Skip to content

Commit f1f18fb

Browse files
committedMar 25, 2021
Docs: clarify that flatten removes alpha channel #2601
1 parent 9fc611f commit f1f18fb

File tree

3 files changed

+17
-3
lines changed

3 files changed

+17
-3
lines changed
 

‎docs/api-operation.md

+9-1
Original file line numberDiff line numberDiff line change
@@ -169,13 +169,21 @@ Returns **Sharp**
169169

170170
## flatten
171171

172-
Merge alpha transparency channel, if any, with a background.
172+
Merge alpha transparency channel, if any, with a background, then remove the alpha channel.
173173

174174
### Parameters
175175

176176
- `options` **[Object][2]?**
177177
- `options.background` **([string][3] \| [Object][2])** background colour, parsed by the [color][4] module, defaults to black. (optional, default `{r:0,g:0,b:0}`)
178178

179+
### Examples
180+
181+
```javascript
182+
await sharp(rgbaInput)
183+
.flatten('#F0A703')
184+
.toBuffer();
185+
```
186+
179187
Returns **Sharp**
180188

181189
## gamma

‎docs/search-index.json

+1-1
Original file line numberDiff line numberDiff line change
@@ -1 +1 @@
1-
[{"t":"Prerequisites","d":"Node.js v10","k":"prerequisites node","l":"/install#prerequisites"},{"t":"Prebuilt binaries","d":"Ready-compiled sharp and libvips binaries are provided for use with Node.js v10 on the most common platforms macOS x64 10.13 Linux x64 glibc 2.17, musl 1.1.24 Linux ARM64 glibc 2.2","k":"prebuilt binaries compiled sharp libvips node common platforms macos linux glibc musl arm","l":"/install#prebuilt-binaries"},{"t":"Common problems","d":"The architecture and platform of Node.js used for npm install must be the same as the architecture and platform of Node.js used at runtime. When using npm v6 or earlier, the npm in","k":"common problems architecture platform node npm install runtime earlier","l":"/install#common-problems"},{"t":"Apple M1","d":"Prebuilt libvips binaries are provided for macOS on ARM64 since sharp v0.28.0. During npm install sharp will be built locally, which requires Xcode and Python - see building from s","k":"apple prebuilt libvips binaries macos arm sharp during npm install built locally requires xcode python building","l":"/install#apple-m1"},{"t":"Custom libvips","d":"To use a custom, globally-installed version of libvips instead of the provided binaries, make sure it is at least the version listed under config.libvips in the package.json file a","k":"custom libvips globally installed version instead binaries make listed config package json file","l":"/install#custom-libvips"},{"t":"Building from source","d":"This module will be compiled from source at npm install time when a globally-installed libvips is detected set the SHARP_IGNORE_GLOBAL_LIBVIPS environment variable to skip this, pr","k":"building source module compiled npm install time globally installed libvips detected environment variable skip","l":"/install#building-from-source"},{"t":"Custom prebuilt binaries","d":"This is an advanced approach that most people will not require. To install the prebuilt sharp binaries from a custom URL, set the sharp_binary_host npm config option or the npm_con","k":"custom prebuilt binaries advanced approach people require install sharp url npm config option npmcon","l":"/install#custom-prebuilt-binaries"},{"t":"Chinese mirror","d":"Alibaba provide a mirror site based in China containing binaries for both sharp and libvips. To use this either set the following configuration sh npm config set sharp_binary_host","k":"chinese mirror alibaba site china binaries sharp libvips following configuration npm config","l":"/install#chinese-mirror"},{"t":"FreeBSD","d":"The vips package must be installed before npm install is run. sh pkg install -y pkgconf vips sh cd /usr/ports/graphics/vips/ make install clean","k":"freebsd vips package installed npm install run pkg pkgconf usr ports graphics make clean","l":"/install#freebsd"},{"t":"Linux memory allocator","d":"The default memory allocator on most glibc-based Linux systems e.g. Debian, Red Hat is unsuitable for long-running, multi-threaded processes that involve lots of small memory alloc","k":"linux memory allocator glibc systems debian red hat unsuitable long running multi threaded processes small alloc","l":"/install#linux-memory-allocator"},{"t":"Heroku","d":"Add the jemalloc buildpack to reduce the effects of