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ID Category Severity Reproducibility Date Submitted Last Update
0006500 [Squeak] Morphic minor always 05-23-07 08:14 05-24-07 01:58
Reporter kks View Status public  
Assigned To
Priority normal Resolution open  
Status new   Product Version 3.10
Summary 0006500: Image snapshot of SystemWindows has a 1px at the top
Description Open a class browser and bring up its halo. Shift-click on viewer icon to generate a snaphot. Notice the resulting image is blurred and there top border is 1px above the actual top.

Open a workspace, move it to 0@0 and inspect it. Do "self extent:100@100"
 bounds is 0@0 corner: 100@100
 fullBounds is 0@-1 corner: 101@101

This error also appears in 3.9-7067
Additional Information I traced the call all the way to TopLeftGripMorph>>layoutInBounds:
      box _ box align: (box perform: aSymbol) with: (cellBounds perform: aSymbol).

Here cellBounds is 1@-2 corner: 23@25. Since TopLeftGrip is symmetric, y appears to be reduced by two. Is its gripLayoutFrame correct?
Attached Files  badbounds.gif [^] (3,414 bytes) 05-23-07 08:14

- Relationships
child of 0006511new  Mother of all Morphic Graphical off-by-one/fencepost -error reports. 

- Notes
(0010751 - 903 - 999 - 999 - 1101 - 1101 - 1101)
05-24-07 01:58
edited on: 05-24-07 02:10

Data Points,
This actually does not cause a problem in 7067 at least the snapshot border is snug to the system window in that image. (subbu mentioned this in a post to the squeak-dev)

I tried in 7097 and found the problem as described.

So I imagine it will be in 7105 but have not confirmed it yet.

This seems to be a new truncation and roundoff error.

Truncation and rounding off towards zero changes the extent of a rectangle if the rectange contains the origin (or has been translated to contain the origin. See 0002453 and look at the pictures to get an idea of the problems.

For 3dot9 some vocabulary was added ti Rectangles and Points to help. Extending the definition of floor and ceiling to these classes. #expanded and #compressed to Rectangle.

These are the key to fixing the off by one errors. They have not been widely applied though they are widely needed.


- Issue History
Date Modified Username Field Change
05-23-07 08:14 kks New Issue
05-23-07 08:14 kks File Added: badbounds.gif
05-24-07 01:58 wiz Note Added: 0010751
05-24-07 02:06 wiz Note Edited: 0010751
05-24-07 02:10 wiz Note Edited: 0010751
05-25-07 02:47 wiz Relationship added child of 0006511

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