SndView Class Reference

SndView is responsible for displaying a amplitude/time plot of Snd data. More...

#import <SndView.h>

List of all members.

Public Member Functions
(id)	- showCursor
	Displays the SndView's cursor.
(BOOL)	- resignFirstResponder
	Resigns the position of first responder.
(BOOL)	- becomeFirstResponder
	Promotes the SndView to first responder, and returns YES.
(void)	- copy:
	Copies the current selection to the pasteboard.
(void)	- cut:
	Deletes the current selection from the SndView, copies it to the pasteboard, and sends a soundDidChange: message to the delegate.
(void)	- delete:
	Deletes the current selection from the SndView's Snd and sends the soundDidChange: message to the delegate.
(void)	- paste:
	Replaces the current selection with a copy of the sound data currently on the pasteboard.
(void)	- selectAll:
	Creates a selection over the SndView's entire Snd.
(id)	- delegate
	Returns the SndView's delegate object.
(id)	- didPlay:duringPerformance:
	Sent to the delegate just after the SndView's sound is played.
(id)	- didRecord:
	Sent to the delegate just after the SndView's sound is recorded into.
(int)	- displayMode
	Returns the SndView's display mode, one of SND_SOUNDVIEW_WAVE (oscilloscopic display) or SND_SOUNDVIEW_MINMAX (minimum/maximum display; this is the default).
(void)	- drawRect:
	Displays the SndView's sound data.
(void)	- getSelection:size:
	Returns the selection by reference.
(void)	- setSelection:size:
	Sets the selection to be sampleCount samples wide, starting with sample firstSample (samples are counted from 0).
(id)	- hadError:
	Sent to the delegate if an error is encountered during recording or playback of the SndView's sound.
(id)	- initWithFrame:
	Initializes the SndView, fitting the object within the rectangle given by frameRect.
(BOOL)	- isAutoScale
	Returns YES if the SndView is in autoscaling mode, otherwise returns NO.
(BOOL)	- isBezeled
	Returns YES if the SndView has a bezeled border, otherwise returns NO (the default).
(BOOL)	- isContinuousSelectionUpdates
	Returns YES if the SndView responds to mouse-dragged events (as set through setContinuousSelectionUpdates:).
(BOOL)	- isEditable
	Returns YES if the SndView's sound data can be edited.
(BOOL)	- isEnabled
	Returns YES if the SndView is enabled, otherwise returns NO.
(BOOL)	- isOptimizedForSpeed
	Returns YES if the SndView is optimized for speedy display.
(BOOL)	- isPlayable
	Returns YES if the SndView's sound data can be played without first being converted.
(BOOL)	- isEntireSoundVisible
	Returns YES if the receiver is displaying the entire sound within the visible rectangle of it's enclosing scrollview.
(void)	- selectionChanged
	Not normally messaged directly by a client class, it's default operation is to inform the delegate that the selection changed if setContinuousSelectionUpdates was set to YES.
(void)	- mouseDown:
	Allows a selection to be defined by clicking and dragging the mouse.
(void)	- pasteboard:provideDataForType:
	Places the SndView's entire sound on the given pasteboard.
(void)	- pause:
	Pauses the current playback or recording session by invoking Snd's pause: method.
(void)	- play:
	Play the current selection by invoking Snd's play: method.
(void)	- resume:
	Resumes the current playback or recording session by invoking Snd's resume: method.
(void)	- record:
	Replaces the SndView's current selection with newly recorded material.
(void)	- stop:
	Stops the SndView's current recording or playback.
(BOOL)	- readSelectionFromPasteboard:
	Replaces the SndView's current selection with the sound data on the given pasteboard.
(void)	- setAmplitudeZoom:
