GNOME Bugzilla – Bug 99672
Display Problems for the selection in the image window
Last modified: 2009-08-15 18:40:50 UTC
Zoom in about 400% to make this easier to see. Use magic wand to select a contiguous area. Hold down shift and select a pixel one pixel to the right of the selection. Rectangle containing selected portion of image will move down and right one pixel. Behavior is still correct, except that the area that appears selected on screen is one pixel northwest of actual area. VERY difficult to work with.
I have no idea what you are talking about here. I followed the steps you described and couldn't find anything wrong here. Please provide a better description of the problem and perhaps illustrate it using a screenshot.
I guess that the problem is the same as described below. When doing various operations with an image the image window does not always reflect the current image properly. The attached screenshot has been made by zooming in a (random) image and use the middle mouse button to scroll in a relatively big window on a slow computer. There are obvious mistakes in the image, not all "pixels" are squares... I fear that this might be a problem with the X Server and some missing (?) expose events. We recently discussed this on IRC and the result was, that the X Server definitely is involved (the screenshot has been made with XFree86 4.2.1 (siliconmotion driver) (II) LoadModule: "siliconmotion" (II) Loading /usr/X11R6/lib/modules/drivers/siliconmotion_drv.o (II) Module siliconmotion: vendor="The XFree86 Project" compiled for 4.2.1, module version = 1.3.1 Module class: XFree86 Video Driver ABI class: XFree86 Video Driver, version 0.5 [...] (II) Silicon Motion: driver (version 1.3.1) for Silicon Motion Lynx chipsets: Lynx, LynxE, Lynx3D, LynxEM, LynxEM+, Lynx3DM (II) Primary Device is: PCI 00:02:0 (--) Assigning device section with no busID to primary device (--) Chipset LynxE found I also see some off by one artefacts in sketch, that the author cannot reproduce. So the problem might be the same. Original Reporter: Could you please give details on the X-Server you use?
Created attachment 12694 [details] Screenshot showing an corrupted image window
Ah, forgot to mention this. You can easily remove the artefacts by zooming in the image and immediately zoom out again.
I am not sure that the problem comes from the X server. Or maybe this affects several X servers, because I have observed similar problems on my Solaris box (Sun OpenWindows). xdpyinfo reports: name of display: :0.0 version number: 11.0 vendor string: Sun Microsystems, Inc. vendor release number: 6410 I have never observed similar problems with a zoom ratio of 800% or 1600%, but only with other values. It is very obvious with 700%, for example. This dependency on the zoom factor makes me think that the problem comes from the GIMP, not from the X server. Here is an easy way to reproduce the problem: - create an image - use Noisify or the Plasma plug-in to fill the image with random colors - make a rectangular selection in the middle of the image and fill it with white or some other color - zoom in at 700% - select the colored rectangle with the magic wand or any other selection tool - if the selection looks fine on the first attempt, then try one of the following operations: - undo (Ctrl-Z) and click again with the magic wand - Shift-click on any pixel just outside the rectangle (on any side) - undo (Crtl-Z) and use the rectangular selection to re-select the same area. For some reason, this bug seems to appear only for the second time a selection is drawn at the same zoom ratio. I have not seen it yet when the selection is drawn for the first time, but I see it all the time after the second selection. This is not limited to the magic wand: it affects all selection tools. Changing the zoom ratio fixes the problem, until the selection has to be re-drawn a second time.
Created attachment 12770 [details] Screenshot showing incorrect selection (magnified x 2)
It looks like the problem that I have is different from the one shown by Simon. Reporter, is my screenshot closer to the problem that you describe?
This image shows, that the border of the selection is in the same grid as the image-pixels at the border of the image. The image-pixels drewn in the bounding rectangle of the selection are offset by one screen-pixel. It *might* be a problem that certain paint operations are wrong with some X Drivers. But maybe I am just stubborn (because I also see the effect in sketch)
Ok, I oversimplified a bit. I'll attach a screenshot with your image and a grid rendered on top of it. As you can see the grid perfectly matches the selection and the image dimensions and some pixels in the upper left corner. However, lots of pixels are offset by one screen-pixel to the right and/or the bottom (if we take the image border as a reference). The row next to the right side of the selection also contains some "broken" (non-rectangular) pixels, so I'd guess that the problem is not the border of the selection but the pixels itself.
Created attachment 12771 [details] Raphaëls Image with a grid on top of it
This also seems to be a duplicate of bug #109933 and bug #111468.
*** This bug has been marked as a duplicate of 111468 ***
The fix for bug #111468 is part of the stable release 1.2.4. Closing this bug.