidth /2 );
                $cropStartY = ( $optimalHeight/ 2) - ( $newHeight/2 );

                $crop = $this->imageResized;
                //imagedestroy($this->imageResized);

                // *** Now crop from center to exact requested size
                $this->imageResized = imagecreatetruecolor($newWidth , $newHeight);
                imagecopyresampled($this->imageResized, $crop , 0, 0, $cropStartX, $cropStartY, $newWidth, $newHeight , $newWidth, $newHeight);
            }

            ## --------------------------------------------------------

            public function saveImage($savePath, $imageQuality="100")
            {
                // *** Get extension
                $extension = strrchr($savePath, '.');
                $extension = strtolower($extension);

                switch($extension)
                {
                    case '.jpg':
                    case '.jpeg':
                        if (imagetypes() & IMG_JPG) {
                            imagejpeg($this->imageResized, $savePath, $imageQuality);
                        }
                        break;

                    case '.gif':
                        if (imagetypes() & IMG_GIF) {
                            imagegif($this->imageResized, $savePath);
                        }
                        break;

                    case '.png':
                        // *** Scale quality from 0-100 to 0-9
                        $scaleQuality = round(($imageQuality/100) * 9);

                        // *** Invert quality setting as 0 is best, not 9
                        $invertScaleQuality = 9 - $scaleQuality;

                        if (imagetypes() & IMG_PNG) {
                             imagepng($this->imageResized, $savePath, $invertScaleQuality);
                        }
                        break;

                    // ... etc

                    default:
                        // *** No extension - No save.
                        break;
                }

                imagedestroy($this->imageResized);
            }


            ## --------------------------------------------------------

        }
?>

Answer 2

加载图像，首先调整其大小，使其最小边为150，然后相对于中心裁切为150的宽度/高度。然后，您只需输出图像：

WideImage::load('yourfile.png/jpg/...')
    ->resize(150, 150, 'outside', 'any')
    ->crop('center', 'center', 150, 150)
    ->output('png');

您可以在以下位置找到源代码，文档，在线演示和API文档：WideImage。

让我知道您是否还有问题。