	Sets the current vertical amplitude axis zoom factor.
(float)	- amplitudeZoom
	Returns the current vertical amplitude axis zoom factor.
(float)	- reductionFactor
	Returns the SndView's reduction factor in the horizontal time axis.
(BOOL)	- setReductionFactor:
	Assigns the reduction factor in the horizontal time axis.
(void)	- scaleTo:
	Sets the proportion of the sound displayed within the SndView frame.
(void)	- scaleToFit
	Recomputes the SndView's reduction factor to fit the sound data (horizontally) within the current frame.
(void)	- resizeToFit
	Resizes the SndView's frame (horizontally) to maintain a constant reduction factor.
(void)	- resizeToFit:
	Resizes the SndView's frame (horizontally) to maintain a constant reduction factor.
(void)	- resizeToScale:
	Resizes the sound within the frame to a normalized scale.
(id)	- setAutoscale:
	Sets the SndView's automatic scaling mode, used to determine how the SndView is redisplayed when its data changes.
(void)	- setBezeled:
	If aFlag is YES, the display is given a bezeled border.
(void)	- setContinuousSelectionUpdates:
	Sets the state of continuous action messages.
(void)	- setDelegate:
	Sets the SndView's delegate to anObject.
(void)	- setDisplayMode:
	Sets the SndView's display mode, either SND_SOUNDVIEW_WAVE or SND_SOUNDVIEW_MINMAX (the default).
(void)	- setEditable:
	Enables or disables editing in the SndView as aFlag is YES or NO.
(void)	- setEnabled:
	Enables or disables the SndView as aFlag is YES or NO.
(void)	- setOptimizedForSpeed:
	Sets the SndView to optimize its display mechanism.
(void)	- setSound:
	Sets the SndView's Snd object to aSound.
(Snd *)	- sound
	Returns the SndView's Snd object being displayed.
(void)	- setFrameSize:
	Sets the width and height of the SndView's frame.
(Snd *)	- soundBeingProcessed
	Returns the Snd object that's currently being played or recorded into.
(void)	- tellDelegate:
	Sends theMessage to the SndView's delegate with the SndView as the argument.
(void)	- tellDelegate:duringPerformance:
	Sends theMessage to the SndView's delegate with the SndView as the argument.
(id)	- validRequestorForSendType:returnType:
	You never invoke this method; it's implemented to support services that act on sound data.
(void)	- willPlay:duringPerformance:
	Sent to the delegate just before the SndView's sound is played.
(void)	- willRecord:
	Sent to the delegate just before the SndView's sound is recorded into.
(BOOL)	- writeSelectionToPasteboard:types:
	write the selected region of sound to the pasteboard.
(void)	- invalidateCache
	Used if you change the data of a sound which is being used in a SndView in any way, to inform the SndView.
(void)	- setDrawsCrosses:
	Determines whether individual samples should be drawn as crosses when displaying sounds at extreme magnification.
(BOOL)	- drawsCrosses
	Returns whether individual samples are drawn as crosses at extreme magnification.
(BOOL)	- setStereoMode:
	Determines how to draw multichannel sounds.
(enum SndViewStereoMode)	- getStereoMode
	Returns the mode of drawing multichannel sounds.
(void)	- setSelectionColor:
	Sets the selection colour.
(NSColor *)	- selectionColor
	Returns the current selection colour.
(void)	- setBackgroundColor:
	Sets the background colour.
(NSColor *)	- backgroundColor
	Returns the current background colour.
(void)	- setForegroundColor:
	Sets the foreground colour.
(NSColor *)	- foregroundColor
	Returns the current foreground colour.
(void)	- setDragIcon:
	Sets the icon used when dragging selections from the SndView.
(NSImage *)	- dragIcon
	Returns the current NSImage instance used when dragging a selection from the receiver.

