Apple Newton Utilities User's Guide download pdf (Page 559)

100

101

CHAPTER 14

Sound

Using Sound 14-5

Creating Sound Frames Procedurally 14

To create a sound frame, you usually need to create a copy of the sound frame you

wish to modify. Because you cannot modify sound frames in ROM, you must copy

the sound frame in order to modify the binary

sample data.

Cloning the original version of a sound frame you want to modify also allows you

to reset values to their original state and provides a means of recovering the original

sound frame easily if an operation fails.

Cloning Sound Frames 14

You can use the Clone function to make a modiﬁable copy of the sound frame by

passing the frame or its reference to

Clone and saving the result in a variable, as in

the following example:

clonedSound := clone(ROM_simpleBeep);

This technique is an extremely efﬁcient means of creating a modiﬁable sound

frame, because the copy created is a shallow clone; that is, the cloned frame

clonedSound does not actually store a copy of the ROM_simpleBeep binary

data. Instead, the

clonedSound frame stores a pointer to the ROM data in its

samples slot. Thus, the clonedSound frame is fairly lightweight in terms of

overhead in the NewtonScript heap.

Playing Sound 14

Newton system software plays sound in two ways. The ﬁrst is to use the global

sound functions

PlaySoundAtVolume or PlaySoundIrregardless. The

other way is to instantiate a sound playback channel and send messages to it. Each

approach has beneﬁts and drawbacks. Using the global functions is the simplest

and most efﬁcient approach, but it offers less control than sending messages to a

sound channel.

Sound channels are appropriate for applications that require greater control over

playback, such as one that allows pausing playback and sound completion. Sound

channels are also useful for games, which might require having many sounds

available on short notice or playing multiple sounds at the same time.

Using a Sound Channel to Play Sound 14

Using a sound channel to play a sound is accomplished by creating a sound

channel and sending the

Start message to it.

1 2 ... 554 555 556 557 558 559 560 561 562 563 564 ... 941 942

Comments to this Manuals

No comments

Apple Newton Utilities User's Guide Page 559

Comments to this Manuals

Related products and manuals for Software Apple Newton Utilities