memory fragmentation. Set NODE_MODULES_CACHE","k":"heroku add jemalloc buildpack reduce effects memory fragmentation","l":"/install#heroku"},{"t":"AWS Lambda","d":"Set the Lambda runtime to nodejs12.x. The binaries in the node_modules directory of the deployment package must be for the Linux x64 platform. When building your deployment package","k":"aws lambda runtime nodejs binaries nodemodules directory deployment package linux platform building your","l":"/install#aws-lambda"},{"t":"Webpack","d":"Ensure sharp is added to the externals configuration. js externals sharp commonjs sharp","k":"webpack sharp added externals configuration commonjs","l":"/install#webpack"},{"t":"Worker threads","d":"The main thread must call requiresharp before worker threads are created to ensure shared libraries remain loaded in memory until after all threads are complete.","k":"worker threads main thread requiresharp created shared libraries remain loaded memory complete","l":"/install#worker-threads"},{"t":"Canvas and Windows","d":"The prebuilt binaries provided by canvas for Windows depend on the unmaintained GTK 2, last updated in 2011. These conflict with the modern, up-to-date binaries provided by sharp.","k":"canvas windows prebuilt binaries depend unmaintained gtk last updated conflict modern date sharp","l":"/install#canvas-and-windows"},{"t":"Sharp","d":"Constructor factory to create an instance of sharp, to which further methods are chained.","k":"sharp constructor factory create instance further methods chained","l":"/api-constructor#sharp"},{"t":"clone","d":"Take a snapshot of the Sharp instance, returning a new instance. Cloned instances inherit the input of their parent instance. This allows multiple output Streams and therefore mult","k":"clone snapshot sharp instance returning new cloned instances inherit input parent multiple output streams mult","l":"/api-constructor#clone"},{"t":"metadata","d":"Fast access to uncached image metadata without decoding any compressed image data. A Promise is returned when callback is not provided.","k":"metadata fast access uncached decoding compressed data promise returned callback","l":"/api-input#metadata"},{"t":"stats","d":"Access to pixel-derived image statistics for every channel in the image. A Promise is returned when callback is not provided.","k":"stats access pixel derived statistics channel promise returned callback","l":"/api-input#stats"},{"t":"toFile","d":"Write output image data to a file.","k":"tofile write output data file","l":"/api-output#tofile"},{"t":"toBuffer","d":"Write output to a Buffer. JPEG, PNG, WebP, AVIF, TIFF and raw pixel data output are supported.","k":"tobuffer write output buffer jpeg png webp avif tiff raw pixel data","l":"/api-output#tobuffer"},{"t":"withMetadata","d":"Include all metadata EXIF, XMP, IPTC from the input image in the output image. This will also convert to and add a web-friendly sRGB ICC profile unless a custom output profile is p","k":"withmetadata include metadata exif xmp iptc input output convert add web friendly srgb icc profile custom","l":"/api-output#withmetadata"},{"t":"toFormat","d":"Force output to a given format.","k":"toformat force output format","l":"/api-output#toformat"},{"t":"jpeg","d":"Use these JPEG options for output image.","k":"jpeg output","l":"/api-output#jpeg"},{"t":"png","d":"Use these PNG options for output image.","k":"png output","l":"/api-output#png"},{"t":"webp","d":"Use these WebP options for output image.","k":"webp output","l":"/api-output#webp"},{"t":"gif","d":"Use these GIF options for output image.","k":"gif output","l":"/api-output#gif"},{"t":"tiff","d":"Use these TIFF options for output image.","k":"tiff output","l":"/api-output#tiff"},{"t":"avif","d":"Use these AVIF options for output image.","k":"avif output","l":"/api-output#avif"},{"t":"heif","d":"Use these HEIF options for output image.","k":"heif output","l":"/api-output#heif"},{"t":"raw","d":"Force output to be raw, uncompressed, 8-bit unsigned integer unit8 pixel data. Pixel ordering is left-to-right, top-to-bottom, without padding. Channel ordering will be RGB or RGBA","k":"raw force output uncompressed bit unsigned integer unit pixel data ordering left right top bottom padding channel rgb rgba","l":"/api-output#raw"},{"t":"tile","d":"Use tile-based deep zoom image pyramid output. Set the