Fix rotate/extract ordering for non-90 angles (#1755)

lib/resize.js

@@ -353,7 +353,7 @@ function extract (options) {
     }
   }, this);
   // Ensure existing rotation occurs before pre-resize extraction
-  if (suffix === 'Pre' && ((this.options.angle % 360) !== 0 || this.options.useExifOrientation === true)) {
+  if (suffix === 'Pre' && ((this.options.angle % 360) !== 0 || this.options.useExifOrientation === true || this.options.rotationAngle !== 0)) {
     this.options.rotateBeforePreExtract = true;
   }
   return this;

src/pipeline.cc

@@ -108,10 +108,17 @@ class PipelineWorker : public Nan::AsyncWorker {
       }
 
       // Rotate pre-extract
-      if (baton->rotateBeforePreExtract && rotation != VIPS_ANGLE_D0) {
+      if (baton->rotateBeforePreExtract) {
+        if (rotation != VIPS_ANGLE_D0) {
           image = image.rot(rotation);
           sharp::RemoveExifOrientation(image);
         }
+        if (baton->rotationAngle != 0.0) {
+          std::vector<double> background;
+          std::tie(image, background) = sharp::ApplyAlpha(image, baton->rotationBackground);
+          image = image.rotate(baton->rotationAngle, VImage::option()->set("background", background));
+        }
+      }
 
       // Trim
       if (baton->trimThreshold > 0.0) {
@@ -403,12 +410,13 @@ class PipelineWorker : public Nan::AsyncWorker {
           ->set("kernel", kernel));
       }
 
-      // Rotate
+      // Rotate post-extract 90-angle
       if (!baton->rotateBeforePreExtract &&  rotation != VIPS_ANGLE_D0) {
           image = image.rot(rotation);
           sharp::RemoveExifOrientation(image);
       }
 
+
       // Flip (mirror about Y axis)
       if (baton->flip) {
         image = image.flip(VIPS_DIRECTION_VERTICAL);
@@ -491,8 +499,8 @@ class PipelineWorker : public Nan::AsyncWorker {
         }
       }
 
-      // Rotate by degree
-      if (baton->rotationAngle != 0.0) {
+      // Rotate post-extract non-90 angle
+      if (!baton->rotateBeforePreExtract && baton->rotationAngle != 0.0) {
         std::vector<double> background;
         std::tie(image, background) = sharp::ApplyAlpha(image, baton->rotationBackground);
         image = image.rotate(baton->rotationAngle, VImage::option()->set("background", background));

test/unit/extract.js

@@ -121,6 +121,32 @@ describe('Partial image extraction', function () {
       });
   });
 
+  it('Extract then rotate non-90 anagle', function (done) {
+    sharp(fixtures.inputPngWithGreyAlpha)
+      .extract({ left: 20, top: 10, width: 380, height: 280 })
+      .rotate(45)
+      .jpeg()
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(467, info.width);
+        assert.strictEqual(467, info.height);
+        fixtures.assertSimilar(fixtures.expected('extract-rotate-45.jpg'), data, done);
+      });
+  });
+
+  it('Rotate then extract non-90 angle', function (done) {
+    sharp(fixtures.inputPngWithGreyAlpha)
+      .rotate(45)
+      .extract({ left: 20, top: 10, width: 380, height: 280 })
+      .jpeg()
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(380, info.width);
+        assert.strictEqual(280, info.height);
+        fixtures.assertSimilar(fixtures.expected('rotate-extract-45.jpg'), data, { threshold: 7 }, done);
+      });
+  });
+
   describe('Invalid parameters', function () {
     describe('using the legacy extract(top,left,width,height) syntax', function () {
       it('String top', function () {