GNOME Bugzilla – Bug 143367
When using "freeze panes", the rule line rendering is messed up during scrolling
Last modified: 2004-12-22 21:47:04 UTC
This seems to be a small rendering bug with frozen panes. Steps: 1) Click on a cell and then freeze panes. 2) Click on the same cell (or any other cell directly to the right of the vertical break) (see attachment 1 [details]). 3) Use the horizontal scroll bar to scroll to the right. 4) The vertical rule showing the frozen column now has a break in it, right where the cursor used to be (see attachment 2 [details]). Maybe a simple re-render forcing is all that is needed? Cheers--
Created attachment 28155 [details] Step 1
Created attachment 28156 [details] Rendering bug, after scrolling to the right
Things are redrawing, but it's likely some sort of 'off by one' error in the pixel bounds that is finally catching up to us.
ahhhh I see. It's more subtle than that. There's no off by one error at all. The problem is that the edge of the cursor is visible. When we draw the cursor border we invert the background so that it can be see no matter what colour it displays on. The border line is black, which inverts to ... white. I've changed the line to a dark gray so that it inverts to something other than white. Not ideal, things still look a bit odd, but manageable.
Makes sense. I just noticed another consequence of the current rendering logic. If the cursor is placed on a cell directly to the LEFT of the freeze line, and you scroll to the right, the right side of the cursor scrolls over (thus disappearing). Is it possible to draw the cursor after the final "frozen" layout is rendered? Ideally, you could also restrict the cursor from being drawn only if the cell is visible. I know this is a trivial bug, but I have to admit it stumped me for a minute (my mind operates on autopilot while working with spreadsheets:) ). When I saw the break in the freeze line, I assumed the line was a cell border and I prompty went over there to repair it. Even if the line changes from black to light gray for a section, I think my initial reaction might be the same. Cheers--
BTW, OpenOffice seems to have the same issue. Except they draw the cursor square big enough so that it draws 1 pixel to the left of the freeze line. When you scroll to the right, it then leaves a nice big black line. This is probably even worse, since it clearly looks like a rogue cell border is left there.