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Expose libvips interpolators #69
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Lovell Fuller
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64
README.md
64
README.md
@ -110,21 +110,33 @@ image.metadata(function(err, metadata) {
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```
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```javascript
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var pipeline = sharp().rotate().resize(null, 200).progressive().toBuffer(function(err, outputBuffer, info) {
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if (err) {
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throw err;
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}
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// outputBuffer contains 200px high progressive JPEG image data, auto-rotated using EXIF Orientation tag
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// info.width and info.height contain the final pixel dimensions of the resized image
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});
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var pipeline = sharp()
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.rotate()
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.resize(null, 200)
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.progressive()
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.toBuffer(function(err, outputBuffer, info) {
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if (err) {
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throw err;
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}
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// outputBuffer contains 200px high progressive JPEG image data,
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// auto-rotated using EXIF Orientation tag
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// info.width and info.height contain the dimensions of the resized image
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});
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readableStream.pipe(pipeline);
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```
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```javascript
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sharp('input.png').rotate(180).resize(300).sharpen().quality(90).webp().toBuffer().then(function(outputBuffer, info) {
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// outputBuffer contains 300px wide, upside down, sharpened, 90% quality WebP image data
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// info.width and info.height contain the final pixel dimensions of the resized image
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});
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sharp('input.png')
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.rotate(180)
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.resize(300)
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.sharpen()
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.quality(90)
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.webp()
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.toBuffer()
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.then(function(outputBuffer) {
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// outputBuffer contains 300px wide, upside down, sharpened,
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// 90% quality WebP image data
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});
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```
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```javascript
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@ -137,10 +149,16 @@ http.createServer(function(request, response) {
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```
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```javascript
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sharp(inputBuffer).resize(200, 300).bicubicInterpolation().embedWhite().toFile('output.tiff').then(function() {
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// output.tiff is a 200 pixels wide and 300 pixels high image containing a bicubic scaled
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// version, embedded on a white canvas, of the image data in buffer
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});
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sharp(inputBuffer)
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.resize(200, 300)
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.interpolateWith(sharp.interpolator.nohalo)
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.embedWhite()
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.toFile('output.tiff')
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.then(function() {
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// output.tiff is a 200 pixels wide and 300 pixels high image
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// containing a bicubic scaled version, embedded on a white canvas,
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// of the image data in inputBuffer
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});
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```
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```javascript
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@ -247,17 +265,17 @@ This is equivalent to GraphicsMagick's `>` geometry option: "change the dimensio
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Perform a mild sharpen of the resultant image. This typically reduces performance by 30%.
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#### bilinearInterpolation()
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#### interpolateWith(interpolator)
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Use [bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation) for image resizing, the default (and fastest) interpolation if none is specified.
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Use the given interpolator for image resizing, where `interpolator` is an attribute of the `sharp.interpolator` Object e.g. `sharp.interpolator.bicubic`.
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#### bicubicInterpolation()
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Possible interpolators, in order of performance, are:
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Use [bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation) for image resizing. This typically reduces performance by 5%.
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#### nohaloInterpolation()
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Use [Nohalo interpolation](http://eprints.soton.ac.uk/268086/) for image resizing. This typically reduces performance by a factor of 2.
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* `bilinear`: Use [bilinear interpolation](http://en.wikipedia.org/wiki/Bilinear_interpolation), the default (and fastest) interpolation.
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* `bicubic`: Use [bicubic interpolation](http://en.wikipedia.org/wiki/Bicubic_interpolation), which typically reduces performance by 5%.
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* `vertexSplitQuadraticBasisSpline`: Use [VSQBS interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/vsqbs.cpp#L48), which prevents "staircasing" when enlarging and typically reduces performance by 5%.
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* `locallyBoundedBicubic`: Use [LBB interpolation](https://github.com/jcupitt/libvips/blob/master/libvips/resample/lbb.cpp#L100), which prevents some "[acutance](http://en.wikipedia.org/wiki/Acutance)" and typically reduces performance by a factor of 2.
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* `nohalo`: Use [Nohalo interpolation](http://eprints.soton.ac.uk/268086/), which prevents acutance and typically reduces performance by a factor of 3.
