Defect #23645

Gantt bars for single-day tasks may be rendered wrongly in PDF

Added by Daniel Ritz almost 4 years ago. Updated 4 months ago.

Status:ClosedStart date:
Priority:NormalDue date:
Assignee:Go MAEDA% Done:

0%

Category:Gantt
Target version:4.0.7
Resolution: Affected version:

Description

When a task starts and ends on the same day, it can happen that the bar in the PDF is rendered wrong, i.e. it's rendered from the start day to the right end of the page.

The problem is in lib/redmine/helpers/gantt.rb. When #pdf_task is called, coords[:bar_end] - coords[:bar_start] happens to be 0. The cause for this is the zoom factor applied in #coordindates and the subsequent #floor. By adding some Rails.logger statements I got this:

coords[start]: 92/1, zoom: 36/73
coords[start]: 45
coords[bar_start]: 92/1, zoom: 36/73
coords[bar_start]: 45
coords[end]: 92/1, zoom: 36/73
coords[end]: 45
coords[bar_end]: 93/1, zoom: 36/73
coords[bar_end]: 45

Each value shown before/after applying zoom. While before zoom, the values where 92/93, the became 45/45 afterwards.

The attached patch fixes the PDF rendering problem by making sure, the with used in the RDMCell() call is at least 0.

gantt-single-day-task-pdf-rendering.patch Magnifier (1.71 KB) Daniel Ritz, 2016-08-23 18:48

gannt_1daytask.JPG (55.3 KB) Sutamin Lynfiled, 2017-01-02 16:53

pdf-vs-png.png (47.3 KB) Daniel Ritz, 2017-01-04 11:42

set-huge-months.png (235 KB) Yuichi HARADA, 2020-03-19 08:25

actual-pdf.png (332 KB) Yuichi HARADA, 2020-03-19 08:25


Related issues

Duplicated by Redmine - Defect #32916: Bar length is wrong when exporting gantt chart to PDF Closed

Associated revisions

Revision 19592
Added by Go MAEDA 4 months ago

Gantt bars for single-day tasks may be rendered wrongly in PDF (#23645).

Patch by Daniel Ritz.

Revision 19593
Added by Go MAEDA 4 months ago

Merged r19592 from trunk to 4.1-stable (#23645).

Revision 19594
Added by Go MAEDA 4 months ago

Merged r19592 from trunk to 4.0-stable (#23645).

History

#1 Updated by Sutamin Lynfiled over 3 years ago

LGTM. I hope for early adoption.

#2 Updated by Go MAEDA over 3 years ago

I have not been able to reproduce the problem yet.
Could you please describe the detailed steps to reproduce the problem and upload screenshots (before fix and after fix) ?

#3 Updated by Daniel Ritz over 3 years ago

Sorry, I have no easy reproducer. I used a dump of our productive DB while working on the fix...

Attached is a screenshot with comparing the Gantt rendered correctly as PNG and incorrectly as PDF. After the fix, the PDF looks correct too (no screenshot taken).
Tasks 3-7 shown on the screenshot are single-day tasks and should all render the same.

#4 Updated by Yuichi HARADA 4 months ago

Daniel Ritz wrote:

When a task starts and ends on the same day, it can happen that the bar in the PDF is rendered wrong, i.e. it's rendered from the start day to the right end of the page.

I have confirmed.
If you set a huge value to the Gantt display months, all Gantt bars for issues with the extremely short the start date and due date will appear in the PDF this way.

The attached patch fixes the PDF rendering problem by making sure, the with used in the RDMCell() call is at least 0.

I think gantt-single-day-task-pdf-rendering.patch should be incorporated. This problem will be solved.

#5 Updated by Go MAEDA 4 months ago

  • Target version set to 4.0.7

Setting the target version to 4.0.7.

#6 Updated by Go MAEDA 4 months ago

  • Status changed from New to Closed
  • Assignee set to Go MAEDA

Committed the patch. Thank you for your contribution.

#7 Updated by Go MAEDA 4 months ago

  • Tracker changed from Patch to Defect
  • Subject changed from Fix Gantt PDF rendering for single-day tasks to Gantt bars for single-day tasks may be rendered wrongly in PDF

#8 Updated by Mischa The Evil 30 days ago

  • Duplicated by Defect #32916: Bar length is wrong when exporting gantt chart to PDF added

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