Allow floating point density input (#1362)

Metadata output will still remain integer

docs/api-composite.md

@@ -18,7 +18,7 @@ If the overlay image contains an alpha channel then composition with premultipli
     -   `options.left` **[Number][4]?** the pixel offset from the left edge.
     -   `options.tile` **[Boolean][5]** set to true to repeat the overlay image across the entire image with the given `gravity`. (optional, default `false`)
     -   `options.cutout` **[Boolean][5]** set to true to apply only the alpha channel of the overlay image to the input image, giving the appearance of one image being cut out of another. (optional, default `false`)
-    -   `options.density` **[Number][4]** integral number representing the DPI for vector overlay image. (optional, default `72`)
+    -   `options.density` **[Number][4]** number representing the DPI for vector overlay image. (optional, default `72`)
     -   `options.raw` **[Object][3]?** describes overlay when using raw pixel data.
         -   `options.raw.width` **[Number][4]?** 
         -   `options.raw.height` **[Number][4]?** 

docs/api-constructor.md

@@ -12,7 +12,7 @@
     -   `options.failOnError` **[Boolean][4]** by default apply a "best effort"
          to decode images, even if the data is corrupt or invalid. Set this flag to true
          if you'd rather halt processing and raise an error when loading invalid images. (optional, default `false`)
-    -   `options.density` **[Number][5]** integral number representing the DPI for vector images. (optional, default `72`)
+    -   `options.density` **[Number][5]** number representing the DPI for vector images. (optional, default `72`)
     -   `options.page` **[Number][5]** page number to extract for multi-page input (GIF, TIFF) (optional, default `0`)
     -   `options.raw` **[Object][3]?** describes raw pixel input image data. See `raw()` for pixel ordering.
         -   `options.raw.width` **[Number][5]?** 

lib/composite.js

@@ -34,7 +34,7 @@ const is = require('./is');
  * @param {Number} [options.left] - the pixel offset from the left edge.
  * @param {Boolean} [options.tile=false] - set to true to repeat the overlay image across the entire image with the given `gravity`.
  * @param {Boolean} [options.cutout=false] - set to true to apply only the alpha channel of the overlay image to the input image, giving the appearance of one image being cut out of another.
- * @param {Number} [options.density=72] - integral number representing the DPI for vector overlay image.
+ * @param {Number} [options.density=72] - number representing the DPI for vector overlay image.
  * @param {Object} [options.raw] - describes overlay when using raw pixel data.
  * @param {Number} [options.raw.width]
  * @param {Number} [options.raw.height]

lib/constructor.js

@@ -96,7 +96,7 @@ const debuglog = util.debuglog('sharp');
  * @param {Boolean} [options.failOnError=false] - by default apply a "best effort"
  *  to decode images, even if the data is corrupt or invalid. Set this flag to true
  *  if you'd rather halt processing and raise an error when loading invalid images.
- * @param {Number} [options.density=72] - integral number representing the DPI for vector images.
+ * @param {Number} [options.density=72] - number representing the DPI for vector images.
  * @param {Number} [options.page=0] - page number to extract for multi-page input (GIF, TIFF)
  * @param {Object} [options.raw] - describes raw pixel input image data. See `raw()` for pixel ordering.
  * @param {Number} [options.raw.width]

lib/input.js

@@ -36,7 +36,7 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
     }
     // Density
     if (is.defined(inputOptions.density)) {
-      if (is.integer(inputOptions.density) && is.inRange(inputOptions.density, 1, 2400)) {
+      if (is.inRange(inputOptions.density, 1, 2400)) {
         inputDescriptor.density = inputOptions.density;
       } else {
         throw new Error('Invalid density (1 to 2400) ' + inputOptions.density);

src/common.cc

@@ -55,7 +55,7 @@ namespace sharp {
     descriptor->failOnError = AttrTo<bool>(input, "failOnError");
     // Density for vector-based input
     if (HasAttr(input, "density")) {
-      descriptor->density = AttrTo<uint32_t>(input, "density");
+      descriptor->density = AttrTo<double>(input, "density");
     }
     // Raw pixel input
     if (HasAttr(input, "rawChannels")) {
@@ -228,7 +228,7 @@ namespace sharp {
               ->set("access", accessMethod)
               ->set("fail", descriptor->failOnError);
             if (imageType == ImageType::SVG || imageType == ImageType::PDF) {
-              option->set("dpi", static_cast<double>(descriptor->density));
+              option->set("dpi", descriptor->density);
             }
             if (imageType == ImageType::MAGICK) {
               option->set("density", std::to_string(descriptor->density).data());
@@ -270,7 +270,7 @@ namespace sharp {
               ->set("access", accessMethod)
               ->set("fail", descriptor->failOnError);
             if (imageType == ImageType::SVG || imageType == ImageType::PDF) {
-              option->set("dpi", static_cast<double>(descriptor->density));
+              option->set("dpi", descriptor->density);
             }
             if (imageType == ImageType::MAGICK) {
               option->set("density", std::to_string(descriptor->density).data());
@@ -355,8 +355,8 @@ namespace sharp {
   /*
     Set pixels/mm resolution based on a pixels/inch density.
   */
-  void SetDensity(VImage image, const int density) {
+  void SetDensity(VImage image, const double density) {
-    const double pixelsPerMm = static_cast<double>(density) / 25.4;
+    const double pixelsPerMm = density / 25.4;
     image.set("Xres", pixelsPerMm);
     image.set("Yres", pixelsPerMm);
     image.set(VIPS_META_RESOLUTION_UNIT, "in");

src/common.h

@@ -49,7 +49,7 @@ namespace sharp {
     char *buffer;
     bool failOnError;
     size_t bufferLength;
-    int density;
+    double density;
     int rawChannels;
     int rawWidth;
     int rawHeight;
@@ -63,7 +63,7 @@ namespace sharp {
       buffer(nullptr),
       failOnError(FALSE),
       bufferLength(0),
-      density(72),
+      density(72.0),
       rawChannels(0),
       rawWidth(0),
       rawHeight(0),
@@ -186,7 +186,7 @@ namespace sharp {
   /*
     Set pixels/mm resolution based on a pixels/inch density.
   */
-  void SetDensity(VImage image, const int density);
+  void SetDensity(VImage image, const double density);
 
   /*
     Check the proposed format supports the current dimensions.

test/unit/io.js

@@ -939,6 +939,21 @@ describe('Input/output', function () {
       });
   });
 
+  it('Convert SVG to PNG at 14.4DPI', function (done) {
+    sharp(fixtures.inputSvg, { density: 14.4 })
+      .toFormat('png')
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('png', info.format);
+        assert.strictEqual(20, info.width);
+        assert.strictEqual(20, info.height);
+        fixtures.assertSimilar(fixtures.expected('svg14.4.png'), data, function (err) {
+          if (err) throw err;
+          done();
+        });
+      });
+  });
+
   it('Convert SVG with embedded images to PNG, respecting dimensions, autoconvert to PNG', function (done) {
     sharp(fixtures.inputSvgWithEmbeddedImages)
       .toBuffer(function (err, data, info) {
@@ -1506,11 +1521,6 @@ describe('Input/output', function () {
         sharp(null, { density: 'zoinks' });
       });
     });
-    it('Invalid density: float', function () {
-      assert.throws(function () {
-        sharp(null, { density: 0.5 });
-      });
-    });
     it('Ignore unknown attribute', function () {
       sharp(null, { unknown: true });
     });