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/*
* Copyright 2002-2017 Drew Noakes
*
* Licensed 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.
*
* More information about this project is available at:
*
* https://drewnoakes.com/code/exif/
* https://github.com/drewnoakes/metadata-extractor
*/
package com.drew.metadata.png;
import com.drew.imaging.png.PngColorType;
import com.drew.lang.KeyValuePair;
import com.drew.lang.SequentialByteArrayReader;
import com.drew.lang.SequentialReader;
import com.drew.lang.annotations.NotNull;
import com.drew.lang.annotations.Nullable;
import com.drew.metadata.TagDescriptor;
import java.io.IOException;
import java.util.List;
import static com.drew.metadata.png.PngDirectory.*;
/**
* @author Drew Noakes https://drewnoakes.com
*/
@SuppressWarnings("WeakerAccess")
public class PngDescriptor extends TagDescriptor<PngDirectory>
{
public PngDescriptor(@NotNull PngDirectory directory)
{
super(directory);
}
@Override
@Nullable
public String getDescription(int tagType)
{
switch (tagType) {
case TAG_COLOR_TYPE:
return getColorTypeDescription();
case TAG_COMPRESSION_TYPE:
return getCompressionTypeDescription();
case TAG_FILTER_METHOD:
return getFilterMethodDescription();
case TAG_INTERLACE_METHOD:
return getInterlaceMethodDescription();
case TAG_PALETTE_HAS_TRANSPARENCY:
return getPaletteHasTransparencyDescription();
case TAG_SRGB_RENDERING_INTENT:
return getIsSrgbColorSpaceDescription();
case TAG_TEXTUAL_DATA:
return getTextualDataDescription();
case TAG_BACKGROUND_COLOR:
return getBackgroundColorDescription();
case TAG_UNIT_SPECIFIER:
return getUnitSpecifierDescription();
default:
return super.getDescription(tagType);
}
}
@Nullable
public String getColorTypeDescription()
{
Integer value = _directory.getInteger(TAG_COLOR_TYPE);
if (value == null)
return null;
PngColorType colorType = PngColorType.fromNumericValue(value);
if (colorType == null)
return null;
return colorType.getDescription();
}
@Nullable
public String getCompressionTypeDescription()
{
return getIndexedDescription(TAG_COMPRESSION_TYPE, "Deflate");
}
@Nullable
public String getFilterMethodDescription()
{
return getIndexedDescription(TAG_FILTER_METHOD, "Adaptive");
}
@Nullable
public String getInterlaceMethodDescription()
{
return getIndexedDescription(TAG_INTERLACE_METHOD, "No Interlace", "Adam7 Interlace");
}
@Nullable
public String getPaletteHasTransparencyDescription()
{
return getIndexedDescription(TAG_PALETTE_HAS_TRANSPARENCY, null, "Yes");
}
@Nullable
public String getIsSrgbColorSpaceDescription()
{
return getIndexedDescription(
TAG_SRGB_RENDERING_INTENT,
"Perceptual",
"Relative Colorimetric",
"Saturation",
"Absolute Colorimetric"
);
}
@Nullable
public String getUnitSpecifierDescription()
{
return getIndexedDescription(
TAG_UNIT_SPECIFIER,
"Unspecified",
"Metres"
);
}
@Nullable
public String getTextualDataDescription()
{
Object object = _directory.getObject(TAG_TEXTUAL_DATA);
if (object == null) {
return null;
}
@SuppressWarnings("unchecked")
List<KeyValuePair> keyValues = (List<KeyValuePair>)object;
StringBuilder sb = new StringBuilder();
for (KeyValuePair keyValue : keyValues) {
if (sb.length() != 0)
sb.append('\n');
sb.append(String.format("%s: %s", keyValue.getKey(), keyValue.getValue()));
}
return sb.toString();
}
@Nullable
public String getBackgroundColorDescription()
{
byte[] bytes = _directory.getByteArray(TAG_BACKGROUND_COLOR);
Integer colorType = _directory.getInteger(TAG_COLOR_TYPE);
if (bytes == null || colorType == null) {
return null;
}
SequentialReader reader = new SequentialByteArrayReader(bytes);
try {
// TODO do we need to normalise these based upon the bit depth?
switch (colorType) {
case 0:
case 4:
return String.format("Greyscale Level %d", reader.getUInt16());
case 2:
case 6:
return String.format("R %d, G %d, B %d", reader.getUInt16(), reader.getUInt16(), reader.getUInt16());
case 3:
return String.format("Palette Index %d", reader.getUInt8());
}
} catch (IOException ex) {
return null;
}
return null;
}
}
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