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Detailed Description

SndView is responsible for displaying a amplitude/time plot of Snd data.

A SndView object provides a graphical representation of sound data. This data is taken from an associated Snd object. In addition to displaying a Snd object's data, a SndView provides methods that let you play and record into the Snd object, and perform simple cut, copy, and paste editing of its data. A cursor into the display is provided, allowing the user to set the insertion point and to create a selection over the sound data.

Sound Display

Sounds are displayed on a two-dimensional graph. The amplitudes of individual samples are measured vertically and plotted against time, which proceeds left to right along the horizontal axis. A SndView's coordinate system is scaled and translated (vertically) so full amplitude fits within the bounds rectangle with 0.0 amplitude running through the center of the view.

For many sounds, the length of the sound data in samples is greater than the horizontal measure of the bounds rectangle. A SndView employs a reduction factor to determine the ratio of samples to display units and plots the minimum and maximum amplitude values of the samples within that ratio. For example, a reduction factor of 10.0 means that the minimum and maximum values among the first ten samples are plotted in the first display unit, the minimum and maximum values of the next ten samples are displayed in the second display unit and so on.

Lines are drawn between the chosen values to yield a continuous shape. Two drawing modes are provided:

• In SND_SOUNDVIEW_WAVE mode, the drawing is rendered in an oscilloscopic fashion.

• In SND_SOUNDVIEW_MINMAX mode, two lines are drawn, one to connect the maximum values, and one to connect the minimum values.

As you zoom in (as the reduction factor decreases), the two drawing modes become indistinguishable.

Autoscaling the Display

When a SndView's sound data changes (due to editing or recording), the manner in which the SndView is redisplayed depends on its autoscale flag. With autoscaling disabled, the SndView's frame grows or shrinks (horizontally) to fit the new sound data and the reduction factor is unchanged. If autoscaling is enabled, the reduction factor is automatically recomputed to maintain a constant frame size. By default, autoscaling is disabled; this is to accommodate the use of a SndView object as the document of an NSScrollView.

Methods Implemented by the Delegate

• selectionChanged: (id) sender Sent to the delegate when the SndView's selection changes.

• soundDidChange: (id) sender Sent to the delegate when the SndView's sound data is edited.

SndView Adds These Features:

• Configurable speed optimizations (see below).
• Non-integer reduction factors (reductionFactor), and reductionFactor down to 0.04 (1 sample per 25 pixels) [SoundView only goes as low as 1].
• For 0.04 <= reductionFactor < 0.34, SndView can be instructed to draw small horizontal bars at each sample (this is the default). This allows for great accuracy in specifying selections for copy/paste operations.
• Configurable maximum recording time.
• Intelligent recording - converts recorded sounds to the format of the rest of the displayed sound if the format is not compatible. Queries hardware for allowable sampling rates/formats [NOT CURRENTLY SUPPORTED ON ANY PLATFORM].
• Can be instructed to display only left channel, only right channel, or average of both channels.
• Triple-click does a Select-All.

SndView fixes these bugs:

• SndView is not susceptable to the "info length" bug (I think...)
• SndView copes a lot better with recording into the sound [NOT CURRENTLY SUPPORTED ON ANY PLATFORM]
• SndView displays "Waveform" view perfectly, without the PostScript errors that plague SoundView
• SndView is scrupulous about floating point numbers and rounding, and should never leave cursor "turds" on the screen
• SndView does not alter the length of the selection if you change reductionFactor. Even if you extend the selection at a reductionFactor different to the one you created the selection at, the sample at the non-changed end will remain the same.

SndView has these bugs:

• If SndView is destroyed without freeing it, and it has told the pasteboard that it has data ready for pasting (from a Copy or Cut operation) the application that requested the data will probably crash. If the application containing SndView quits normally, SndView does provide the data though (as does SoundView, I think).
• With reductionFactor <= 1, reducing the selection while auto-scrolling leaves a horrible mess on the screen, until you take your finger off the mouse. This is because when a section of the view is drawn, it highlights the part of the new section that it thinks is within the selection rectangle. For reductionFactor <= 1, this is not immediately obvious, and I need to force the start and end of selection rectangle in this case to be midway between samples.

SndView is incompatible in these ways:

• The bounds rectangle is not scaled the same as SoundView's is. SoundView scales it's bounds so that (y = 0) runs through the centre of the view, and the maximum +y and -y limits correspond to the limits of the format of the sound it is displaying. SndView does not scale at all. It could be changed quite easily. As it is, this breaks any subclasses of SoundView that draw into the view.
• "drawSamples from:to:" is not implemented (yet). But all you would have to do would be to invalidate the caches for that area (if necessary), and -display: the SndView
• Because of the caching mechanism, if you change samples "behind SndView's back" you must invalidate the cache for the affected samples, with "invalidateCacheStartSample:end:" before displaying.
• SoundView considers the left and right channels of the sound individually when it comes to finding maximum and minimum values for display. This makes display at some resolutions look very odd, and it's not really intuitive, although at low resolutions it does have the side effect of in fact showing both channels (one as maximum and 1 as minimum). SndView on the other hand shows either only one channel, or the average of both channels. Ideally it should have the option of showing both.