format and options for tile images via the toFormat, jpeg, png or webp functions. Use a .zip or .szi file extension with toFi","k":"tile deep zoom pyramid output format images via toformat jpeg png webp functions zip szi file extension tofi","l":"/api-output#tile"},{"t":"resize","d":"Resize image to width, height or width x height.","k":"resize width height","l":"/api-resize#resize"},{"t":"extend","d":"Extends/pads the edges of the image with the provided background colour. This operation will always occur after resizing and extraction, if any.","k":"extend extends pads edges background colour operation resizing extraction","l":"/api-resize#extend"},{"t":"extract","d":"Extract/crop a region of the image.","k":"extract crop region","l":"/api-resize#extract"},{"t":"trim","d":"Trim boring pixels from all edges that contain values similar to the top-left pixel. Images consisting entirely of a single colour will calculate boring using the alpha channel, if","k":"trim boring pixels edges contain similar top left pixel images consisting entirely single colour calculate alpha channel","l":"/api-resize#trim"},{"t":"composite","d":"Composite images over the processed resized, extracted etc. image.","k":"composite images processed resized extracted","l":"/api-composite#composite"},{"t":"rotate","d":"Rotate the output image by either an explicit angle or auto-orient based on the EXIF Orientation tag.","k":"rotate output explicit angle auto orient exif orientation tag","l":"/api-operation#rotate"},{"t":"flip","d":"Flip the image about the vertical Y axis. This always occurs after rotation, if any. The use of flip implies the removal of the EXIF Orientation tag, if any.","k":"flip vertical axis rotation implies removal exif orientation tag","l":"/api-operation#flip"},{"t":"flop","d":"Flop the image about the horizontal X axis. This always occurs after rotation, if any. The use of flop implies the removal of the EXIF Orientation tag, if any.","k":"flop horizontal axis rotation implies removal exif orientation tag","l":"/api-operation#flop"},{"t":"affine","d":"Perform an affine transform on an image. This operation will always occur after resizing, extraction and rotation, if any.","k":"affine transform operation resizing extraction rotation","l":"/api-operation#affine"},{"t":"sharpen","d":"Sharpen the image. When used without parameters, performs a fast, mild sharpen of the output image. When a sigma is provided, performs a slower, more accurate sharpen of the L chan","k":"sharpen parameters fast mild output sigma slower accurate chan","l":"/api-operation#sharpen"},{"t":"median","d":"Apply median filter. When used without parameters the default window is 3x3.","k":"median apply filter parameters window","l":"/api-operation#median"},{"t":"blur","d":"Blur the image. When used without parameters, performs a fast, mild blur of the output image. When a sigma is provided, performs a slower, more accurate Gaussian blur.","k":"blur parameters fast mild output sigma slower accurate gaussian","l":"/api-operation#blur"},{"t":"flatten","d":"Merge alpha transparency channel, if any, with a background.","k":"flatten merge alpha transparency channel background","l":"/api-operation#flatten"},{"t":"gamma","d":"Apply a gamma correction by reducing the encoding darken pre-resize at a factor of 1/gamma then increasing the encoding brighten post-resize at a factor of gamma. This can improve","k":"gamma apply correction reducing encoding darken pre resize factor then increasing brighten post improve","l":"/api-operation#gamma"},{"t":"negate","d":"Produce the negative of the image.","k":"negate produce negative","l":"/api-operation#negate"},{"t":"normalise","d":"Enhance output image contrast by stretching its luminance to cover the full dynamic range.","k":"normalise enhance output contrast stretching luminance cover full dynamic range","l":"/api-operation#normalise"},{"t":"normalize","d":"Alternative spelling of normalise.","k":"normalize normalise","l":"/api-operation#normalize"},{"t":"convolve","d":"Convolve the image with the specified kernel.","k":"convolve specified kernel","l":"/api-operation#convolve"},{"t":"threshold","d":"Any pixel value greater than or equal to the threshold value will be set to 255, otherwise it will be set to 0.","k":"threshold pixel greater than equal