feature: min

README.md

@@ -332,6 +332,12 @@ Preserving aspect ratio, resize the image to the maximum `width` or `height` spe
 
 Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`.
 
+#### min()
+
+Preserving aspect ratio, resize the image to the minimum `width` or `height` specified.
+
+Both `width` and `height` must be provided via `resize` otherwise the behaviour will default to `crop`.
+
 #### background(rgba)
 
 Set the background for the `embed` and `flatten` operations.

index.js

@@ -41,7 +41,7 @@ var Sharp = function(input) {
     heightPost: -1,
     width: -1,
     height: -1,
-    canvas: 'c',
+    canvas: 'crop',
     gravity: 0,
     angle: 0,
     rotateBeforePreExtract: false,
@@ -136,7 +136,7 @@ Sharp.prototype._write = function(chunk, encoding, callback) {
 module.exports.gravity = {'center': 0, 'centre': 0, 'north': 1, 'east': 2, 'south': 3, 'west': 4};
 
 Sharp.prototype.crop = function(gravity) {
-  this.options.canvas = 'c';
+  this.options.canvas = 'crop';
   if (typeof gravity === 'number' && !Number.isNaN(gravity) && gravity >= 0 && gravity <= 4) {
     this.options.gravity = gravity;
   } else {
@@ -176,12 +176,17 @@ Sharp.prototype.background = function(rgba) {
 };
 
 Sharp.prototype.embed = function() {
-  this.options.canvas = 'e';
+  this.options.canvas = 'embed';
   return this;
 };
 
 Sharp.prototype.max = function() {
-  this.options.canvas = 'm';
+  this.options.canvas = 'max';
+  return this;
+};
+
+Sharp.prototype.min = function() {
+  this.options.canvas = 'min';
   return this;
 };
 

package.json

@@ -12,7 +12,8 @@
     "Amit Pitaru <pitaru.amit@gmail.com>",
     "Brandon Aaron <hello.brandon@aaron.sh>",
     "Andreas Lind <andreas@one.com>",
-    "Maurus Cuelenaere <mcuelenaere@gmail.com>"
+    "Maurus Cuelenaere <mcuelenaere@gmail.com>",
+    "Linus Unnebäck <linus@folkdatorn.se>"
   ],
   "description": "High performance Node.js module to resize JPEG, PNG, WebP and TIFF images using the libvips library",
   "scripts": {

src/resize.cc

@@ -37,8 +37,9 @@ using sharp::counterQueue;
 
 enum class Canvas {
   CROP,
+  EMBED,
   MAX,
-  EMBED
+  MIN
 };
 
 enum class Angle {
@@ -252,14 +253,29 @@ class ResizeWorker : public NanAsyncWorker {
       // Fixed width and height
       double xfactor = static_cast<double>(inputWidth) / static_cast<double>(baton->width);
       double yfactor = static_cast<double>(inputHeight) / static_cast<double>(baton->height);
-      factor = (baton->canvas == Canvas::CROP) ? std::min(xfactor, yfactor) : std::max(xfactor, yfactor);
+      switch (baton->canvas) {
-      // if max is set, we need to compute the real size of the thumb image
+        case Canvas::CROP:
-      if (baton->canvas == Canvas::MAX) {
+          factor = std::min(xfactor, yfactor);
-        if (xfactor > yfactor) {
+          break;
-          baton->height = round(static_cast<double>(inputHeight) / xfactor);
+        case Canvas::EMBED:
-        } else {
+          factor = std::max(xfactor, yfactor);
-          baton->width = round(static_cast<double>(inputWidth) / yfactor);
+          break;
-        }
+        case Canvas::MAX:
+          factor = std::max(xfactor, yfactor);
+          if (xfactor > yfactor) {
+            baton->height = round(static_cast<double>(inputHeight) / xfactor);
+          } else {
+            baton->width = round(static_cast<double>(inputWidth) / yfactor);
+          }
+          break;
+        case Canvas::MIN:
+          factor = std::min(xfactor, yfactor);
+          if (xfactor < yfactor) {
+            baton->height = round(static_cast<double>(inputHeight) / xfactor);
+          } else {
+            baton->width = round(static_cast<double>(inputWidth) / yfactor);
+          }
+          break;
       }
     } else if (baton->width > 0) {
       // Fixed width, auto height
@@ -549,7 +565,7 @@ class ResizeWorker : public NanAsyncWorker {
         vips_object_local(hook, embedded);
         image = embedded;
       } else {
-        // Crop/max
+        // Crop/max/min
         int left;
         int top;
         std::tie(left, top) = CalculateCrop(image->Xsize, image->Ysize, baton->width, baton->height, baton->gravity);
@@ -963,12 +979,14 @@ NAN_METHOD(resize) {
   baton->height = options->Get(NanNew<String>("height"))->Int32Value();
   // Canvas option
   Local<String> canvas = options->Get(NanNew<String>("canvas"))->ToString();
-  if (canvas->Equals(NanNew<String>("c"))) {
+  if (canvas->Equals(NanNew<String>("crop"))) {
     baton->canvas = Canvas::CROP;
-  } else if (canvas->Equals(NanNew<String>("m"))) {
+  } else if (canvas->Equals(NanNew<String>("embed"))) {
-    baton->canvas = Canvas::MAX;
-  } else if (canvas->Equals(NanNew<String>("e"))) {
     baton->canvas = Canvas::EMBED;
+  } else if (canvas->Equals(NanNew<String>("max"))) {
+    baton->canvas = Canvas::MAX;
+  } else if (canvas->Equals(NanNew<String>("min"))) {
+    baton->canvas = Canvas::MIN;
   }
   // Background colour
   Local<Array> background = Local<Array>::Cast(options->Get(NanNew<String>("background")));

test/unit/resize.js

@@ -185,6 +185,39 @@ describe('Resize dimensions', function() {
     });
   });
 
+  it('Min width or height considering ratio (landscape)', function(done) {
+    sharp(fixtures.inputJpg).resize(320, 320).min().toBuffer(function(err, data, info) {
+      if (err) throw err;
+      assert.strictEqual(true, data.length > 0);
+      assert.strictEqual('jpeg', info.format);
+      assert.strictEqual(392, info.width);
+      assert.strictEqual(320, info.height);
+      done();
+    });
+  });
+
+  it('Min width or height considering ratio (portrait)', function(done) {
+    sharp(fixtures.inputTiff).resize(320, 320).min().jpeg().toBuffer(function(err, data, info) {
+      if (err) throw err;
+      assert.strictEqual(true, data.length > 0);
+      assert.strictEqual('jpeg', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(422, info.height);
+      done();
+    });
+  });
+
+  it('Provide only one dimension with min, should default to crop', function(done) {
+    sharp(fixtures.inputJpg).resize(320).min().toBuffer(function(err, data, info) {
+      if (err) throw err;
+      assert.strictEqual(true, data.length > 0);
+      assert.strictEqual('jpeg', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(261, info.height);
+      done();
+    });
+  });
+
   it('Do not enlarge when input width is already less than output width', function(done) {
     sharp(fixtures.inputJpg)
       .resize(2800)