BBC BASIC for Windows
« Scrolling (or sliding) pictures »
Welcome Guest. Please Login or Register. Apr 6th, 2018, 12:24am
ATTENTION MEMBERS: Conforums will be closing it doors and discontinuing its service on April 15, 2018. Ad-Free has been deactivated. Outstanding Ad-Free credits will be reimbursed to respective payment methods.
If you require a dump of the post on your message board, please come to the support board and request it.
Re: Scrolling (or sliding) pictures
« Reply #8 on: May 5th, 2015, 07:56am »
Hmmm. Scrub my last comment. I was just using graphics (RECTANGLEFILL). However when I tried plotting a picture, the whole picture did appear, so sorry about that.
As for putting a negative value into @ox%, it doesn't appear to cause any problems apart from the "smearing" effect, which can be bodged.
Oh, and the line the followed text is, in fact, the cursor and is solved by incorporating OFF.
Logged
rtr2 Guest
Re: Scrolling (or sliding) pictures
« Reply #9 on: May 5th, 2015, 08:45am »
As for putting a negative value into @ox%, it doesn't appear to cause any problems apart from the "smearing" effect, which can be bodged.
It may not "appear" to, but I can assure you it does. I'm sorry, but you must never store a negative value into @ox% or @oy% (I have now amended the BB4W documentation to state this explicitly).
If you really want to see the sort of unwanted effects doing so can cause, try storing a negative value in @ox% and then minimise/restore the window!
No common application, whether text or graphics, allows you to scroll to the right from the 'home' position. Try it in Notepad or Paint (or even the BB4W editor): that's as far right as you can go. The @ox% and @oy% system variables are designed to support only this 'conventional' kind of scrolling.
Logged