otherwise","l":"/api-operation#threshold"},{"t":"boolean","d":"Perform a bitwise boolean operation with operand image.","k":"boolean bitwise operation operand","l":"/api-operation#boolean"},{"t":"linear","d":"Apply the linear formula a input b to the image levels adjustment","k":"linear apply formula input levels adjustment","l":"/api-operation#linear"},{"t":"recomb","d":"Recomb the image with the specified matrix.","k":"recomb specified matrix","l":"/api-operation#recomb"},{"t":"modulate","d":"Transforms the image using brightness, saturation and hue rotation.","k":"modulate transforms brightness saturation hue rotation","l":"/api-operation#modulate"},{"t":"removeAlpha","d":"Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.","k":"removealpha remove alpha channel","l":"/api-channel#removealpha"},{"t":"ensureAlpha","d":"Ensure alpha channel, if missing. The added alpha channel will be fully opaque. This is a no-op if the image already has an alpha channel.","k":"ensurealpha alpha channel missing added fully opaque","l":"/api-channel#ensurealpha"},{"t":"extractChannel","d":"Extract a single channel from a multi-channel image.","k":"extractchannel extract single channel multi","l":"/api-channel#extractchannel"},{"t":"joinChannel","d":"Join one or more channels to the image. The meaning of the added channels depends on the output colourspace, set with toColourspace. By default the output image will be web-friendl","k":"joinchannel join one channels meaning added depends output colourspace tocolourspace web friendl","l":"/api-channel#joinchannel"},{"t":"bandbool","d":"Perform a bitwise boolean operation on all input image channels bands to produce a single channel output image.","k":"bandbool bitwise boolean operation input channels bands produce single channel output","l":"/api-channel#bandbool"},{"t":"tint","d":"Tint the image using the provided chroma while preserving the image luminance. An alpha channel may be present and will be unchanged by the operation.","k":"tint chroma preserving luminance alpha channel present unchanged operation","l":"/api-colour#tint"},{"t":"greyscale","d":"Convert to 8-bit greyscale 256 shades of grey. This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use gamma with greyscale for the best re","k":"greyscale convert bit shades grey linear operation input colour space srgb gamma best","l":"/api-colour#greyscale"},{"t":"grayscale","d":"Alternative spelling of greyscale.","k":"grayscale greyscale","l":"/api-colour#grayscale"},{"t":"toColourspace","d":"Set the output colourspace. By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.","k":"tocolourspace output colourspace web friendly srgb additional channels interpreted alpha","l":"/api-colour#tocolourspace"},{"t":"toColorspace","d":"Alternative spelling of toColourspace.","k":"tocolorspace tocolourspace","l":"/api-colour#tocolorspace"},{"t":"format","d":"An Object containing nested boolean values representing the available input and output formats/methods.","k":"format object nested boolean representing available input output formats methods","l":"/api-utility#format"},{"t":"interpolators","d":"An Object containing the available interpolators and their proper values","k":"interpolators object available proper","l":"/api-utility#interpolators"},{"t":"versions","d":"An Object containing the version numbers of libvips and its dependencies.","k":"versions object version numbers libvips dependencies","l":"/api-utility#versions"},{"t":"cache","d":"Gets or, when options are provided, sets the limits of _libvips_ operation cache. Existing entries in the cache will be trimmed after any change in limits. This method always retur","k":"cache limits libvips operation existing entries trimmed change method retur","l":"/api-utility#cache"},{"t":"concurrency","d":"Gets or, when a concurrency is provided, sets the number of threads _libvips_ should create to process each image.","k":"concurrency number threads libvips create process","l":"/api-utility#concurrency"},{"t":"queue","d":"An EventEmitter that emits a change event when a task is either","k":"queue eventemitter emits change event task","l":"/api-utility#queue"},{"t":"counters","d":"Provides access to internal task counters.","k":"counters provides access internal task","l":"/api-utility#counters"},{"t":"simd","d":"Get and set use of SIMD vector unit instructions. Requires libvips to have been compiled with liborc support.","k":"simd vector unit instructions requires libvips compiled liborc","l":"/api-utility#simd"}]
