Gary Lucas created IMAGING-94:
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Summary: Add ability to load partial TIFF images
Key: IMAGING-94
URL: https://issues.apache.org/jira/browse/IMAGING-94
Project: Commons Imaging
Issue Type: New Feature
Components: Format: TIFF
Reporter: Gary Lucas
For most Apache Commons Imaging applications, the easiest way to obtain a sub
image from a file is to simply use the Imaging class to load it as a
BufferedImage and then use BufferedImage’s getSubimage() method to extract the
portion of the image you wish to use. The TIFF format presents a special
problem because it is very common to have huge images (100’s or even 1000’s of
megapixel). Examples include Landsat satellite images, global-scale GeoTIFF
images, etc. In such cases, loading the entire image into memory is not
practical because it would require too much memory. For example, I am
currently working with a 21600 by 10800 image that requires more than 890
megabytes to store as a BufferedImage. That value is pushing the limit of what
I can configure Java to handle on my particular OS.
I propose to implement features for TIFF files that would permit Commons
Imaging to load a partial image of a TIFF file using only the amount memory
actually needed to hold the sub-image.
These changes would not interfere with normal operations of TIFF files and
would not affect other image formats. If there were a need for similar
features for other image formats, they could be phased in through future
changes.
The specification for a sub-image would be through the use of the params
argument in the getBufferedImage call as follows:
HashMap<String, Object> params = new HashMap<String, Object>();
params.put(TiffConstants.PARAM_KEY_SUBIMAGE_X, new Integer(x));
params.put(TiffConstants.PARAM_KEY_SUBIMAGE_Y, new Integer(y));
params.put(TiffConstants.PARAM_KEY_SUBIMAGE_WIDTH, new Integer(width));
params.put(TiffConstants.PARAM_KEY_SUBIMAGE_HEIGHT, new
Integer(height));
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