Add bandbool feature for channel-wise boolean operations (#496)

src/operations.cc

@@ -392,4 +392,11 @@ namespace sharp {
     return image.colourspace(VIPS_INTERPRETATION_B_W) >= threshold;
   }
 
+  /*
+    Perform boolean/bitwise operation on image color channels - results in one channel image
+  */
+  VImage Bandbool(VImage image, VipsOperationBoolean const boolean) {
+    return image.bandbool(boolean);
+  }
+
 }  // namespace sharp

src/operations.h

@@ -82,6 +82,11 @@ namespace sharp {
   */
   VImage Threshold(VImage image, double const threshold, bool const thresholdColor);
 
+  /*
+    Perform boolean/bitwise operation on image color channels - results in one channel image
+  */
+  VImage Bandbool(VImage image, VipsOperationBoolean const boolean);
+
 }  // namespace sharp
 
 #endif  // SRC_OPERATIONS_H_

src/pipeline.cc

@@ -55,6 +55,7 @@ using sharp::Sharpen;
 using sharp::EntropyCrop;
 using sharp::TileCache;
 using sharp::Threshold;
+using sharp::Bandbool;
 
 using sharp::ImageType;
 using sharp::ImageTypeId;
@@ -470,6 +471,8 @@ class PipelineWorker : public AsyncWorker {
       bool shouldSharpen = baton->sharpenSigma != 0.0;
       bool shouldThreshold = baton->threshold != 0;
       bool shouldCutout = baton->overlayCutout;
+      bool shouldBandbool = baton->bandBoolOp < VIPS_OPERATION_BOOLEAN_LAST &&
+                            baton->bandBoolOp >= VIPS_OPERATION_BOOLEAN_AND;
       bool shouldPremultiplyAlpha = HasAlpha(image) &&
         (shouldAffineTransform || shouldBlur || shouldConv || shouldSharpen || (hasOverlay && !shouldCutout));
 
@@ -774,6 +777,11 @@ class PipelineWorker : public AsyncWorker {
         }
       }
 
+      // Apply per-channel Bandbool bitwise operations after all other operations
+      if (shouldBandbool) {
+        image = Bandbool(image, baton->bandBoolOp);
+      }
+
       // Override EXIF Orientation tag
       if (baton->withMetadata && baton->withMetadataOrientation != -1) {
         SetExifOrientation(image, baton->withMetadataOrientation);
@@ -1194,6 +1202,15 @@ NAN_METHOD(pipeline) {
       baton->convKernel[i] = To<double>(Get(kdata, i).ToLocalChecked()).FromJust();
     }
   }
+  // Bandbool operation
+  std::string opStr = attrAsStr(options, "bandBoolOp");
+  if(opStr == "and" ) {
+    baton->bandBoolOp = VIPS_OPERATION_BOOLEAN_AND;
+  } else if(opStr == "or") {
+    baton->bandBoolOp = VIPS_OPERATION_BOOLEAN_OR;
+  } else if(opStr == "eor") {
+    baton->bandBoolOp = VIPS_OPERATION_BOOLEAN_EOR;
+  }
 
   // Function to notify of queue length changes
   Callback *queueListener = new Callback(

src/pipeline.h

@@ -92,6 +92,7 @@ struct PipelineBaton {
   int convKernelHeight;
   double convKernelScale;
   double convKernelOffset;
+  VipsOperationBoolean bandBoolOp;
   int tileSize;
   int tileOverlap;
   VipsForeignDzContainer tileContainer;
@@ -151,6 +152,7 @@ struct PipelineBaton {
     convKernelHeight(0),
     convKernelScale(0.0),
     convKernelOffset(0.0),
+    bandBoolOp(VIPS_OPERATION_BOOLEAN_LAST),
     tileSize(256),
     tileOverlap(0),
     tileContainer(VIPS_FOREIGN_DZ_CONTAINER_FS),