gwlucastrig commented on a change in pull request #72: URL: https://github.com/apache/commons-imaging/pull/72#discussion_r422128692
########## File path: src/main/java/org/apache/commons/imaging/formats/tiff/TiffRasterData.java ########## @@ -0,0 +1,155 @@ +/* + * 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 org.apache.commons.imaging.formats.tiff; + +/** + * Provides a simple container for floating-point data. Some TIFF files are used + * to store floating-point data rather than images. This class is intended to + * support access to those TIFF files. + */ +public class TiffRasterData { + + + private final int width; + private final int height; + private final float[] data; + + /** + * Construct an instance allocating memory for the specified dimensions. + * + * @param width a value of 1 or greater + * @param height a value of 1 or greater + */ + public TiffRasterData(int width, int height) { + if (width <= 0 || height <= 0) { + throw new IllegalArgumentException( + "Raster dimensions less than or equal to zero are not supported"); + } + int nCells = width * height; + data = new float[nCells]; + this.width = width; + this.height = height; + + } + + /** + * Construct an instance allocating memory for the specified dimensions. + * + * @param width a value of 1 or greater + * @param height a value of 1 or greater + * @param data the data to be stored in the raster. + */ + public TiffRasterData(int width, int height, float[] data) { + if (width <= 0 || height <= 0) { + throw new IllegalArgumentException( + "Raster dimensions less than or equal to zero are not supported"); + } + if (data == null || data.length < width * height) { + throw new IllegalArgumentException( + "Specified data does not contain sufficient elements"); + } + this.width = width; + this.height = height; + this.data = data; + + } + + /** + * Sets the value stored at the specified raster coordinates. + * + * @param x integer coordinate in the columnar direction + * @param y integer coordinate in the row direction + * @param value the value to be stored at the specified location; + * potentially a Float.NaN. + */ + public void setValue(int x, int y, float value) { + if (x < 0 || x >= width || y < 0 || y >= height) { + throw new IllegalArgumentException( + "Coordinates out of range (" + x + ", " + y + ")"); + } + data[y * width + x] = value; + } + + /** + * Gets the value stored at the specified raster coordinates. + * + * @param x integer coordinate in the columnar direction + * @param y integer coordinate in the row direction + * @return the value stored at the specified location; potentially a + * Float.NaN. + */ + public float getValue(int x, int y) { + if (x < 0 || x >= width || y < 0 || y >= height) { + throw new IllegalArgumentException( + "Coordinates out of range (" + x + ", " + y + ")"); + } + return data[y * width + x]; + } + + /** + * Tabulates simple statistics for the raster and returns an instance + * containing general metadata. + * + * @return a valid instance. + */ + public TiffRasterStatistics getSimpleStatistics() { + return new TiffRasterStatistics(this, Float.NaN); + } + + /** + * Tabulates simple statistics for the raster excluding the specified value + * and returns an instance containing general metadata, + * + * @param valueToExclude exclude samples with this specified value. + * @return a valid instance. + */ + public TiffRasterStatistics getSimpleStatistics(float valueToExclude) { + return new TiffRasterStatistics(this, valueToExclude); + } + + /** + * Gets the width (number of columns) of the raster. + * + * @return the width of the raster + */ + public int getWidth() { + return width; + } + + /** + * Gets the height (number of rows) of the raster. + * + * @return the height of the raster. + */ + public int getHeight() { + return height; + } + + /** + * Returns a reference to the data array stored in this instance. Note that + * value is <strong>not</strong> a safe copy and that modifying it would + * directly affect the content of the instance. While this design approach + * carries some risk in terms of data security, it was chosen for reasons of + * performance and memory conservation. + * + * @return a direct reference to the data array stored in this instance. + */ + public float[] getData() { + return data; Review comment: To me, the right design choice here was not at all clear. I am still not entirely sure. Returning a copy of the data would be safer and more in keeping with "secure coding" practices. The problem is that GeoTIFF images are often quite large. The US Geological Survey files I've been using are 10800x10800 pixels in size. So the memory they use is about 445 megabytes. To make a duplicate copy of such a large block of data seems like it could be a problem. Also, I wrote the getData() to supplement the getData(int x, int y) for efficiency. The getData(int x, int y) call has to perform bounds checking. If an application has access to the whole array, then it can bypass that. In practice, when an application is dealing with images that large, it should probably be reading them in in smaller pieces. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