The optimization mechanism:

When the reductionFactor starts to climb, more samples are crammed into each horizontal pixel in the view. Each pixel shows the maximum and minimum value represented within that number of samples.

To display a very large sound in a small view, the reductionFactor may be in the 1000's. This means that eg 10,000 samples may need to be read, times the width of the view (perhaps 300). SndView seeks to reduce this number of reads by skipping samples when they are nowhere near its current maximum or minimum.

• Optimization only kicks in when reductionFactor > "threshold".
• At the start of the read for any particular pixel, SndView single-steps through the samples until it finds a local maximum/minimum. Thereafter it calculates 5% of the top of the peaks (or bottom of troughs), and if a particular sample is not within this "hot region", it takes bigger jumps until it finds a sample that is within the region. Once it finds this, it goes back to looking at every sample, until it moves out of the hot region again.
• "peak fraction" sets the percentage of the hot region (0.05 == 5%, default). Theoretically, the smaller this region, the faster the calculation, but in practice it doesn't make a lot of difference.
• "skip" should ideally increase in some sort of proportion to the reductionFactor. At present it is a fixed value, but a controller object could set it to, say, sqrroot(reductionFactor). I have not really tested this, but that's what this test application is for!

The caching mechanism

• When reductionFactor > 1, all display data is cached using the SndDisplayData and SndDisplayDataList classes.
• If reductionFactor changes, the caches are destroyed.
• Caches for display data after the origin of a paste or cut operation are destroyed.
• Adjacent caches are joined together as the user scrolls through the view
• Caching can make it hard to test the optimization mechanism

Other Features of the Source Code

• There are #ifdefs for turning on/off the SndView timing. There's not much reason to use the timing any more really.
• I have put any thought into the setting of zones. If anyone would like to advise on this I'd be happy to hear from you.
• The mechanism for retrieving data from fragmented sound files is (I think) rather elegant and should be really fast.
• The archival -read and -write methods are untested.
• Support for "floating point" and "double" sound format files is included.

Future Enhancements for SndView

• Support for direct from disk Snd subclasses. Saves having to load the entire file into memory before it is displayed (though once it has been displayed, there's no difference to the amount of actual memory/swap space used).
• SndView should utilise a control/cell paradigm so that channels can be displayed separately within the view.

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Member Function Documentation

- (BOOL) resignFirstResponder

Resigns the position of first responder.

Returns:

Returns a BOOL. Returns YES.

- (BOOL) becomeFirstResponder

Promotes the SndView to first responder, and returns YES.

Returns:

Returns a BOOL. You never invoke this method directly.

- (void) copy:

(id)

sender

Copies the current selection to the pasteboard.

Parameters:

sender

is an id.

- (void) cut:

(id)

sender

Deletes the current selection from the SndView, copies it to the pasteboard, and sends a soundDidChange: message to the delegate.

Parameters:

sender

is an id. The insertion point is positioned to where the selection used to start.

- (void) delete:

(id)

sender

Deletes the current selection from the SndView's Snd and sends the soundDidChange: message to the delegate.

Parameters:

sender

is an id. The deletion isn't placed on the pasteboard.

- (void) paste:

(id)

sender

Replaces the current selection with a copy of the sound data currently on the pasteboard.

Parameters:

sender

is an id. If there is no selection the pasteboard data is inserted at the cursor position. The pasteboard data must be compatible with the SndView's data, as determined by the Snd method compatibleWithSound:. If the paste is successful, the soundDidChange: message is sent to the delegate.

- (void) selectAll:

(id)

sender

Creates a selection over the SndView's entire Snd.

Parameters:

sender

is an id.

- (id) delegate

Returns the SndView's delegate object.

Returns:

Returns an id.

- (id) didPlay:		(id)	sender
duringPerformance:		(SndPerformance *)	performance

Sent to the delegate just after the SndView's sound is played.

Method implemented by the delegate. Used to redirect delegate messages from the SndView's Snd object; you never invoke this method directly.

Parameters:

	sender	is an id.
	performance	is a SndPerformance.

- (id) didRecord:

(id)

sender

Sent to the delegate just after the SndView's sound is recorded into.

