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NIHVIVO-1208 When creating a thumbnail from a PNG image, suppress the alpha channel so the colors of the thumbnail won't be screwed up.

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jeb228 2010-10-11 18:17:00 +00:00
parent 54349c7427
commit 49e4badda7
1 changed files with 25 additions and 3 deletions
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28
webapp/src/edu/cornell/mannlib/vitro/webapp/controller/freemarker/ImageUploadHelper.java
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@ -33,6 +33,7 @@ import org.apache.commons.logging.LogFactory;
import com.sun.media.jai.codec.JPEGEncodeParam;
import com.sun.media.jai.codec.MemoryCacheSeekableStream;
import com.sun.media.jai.codec.PNGDecodeParam;
import edu.cornell.mannlib.vitro.webapp.beans.Individual;
import edu.cornell.mannlib.vitro.webapp.controller.VitroRequest;
@ -284,7 +285,7 @@ public class ImageUploadHelper {
mainStream = fileStorage.getInputStream(mainBytestreamUri,
mainFilename);
thumbStream = scaleImageForThumbnail(mainStream, crop);
thumbStream = scaleImageForThumbnail(mainStream, crop, newImage);
String mimeType = RECOGNIZED_FILE_TYPES.get(".jpg");
String filename = createThumbnailFilename(mainFilename);
@ -392,12 +393,17 @@ public class ImageUploadHelper {
* width, height).
*/
private InputStream scaleImageForThumbnail(InputStream source,
CropRectangle crop) throws IOException {
CropRectangle crop, FileInfo newImage) throws IOException {
try {
// Read the main image.
MemoryCacheSeekableStream stream = new MemoryCacheSeekableStream(
source);
RenderedOp mainImage = JAI.create("stream", stream);
ParameterBlock streamParams = new ParameterBlock();
streamParams.add(stream);
addDecodeParametersAsNeeded(newImage, streamParams);
RenderedOp mainImage = JAI.create("stream", streamParams);
int imageWidth = mainImage.getWidth();
int imageHeight = mainImage.getHeight();
@ -445,6 +451,22 @@ public class ImageUploadHelper {
}
}
/**
* The JAI 1.1.3 package has a known bug writing JPEG images from sources
* that have transparency (alpha channel) enabled.
*
* For PNG images, we can add a parameter that will disable the alpha
* channel.
*/
private void addDecodeParametersAsNeeded(FileInfo newImage,
ParameterBlock streamParams) {
if ("image/png".equals(newImage.getMimeType())) {
PNGDecodeParam pdp = new PNGDecodeParam();
pdp.setSuppressAlpha(true);
streamParams.add(pdp);
}
}
/**
* The bounds of the cropping rectangle should be limited to the bounds of
* the image.