0000152: Chart zooming broken: coordinate overflows reported too soon

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Date Submitted

Last Update

0000152

OMNeT++

IDE / result analysis

public

2010-04-16 10:08

2010-05-06 09:30

Reporter

andras

Assigned To

andras

Priority

normal

Severity

major

Reproducibility

always

Status

resolved

Resolution

fixed

Platform

OS Version

Product Version

4.1b3

Target Version

Fixed in Version

4.1rc1

Summary

0000152: Chart zooming broken: coordinate overflows reported too soon

Description

On a line chart, after clicking Zoom a few times (0000002:0000011 times), the chart reports "coordinate overflows". 11 clicks correspond to 2^11 = ~2000 zoom factor, which the chart should be able to handle.

With a 2000x zoom, the full (say 1000 pixel wide) chart would be only 2,000,000 pixels. The range of a 32-bit int is about +-2 billion, so with 32-bit coordinates, the chart should be able to support a 2,000,000x zoom not 2000x, not to speak of the 64-bit coordinates used by LargeScrollableCanvas which the chart subclasses from.

Steps To Reproduce

Open any line chart, and click Zoom 11 times. The text "There were coordinate overflows during plotting, and the resulting chart may not be accurate. Please decrease zoom level." appears. It should only appear after about 20 (32-bit coords) or 50 (64-bit coords) clicks.

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Notes
(0000275) andras (administrator) 2010-05-06 09:25	Looks like the limit was built in there because Windows GDI drawing chokes on coordinates greater than about 2 million. On Linux, Cairo has the +-32768 pixels limit.

(0000276) andras (administrator) 2010-05-06 09:30	Fixed: now we compute all coordinates as 64-bit integers, and perform a rough pre-clipping before passing drawing operations to the SWT Graphics. Pre-clipping clips or discards drawing operations that fall outside the range that can be safely handled by the graphics engines (GDI, Cairo) underlying SWT; this range is assumed to be +-10,000 pixels.

Issue History
Date Modified	Username	Field	Change
2010-04-16 10:08	andras	New Issue
2010-04-16 10:11	andras	Description Updated
2010-05-06 09:25	andras	Note Added: 0000275
2010-05-06 09:30	andras	Note Added: 0000276
2010-05-06 09:30	andras	Status	new => resolved
2010-05-06 09:30	andras	Fixed in Version	=> 4.1rc1
2010-05-06 09:30	andras	Resolution	open => fixed
2010-05-06 09:30	andras	Assigned To	=> andras