Method implemented by the delegate. Used to redirect delegate messages from the SndView's Snd object; you never invoke this method directly.

Parameters:

sender

is an id.

- (int) displayMode

Returns the SndView's display mode, one of SND_SOUNDVIEW_WAVE (oscilloscopic display) or SND_SOUNDVIEW_MINMAX (minimum/maximum display; this is the default).

Returns:

Returns an int.

- (void) drawRect:

(NSRect)

rects

Displays the SndView's sound data.

Parameters:

rects

is a NSRect. The selection is highlighted and the cursor is drawn (if it isn't currently hidden).

You never send the drawRect: message directly to a SndView object. To cause a SndView to draw itself, send it one of the display messages defined by the NSView class.

- (void) getSelection:		(unsigned int *)	firstSample
size:		(unsigned int *)	sampleCount

Returns the selection by reference.

Parameters:

	firstSample	is an unsigned int *.
	sampleCount	is an unsigned int *. The index of the selection's first sample (counting from 0) is returned in firstSample. The size of the selection in samples is returned in sampleCount.

- (void) setSelection:		(int)	firstSample
size:		(int)	sampleCount

Sets the selection to be sampleCount samples wide, starting with sample firstSample (samples are counted from 0).

Parameters:

	firstSample	is an int.
	sampleCount	is an int.

- (id) hadError:

(id)

sender

Sent to the delegate if an error is encountered during recording or playback of the SndView's sound.

Used to redirect delegate messages from the SndView's Snd object; you never invoke this method directly.

Parameters:

sender

is an id.

- (id) initWithFrame:

(NSRect)

frameRect

Initializes the SndView, fitting the object within the rectangle given by frameRect.

The initialized SndView doesn't contain any sound data.

Parameters:

frameRect

is a NSRect.

Returns:

Returns self.

- (BOOL) isAutoScale

Returns YES if the SndView is in autoscaling mode, otherwise returns NO.

Returns:

Returns a BOOL.

- (BOOL) isBezeled

Returns YES if the SndView has a bezeled border, otherwise returns NO (the default).

Returns:

Returns a BOOL.

- (BOOL) isContinuousSelectionUpdates

Returns YES if the SndView responds to mouse-dragged events (as set through setContinuousSelectionUpdates:).

Returns:

Returns a BOOL. The default is NO.

- (BOOL) isEditable

Returns YES if the SndView's sound data can be edited.

Returns:

Returns a BOOL.

- (BOOL) isEnabled

Returns YES if the SndView is enabled, otherwise returns NO.

Returns:

Returns a BOOL. The mouse has no effect in a disabled SndView. By default, a SndView is enabled.

- (BOOL) isOptimizedForSpeed

Returns YES if the SndView is optimized for speedy display.

Returns:

Returns a BOOL. SndViews are optimized by default.

- (BOOL) isPlayable

Returns YES if the SndView's sound data can be played without first being converted.

Returns:

Returns a BOOL.

- (BOOL) isEntireSoundVisible

Returns YES if the receiver is displaying the entire sound within the visible rectangle of it's enclosing scrollview.

Returns:

Returns a BOOL

- (void) selectionChanged

Not normally messaged directly by a client class, it's default operation is to inform the delegate that the selection changed if setContinuousSelectionUpdates was set to YES.

This allows subclasses to know when selections change and override default behaviour.

- (void) mouseDown:

(NSEvent *)

theEvent

Allows a selection to be defined by clicking and dragging the mouse.

Parameters:

theEvent

is an NSEvent instance. This method takes control until a mouse-up occurs. While dragging, the selected region is highlighted. On mouse up, the delegate is sent the selectionChanged: message. If isContinuous is YES, selectionChanged: messages are also sent while the mouse is being dragged. You never invoke this method; it's invoked automatically in response to the user's actions.

- (void) pasteboard:		(NSPasteboard *)	thePasteboard
provideDataForType:		(NSString *)	pboardType

Places the SndView's entire sound on the given pasteboard.

Parameters:

	thePasteboard	is a NSPasteboard instance.
	pboardType	is a NSString instance. Currently, the type argument must be “SndPasteboardType”, the pasteboard type that represents sound data.

- (void) pause:

(id)

sender

Pauses the current playback or recording session by invoking Snd's pause: method.

