Add raw, uncompressed image data output #136

README.md

@@ -392,6 +392,18 @@ Use PNG format for the output image.
 
 Use WebP format for the output image.
 
+#### raw()
+
+_Requires libvips 7.42.0+_
+
+Provide raw, uncompressed uint8 (unsigned char) image data for Buffer and Stream based output.
+
+The number of channels depends on the input image and selected options.
+
+* 1 channel for images converted to `greyscale()`, with each byte representing one pixel.
+* 3 channels for colour images without alpha transparency, with bytes ordered \[red, green, blue, red, green, blue, etc.\]).
+* 4 channels for colour images with alpha transparency, with bytes ordered \[red, green, blue, alpha, red, green, blue, alpha, etc.\].
+
 #### quality(quality)
 
 The output quality to use for lossy JPEG, WebP and TIFF output formats. The default quality is `80`.

index.js

@@ -341,10 +341,10 @@ Sharp.prototype.compressionLevel = function(compressionLevel) {
 };
 
 /*
-  Disable the use of adaptive row filtering for PNG output - requires libvips 7.41.0+
+  Disable the use of adaptive row filtering for PNG output - requires libvips 7.42.0+
 */
 Sharp.prototype.withoutAdaptiveFiltering = function(withoutAdaptiveFiltering) {
-  if (semver.gte(libvipsVersion, '7.41.0')) {
+  if (semver.gte(libvipsVersion, '7.42.0')) {
     this.options.withoutAdaptiveFiltering = (typeof withoutAdaptiveFiltering === 'boolean') ? withoutAdaptiveFiltering : true;
   } else {
     console.error('withoutAdaptiveFiltering requires libvips 7.41.0+');
@@ -425,6 +425,15 @@ Sharp.prototype.webp = function() {
   return this;
 };
 
+Sharp.prototype.raw = function() {
+  if (semver.gte(libvipsVersion, '7.42.0')) {
+    this.options.output = '__raw';
+  } else {
+    console.error('Raw output requires libvips 7.42.0+');
+  }
+  return this;
+};
+
 /*
   Used by a Writable Stream to notify that it is ready for data
 */

src/resize.cc

@@ -635,6 +635,35 @@ class ResizeWorker : public NanAsyncWorker {
         return Error(baton, hook);
       }
       baton->outputFormat = "webp";
+#if (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 42)
+    } else if (baton->output == "__raw") {
+      // Write raw, uncompressed image data to buffer
+      if (baton->greyscale) {
+        // Extract first band for greyscale image
+        VipsImage *grey;
+        if (vips_extract_band(image, &grey, 1, NULL)) {
+          return Error(baton, hook);
+        }
+        vips_object_local(hook, grey);
+        image = grey;
+      }
+      if (image->BandFmt != VIPS_FORMAT_UCHAR) {
+        // Cast pixels to uint8 (unsigned char)
+        VipsImage *uchar;
+        if (vips_cast(image, &uchar, VIPS_FORMAT_UCHAR, NULL)) {
+          return Error(baton, hook);
+        }
+        vips_object_local(hook, uchar);
+        image = uchar;
+      }
+      // Get raw image data
+      baton->bufferOut = vips_image_write_to_memory(image, &baton->bufferOutLength);
+      if (baton->bufferOut == NULL) {
+        (baton->err).append("Could not allocate enough memory for raw output");
+        return Error(baton, hook);
+      }
+      baton->outputFormat = "raw";
+#endif
     } else {
       bool outputJpeg = IsJpeg(baton->output);
       bool outputPng = IsPng(baton->output);
@@ -649,7 +678,7 @@ class ResizeWorker : public NanAsyncWorker {
         }
         baton->outputFormat = "jpeg";
       } else if (outputPng || (matchInput && inputImageType == ImageType::PNG)) {
-#if (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 41)
+#if (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 42)
         // Select PNG row filter
         int filter = baton->withoutAdaptiveFiltering ? VIPS_FOREIGN_PNG_FILTER_NONE : VIPS_FOREIGN_PNG_FILTER_ALL;
         // Write PNG to file

test/unit/io.js

@@ -384,8 +384,8 @@ describe('Input/output', function() {
       done();
     });
 
-    if (semver.gte(sharp.libvipsVersion(), '7.41.0')) {
-      it('withoutAdaptiveFiltering generates smaller file [libvips ' + sharp.libvipsVersion() + '>=7.41.0]', function(done) {
+    if (semver.gte(sharp.libvipsVersion(), '7.42.0')) {
+      it('withoutAdaptiveFiltering generates smaller file [libvips ' + sharp.libvipsVersion() + '>=7.42.0]', function(done) {
         // First generate with adaptive filtering
         sharp(fixtures.inputPng)
           .resize(320, 240)
@@ -463,4 +463,49 @@ describe('Input/output', function() {
     });
   }
 
+  if (semver.gte(sharp.libvipsVersion(), '7.42.0')) {
+    describe('Ouput raw, uncompressed image data [libvips ' + sharp.libvipsVersion() + '>=7.42.0]', function() {
+      it('1 channel greyscale image', function(done) {
+        sharp(fixtures.inputJpg)
+          .greyscale()
+          .resize(32, 24)
+          .raw()
+          .toBuffer(function(err, data, info) {
+            assert.strictEqual(32 * 24 * 1, info.size);
+            assert.strictEqual(data.length, info.size);
+            assert.strictEqual('raw', info.format);
+            assert.strictEqual(32, info.width);
+            assert.strictEqual(24, info.height);
+            done();
+          });
+      });
+      it('3 channel colour image without transparency', function(done) {
+        sharp(fixtures.inputJpg)
+          .resize(32, 24)
+          .raw()
+          .toBuffer(function(err, data, info) {
+            assert.strictEqual(32 * 24 * 3, info.size);
+            assert.strictEqual(data.length, info.size);
+            assert.strictEqual('raw', info.format);
+            assert.strictEqual(32, info.width);
+            assert.strictEqual(24, info.height);
+            done();
+          });
+      });
+      it('4 channel colour image with transparency', function(done) {
+        sharp(fixtures.inputPngWithTransparency)
+          .resize(32, 24)
+          .raw()
+          .toBuffer(function(err, data, info) {
+            assert.strictEqual(32 * 24 * 4, info.size);
+            assert.strictEqual(data.length, info.size);
+            assert.strictEqual('raw', info.format);
+            assert.strictEqual(32, info.width);
+            assert.strictEqual(24, info.height);
+            done();
+          });
+      });
+    });
+  }
+
 });