1+
[{"t":"Prerequisites","d":"Node.js v10","k":"prerequisites node","l":"/install#prerequisites"},{"t":"Prebuilt binaries","d":"Ready-compiled sharp and libvips binaries are provided for use with Node.js v10 on the most common platforms macOS x64 10.13 Linux x64 glibc 2.17, musl 1.1.24 Linux ARM64 glibc 2.2","k":"prebuilt binaries compiled sharp libvips node common platforms macos linux glibc musl arm","l":"/install#prebuilt-binaries"},{"t":"Common problems","d":"The architecture and platform of Node.js used for npm install must be the same as the architecture and platform of Node.js used at runtime. When using npm v6 or earlier, the npm in","k":"common problems architecture platform node npm install runtime earlier","l":"/install#common-problems"},{"t":"Apple M1","d":"Prebuilt libvips binaries are provided for macOS on ARM64 since sharp v0.28.0. During npm install sharp will be built locally, which requires Xcode and Python - see building from s","k":"apple prebuilt libvips binaries macos arm sharp during npm install built locally requires xcode python building","l":"/install#apple-m1"},{"t":"Custom libvips","d":"To use a custom, globally-installed version of libvips instead of the provided binaries, make sure it is at least the version listed under config.libvips in the package.json file a","k":"custom libvips globally installed version instead binaries make listed config package json file","l":"/install#custom-libvips"},{"t":"Building from source","d":"This module will be compiled from source at npm install time when a globally-installed libvips is detected set the SHARP_IGNORE_GLOBAL_LIBVIPS environment variable to skip this, pr","k":"building source module compiled npm install time globally installed libvips detected environment variable skip","l":"/install#building-from-source"},{"t":"Custom prebuilt binaries","d":"This is an advanced approach that most people will not require. To install the prebuilt sharp binaries from a custom URL, set the sharp_binary_host npm config option or the npm_con","k":"custom prebuilt binaries advanced approach people require install sharp url npm config option npmcon","l":"/install#custom-prebuilt-binaries"},{"t":"Chinese mirror","d":"Alibaba provide a mirror site based in China containing binaries for both sharp and libvips. To use this either set the following configuration sh npm config set sharp_binary_host","k":"chinese mirror alibaba site china binaries sharp libvips following configuration npm config","l":"/install#chinese-mirror"},{"t":"FreeBSD","d":"The vips package must be installed before npm install is run. sh pkg install -y pkgconf vips sh cd /usr/ports/graphics/vips/ make install clean","k":"freebsd vips package installed npm install run pkg pkgconf usr ports graphics make clean","l":"/install#freebsd"},{"t":"Linux memory allocator","d":"The default memory allocator on most glibc-based Linux systems e.g. Debian, Red Hat is unsuitable for long-running, multi-threaded processes that involve lots of small memory alloc","k":"linux memory allocator glibc systems debian red hat unsuitable long running multi threaded processes small alloc","l":"/install#linux-memory-allocator"},{"t":"Heroku","d":"Add the jemalloc buildpack to reduce the effects of memory fragmentation. Set NODE_MODULES_CACHE","k":"heroku add jemalloc buildpack reduce effects memory fragmentation","l":"/install#heroku"},{"t":"AWS Lambda","d":"Set the Lambda runtime to nodejs12.x. The binaries in the node_modules directory of the deployment package must be for the Linux x64 platform. When building your deployment package","k":"aws lambda runtime nodejs binaries nodemodules directory deployment package linux platform building your","l":"/install#aws-lambda"},{"t":"Webpack","d":"Ensure sharp is added to the externals configuration. js externals sharp commonjs sharp","k":"webpack sharp added externals configuration commonjs","l":"/install#webpack"},{"t":"Worker threads","d":"The main thread must call requiresharp before worker threads are created to ensure shared libraries remain loaded in memory until after all threads are complete.","k":"worker threads main thread requiresharp created shared libraries remain