Parameters:

sender

is an id.

- (void) play:

(id)

sender

Play the current selection by invoking Snd's play: method.

If there is no selection, the SndView's entire Snd is played. The willPlay: message is sent to the delegate before the selection is played; didPlay: is sent when the selection is done playing.

Parameters:

sender

is an id.

- (void) resume:

(id)

sender

Resumes the current playback or recording session by invoking Snd's resume: method.

Parameters:

sender

is an id.

- (void) record:

(id)

sender

Replaces the SndView's current selection with newly recorded material.

Parameters:

sender

is an id. If there is no selection, the recording is inserted at the cursor. The willRecord: message is sent to the delegate before the recording is started; didRecord: is sent after the recording has completed. Recorded data is always taken from the CODEC microphone input.

- (void) stop:

(id)

sender

Stops the SndView's current recording or playback.

Parameters:

sender

is an id.

- (BOOL) readSelectionFromPasteboard:

(NSPasteboard *)

thePasteboard

Replaces the SndView's current selection with the sound data on the given pasteboard.

Parameters:

thePasteboard

is a NSPasteboard instance.

Returns:

Returns a BOOL. The pasteboard data is converted to the format of the data in the SndView (if possible). If the SndView has no selection, the pasteboard data is inserted at the cursor position. Sets the current error code for the SndView's Snd object (which you can retrieve by sending processingError to the Snd) and returns YES.

- (void) setAmplitudeZoom:

(float)

newAmplitudeZoom

Sets the current vertical amplitude axis zoom factor.

Parameters:

newAmplitudeZoom

The new amplitude zoom factor. If 1.0, this displays a full amplitude signal in the maximum vertical view width. If greater than 1.0 a signal will be zoomed and clipped against the view. If less than 1.0 the signal will be reduced within the view. Values less than or equal to zero are not set.

- (float) amplitudeZoom

Returns the current vertical amplitude axis zoom factor.

Returns:

Returns a float.

- (float) reductionFactor

Returns the SndView's reduction factor in the horizontal time axis.

Returns:

Returns a float. Computed as follows: reductionFactor = sampleCount / displayUnits

- (BOOL) setReductionFactor:

(float)

reductionFactor

Assigns the reduction factor in the horizontal time axis.

Parameters:

reductionFactor

is a float.

Returns:

Returns a BOOL. Recomputes the size of the SndView's frame, if autoscaling is disabled. The frame's size (in display units) is set according to the following formula:

displayUnits = sampleCount / reductionFactor

Increasing the reduction factor zooms out, decreasing zooms in on the data. If autodisplaying is enabled, the Snd is automatically redisplayed.

If the SndView is in autoscaling mode, or reductionFactor is less than 1.0, the method avoids computing the frame size and returns NO. (In autoscaling mode, the reduction factor is automatically recomputed when the sound data changes - see scaleToFit:.) Otherwise, the method returns YES. If reductionFactor is the same as the current reduction factor, the method returns immediately without recomputing the frame size.

- (void) scaleTo:

(float)

scaleRatio

Sets the proportion of the sound displayed within the SndView frame.

Recomputes the SndViews reduction factor to fit a portion of the sound data (horizontally) within the views frame.

Parameters:

scaleRatio

The ratio of displayed content within the frame 1.0 = entire sound, 0.5 = half the sound etc.

- (void) scaleToFit

Recomputes the SndView's reduction factor to fit the sound data (horizontally) within the current frame.

Invoked automatically when the SndView's data changes and the SndView is in autoscale mode. If the SndView isn't in autoscale mode, resizeToFit is invoked when the data changes. You never invoke this method directly; a subclass can reimplement this method to provide specialized behavior.

- (void) resizeToFit

Resizes the SndView's frame (horizontally) to maintain a constant reduction factor.

This method is invoked automatically when the SndView's data changes and the SndView isn't in autoscale mode. If the SndView is in autoscale mode, scaleToFit is invoked when the data changes. You never invoke this method directly; a subclass can reimplement this method to provide specialized behavior.

- (void) resizeToFit:

(BOOL)

withAutoscaling

Resizes the SndView's frame (horizontally) to maintain a constant reduction factor.

