| Summary: | [WMF/EMF] RestoreDC should read and use 'SavedDC' value | ||
|---|---|---|---|
| Product: | LibreOffice | Reporter: | Valek Filippov <frob> |
| Component: | graphics stack | Assignee: | Bartosz <gang65> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | gang65 |
| Priority: | medium | ||
| Version: | unspecified | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | target:7.2.0 | ||
| Crash report or crash signature: | Regression By: | ||
| Bug Depends on: | |||
| Bug Blocks: | 59814, 103859 | ||
| Attachments: |
EMF sample with SOME RestoreDC using "-2" for 'SavedDC' value
How it should look like WMF sample with RestoreDC other than "nSavedDc == -1" Screenshot of WMF sample opened in LO 7.2 and MS Paint side by side EMF with SavedDC set to 0 EMF sample with 'SavedDC' set to 3 |
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Description
Valek Filippov
2021-05-30 15:02:54 UTC
Created attachment 172454 [details]
EMF sample with SOME RestoreDC using "-2" for 'SavedDC' value
Implementation in WMF has the same problem. However, implementation is not the same. From [MS-WMF] 2.3.5.10: "nSavedDC (2 bytes): A 16-bit signed integer that defines the saved state to be restored. If this member is positive, nSavedDC represents a specific instance of the state to be restored. If this member is negative, nSavedDC represents an instance relative to the current state." I will try to make a sample to demonstrate a problem for both: negative below -1 and positive values. Unfortunately it's unclear if in case of WMF newer contexts are preserved or disposed after restoring to the older one in the stack. Ability to point out to the specific context could allow re-entrance to the previously used context (eg. switch back and forth between two contexts w/o setting the values again for the "newer" one). Created attachment 172455 [details]
How it should look like
Created attachment 172461 [details]
WMF sample with RestoreDC other than "nSavedDc == -1"
It should look like red/blue/red rectangles. LO shows it as three green rectangles.
Observations:
1. RestoreDC with nSavedDC==0 is doing nothing in WMF. (LO currently pops the context.)
2. If context is switched to the bottom of the stack, then all jumped other contexts seem to become unavailable -- switching to one of them using positive nSavedDC has not effect.
Created attachment 172462 [details]
Screenshot of WMF sample opened in LO 7.2 and MS Paint side by side
Created attachment 172463 [details]
EMF with SavedDC set to 0
Created attachment 172464 [details]
EMF sample with 'SavedDC' set to 3
In EMF all non-negative values for SavedDC in RestoreDC EMR seems to be handled the same as "-1" value.
Bartosz Kosiorek committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/cabb9f5c8e22a23a453559636d9c9b3c2b0a5984 WMF/EMF tdf#59814 tdf#142567 Fix RestoreDC record It will be available in 7.2.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback. Bartosz Kosiorek committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/8d3e7b2f5836106eac5172d8f4868bb540d652e6 EMF tdf#59814 tdf#142567 Align RestoreDC record with MSO implementation It will be available in 7.2.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback. |