Apache OpenOffice (AOO) Bugzilla – Issue 84490
Disturbed objects during animations
Last modified: 2017-05-20 10:35:40 UTC
In my presentation objects are added one by one with animation effect, e.g. "fade in". Objects already present on the page should not be influenced by objects coming in later. But very often those objects disappear while the animation is drawing a new object, thus leading to blinking or flickering of the elder objects. I have got the impression, that this effect at least in parts is caused by a unnecessary redrawing of objects that are already present on the page. This can be seen clearly for math formulas, because during (re-)rendering the formula graphics is drawn only in black and white and the interpolated gray scale pixels disappear. This might also be a cause for some of the reported performance problems with animations. The attached document shows the above problems. Slide 1) The colored transparent rectangles on the right side disappear Slide 2) The yellow transparent rectangles on the bottom of the left side disappear Slide 3) The blue and red transparent rectangles above the formulas do flicker. In every animation step also the gray-shaded pixels of the formulas disappear (because of redrawing?) Slide 4) Similar to three, just another example
Created attachment 50260 [details] Presentation with animations
The problem is also present in the release version OOo 2.3.1, but the version selector in issuezilla doesn't offer this version.
Confirming using 2.4m241 on WinXP - for example, on slide 2 we have two yellowish rectangles. They disappear when other objects (text frames, for example) are animated.
I can repoduce the bug in the attached document. the 'blinking' object have a transparency. When I switch off the transparency the objects doesn't blink. Please have a look.
I have just run the presentation of the attached document with OOo2.4 release version. The problem with the transparent rectangles seems to be fixed. That looks good. But the problem with the unnecessary redrawing of math formulas on slides 3 and 4 still persists: in most animation steps formulas do flicker that are not touched by the actual animation step - the gray-shaded pixels of those formulas temporary disappear. This is very disturbing, especially when you have many formulas on a slide. Would be nice if this could be fixed too.
@khbellgardt: unfortunately the on/off-switching of text antialiasing is a technical shortcoming currently unavoidable (the vcl-based canvas does it for speed reasons, and the DX-based one because there's a bug in Windows GDI that prevents using text AA on ARGB surfaces). Under Linux, using an OOo version that ships with cairocanvas (usually the distro-specific ones do) should not show this issue. If you really need this fixed, there's a (somewhat involved) workaround, but that enables an old shortcoming again (see issue 37778).
@af: Thanks for taking a look. Most of this seems fixed, for the remainder I'd lean towards wontfix, the z order fix was requested.
I can't reproduce such "... disappears" with 3.1.0, but I remember that such problems DID exist. Fixed for now. Please feel free to submit a new Bug if you find out that one of the problems still exists in the latest public release of AOO and if you can provide requested additional information. We need a test kit (Attachment here in the Bug report) and a detailed step by step instruction how to reproduce your problem, for details please see <http://wiki.openoffice.org/wiki/QA/HowToFileIssue>!