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PHP GD2 库的对象封装
v1.0.0
2016-01-05 22:42 UTC
Requires
- php: >=5.3.0
This package is not auto-updated.
Last update: 2024-09-24 19:06:30 UTC
README
GdWrapper 是 PHP GD2 库的对象封装。
安装
使用 composer
将以下代码添加到您的 composer.json
// ... "require": { // ... "hbarcelos/gd-wrapper": "dev-master" } // ...
然后在您的项目根目录下运行以下命令
$ composer update
要自动加载此库中的类，只需调用默认的 composer 自动加载器
require_once 'vendor/autoload.php';
手动
GdWrapper 兼容 PSR-4，您可以在这里找到示例自动加载器。
组件
资源
表示内存中的图像资源。这些实际上是 GD 的原生资源类型的封装对象。此库支持的所有操作都是在 Resource 对象上完成的。
IO
此包负责图像 IO（从磁盘读取并写回/显示在屏幕上）。每种支持的图像类型都有自己的 IO 类。
几何
简化图像尺寸操作的帮助组件，例如定位、方向、填充等。
操作
可以应用于图像的操作。目前有 3 种受支持的操作
- 调整大小
- 裁剪
- 合并
使用
从磁盘加载图像
如果您只需要加载特定扩展名的文件，可以直接实例化一个针对该扩展名的图像 Reader
use Hbarcelos\GdWrapper\Io\Reader; $jpegReader = new JpegReader(); $imageResource = $jpegReader->read('/path/to/file.jpg');
对于 gif 和 png 图像，代码类似，只需将 JpegReader 更改为 GifReader 或 PngReader。
当您有更动态的图像输入时，可以考虑使用工厂来简化操作
use Hbarcelos\GdWrapper\Io\ReaderFactory; $file = '/path/to/file.png'; $readerFactory = new ReaderFactory(); $reader = $readerFactory->create($file); // Will create a factory based on the type of the image $imageResource = $reader->read($file);
上述代码示例用于创建原始 GD 资源，这些资源用于 GD 库的几乎所有功能。但是，它们很难处理，因为它们不是对象，并且在不再需要时需要手动释放。
使用资源封装
一旦创建了原始资源，就应该将其封装到 Resource 对象中。对于从磁盘读取的图像，有 ImageResource 类
use Hbarcelos\GdWrapper\Io\Reader; use Hbarcelos\GdWrapper\Resource\ImageResource; $jpegReader = new JpegReader(); $imageResource = $jpegReader->read('/path/to/file.jpg'); $objResource = new ImageResource($imageResource);
基于磁盘中的图像创建资源可以通过以下方式委托给 ImageResourceFactory
use Hbarcelos\GdWrapper\Resource\ResourceFactory; $resourceFactory = new ImageResourceFactory('/path/to/file.jpg'); $objResource = $resourceFactory->create(); // Will create a ImageResource object
您可以通过再次调用 create 方法创建多个基于同一图像的资源
$resourceFactory = new ImageResourceFactory('/path/to/file.jpg'); $objResource = $resourceFactory->create(); // Will create a ImageResource object $objResource = $resourceFactory->create(); // Will create another ImageResource object for the same image
也可以通过设置新的图像路径（使用 setPathName 方法）来重用相同的工厂为其他图像创建资源对象
$resourceFactory = new ImageResourceFactory('/path/to/file.jpg'); $objResource = $resourceFactory->create(); // Will create a ImageResource object for /path/to/file.jpg $resourceFactory->setPathName('/path/to/another_file.png'); $objResource = $resourceFactory->create(); // Will create another ImageResource object for /path/to/another_file.png
请注意，您甚至可以更改图像类型。 ImageResourceFactory 足够智能，可以识别这一点并切换到适当的读取器。
生成图像输出
要生成图像输出，必须使用 IO 包中的 Writer 组件。
与读取图像不同，在尝试写入图像时，您应该已经知道您想要的图像格式。
这样可以将 JPEG 图像转换为 PNG
use Hbarcelos\GdWrapper\Resource\ImageResource; use Hbarcelos\GdWrapper\Io\PngWriter; $resourceFactory = new ImageResourceFactory('/path/to/file.jpg'); $objResource = $resourceFactory->create(); // Will create a ImageResource object for /path/to/file.jpg $writer = new PngWriter($objResource->getRaw()); // Writers just need the raw GD resource to work $writer->write('/path/to/new_file.png'); // will save a PNG image on /path/to/new_file.png
有时，您需要在动态中生成图像而不是输出到文件。在这种情况下，您可以写入 Writer::STDOUT 以使输出发送到标准输出（通常是一个浏览器）
header('Content: image/png'); // This is important to make the image be properly rendered by the browser $writer->write(PngWritter::STDOUT); // will generate a PNG image binary and send it to the browser
在图像上应用操作
操作以级联方式应用于图像，即执行的操作是累积的：如果您裁剪一个图像然后调整大小，您将调整裁剪后的图像的大小。
调整大小
调整大小可以通过以下三种方式进行
- 按比例
- 调整为精确的固定大小
- 保持纵横比