loaded memory complete","l":"/install#worker-threads"},{"t":"Canvas and Windows","d":"The prebuilt binaries provided by canvas for Windows depend on the unmaintained GTK 2, last updated in 2011. These conflict with the modern, up-to-date binaries provided by sharp.","k":"canvas windows prebuilt binaries depend unmaintained gtk last updated conflict modern date sharp","l":"/install#canvas-and-windows"},{"t":"Sharp","d":"Constructor factory to create an instance of sharp, to which further methods are chained.","k":"sharp constructor factory create instance further methods chained","l":"/api-constructor#sharp"},{"t":"clone","d":"Take a snapshot of the Sharp instance, returning a new instance. Cloned instances inherit the input of their parent instance. This allows multiple output Streams and therefore mult","k":"clone snapshot sharp instance returning new cloned instances inherit input parent multiple output streams mult","l":"/api-constructor#clone"},{"t":"metadata","d":"Fast access to uncached image metadata without decoding any compressed image data. A Promise is returned when callback is not provided.","k":"metadata fast access uncached decoding compressed data promise returned callback","l":"/api-input#metadata"},{"t":"stats","d":"Access to pixel-derived image statistics for every channel in the image. A Promise is returned when callback is not provided.","k":"stats access pixel derived statistics channel promise returned callback","l":"/api-input#stats"},{"t":"toFile","d":"Write output image data to a file.","k":"tofile write output data file","l":"/api-output#tofile"},{"t":"toBuffer","d":"Write output to a Buffer. JPEG, PNG, WebP, AVIF, TIFF and raw pixel data output are supported.","k":"tobuffer write output buffer jpeg png webp avif tiff raw pixel data","l":"/api-output#tobuffer"},{"t":"withMetadata","d":"Include all metadata EXIF, XMP, IPTC from the input image in the output image. This will also convert to and add a web-friendly sRGB ICC profile unless a custom output profile is p","k":"withmetadata include metadata exif xmp iptc input output convert add web friendly srgb icc profile custom","l":"/api-output#withmetadata"},{"t":"toFormat","d":"Force output to a given format.","k":"toformat force output format","l":"/api-output#toformat"},{"t":"jpeg","d":"Use these JPEG options for output image.","k":"jpeg output","l":"/api-output#jpeg"},{"t":"png","d":"Use these PNG options for output image.","k":"png output","l":"/api-output#png"},{"t":"webp","d":"Use these WebP options for output image.","k":"webp output","l":"/api-output#webp"},{"t":"gif","d":"Use these GIF options for output image.","k":"gif output","l":"/api-output#gif"},{"t":"tiff","d":"Use these TIFF options for output image.","k":"tiff output","l":"/api-output#tiff"},{"t":"avif","d":"Use these AVIF options for output image.","k":"avif output","l":"/api-output#avif"},{"t":"heif","d":"Use these HEIF options for output image.","k":"heif output","l":"/api-output#heif"},{"t":"raw","d":"Force output to be raw, uncompressed, 8-bit unsigned integer unit8 pixel data. Pixel ordering is left-to-right, top-to-bottom, without padding. Channel ordering will be RGB or RGBA","k":"raw force output uncompressed bit unsigned integer unit pixel data ordering left right top bottom padding channel rgb rgba","l":"/api-output#raw"},{"t":"tile","d":"Use tile-based deep zoom image pyramid output. Set the format and options for tile images via the toFormat, jpeg, png or webp functions. Use a .zip or .szi file extension with toFi","k":"tile deep zoom pyramid output format images via toformat jpeg png webp functions zip szi file extension tofi","l":"/api-output#tile"},{"t":"resize","d":"Resize image to width, height or width x height.","k":"resize width height","l":"/api-resize#resize"},{"t":"extend","d":"Extends/pads the edges of the image with the provided background colour. This operation will always occur after resizing and extraction, if any.","k":"extend extends pads edges background colour operation resizing extraction","l":"/api-resize#extend"},{"t":"extract","d":"Extract/crop a region of the image.","k":"extract crop region","l":"/api-resize#extract"},{"t":"trim","d":"Trim boring pixels from all edges that contain values similar to the top-left pixel. Images consisting entirely of a single colour will calculate boring