Improve support for extension-less output filenames

src/sharp.cc

@@ -630,28 +630,34 @@ class ResizeWorker : public NanAsyncWorker {
         return resize_error(baton, output);
       }
       baton->output_format = "webp";
-    } else if (is_jpeg(baton->output))  {
+    } else {
+      bool output_jpeg = is_jpeg(baton->output);
+      bool output_png = is_png(baton->output);
+      bool output_webp = is_webp(baton->output);
+      bool output_tiff = is_tiff(baton->output);
+      bool match_input = !(output_jpeg || output_png || output_webp || output_tiff);
+      if (output_jpeg || (match_input && inputImageType == JPEG)) {
         // Write JPEG to file
         if (vips_jpegsave(output, baton->output.c_str(), "strip", !baton->withMetadata,
           "Q", baton->quality, "optimize_coding", TRUE, "interlace", baton->progressive, NULL)) {
           return resize_error(baton, output);
         }
         baton->output_format = "jpeg";
-    } else if (is_png(baton->output)) {
+      } else if (output_png || (match_input && inputImageType == PNG)) {
         // Write PNG to file
         if (vips_pngsave(output, baton->output.c_str(), "strip", !baton->withMetadata,
           "compression", baton->compressionLevel, "interlace", baton->progressive, NULL)) {
           return resize_error(baton, output);
         }
         baton->output_format = "png";
-    } else if (is_webp(baton->output)) {
+      } else if (output_webp || (match_input && inputImageType == WEBP)) {
         // Write WEBP to file
         if (vips_webpsave(output, baton->output.c_str(), "strip", !baton->withMetadata,
           "Q", baton->quality, NULL)) {
           return resize_error(baton, output);
         }
         baton->output_format = "webp";
-    } else if (is_tiff(baton->output)) {
+      } else if (output_tiff || (match_input && inputImageType == TIFF)) {
         // Write TIFF to file
         if (vips_tiffsave(output, baton->output.c_str(), "strip", !baton->withMetadata,
           "compression", VIPS_FOREIGN_TIFF_COMPRESSION_JPEG, "Q", baton->quality, NULL)) {
@@ -660,6 +666,8 @@ class ResizeWorker : public NanAsyncWorker {
         baton->output_format = "tiff";
       } else {
         (baton->err).append("Unsupported output " + baton->output);
+        return resize_error(baton, output);
+      }
     }
     g_object_unref(output);
 

tests/unit.js

@@ -21,7 +21,7 @@ var inputJpgWithExif = path.join(fixturesPath, "Landscape_8.jpg"); // https://gi
 var inputJpgWithGammaHoliness = path.join(fixturesPath, "gamma_dalai_lama_gray.jpg"); // http://www.4p8.com/eric.brasseur/gamma.html
 
 var inputPng = path.join(fixturesPath, "50020484-00001.png"); // http://c.searspartsdirect.com/lis_png/PLDM/50020484-00001.png
-var inputWebp = path.join(fixturesPath, "4.webp"); // http://www.gstatic.com/webp/gallery/4.webp
+var inputWebP = path.join(fixturesPath, "4.webp"); // http://www.gstatic.com/webp/gallery/4.webp
 var inputGif = path.join(fixturesPath, "Crash_test.gif"); // http://upload.wikimedia.org/wikipedia/commons/e/e3/Crash_test.gif
 
 // Ensure cache limits can be set
@@ -493,6 +493,48 @@ async.series([
           });
       });
   },
+  // Output filename without extension should mirror input format
+  function(done) {
+    sharp(inputJpg).resize(320, 80).toFile(path.join(fixturesPath, 'output.zoinks'), function(err, info) {
+      if (err) throw err;
+      assert.strictEqual('jpeg', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(80, info.height);
+      done();
+    });
+  },
+  function(done) {
+    sharp(inputPng).resize(320, 80).toFile(path.join(fixturesPath, 'output.zoinks'), function(err, info) {
+      if (err) throw err;
+      assert.strictEqual('png', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(80, info.height);
+      done();
+    });
+  },
+  function(done) {
+    sharp(inputWebP).resize(320, 80).toFile(path.join(fixturesPath, 'output.zoinks'), function(err, info) {
+      if (err) throw err;
+      assert.strictEqual('webp', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(80, info.height);
+      done();
+    });
+  },
+  function(done) {
+    sharp(inputTiff).resize(320, 80).toFile(path.join(fixturesPath, 'output.zoinks'), function(err, info) {
+      if (err) throw err;
+      assert.strictEqual('tiff', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(80, info.height);
+      done();
+    });
+  },
+  function(done) {
+    sharp(inputGif).resize(320, 80).toFile(path.join(fixturesPath, 'output.zoinks'), function(err, info) {
+      assert(!!err);
+    });
+  },
   // Metadata - JPEG
   function(done) {
     sharp(inputJpg).metadata(function(err, metadata) {
@@ -545,7 +587,7 @@ async.series([
   },
   // Metadata - WebP
   function(done) {
-    sharp(inputWebp).metadata(function(err, metadata) {
+    sharp(inputWebP).metadata(function(err, metadata) {
       if (err) throw err;
       assert.strictEqual('webp', metadata.format);
       assert.strictEqual(1024, metadata.width);