Parameters:

withAutoscaling

is a BOOL. This method is invoked automatically when the SndView's data changes and the SndView isn't in autoscale mode. If the SndView is in autoscale mode, scaleToFit is invoked when the data changes. You never invoke this method directly; a subclass can reimplement this method to provide specialized behavior.

- (void) resizeToScale:

(float)

scaleRatio

Resizes the sound within the frame to a normalized scale.

Parameters:

scaleRatio

Scaling of the sound within the frame: 0 > scaleRatio <= 1.0

- (id) setAutoscale:

(BOOL)

aFlag

Sets the SndView's automatic scaling mode, used to determine how the SndView is redisplayed when its data changes.

Parameters:

aFlag

is a BOOL. With autoscaling enabled (aFlag is YES), the SndView's reduction factor is recomputed so the sound data fits within the view frame. If it's disabled (aFlag is NO), the frame is resized and the reduction factor is unchanged. If the SndView is in an NSScrollView, autoscaling should be disabled (autoscaling is disabled by default).

- (void) setBezeled:

(BOOL)

aFlag

If aFlag is YES, the display is given a bezeled border.

Parameters:

aFlag

is a BOOL. By default, the border of a SndView display isn't bezeled. If autodisplay is enabled, the Snd is automatically redisplayed.

- (void) setContinuousSelectionUpdates:

(BOOL)

aFlag

Sets the state of continuous action messages.

Parameters:

aFlag

is a BOOL. If aFlag is YES, selectionChanged: messages are sent to the delegate as the mouse is being dragged. If NO, the message is sent only on mouse up. The default is NO.

- (void) setDelegate:

(id)

anObject

Sets the SndView's delegate to anObject.

Parameters:

anObject

is an id. The delegate is sent messages when the user changes or acts on the selection.

- (void) setDisplayMode:

(int)

aMode

Sets the SndView's display mode, either SND_SOUNDVIEW_WAVE or SND_SOUNDVIEW_MINMAX (the default).

Parameters:

aMode

is an int. If autodisplaying is enabled, the Snd is automatically redisplayed.

- (void) setEditable:

(BOOL)

aFlag

Enables or disables editing in the SndView as aFlag is YES or NO.

Parameters:

aFlag

is a BOOL. By default, a SndView is editable.

- (void) setEnabled:

(BOOL)

aFlag

Enables or disables the SndView as aFlag is YES or NO.

Parameters:

aFlag

is a BOOL. The mouse has no effect in a disabled SndView. By default, a SndView is enabled.

- (void) setOptimizedForSpeed:

(BOOL)

flag

Sets the SndView to optimize its display mechanism.

Parameters:

flag

is a BOOL. Optimization greatly increases the speed with which data can be drawn, particularly for large sounds. It does so at the loss of some precision in representing the sound data; however, these inaccuracies are corrected as you zoom in on the data. All SndView's are optimized by default.

- (void) setSound:

(Snd *)

aSound

Sets the SndView's Snd object to aSound.

Parameters:

aSound

is a Snd instance. If autoscaling is enabled, the drawing coordinate system is adjusted so aSound's data fits within the current frame. Otherwise, the frame is resized to accommodate the length of the data. If autodisplaying is enabled, the SndView is automatically redisplayed.

- (Snd *) sound

Returns the SndView's Snd object being displayed.

Returns:

Returns a Snd instance.

- (void) setFrameSize:

(NSSize)

newSize

Sets the width and height of the SndView's frame.

If autodisplaying is enabled, the SndView is automatically redisplayed.

Parameters:

newSize

is a NSSize.

- (Snd *) soundBeingProcessed

Returns the Snd object that's currently being played or recorded into.

Returns:

Returns an Snd. Note that the actual Snd object that's being performed isn't necessarily the object returned by SndView's sound method; for efficiency, SndView creates a private performance Snd object. While this is generally an implementation detail, this method is supplied in case the SndView's delegate needs to know exactly which object will be (or was) performed.

- (void) tellDelegate:

(SEL)

theMessage

Sends theMessage to the SndView's delegate with the SndView as the argument.

Parameters:

theMessage

is a SEL. If the delegate doesn't respond to the message, then it isn't sent. You normally never invoke this method; it's invoked automatically when an action, such as playing or editing, is performed. However, you can invoke it in the design of a SndView subclass.

