### Table of Contents - [resize](#resize) - [crop](#crop) - [embed](#embed) - [max](#max) - [min](#min) - [ignoreAspectRatio](#ignoreaspectratio) - [withoutEnlargement](#withoutenlargement) ## resize Resize image to `width` x `height`. By default, the resized image is centre cropped to the exact size specified. Possible kernels are: - `nearest`: Use [nearest neighbour interpolation](http://en.wikipedia.org/wiki/Nearest-neighbor_interpolation). - `cubic`: Use a [Catmull-Rom spline](https://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline). - `lanczos2`: Use a [Lanczos kernel](https://en.wikipedia.org/wiki/Lanczos_resampling#Lanczos_kernel) with `a=2`. - `lanczos3`: Use a Lanczos kernel with `a=3` (the default). **Parameters** - `width` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** pixels wide the resultant image should be. Use `null` or `undefined` to auto-scale the width to match the height. - `height` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** pixels high the resultant image should be. Use `null` or `undefined` to auto-scale the height to match the width. - `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** - `options.kernel` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** the kernel to use for image reduction. (optional, default `'lanczos3'`) - `options.fastShrinkOnLoad` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** take greater advantage of the JPEG and WebP shrink-on-load feature, which can lead to a slight moiré pattern on some images. (optional, default `true`) **Examples** ```javascript sharp(inputBuffer) .resize(200, 300, { kernel: sharp.kernel.nearest }) .background('white') .embed() .toFile('output.tiff') .then(function() { // output.tiff is a 200 pixels wide and 300 pixels high image // containing a nearest-neighbour scaled version, embedded on a white canvas, // of the image data in inputBuffer }); ``` - Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters Returns **Sharp** ## crop Crop the resized image to the exact size specified, the default behaviour. Possible attributes of the optional `sharp.gravity` are `north`, `northeast`, `east`, `southeast`, `south`, `southwest`, `west`, `northwest`, `center` and `centre`. The experimental strategy-based approach resizes so one dimension is at its target length then repeatedly ranks edge regions, discarding the edge with the lowest score based on the selected strategy. - `entropy`: focus on the region with the highest [Shannon entropy](https://en.wikipedia.org/wiki/Entropy_%28information_theory%29). - `attention`: focus on the region with the highest luminance frequency, colour saturation and presence of skin tones. **Parameters** - `crop` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** A member of `sharp.gravity` to crop to an edge/corner or `sharp.strategy` to crop dynamically. (optional, default `'centre'`) **Examples** ```javascript const transformer = sharp() .resize(200, 200) .crop(sharp.strategy.entropy) .on('error', function(err) { console.log(err); }); // Read image data from readableStream // Write 200px square auto-cropped image data to writableStream readableStream.pipe(transformer).pipe(writableStream); ``` - Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters Returns **Sharp** ## embed Preserving aspect ratio, resize the image to the maximum `width` or `height` specified then embed on a background of the exact `width` and `height` specified. If the background contains an alpha value then WebP and PNG format output images will contain an alpha channel, even when the input image does not. **Parameters** - `embed` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** A member of `sharp.gravity` to embed to an edge/corner. (optional, default `'centre'`) **Examples** ```javascript sharp('input.gif') .resize(200, 300) .background({r: 0, g: 0, b: 0, alpha: 0}) .embed() .toFormat(sharp.format.webp) .toBuffer(function(err, outputBuffer) { if (err) { throw err; } // outputBuffer contains WebP image data of a 200 pixels wide and 300 pixels high // containing a scaled version, embedded on a transparent canvas, of input.gif }); ``` - Throws **[Error](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters Returns **Sharp** ## max Preserving aspect ratio, resize the image to be as large as possible while ensuring its dimensions are less than or equal to the `width` and `height` specified. Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`. **Examples** ```javascript sharp(inputBuffer) .resize(200, 200) .max() .toFormat('jpeg') .toBuffer() .then(function(outputBuffer) { // outputBuffer contains JPEG image data no wider than 200 pixels and no higher // than 200 pixels regardless of the inputBuffer image dimensions }); ``` Returns **Sharp** ## min Preserving aspect ratio, resize the image to be as small as possible while ensuring its dimensions are greater than or equal to the `width` and `height` specified. Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`. Returns **Sharp** ## ignoreAspectRatio Ignoring the aspect ratio of the input, stretch the image to the exact `width` and/or `height` provided via `resize`. Returns **Sharp** ## withoutEnlargement Do not enlarge the output image if the input image width _or_ height are already less than the required dimensions. This is equivalent to GraphicsMagick's `>` geometry option: "_change the dimensions of the image only if its width or height exceeds the geometry specification_". The default behaviour _before_ function call is `false`, meaning the image will be enlarged. **Parameters** - `withoutEnlargement` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** (optional, default `true`) Returns **Sharp**