Add withoutReduction option to resize operation (#3006)

docs/api-resize.md

@@ -49,6 +49,7 @@ Possible interpolation kernels are:
     *   `options.background` **([String][10] | [Object][9])** background colour when using a `fit` of `contain`, parsed by the [color][11] module, defaults to black without transparency. (optional, default `{r:0,g:0,b:0,alpha:1}`)
     *   `options.kernel` **[String][10]** the kernel to use for image reduction. (optional, default `'lanczos3'`)
     *   `options.withoutEnlargement` **[Boolean][12]** do not enlarge if the width *or* height are already less than the specified dimensions, equivalent to GraphicsMagick's `>` geometry option. (optional, default `false`)
+    *   `options.withoutReduction` **[Boolean][12]** do not reduce if the width *or* height are already greater than the specified dimensions, equivalent to GraphicsMagick's `<` geometry option. (optional, default `false`)
     *   `options.fastShrinkOnLoad` **[Boolean][12]** 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
@@ -117,6 +118,21 @@ sharp(input)
   });
 ```
 
+```javascript
+sharp(input)
+  .resize(200, 200, {
+    fit: sharp.fit.outside,
+    withoutReduction: true
+  })
+  .toFormat('jpeg')
+  .toBuffer()
+  .then(function(outputBuffer) {
+    // outputBuffer contains JPEG image data
+    // of at least 200 pixels wide and 200 pixels high while maintaining aspect ratio
+    // and no smaller than the input image
+  });
+```
+
 ```javascript
 const scaleByHalf = await sharp(input)
   .metadata()

lib/constructor.js

@@ -166,6 +166,7 @@ const Sharp = function (input, options) {
     extendRight: 0,
     extendBackground: [0, 0, 0, 255],
     withoutEnlargement: false,
+    withoutReduction: false,
     affineMatrix: [],
     affineBackground: [0, 0, 0, 255],
     affineIdx: 0,

lib/resize.js

@@ -183,6 +183,20 @@ function isRotationExpected (options) {
  *   });
  *
  * @example
+ * sharp(input)
+ *   .resize(200, 200, {
+ *     fit: sharp.fit.outside,
+ *     withoutReduction: true
+ *   })
+ *   .toFormat('jpeg')
+ *   .toBuffer()
+ *   .then(function(outputBuffer) {
+ *     // outputBuffer contains JPEG image data
+ *     // of at least 200 pixels wide and 200 pixels high while maintaining aspect ratio
+ *     // and no smaller than the input image
+ *   });
+ *
+ * @example
  * const scaleByHalf = await sharp(input)
  *   .metadata()
  *   .then(({ width }) => sharp(input)
@@ -200,6 +214,7 @@ function isRotationExpected (options) {
  * @param {String|Object} [options.background={r: 0, g: 0, b: 0, alpha: 1}] - background colour when using a `fit` of `contain`, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black without transparency.
  * @param {String} [options.kernel='lanczos3'] - the kernel to use for image reduction.
  * @param {Boolean} [options.withoutEnlargement=false] - do not enlarge if the width *or* height are already less than the specified dimensions, equivalent to GraphicsMagick's `>` geometry option.
+ * @param {Boolean} [options.withoutReduction=false] - do not reduce if the width *or* height are already greater than the specified dimensions, equivalent to GraphicsMagick's `<` geometry option.
  * @param {Boolean} [options.fastShrinkOnLoad=true] - take greater advantage of the JPEG and WebP shrink-on-load feature, which can lead to a slight moiré pattern on some images.
  * @returns {Sharp}
  * @throws {Error} Invalid parameters
@@ -276,6 +291,10 @@ function resize (width, height, options) {
     if (is.defined(options.withoutEnlargement)) {
       this._setBooleanOption('withoutEnlargement', options.withoutEnlargement);
     }
+    // Without reduction
+    if (is.defined(options.withoutReduction)) {
+      this._setBooleanOption('withoutReduction', options.withoutReduction);
+    }
     // Shrink on load
     if (is.defined(options.fastShrinkOnLoad)) {
       this._setBooleanOption('fastShrinkOnLoad', options.fastShrinkOnLoad);

package.json

@@ -79,7 +79,8 @@
     "Michael Nutt <michael@nutt.im>",
     "Brad Parham <baparham@gmail.com>",
     "Taneli Vatanen <taneli.vatanen@gmail.com>",
-    "Joris Dugué <zaruike10@gmail.com>"
+    "Joris Dugué <zaruike10@gmail.com>",
+    "Chris Banks <christopher.bradley.banks@gmail.com>"
   ],
   "scripts": {
     "install": "(node install/libvips && node install/dll-copy && prebuild-install) || (node install/can-compile && node-gyp rebuild && node install/dll-copy)",

src/pipeline.cc

@@ -130,6 +130,17 @@ class PipelineWorker : public Napi::AsyncWorker {
         pageHeight = inputHeight;
       }
 
