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https://issues.apache.org/jira/browse/IMAGING-251?focusedWorklogId=417504&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-417504
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ASF GitHub Bot logged work on IMAGING-251:
------------------------------------------
Author: ASF GitHub Bot
Created on: 07/Apr/20 07:32
Start Date: 07/Apr/20 07:32
Worklog Time Spent: 10m
Work Description: kinow commented on pull request #72: IMAGING-251
support for TIFF floating-point formats
URL: https://github.com/apache/commons-imaging/pull/72#discussion_r404594350
##########
File path:
src/main/java/org/apache/commons/imaging/formats/tiff/photometricinterpreters/fp/PhotometricInterpreterFloat.java
##########
@@ -0,0 +1,312 @@
+/*
+ * 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.photometricinterpreters.fp;
+
+import java.awt.Color;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import org.apache.commons.imaging.ImageReadException;
+import org.apache.commons.imaging.common.ImageBuilder;
+import org.apache.commons.imaging.formats.tiff.TiffDirectory;
+import org.apache.commons.imaging.formats.tiff.TiffField;
+import org.apache.commons.imaging.formats.tiff.constants.TiffTagConstants;
+import
org.apache.commons.imaging.formats.tiff.photometricinterpreters.PhotometricInterpreter;
+
+/**
+ * Implements a custom photometric interpreter that can be supplied by
+ * applications in order to render Java images from real-valued TIFF data
+ * products. Most TIFF files include a specification for a "photometric
+ * interpreter" that implements logic for transforming the raw data in a TIFF
+ * file to a rendered image. But the TIFF standard does not include a
+ * specification for a photometric interpreter that can be used for rendering
+ * floating-point data. TIFF files are sometimes used to specify non-image data
+ * as a floating-point raster. This approach is particularly common in GeoTIFF
+ * files (TIFF files that contain tags for supporting geospatial reference
+ * metadata for Geographic Information Systems). Because of the limits of the
+ * stock photometric interpreters, most floating-point TIFF files to not
produce
+ * useful images.
+ * <p>
+ * This class allows an Apache Commons implementation to construct and specify
a
+ * custom photometric interpreter when reading from a TIFF file. Applications
+ * may supply their own palette that maps real-valued data to specified colors.
+ * <p>
+ * This class provides two constructors:
+ * <ol>
+ * <li>A simple constructor to support gray scales</li>
+ * <li>A constructor to support a color palette (with potential
+ * interpolation)</li>
+ * </ol>
+ * <p>
+ * To use this class, an application must access the TIFF file using the
+ * low-level, TIFF-specific API provided by the Apache Commons Imaging library.
+ *
+ */
+public class PhotometricInterpreterFloat extends PhotometricInterpreter {
+
+ ArrayList<IPaletteEntry> rangePaletteEntries = new ArrayList<>();
+ ArrayList<IPaletteEntry> singleValuePaletteEntries = new ArrayList<>();
+
+ float minFound = Float.POSITIVE_INFINITY;
+ float maxFound = Float.NEGATIVE_INFINITY;
+ int xMin;
+ int yMin;
+ int xMax;
+ int yMax;
+
+ double sumFound;
+ int nFound;
Review comment:
Could we make the members above `private` or some other access modifier?
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Issue Time Tracking
-------------------
Worklog Id: (was: 417504)
Time Spent: 1h 50m (was: 1h 40m)
> Support TIFF standard floating point data
> -----------------------------------------
>
> Key: IMAGING-251
> URL: https://issues.apache.org/jira/browse/IMAGING-251
> Project: Commons Imaging
> Issue Type: New Feature
> Components: Format: TIFF
> Affects Versions: 1.x
> Reporter: Gary Lucas
> Priority: Major
> Fix For: 1.x
>
> Attachments: Imaging252_USGS_n38w077.jpg
>
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> Commons Imaging does not support the floating-point format included in the
> TIFF specification. There are prominent data sources that issue products in
> this format. The ability to support this information would open up new
> application areas for Commons Imaging.
> TIFF is often used as a mechanism for distributing data from geophysical
> applications in the form of GeoTIFF files. Some of this is not imagery, but
> data. For example, the US Geological Survey is currently releasing
> high-resolution elevation data grids for the 3DEP program under the name
> Cloud-Optimized GeoTIFF (COG). It is a substantial data set with significant
> potential commercial and academic applications.
> To access this data means modifying the TIFF DataReaderStrips and
> DataReaderTile classes to recognize floating point data (which is typically
> indicated using TIFF tag #339, SampleFormat). Also, returning the data in the
> form of a BufferedImage makes no sense at all, so the API on the
> TiffImageParser and supporting classes would need additional methods to
> return arrays of floats. The good news here is that that requirement would
> mean adding new methods to the classes rather than making significant changes
> to existing classes. So the probability of unintended consequences or new
> bugs in existing code would be minimized.
> Specification details for floating-point are given in the main TIFF-6
> documentations and Adobe Photoshop TIFF Technical Note 3.
>
> I am willing to volunteer to make these changes provided that there is
> interest and a high probability that my contributions would be evaluated and,
> if suitable, integrated into the Commons Imaging code base.
> Thank you for your attention in this matter.
>
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