Add support for Buffer and Stream-based TIFF output

docs/api-output.md

@@ -38,7 +38,7 @@ Returns **[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe
 ## toBuffer
 
 Write output to a Buffer.
-JPEG, PNG, WebP, and RAW output are supported.
+JPEG, PNG, WebP, TIFF and RAW output are supported.
 By default, the format will match the input image, except GIF and SVG input which become PNG output.
 
 `callback`, if present, gets three arguments `(err, data, info)` where:

docs/changelog.md

@@ -10,6 +10,10 @@ Requires libvips v8.5.2.
   [#573](https://github.com/lovell/sharp/issues/573)
   [@strarsis](https://github.com/strarsis)
 
+* Add support for Buffer and Stream-based TIFF output.
+  [#587](https://github.com/lovell/sharp/issues/587)
+  [@strarsis](https://github.com/strarsis)
+
 * Expose warnings from libvips via NODE_DEBUG=sharp environment variable.
   [#607](https://github.com/lovell/sharp/issues/607)
   [@puzrin](https://github.com/puzrin)

docs/index.md

@@ -22,7 +22,7 @@ the installation of any external runtime dependencies.
 
 This module supports reading JPEG, PNG, WebP, TIFF, GIF and SVG images.
 
-Output images can be in JPEG, PNG and WebP formats as well as uncompressed raw pixel data.
+Output images can be in JPEG, PNG, WebP and TIFF formats as well as uncompressed raw pixel data.
 
 Streams, Buffer objects and the filesystem can be used for input and output.
 

lib/constructor.js

@@ -32,7 +32,7 @@ const debuglog = util.debuglog('sharp');
  *
  * Constructor factory to create an instance of `sharp`, to which further methods are chained.
  *
- * JPEG, PNG or WebP format image data can be streamed out from this object.
+ * JPEG, PNG, WebP or TIFF format image data can be streamed out from this object.
  * When using Stream based output, derived attributes are available from the `info` event.
  *
  * Implements the [stream.Duplex](http://nodejs.org/api/stream.html#stream_class_stream_duplex) class.

lib/output.js

@@ -46,7 +46,7 @@ function toFile (fileOut, callback) {
 
 /**
  * Write output to a Buffer.
- * JPEG, PNG, WebP, and RAW output are supported.
+ * JPEG, PNG, WebP, TIFF and RAW output are supported.
  * By default, the format will match the input image, except GIF and SVG input which become PNG output.
  *
  * `callback`, if present, gets three arguments `(err, data, info)` where:

src/pipeline.cc

@@ -734,7 +734,7 @@ class PipelineWorker : public Nan::AsyncWorker {
       baton->width = image.width();
       baton->height = image.height();
       // Output
-      if (baton->fileOut == "") {
+      if (baton->fileOut.empty()) {
         // Buffer output
         if (baton->formatOut == "jpeg" || (baton->formatOut == "input" && inputImageType == ImageType::JPEG)) {
           // Write JPEG to buffer
@@ -786,6 +786,24 @@ class PipelineWorker : public Nan::AsyncWorker {
           area->free_fn = nullptr;
           vips_area_unref(area);
           baton->formatOut = "webp";
+        } else if (baton->formatOut == "tiff" || (baton->formatOut == "input" && inputImageType == ImageType::TIFF)) {
+          // Cast pixel values to float, if required
+          if (baton->tiffPredictor == VIPS_FOREIGN_TIFF_PREDICTOR_FLOAT) {
+            image = image.cast(VIPS_FORMAT_FLOAT);
+          }
+          // Write TIFF to buffer
+          VipsArea *area = VIPS_AREA(image.tiffsave_buffer(VImage::option()
+            ->set("strip", !baton->withMetadata)
+            ->set("Q", baton->tiffQuality)
+            ->set("squash", baton->tiffSquash)
+            ->set("compression", baton->tiffCompression)
+            ->set("predictor", baton->tiffPredictor)));
+          baton->bufferOut = static_cast<char*>(area->data);
+          baton->bufferOutLength = area->length;
+          area->free_fn = nullptr;
+          vips_area_unref(area);
+          baton->formatOut = "tiff";
+          baton->channels = std::min(baton->channels, 3);
         } else if (baton->formatOut == "raw" || (baton->formatOut == "input" && inputImageType == ImageType::RAW)) {
           // Write raw, uncompressed image data to buffer
           if (baton->greyscale || image.interpretation() == VIPS_INTERPRETATION_B_W) {

test/unit/io.js

@@ -837,6 +837,20 @@ describe('Input/output', function () {
       });
   });
 
+  it('Save TIFF to Buffer', function (done) {
+    sharp(fixtures.inputTiff)
+      .resize(320, 240)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(true, data.length > 0);
+        assert.strictEqual(data.length, info.size);
+        assert.strictEqual('tiff', info.format);
+        assert.strictEqual(320, info.width);
+        assert.strictEqual(240, info.height);
+        done();
+      });
+  });
+
   it('Invalid WebP quality throws error', function () {
     assert.throws(function () {
       sharp().webp({ quality: 101 });
@@ -914,7 +928,7 @@ describe('Input/output', function () {
       });
   });
 
-  it('TIFF deflate compression with hoizontal predictor shrinks test file', function (done) {
+  it('TIFF deflate compression with horizontal predictor shrinks test file', function (done) {
     const startSize = fs.statSync(fixtures.inputTiffUncompressed).size;
     sharp(fixtures.inputTiffUncompressed)
       .tiff({