Add support for squashing TIFF output to 1-bit (#783)

lib/constructor.js

@@ -171,6 +171,7 @@ const Sharp = function (input, options) {
     tiffQuality: 80,
     tiffCompression: 'jpeg',
     tiffPredictor: 'none',
+    tiffSquash: false,
     tileSize: 256,
     tileOverlap: 0,
     // Function to notify of queue length changes

lib/output.js

@@ -213,6 +213,7 @@ function webp (options) {
  * @param {Boolean} [options.force=true] - force TIFF output, otherwise attempt to use input format
  * @param {Boolean} [options.compression='jpeg'] - compression options: lzw, deflate, jpeg
  * @param {Boolean} [options.predictor='none'] - compression predictor options: none, horizontal, float
+ * @param {Boolean} [options.squash=false] - squash 8-bit images down to 1 bit
  * @returns {Sharp}
  * @throws {Error} Invalid options
  */
@@ -224,6 +225,13 @@ function tiff (options) {
       throw new Error('Invalid quality (integer, 1-100) ' + options.quality);
     }
   }
+  if (is.object(options) && is.defined(options.squash)) {
+    if (is.bool(options.squash)) {
+      this.options.tiffSquash = options.squash;
+    } else {
+      throw new Error('Invalid Value for squash ' + options.squash + ' Only Boolean Values allowed for options.squash.');
+    }
+  }
   // compression
   if (is.defined(options) && is.defined(options.compression)) {
     if (is.string(options.compression) && is.inArray(options.compression, ['lzw', 'deflate', 'jpeg', 'none'])) {

src/pipeline.cc

@@ -846,8 +846,9 @@ class PipelineWorker : public Nan::AsyncWorker {
           image.tiffsave(const_cast<char*>(baton->fileOut.data()), VImage::option()
             ->set("strip", !baton->withMetadata)
             ->set("Q", baton->tiffQuality)
+            ->set("squash", baton->tiffSquash)
             ->set("compression", baton->tiffCompression)
-            ->set("predictor", baton->tiffPredictor) );
+            ->set("predictor", baton->tiffPredictor));
           baton->formatOut = "tiff";
           baton->channels = std::min(baton->channels, 3);
         } else if (baton->formatOut == "dz" || isDz || isDzZip) {
@@ -1204,6 +1205,7 @@ NAN_METHOD(pipeline) {
   baton->webpLossless = AttrTo<bool>(options, "webpLossless");
   baton->webpNearLossless = AttrTo<bool>(options, "webpNearLossless");
   baton->tiffQuality = AttrTo<uint32_t>(options, "tiffQuality");
+  baton->tiffSquash = AttrTo<bool>(options, "tiffSquash");
   // tiff compression options
   baton->tiffCompression = static_cast<VipsForeignTiffCompression>(
   vips_enum_from_nick(nullptr, VIPS_TYPE_FOREIGN_TIFF_COMPRESSION,

src/pipeline.h

@@ -106,6 +106,7 @@ struct PipelineBaton {
   int tiffQuality;
   VipsForeignTiffCompression tiffCompression;
   VipsForeignTiffPredictor tiffPredictor;
+  bool tiffSquash;
   std::string err;
   bool withMetadata;
   int withMetadataOrientation;
@@ -176,6 +177,7 @@ struct PipelineBaton {
     tiffQuality(80),
     tiffCompression(VIPS_FOREIGN_TIFF_COMPRESSION_JPEG),
     tiffPredictor(VIPS_FOREIGN_TIFF_PREDICTOR_NONE),
+    tiffSquash(false),
     withMetadata(false),
     withMetadataOrientation(-1),
     convKernelWidth(0),

test/fixtures/index.js

@@ -85,6 +85,7 @@ module.exports = {
   inputTiff: getPath('G31D.TIF'), // http://www.fileformat.info/format/tiff/sample/e6c9a6e5253348f4aef6d17b534360ab/index.htm
   inputTiffCielab: getPath('cielab-dagams.tiff'), // https://github.com/lovell/sharp/issues/646
   inputTiffUncompressed: getPath('uncompressed_tiff.tiff'), // https://code.google.com/archive/p/imagetestsuite/wikis/TIFFTestSuite.wiki file: 0c84d07e1b22b76f24cccc70d8788e4a.tif
+  inputTiff8BitDepth: getPath('8bit_depth.tiff'),
   inputGif: getPath('Crash_test.gif'), // http://upload.wikimedia.org/wikipedia/commons/e/e3/Crash_test.gif
   inputGifGreyPlusAlpha: getPath('grey-plus-alpha.gif'), // http://i.imgur.com/gZ5jlmE.gif
   inputSvg: getPath('check.svg'), // http://dev.w3.org/SVG/tools/svgweb/samples/svg-files/check.svg

test/unit/io.js

@@ -861,6 +861,44 @@ describe('Input/output', function () {
     });
   });
 
+  it('Not squashing TIFF to a bit depth of 1 should not change the file size', function (done) {
+    const startSize = fs.statSync(fixtures.inputTiff8BitDepth).size;
+    sharp(fixtures.inputTiff8BitDepth)
+      .toColourspace('b-w') // can only squash 1 band uchar images
+      .tiff({
+        squash: false,
+        compression: 'none'
+      })
+      .toFile(fixtures.outputTiff, (err, info) => {
+        if (err) throw err;
+        assert.strictEqual('tiff', info.format);
+        assert(info.size === startSize);
+        fs.unlink(fixtures.outputTiff, done);
+      });
+  });
+
+  it('Squashing TIFF to a bit depth of 1 should significantly reduce file size', function (done) {
+    const startSize = fs.statSync(fixtures.inputTiff8BitDepth).size;
+    sharp(fixtures.inputTiff8BitDepth)
+      .toColourspace('b-w') // can only squash 1 band uchar images
+      .tiff({
+        squash: true,
+        compression: 'none'
+      })
+      .toFile(fixtures.outputTiff, (err, info) => {
+        if (err) throw err;
+        assert.strictEqual('tiff', info.format);
+        assert(info.size < (startSize / 2));
+        fs.unlink(fixtures.outputTiff, done);
+      });
+  });
+
+  it('Invalid TIFF squash value throws error', function () {
+    assert.throws(function () {
+      sharp().tiff({ squash: 'true' });
+    });
+  });
+
   it('TIFF lzw compression with horizontal predictor shrinks test file', function (done) {
     const startSize = fs.statSync(fixtures.inputTiffUncompressed).size;
     sharp(fixtures.inputTiffUncompressed)