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### Output options
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36
index.js
36
index.js
@ -135,28 +135,32 @@ Sharp.prototype.sharpen = function(sharpen) {
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};
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/*
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Use bilinear interpolation for the affine transformation (fastest, default)
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Set the interpolator to use for the affine transformation
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*/
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Sharp.prototype.bilinearInterpolation = function() {
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this.options.interpolator = 'bilinear';
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module.exports.interpolator = {
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bilinear: 'bilinear',
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bicubic: 'bicubic',
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nohalo: 'nohalo',
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locallyBoundedBicubic: 'lbb',
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vertexSplitQuadraticBasisSpline: 'vsqbs'
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};
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Sharp.prototype.interpolateWith = function(interpolator) {
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this.options.interpolator = interpolator;
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return this;
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};
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/*
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Use bicubic interpolation for the affine transformation
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Deprecated interpolation methods, to be removed in v0.7.0
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*/
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Sharp.prototype.bicubicInterpolation = function() {
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this.options.interpolator = 'bicubic';
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return this;
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};
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/*
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Use Nohalo interpolation for the affine transformation
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*/
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Sharp.prototype.nohaloInterpolation = function() {
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this.options.interpolator = 'nohalo';
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return this;
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};
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Sharp.prototype.bilinearInterpolation = util.deprecate(function() {
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return this.interpolateWith(module.exports.interpolator.bilinear);
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}, 'bilinearInterpolation() is deprecated, use interpolateWith(sharp.interpolator.bilinear) instead');
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Sharp.prototype.bicubicInterpolation = util.deprecate(function() {
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return this.interpolateWith(module.exports.interpolator.bicubic);
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}, 'bicubicInterpolation() is deprecated, use interpolateWith(sharp.interpolator.bicubic) instead');
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Sharp.prototype.nohaloInterpolation = util.deprecate(function() {
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return this.interpolateWith(module.exports.interpolator.nohalo);
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}, 'nohaloInterpolation() is deprecated, use interpolateWith(sharp.interpolator.nohalo) instead');
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Sharp.prototype.progressive = function(progressive) {
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this.options.progressive = (typeof progressive === 'boolean') ? progressive : true;
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@ -188,7 +188,7 @@ async.series({
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}).add("sharp-file-buffer-bicubic", {
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defer: true,
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fn: function(deferred) {
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sharp(inputJpg).resize(width, height).bicubicInterpolation().toBuffer(function(err, buffer) {
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sharp(inputJpg).resize(width, height).interpolateWith(sharp.interpolator.bicubic).toBuffer(function(err, buffer) {
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if (err) {
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throw err;
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} else {
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@ -200,7 +200,31 @@ async.series({
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}).add("sharp-file-buffer-nohalo", {
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defer: true,
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fn: function(deferred) {
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sharp(inputJpg).resize(width, height).nohaloInterpolation().toBuffer(function(err, buffer) {
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sharp(inputJpg).resize(width, height).interpolateWith(sharp.interpolator.nohalo).toBuffer(function(err, buffer) {
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if (err) {
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throw err;
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} else {
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assert.notStrictEqual(null, buffer);
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deferred.resolve();
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}
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});
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}
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}).add("sharp-file-buffer-locallyBoundedBicubic", {
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defer: true,
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fn: function(deferred) {
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sharp(inputJpg).resize(width, height).interpolateWith(sharp.interpolator.locallyBoundedBicubic).toBuffer(function(err, buffer) {
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if (err) {
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throw err;
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} else {
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assert.notStrictEqual(null, buffer);
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deferred.resolve();
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}
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});
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}
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}).add("sharp-file-buffer-vertexSplitQuadraticBasisSpline", {
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defer: true,
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fn: function(deferred) {
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sharp(inputJpg).resize(width, height).interpolateWith(sharp.interpolator.vertexSplitQuadraticBasisSpline).toBuffer(function(err, buffer) {
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if (err) {
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throw err;
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} else {
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@ -249,7 +249,7 @@ async.series([
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},
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// Interpolation: bilinear
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function(done) {
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sharp(inputJpg).resize(320, 240).bilinearInterpolation().toBuffer(function(err, data, info) {
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sharp(inputJpg).resize(320, 240).interpolateWith(sharp.interpolator.bilinear).toBuffer(function(err, data, info) {
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if (err) throw err;
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assert.strictEqual(true, data.length > 0);
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assert.strictEqual(320, info.width);
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@ -259,7 +259,7 @@ async.series([
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},
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// Interpolation: bicubic
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function(done) {
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sharp(inputJpg).resize(320, 240).bicubicInterpolation().toBuffer(function(err, data, info) {
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sharp(inputJpg).resize(320, 240).interpolateWith(sharp.interpolator.bicubic).toBuffer(function(err, data, info) {
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if (err) throw err;
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assert.strictEqual(true, data.length > 0);
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assert.strictEqual(320, info.width);
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@ -269,7 +269,27 @@ async.series([
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},
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// Interpolation: nohalo
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function(done) {
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sharp(inputJpg).resize(320, 240).nohaloInterpolation().toBuffer(function(err, data, info) {
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sharp(inputJpg).resize(320, 240).interpolateWith(sharp.interpolator.nohalo).toBuffer(function(err, data, info) {
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if (err) throw err;
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assert.strictEqual(true, data.length > 0);
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assert.strictEqual(320, info.width);
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assert.strictEqual(240, info.height);
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done();
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});
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},
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// Interpolation: locally bounded bicubic (LBB)
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function(done) {
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sharp(inputJpg).resize(320, 240).interpolateWith(sharp.interpolator.locallyBoundedBicubic).toBuffer(function(err, data, info) {
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if (err) throw err;
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assert.strictEqual(true, data.length > 0);
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assert.strictEqual(320, info.width);
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assert.strictEqual(240, info.height);
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done();
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});
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},
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// Interpolation: vertex split quadratic basis spline (VSQBS)
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function(done) {
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sharp(inputJpg).resize(320, 240).interpolateWith(sharp.interpolator.vertexSplitQuadraticBasisSpline).toBuffer(function(err, data, info) {
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if (err) throw err;
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assert.strictEqual(true, data.length > 0);
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assert.strictEqual(320, info.width);
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@ -346,7 +366,7 @@ async.series([
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});
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});
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var pipeline = sharp().resize(320, 240);
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readable.pipe(pipeline).pipe(writable)
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readable.pipe(pipeline).pipe(writable);
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},
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// Crop, gravity=north
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function(done) {
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@ -516,7 +536,7 @@ async.series([
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assert.strictEqual(1362, info.width);
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assert.strictEqual(1112, info.height);
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done();
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})
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});
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});
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},
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// Verify internal counters
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