using the alpha channel, if","k":"trim boring pixels edges contain similar top left pixel images consisting entirely single colour calculate alpha channel","l":"/api-resize#trim"},{"t":"composite","d":"Composite images over the processed resized, extracted etc. image.","k":"composite images processed resized extracted","l":"/api-composite#composite"},{"t":"rotate","d":"Rotate the output image by either an explicit angle or auto-orient based on the EXIF Orientation tag.","k":"rotate output explicit angle auto orient exif orientation tag","l":"/api-operation#rotate"},{"t":"flip","d":"Flip the image about the vertical Y axis. This always occurs after rotation, if any. The use of flip implies the removal of the EXIF Orientation tag, if any.","k":"flip vertical axis rotation implies removal exif orientation tag","l":"/api-operation#flip"},{"t":"flop","d":"Flop the image about the horizontal X axis. This always occurs after rotation, if any. The use of flop implies the removal of the EXIF Orientation tag, if any.","k":"flop horizontal axis rotation implies removal exif orientation tag","l":"/api-operation#flop"},{"t":"affine","d":"Perform an affine transform on an image. This operation will always occur after resizing, extraction and rotation, if any.","k":"affine transform operation resizing extraction rotation","l":"/api-operation#affine"},{"t":"sharpen","d":"Sharpen the image. When used without parameters, performs a fast, mild sharpen of the output image. When a sigma is provided, performs a slower, more accurate sharpen of the L chan","k":"sharpen parameters fast mild output sigma slower accurate chan","l":"/api-operation#sharpen"},{"t":"median","d":"Apply median filter. When used without parameters the default window is 3x3.","k":"median apply filter parameters window","l":"/api-operation#median"},{"t":"blur","d":"Blur the image. When used without parameters, performs a fast, mild blur of the output image. When a sigma is provided, performs a slower, more accurate Gaussian blur.","k":"blur parameters fast mild output sigma slower accurate gaussian","l":"/api-operation#blur"},{"t":"flatten","d":"Merge alpha transparency channel, if any, with a background, then remove the alpha channel.","k":"flatten merge alpha transparency channel background then remove","l":"/api-operation#flatten"},{"t":"gamma","d":"Apply a gamma correction by reducing the encoding darken pre-resize at a factor of 1/gamma then increasing the encoding brighten post-resize at a factor of gamma. This can improve","k":"gamma apply correction reducing encoding darken pre resize factor then increasing brighten post improve","l":"/api-operation#gamma"},{"t":"negate","d":"Produce the negative of the image.","k":"negate produce negative","l":"/api-operation#negate"},{"t":"normalise","d":"Enhance output image contrast by stretching its luminance to cover the full dynamic range.","k":"normalise enhance output contrast stretching luminance cover full dynamic range","l":"/api-operation#normalise"},{"t":"normalize","d":"Alternative spelling of normalise.","k":"normalize normalise","l":"/api-operation#normalize"},{"t":"convolve","d":"Convolve the image with the specified kernel.","k":"convolve specified kernel","l":"/api-operation#convolve"},{"t":"threshold","d":"Any pixel value greater than or equal to the threshold value will be set to 255, otherwise it will be set to 0.","k":"threshold pixel greater than equal otherwise","l":"/api-operation#threshold"},{"t":"boolean","d":"Perform a bitwise boolean operation with operand image.","k":"boolean bitwise operation operand","l":"/api-operation#boolean"},{"t":"linear","d":"Apply the linear formula a input b to the image levels adjustment","k":"linear apply formula input levels adjustment","l":"/api-operation#linear"},{"t":"recomb","d":"Recomb the image with the specified matrix.","k":"recomb specified matrix","l":"/api-operation#recomb"},{"t":"modulate","d":"Transforms the image using brightness, saturation and hue rotation.","k":"modulate transforms brightness saturation hue rotation","l":"/api-operation#modulate"},{"t":"removeAlpha","d":"Remove alpha channel, if any. This is a no-op if the image does not have an alpha channel.","k":"removealpha remove alpha channel","l":"/api-channel#removealpha"},{"t":"ensureAlpha","d":"Ensure alpha channel, if missing. The added alpha