mithomas@bsu-cs.bsu.edu (Michael Thomas Niehaus) (09/01/89)
The subject says it all: How do you go about changing the volume from within
an application. I am doing this right now:
thePRAM = GetSysPPtr();
BitAnd( *(thePRAM->volClik),0x9F );
BitOr( *(thePRAM->volClik),(newVol*256));
WriteParam();
This changes the volume in the parameter RAM. I know that for sure. It
also changes the value of the low-memory SPVolCtl to what it should be.
But, the volume doesn't actually change. The Control Panel shows the volume
as what I set it to, but if I try to make a sound, it will be at the same old
volume. Unless I click on the Control Panel's volume control (without moving
the slider). So I assume that the Control Panel is doing something that I
am not. So what could that be?
Any suggestions would be appreciated.
-Michael
--
Michael Niehaus UUCP: <backbones>!{iuvax,pur-ee}!bsu-cs!mithomas
Apple Student Rep ARPA: mithomas@bsu-cs.bsu.edu
Ball State University AppleLink: ST0374 (from UUCP: st0374@applelink.apple.com)d88-jwa@nada.kth.se (Jon W{tte) (09/02/89)
In article <10068@bsu-cs.bsu.edu> mithomas@bsu-cs.bsu.edu (Michael Thomas Niehaus) writes: >The subject says it all: How do you go about changing the volume from within >an application. I am doing this right now: [ Sort of technical code deleted ] >This changes the volume in the parameter RAM. I know that for sure. It >also changes the value of the low-memory SPVolCtl to what it should be. >But, the volume doesn't actually change. The Control Panel shows the volume How about SetSoundVol((int) Volume); ? I see no wrong in this easy-to-use, well-documented Toolbox call. Sometimes you get too technical to see the obvious :-) (Oh, by the way: You shouldn't change the volume in PRAM, since this is a) considered a brach of the HIGL and you risk the wrath of the HITP (Human Interface Thought Police) and b) subject to change without notice (well, almost :-)) The user can do this through the Control Panel if he wants to do it. Unless you're writing a "General" cdev substitute, of course... Happy Hacking ! (Oh, by the way, SetSoundVol is on page 233 of IM-II, and there's even no TechNote about it, so I think it's still valid, all according to my XRef) -- This is your fortune from h+@nada.kth.se: Quoting one is plagiarism. Quoting many is research.