use Hbarcelos\GdWrapper\Resource\ResourceFactory; use Hbarcelos\GdWrapper\Action\Resize; use Hbarcelos\GdWrapper\Action\ResizeMode\Proportional as ResizeProportional; use Hbarcelos\GdWrapper\Action\ResizeMode\KeepRatio as ResizeKeepRatio; use Hbarcelos\GdWrapper\Action\ResizeMode\Exact as ResizeExact; $resourceFactory = new ImageResourceFactory('/path/to/file.jpg'); $objResource1 = $resourceFactory->create(); $objResource2 = $resourceFactory->create(); $objResource3 = $resourceFactory->create(); /* Will resize the image to 80% of its original size (both width and height). * You can also scale up an image, by passing a value > 1 to ResizeProportional constructor, * but that is inadivisable, since it will deteriorate the image quality. */ $resizeMode = new ResizeProportional(0.8); $resizeAction = new Resize($resizeMode); $resizeAction->execute($objResource1); // $objResource1 now refers to the 80%-resized image resource /* This will resize the image to the exact dimensions passed to ResizeExact construtor (width, height). * Needless to say that this can cause distortions (stretching or shrinking) on the image. */ $resizeMode = new ResizeExact(400, 300); $resizeAction->execute($objResource2); // $objResource1 now refers to the 400x300 px resized image resource /* This is a hybrid resizing mode: you pass both width and length that will be considered the maximum * allowed dimensions for the image. * * If the image dimensions have the same ratio as the dimensions passed to ResizeKeepRatio constructor, * this action will perform the same way ResizeExact would do. * If not, then one of the dimensions will be set to the maximum allowed and the other will be proportionally * scaled in order to stay within the predefined limits. */ $resizeMode = new ResizeKeepRatio(400, 300); // This is a 4:3 ratio // Now imagine that $objResource3 refers to an image with 16:9 ratio (1920x1080 px, AKA full HD) $resizeAction->execute($objResource3); // $objResource1 now refers to a 400x225 px image (keeping the 16:9 ratio)
裁剪
裁剪可以以以下四种方式进行
- 使用固定尺寸（宽度和高度），基于参考位置
- 基于固定点，一个作为参考点，另一个用于计算宽度和高度
- 使用其边缘作为参考，创建“填充”
- 按比例，基于参考位置
use Hbarcelos\GdWrapper\Resource\ResourceFactory; use Hbarcelos\GdWrapper\Action\Crop; use Hbarcelos\GdWrapper\Action\CropMode\Proportional as CropProportional; use Hbarcelos\GdWrapper\Action\CropMode\FixedDimensions as CropFixedDimensions; use Hbarcelos\GdWrapper\Action\CropMode\FromEdges as CropFromEdges; use Hbarcelos\GdWrapper\Action\CropMode\FixedPoints as CropFixedPoints; use Hbarcelos\GdWrapper\Geometry\Point; use Hbarcelos\GdWrapper\Geometry\Padding\Fixed as FixedPadding; use Hbarcelos\GdWrapper\Geometry\Padding\Proportional as ProportionalPadding; use Hbarcelos\GdWrapper\Geometry\Position\FixedPoint as FixedPointPosition; use Hbarcelos\GdWrapper\Geometry\Position\Aligned as AlignedPosition; use Hbarcelos\GdWrapper\Geometry\Alignment\Center; use Hbarcelos\GdWrapper\Geometry\Alignment\Start; use Hbarcelos\GdWrapper\Geometry\Alignment\End; $resourceFactory = new ImageResourceFactory('/path/to/file.jpg'); $objResource1 = $resourceFactory->create(); $objResource2 = $resourceFactory->create(); $objResource3 = $resourceFactory->create(); $objResource4 = $resourceFactory->create(); /* Point(x,y) represents the (x,y) point of the inverted y-axis cartesian plan. * Inverted because the way GD referential point is the top left corner of the image. * The x coordinates increase from left to right. * The y coordinates increase from top to down. */ /* Fixed points cropping will be done using the rectangle defined by the $start and $end points. * * Will generate a 800x500 px image, from the point (0,0) to the point (800,500) of the original image. * * Imagine this: * * .----------------------------------------------------------> 1920 px * |(0,0) + > 800 px | * | + | * | + | * | + | * | + | * | + | * | + | * | + | * |++++++++++++++++++++++++++.(500,300) | * | v | * | 500 px | * | | * | | * | | * | | * | | * ----------------------------------------------------------- * v * 1080 px */ $cropMode = new CropFixedPoints(new Point(0,0), new Point(800,500)); $cropAction = new Crop($cropMode); $crop->execute($objResource1); /* Padding cropping can be done using fixed paddings... * * Will Generate a 1720x880 image, cropping out 100 px from each side of the original image. * * Imagine this: * * -----------------------------------------------------------> 1920 px * | A 100px | * | V 100 px| * | +++++++++++++++++++++++++++++++++++++++++++++++<--->| * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * |<--->+++++++++++++++++++++++++++++++++++++++++++++++ | * | 100 px 100 px A | * | V | * ----------------------------------------------------------- * v * 1080 px */ $padding = new FixedPadding(100); // --> same padding for both sides // To use different vertical and horizontal paddings: new FixedPadding(100, 200) --> 100 px on vert. and 200 horiz. // To use 4 different paddings: new FixedPadding(100, 200, 50, 80) --> top, right, bottom, left $cropMode = new CropFromEdges($padding); $crop->execute($objResource2); /* ... or it can be done with proportional paddings. * The proportion will be relative to the original image dimensions. * * Imagine this: * * -----------------------------------------------------------> 2000 px * | A 120px | * | V 200 px| * | +++++++++++++++++++++++++++++++++++++++++++++++<--->| * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * | + + | * |<--->+++++++++++++++++++++++++++++++++++++++++++++++ | * | 200 px 120 px A | * | V | * ----------------------------------------------------------- * v * 1200 px */ $padding = new ProportionalPadding(0.1); // 10% // Different paddings can be used just like the example above $cropMode = new CropFromEdges($padding); $crop->execute($objResource3); /* FixedDimensionsCrop is a Positioned cropping mode. * This means you have to determine a reference position for it. * Reference positions can be either a fixed point or anchored to some image notable point (aligned). * * For fixed point references, the cropping will behave almost like FixedPointsCrop, but you should pass * the desired width and height of the cropped image instead of the end point. * * Imagine this: * * -----------------------------------------------------------> 1920 px * | | * | | * | | * |(200,200).++++++++++++++++++++++++++++++++ A | * | + + | | * | + + | | * | + + | | * | + + | | * | + + | 900 px | * | + + | | * | + + | | * | + + | | * | + + | | * | +++++++++++++++++++++++++++++++++ V | * | <----------- 1200 px -----------> | * | | * ----------------------------------------------------------- * v * 1080 px */ $pos = new FixedPosition(new Point(200, 200)); $cropMode = new CropFixedDimensions($pos, 1200, 900); /* An alignment is either start, center or end, for both vertical and horizontal directions. * For the horizontal direction: * start --> left * end --> right * * For the vertical direction: * start --> top * end --> bottom */ /* An aligned position consists of a horizontal AND a vertical alignment. * The two alignment coordinates will generate a reference point. */ /* For aligned reference, the cropping will be aligned to source image anchor points and you should also pass * the desired width and height for the cropped image. * Imagine this: * * -----------------------------------------------------------> 1920 px * | | * | | * | +++++++++++++++++++++++++++++++++++++++ A | * | + + | | * | + + | | * | + + | | * | + + | | * | + + | | * | + + | 800 px| * | + + | | * | + + | | * | + + | | * | + + | | * | +++++++++++++++++++++++++++++++++++++++ V | * | <-------------- 1200 px --------------> | * | | * ----------------------------------------------------------- * v * 1080 px */ $pos = new AlignedPosition(new Center()); /* If you want different alingments in horizontal and vertical, you can pass a second argument: * $post = new AlignedPosition(new Center(), new Start()); // horizontal, vertical = center, top */ $cropMode = new CropFixedDimensions($pos, 1200, 800); $crop->execute($objResource3); /* Much like the above example, it's also possible do crop an image proportionally, based on a reference position. * The arguments to the CropProportional constructor are the position and the proportio. * * Imagine this: * * -----------------------------------------------------------> 2000 px * | A (10%) | * | V 120 px | * | +++++++++++++++++++++++++++++++++++++++ A | * | + + | | * | + + | | * | + + | | * | + + | | * | + + | | * | + + | 960 px| * | + + | | * | + + | | * | (10%) + + | | * | 200 px + + | | * |<------->+++++++++++++++++++++++++++++++++++++++ V | * | <-------------- 1600 px --------------> | * | | * ----------------------------------------------------------- * v * 1200 px */
合并
@待办