channel will be fully opaque. This is a no-op if the image already has an alpha channel.","k":"ensurealpha alpha channel missing added fully opaque","l":"/api-channel#ensurealpha"},{"t":"extractChannel","d":"Extract a single channel from a multi-channel image.","k":"extractchannel extract single channel multi","l":"/api-channel#extractchannel"},{"t":"joinChannel","d":"Join one or more channels to the image. The meaning of the added channels depends on the output colourspace, set with toColourspace. By default the output image will be web-friendl","k":"joinchannel join one channels meaning added depends output colourspace tocolourspace web friendl","l":"/api-channel#joinchannel"},{"t":"bandbool","d":"Perform a bitwise boolean operation on all input image channels bands to produce a single channel output image.","k":"bandbool bitwise boolean operation input channels bands produce single channel output","l":"/api-channel#bandbool"},{"t":"tint","d":"Tint the image using the provided chroma while preserving the image luminance. An alpha channel may be present and will be unchanged by the operation.","k":"tint chroma preserving luminance alpha channel present unchanged operation","l":"/api-colour#tint"},{"t":"greyscale","d":"Convert to 8-bit greyscale 256 shades of grey. This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use gamma with greyscale for the best re","k":"greyscale convert bit shades grey linear operation input colour space srgb gamma best","l":"/api-colour#greyscale"},{"t":"grayscale","d":"Alternative spelling of greyscale.","k":"grayscale greyscale","l":"/api-colour#grayscale"},{"t":"toColourspace","d":"Set the output colourspace. By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.","k":"tocolourspace output colourspace web friendly srgb additional channels interpreted alpha","l":"/api-colour#tocolourspace"},{"t":"toColorspace","d":"Alternative spelling of toColourspace.","k":"tocolorspace tocolourspace","l":"/api-colour#tocolorspace"},{"t":"format","d":"An Object containing nested boolean values representing the available input and output formats/methods.","k":"format object nested boolean representing available input output formats methods","l":"/api-utility#format"},{"t":"interpolators","d":"An Object containing the available interpolators and their proper values","k":"interpolators object available proper","l":"/api-utility#interpolators"},{"t":"versions","d":"An Object containing the version numbers of libvips and its dependencies.","k":"versions object version numbers libvips dependencies","l":"/api-utility#versions"},{"t":"cache","d":"Gets or, when options are provided, sets the limits of _libvips_ operation cache. Existing entries in the cache will be trimmed after any change in limits. This method always retur","k":"cache limits libvips operation existing entries trimmed change method retur","l":"/api-utility#cache"},{"t":"concurrency","d":"Gets or, when a concurrency is provided, sets the number of threads _libvips_ should create to process each image.","k":"concurrency number threads libvips create process","l":"/api-utility#concurrency"},{"t":"queue","d":"An EventEmitter that emits a change event when a task is either","k":"queue eventemitter emits change event task","l":"/api-utility#queue"},{"t":"counters","d":"Provides access to internal task counters.","k":"counters provides access internal task","l":"/api-utility#counters"},{"t":"simd","d":"Get and set use of SIMD vector unit instructions. Requires libvips to have been compiled with liborc support.","k":"simd vector unit instructions requires libvips compiled liborc","l":"/api-utility#simd"}]

‎lib/operation.js

+7-1
Original file line numberDiff line numberDiff line change
@@ -268,7 +268,13 @@ function blur (sigma) {
268268
}
269269

270270
/**
271-
* Merge alpha transparency channel, if any, with a background.
271+
* Merge alpha transparency channel, if any, with a background, then remove the alpha channel.
272+
*
273+
* @example
274+
* await sharp(rgbaInput)
275+
* .flatten('#F0A703')
276+
* .toBuffer();
277+
*
272278
* @param {Object} [options]
273279
* @param {string|Object} [options.background={r: 0, g: 0, b: 0}] - background colour, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black.
274280
* @returns {Sharp}

0 commit comments

Comments
 (0)
Please sign in to comment.