Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.jeremydyer.nifi; import org.apache.commons.io.IOUtils; import org.apache.nifi.annotation.behavior.ReadsAttribute; import org.apache.nifi.annotation.behavior.ReadsAttributes; import org.apache.nifi.annotation.behavior.WritesAttribute; import org.apache.nifi.annotation.behavior.WritesAttributes; import org.apache.nifi.annotation.documentation.CapabilityDescription; import org.apache.nifi.annotation.documentation.Tags; import org.apache.nifi.components.PropertyDescriptor; import org.apache.nifi.flowfile.FlowFile; import org.apache.nifi.processor.*; import org.apache.nifi.processor.exception.ProcessException; import org.apache.nifi.processor.io.InputStreamCallback; import org.apache.nifi.processor.io.OutputStreamCallback; import org.apache.nifi.processor.util.StandardValidators; import org.opencv.core.*; import org.opencv.imgcodecs.Imgcodecs; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.*; @Tags({ "opencv", "crop", "image" }) @CapabilityDescription("Crops an image to the desired dimensions") @ReadsAttributes({ @ReadsAttribute(attribute = "", description = "") }) @WritesAttributes({ @WritesAttribute(attribute = "image.width", description = "Width of the original image"), @WritesAttribute(attribute = "image.height", description = "Height of the original image") }) public class CropImageProcessor extends AbstractProcessor { public static final PropertyDescriptor X_POINT = new PropertyDescriptor.Builder().name("X Point") .description("X coordinate location to begin the image cropping.").required(true) .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR).expressionLanguageSupported(true) .build(); public static final PropertyDescriptor Y_POINT = new PropertyDescriptor.Builder().name("Y Point") .description("Y coordinate location to begin the image cropping.").required(true) .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR).expressionLanguageSupported(true) .build(); public static final PropertyDescriptor CROP_WIDTH = new PropertyDescriptor.Builder().name("Crop Width") .description("Number of pixels width to crop the image").required(true) .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR).expressionLanguageSupported(true) .build(); public static final PropertyDescriptor CROP_HEIGHT = new PropertyDescriptor.Builder().name("Crop Height") .description("Number of pixels heigh to crop the image").required(true) .addValidator(StandardValidators.NON_NEGATIVE_INTEGER_VALIDATOR).expressionLanguageSupported(true) .build(); public static final Relationship REL_ORIGINAL = new Relationship.Builder().name("original") .description("original input").build(); public static final Relationship REL_CROPPED_IMAGE = new Relationship.Builder().name("cropped_image") .description("cropped image").build(); public static final Relationship REL_FAILURE = new Relationship.Builder().name("failure") .description("failure during processing").build(); private List<PropertyDescriptor> descriptors; private Set<Relationship> relationships; @Override protected void init(final ProcessorInitializationContext context) { final List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>(); descriptors.add(X_POINT); descriptors.add(Y_POINT); descriptors.add(CROP_WIDTH); descriptors.add(CROP_HEIGHT); this.descriptors = Collections.unmodifiableList(descriptors); final Set<Relationship> relationships = new HashSet<Relationship>(); relationships.add(REL_ORIGINAL); relationships.add(REL_CROPPED_IMAGE); relationships.add(REL_FAILURE); this.relationships = Collections.unmodifiableSet(relationships); //Load the OpenCV Native Library System.loadLibrary(Core.NATIVE_LIBRARY_NAME); } @Override public Set<Relationship> getRelationships() { return this.relationships; } @Override public final List<PropertyDescriptor> getSupportedPropertyDescriptors() { return descriptors; } @Override public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException { final FlowFile original = session.get(); if (original == null) { return; } session.read(original, new InputStreamCallback() { @Override public void process(InputStream inputStream) throws IOException { try { byte[] imgData = IOUtils.toByteArray(inputStream); Mat image = Imgcodecs.imdecode(new MatOfByte(imgData), Imgcodecs.CV_LOAD_IMAGE_COLOR); cropImage(session, context, original, image); } catch (Exception ex) { getLogger().error(ex.getMessage()); ex.printStackTrace(); } } }); session.transfer(original, REL_ORIGINAL); } final public void cropImage(final ProcessSession session, ProcessContext context, FlowFile original, final Mat image) { final int x = context.getProperty(X_POINT).evaluateAttributeExpressions(original).asInteger(); final int y = context.getProperty(Y_POINT).evaluateAttributeExpressions(original).asInteger(); final int width = context.getProperty(CROP_WIDTH).evaluateAttributeExpressions(original).asInteger(); final int height = context.getProperty(CROP_HEIGHT).evaluateAttributeExpressions(original).asInteger(); FlowFile croppedImage = session.write(session.create(original), new OutputStreamCallback() { @Override public void process(OutputStream outputStream) throws IOException { Rect rectCrop = new Rect(x, y, width, height); Mat croppedImage = new Mat(image, rectCrop); MatOfByte updatedImage = new MatOfByte(); Imgcodecs.imencode(".jpg", croppedImage, updatedImage); outputStream.write(updatedImage.toArray()); } }); Map<String, String> atts = new HashMap<>(); atts.put("image.width", new Integer(width).toString()); atts.put("image.height", new Integer(height).toString()); croppedImage = session.putAllAttributes(croppedImage, atts); session.transfer(croppedImage, REL_CROPPED_IMAGE); } }