+      // If withoutReduction is specified,
+      // Override target width and height if less than respective value from input file
+       if (baton->withoutReduction) {
+          if (baton->width < inputWidth) {
+            baton->width = inputWidth;
+          }
+          if (baton->height < inputHeight) {
+            baton->height = inputHeight;
+          }
+      }
+
       // Scaling calculations
       double hshrink;
       double vshrink;
@@ -1356,6 +1367,7 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   }
   // Resize options
   baton->withoutEnlargement = sharp::AttrAsBool(options, "withoutEnlargement");
+  baton->withoutReduction = sharp::AttrAsBool(options, "withoutReduction");
   baton->position = sharp::AttrAsInt32(options, "position");
   baton->resizeBackground = sharp::AttrAsVectorOfDouble(options, "resizeBackground");
   baton->kernel = sharp::AttrAsStr(options, "kernel");

src/pipeline.h

@@ -119,6 +119,7 @@ struct PipelineBaton {
   int extendRight;
   std::vector<double> extendBackground;
   bool withoutEnlargement;
+  bool withoutReduction;
   std::vector<double> affineMatrix;
   std::vector<double> affineBackground;
   double affineIdx;
@@ -259,6 +260,7 @@ struct PipelineBaton {
     extendRight(0),
     extendBackground{ 0.0, 0.0, 0.0, 255.0 },
     withoutEnlargement(false),
+    withoutReduction(false),
     affineMatrix{ 1.0, 0.0, 0.0, 1.0 },
     affineBackground{ 0.0, 0.0, 0.0, 255.0 },
     affineIdx(0),

test/unit/resize.js

@@ -357,6 +357,127 @@ describe('Resize dimensions', function () {
       });
   });
 
+  it('Do enlarge when input width is less than output width', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize({
+        width: 2800,
+        withoutReduction: true
+      })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(2800, info.width);
+        assert.strictEqual(2225, info.height);
+        done();
+      });
+  });
+
+  it('Do enlarge when input height is less than output height', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize({
+        height: 2300,
+        withoutReduction: true
+      })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(2725, info.width);
+        assert.strictEqual(2300, info.height);
+        done();
+      });
+  });
+
+  it('Do not crop when fit = cover and withoutReduction = true and width >= outputWidth, and height < outputHeight', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize({
+        width: 3000,
+        height: 1000,
+        withoutReduction: true
+      })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(3000, info.width);
+        assert.strictEqual(2225, info.height);
+        done();
+      });
+  });
+
+  it('Do not crop when fit = cover and withoutReduction = true and width < outputWidth, and height >= outputHeight', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize({
+        width: 1500,
+        height: 2226,
+        withoutReduction: true
+      })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(2725, info.width);
+        assert.strictEqual(2226, info.height);
+        done();
+      });
+  });
+
+  it('Do enlarge when input width is less than output width', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize({
+        width: 2800,
+        withoutReduction: false
+      })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(2800, info.width);
+        assert.strictEqual(2286, info.height);
+        done();
+      });
+  });
+
+  it('Do not resize when both withoutEnlargement and withoutReduction are true', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize(320, 320, { fit: 'fill', withoutEnlargement: true, withoutReduction: true })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(2725, info.width);
+        assert.strictEqual(2225, info.height);
+        done();
+      });
+  });
+
+  it('Do not reduce size when fit = outside and withoutReduction are true and height > outputHeight and width > outputWidth', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize(320, 320, { fit: 'outside', withoutReduction: true })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(2725, info.width);
+        assert.strictEqual(2225, info.height);
+        done();
+      });
+  });
+
+  it('Do resize when fit = outside and withoutReduction are true and input height > height and input width > width ', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize(3000, 3000, { fit: 'outside', withoutReduction: true })
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(3674, info.width);
+        assert.strictEqual(3000, info.height);
+        done();
+      });
+  });
+
   it('fit=fill, downscale width and height', function (done) {
     sharp(fixtures.inputJpg)
       .resize(320, 320, { fit: 'fill' })