- (void) tellDelegate:		(SEL)	theMessage
duringPerformance:		(SndPerformance *)	performance

Sends theMessage to the SndView's delegate with the SndView as the argument.

If the delegate doesn't respond to the message, then it isn't sent. You normally never invoke this method; it's invoked automatically when an action, such as playing or editing, is performed. However, you can invoke it in the design of a SndView subclass.

Parameters:

	theMessage	is a SEL.
	performance	The SndPerformance instance performing when the message is sent.

- (id) validRequestorForSendType:		(NSString *)	sendType
returnType:		(NSString *)	returnType

You never invoke this method; it's implemented to support services that act on sound data.

Parameters:

	sendType	is a NSString instance.
	returnType	is a NSString instance.

Returns:

Returns an id.

- (void) willPlay:		(id)	sender
duringPerformance:		(SndPerformance *)	performance

Sent to the delegate just before the SndView's sound is played.

Parameters:

	sender	is an id.
	performance	A SndPerformance instance indicating which performance is about to play.

Method implemented by the delegate. Used to redirect delegate messages from the SndView's Snd object; you never invoke this method directly.

- (void) willRecord:

(id)

sender

Sent to the delegate just before the SndView's sound is recorded into.

Parameters:

sender

is an id.

Method implemented by the delegate. Used to redirect delegate messages from the SndView's Snd object; you never invoke this method directly.

- (BOOL) writeSelectionToPasteboard:		(NSPasteboard *)	thePasteboard
types:		(NSArray *)	pboardTypes

write the selected region of sound to the pasteboard.

Parameters:

	thePasteboard	The pasteboard to receive the sound region.
	pboardTypes	An array of ? sound formats?

- (void) invalidateCache

Used if you change the data of a sound which is being used in a SndView in any way, to inform the SndView.

The easiest message to use is -invalidateCache, but you can be more specific and tell it the exact sample number with -invalidateCacheStartSample:end:

- (void) setDrawsCrosses:

(BOOL)

aFlag

Determines whether individual samples should be drawn as crosses when displaying sounds at extreme magnification.

Defaults to YES.

Parameters:

aFlag

YES to draw crosses linked by line segments, NO to draw samples as points linked by line segments.

- (BOOL) drawsCrosses

Returns whether individual samples are drawn as crosses at extreme magnification.

Returns:

Returns YES if samples are drawn with a cross, NO if they are drawn as points.

- (BOOL) setStereoMode:

(enum SndViewStereoMode)

stereoMode

Determines how to draw multichannel sounds.

Parameters:

stereoMode

one of the values SV_LEFTONLY, SV_RIGHTONLY, SV_STEREOMODE

- (enum SndViewStereoMode) getStereoMode

Returns the mode of drawing multichannel sounds.

Returns:

Returns

- (void) setSelectionColor:

(NSColor *)

color

Sets the selection colour.

Parameters:

color

An NSColor.

- (NSColor *) selectionColor

Returns the current selection colour.

Returns:

Returns an NSColor.

- (void) setBackgroundColor:

(NSColor *)

color

Sets the background colour.

Parameters:

color

An NSColor.

- (NSColor *) backgroundColor

Returns the current background colour.

Returns:

Returns an NSColor.

- (void) setForegroundColor:

(NSColor *)

color

Sets the foreground colour.

Parameters:

color

An NSColor instance.

- (NSColor *) foregroundColor

Returns the current foreground colour.

Returns:

Returns an NSColor instance.

- (void) setDragIcon:

(NSImage *)

newDragIcon

Sets the icon used when dragging selections from the SndView.

If the default workspace image icon is desired, use: [sndView setDragIcon: [[NSWorkspace sharedWorkspace] iconForFileType: [Snd defaultFileExtension]]];

Parameters:

newDragIcon

An NSImage instance to be used as the drag image. If nil, the icon to appear will be the visible region of the selected SndView.

- (NSImage *) dragIcon

Returns the current NSImage instance used when dragging a selection from the receiver.

If nil, the icon to appear will be the visible region of the selected SndView.

Returns:

Returns an NSImage instance.

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The documentation for this class was generated from the following file:

• SndView.h