Bug 45829 - HSSFPicture.getImageDimension() fails when DPI of image is zero
Summary: HSSFPicture.getImageDimension() fails when DPI of image is zero
Status: RESOLVED FIXED
Alias: None
Product: POI
Classification: Unclassified
Component: HSSF (show other bugs)
Version: unspecified
Hardware: PC Windows XP
: P2 normal (vote)
Target Milestone: ---
Assignee: POI Developers List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2008-09-17 17:15 UTC by Peter Runge
Modified: 2008-09-18 03:28 UTC (History)
1 user (show)


Attachments
Test PNG image with zero DPI (259 bytes, image/png)
2008-09-17 17:15 UTC, Peter Runge 		Details
Patch for HSSFPicture.java (645 bytes, patch)
2008-09-17 17:37 UTC, Peter Runge 		Details | Diff
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Description Peter Runge 2008-09-17 17:15:11 UTC 
Created attachment 22597 [details]
Test PNG image with zero DPI

POI version 3.1-FINAL-20080629.

When calling HSSFPicture.resize() for a PNG image that does not specify a DPI (DPI width and height is zero), HSSFPicture.getImageDimension() method fails with ArithmeticException (/ by zero).

It seems that in getResolution() the HorizontalPixelSize and VerticalPixelSize image metadata elements have values of zero if DPI is set to zero in PNG files.  While this might indicate a problem with the PNG file, failing with / by zero error is not appropriate as other software can happily load and display these files.  It would be more appropriate to either fall back to DPI defaults (96 DPI) rather than returning zeroes from this method or have special handling in getImageDimension() so that DPI is not used if it is zero.

Stack trace:
java.lang.ArithmeticException: / by zero
	at org.apache.poi.hssf.usermodel.HSSFPicture.getImageDimension(HSSFPicture.java:238)
	at org.apache.poi.hssf.usermodel.HSSFPicture.getPreferredSize(HSSFPicture.java:120)
	at org.apache.poi.hssf.usermodel.HSSFPicture.resize(HSSFPicture.java:97)
	...
Comment 1 Peter Runge 2008-09-17 17:37:42 UTC 
Created attachment 22598 [details]
Patch for HSSFPicture.java
Comment 2 Peter Runge 2008-09-17 17:38:48 UTC 
Created patch for HSSFPicture.java against
trunk/src/java/org/apache/poi/hssf/usermodel/HSSFPicture.java.

Added zero checking in getImageDimension() before division and using defaults
if zero is found.
Comment 3 Yegor Kozlov 2008-09-18 03:28:44 UTC 
Fixed in r696622

Yegor