This is a very general-purpose view class that provides some handy high-level methods for doing zooming. More...

Inheritance diagram for GCZoomView:

Instance Methods
(NSPoint)	- centredPointInDocView
	Calculates the coordinates of the point that is visually centred in the view at the current scroll position and zoom. More...

(BOOL)	- isChangingScale
	Returns whether the scale is being changed. More...

(CGFloat)	- maximumScale
	Returns the maximum permitted view scale (zoom) More...

(CGFloat)	- minimumScale
	Returns the minimum permitted view scale (zoom) More...

(CGFloat)	- scale
	Returns the current view scale (zoom) More...

(void)	- scrollPointToCentre:
	Scrolls the view so that the point ends up visually centred. More...

(void)	- setMaximumScale:
	Sets the maximum permitted view scale (zoom) More...

(void)	- setMinimumScale:
	Sets the minimum permitted view scale (zoom) More...

(void)	- setScale:
	Zooms the view to the given scale. More...

(IBAction)	- zoomFitInWindow:
	Zoom so that the entire extent of the enclosing frame is visible. More...

(IBAction)	- zoomIn:
	Zoom in (scale up) by a factor of 2. More...

(IBAction)	- zoomMax:

(IBAction)	- zoomMin:

(IBAction)	- zoomOut:
	Zoom out (scale down) by a factor of 2. More...

(IBAction)	- zoomToActualSize:
	Restore the zoom to 100%. More...

(IBAction)	- zoomToPercentageWithTag:
	Takes the senders tag value as the desired percentage. More...

(void)	- zoomViewByFactor:
	Zoom by the desired scaling factor. More...

(void)	- zoomViewByFactor:andCentrePoint:
	Zooms the view by the given factor and centres the passed point. More...

(void)	- zoomViewToAbsoluteScale:

(void)	- zoomViewToFitRect:
	Zooms so that the passed rect will fit in the view. More...

(void)	- zoomViewToRect:
	Zooms so that the passed rect fills the view. More...

(void)	- zoomWithScrollWheelDelta:toCentrePoint:

Instance Methods inherited from NSObject
(NSString *)	- address

(DKStyleRegistry *)	- applicationWillReturnStyleRegistry

(BOOL)	- canBeUsedWithSelectionTool

(id)	- categoryManager:shouldReplaceObject:withObject:

(Class)	- classForCoder

(NSColor *)	- colorValue

(NSColor *)	- colourValue

(id)	- copy

(void)	- dealloc

(id)	- deepCopy

(NSDictionary *)	- dimensionValuesForArrowStroke:

(CGFloat)	- drawing:convertDistanceToExternalCoordinates:

(NSPoint)	- drawing:convertLocationToExternalCoordinates:

(void)	- drawing:didDrawRect:inView:

(void)	- drawing:willDrawRect:inView:

(NSString *)	- drawing:willReturnAbbreviationForUnit:

(NSString *)	- drawing:willReturnFormattedCoordinateForDistance:

(CGFloat)	- drawingWillReturnUnitToPointsConversonFactor:

(void)	- finalize

(NSString *)	- hexString

(void)	- hotspot:didEndTrackingWithEvent:inView:

(void)	- hotspot:isTrackingWithEvent:inView:

(void)	- hotspot:willBeginTrackingWithEvent:inView:

(NSData *)	- imageData

(NSImage *)	- imageResourceNamed:

(id)	- init

(id)	- initWithExpression:

(id)	- instantiateObjectWithShortName:parameters:

(BOOL)	- isLiteralValue

(void)	- layoutManager:willPlaceGlyphAtIndex:atLocation:pathAngle:yOffset:

(void)	- menuItem:wasAddedForObject:inCategory:

(BOOL)	- moveObjectTo:position:slope:userInfo:

(id)	- mutableCopy

(void)	- oneShotComplete

(void)	- oneShotHasReached:

(void)	- oneShotWillBegin

(void)	- path:elementIndex:type:points:subPathIndex:subPathClosed:contextInfo:

(id)	- placeLinkFromPoint:toPoint:onPath:linkNumber:userInfo:

(id)	- placeObjectAtPoint:onPath:position:slope:userInfo:

(NSPoint)	- point

(NSPoint)	- pointForTextLayout

(DKStyle *)	- registry:shouldReplaceStyle:withStyle:

(NSBezierPath *)	- renderer:willRenderPath:

(void)	- routeFinder:progressHasReached:

(void)	- setValue:forNumericParameter:

(NSString *)	- stringValue

(CGFloat)	- taperFactorAtDistance:onPath:ofLength:

(void)	- toolDidPerformUndoableAction:

(void)	- toolWillPerformUndoableAction:

(NSURL *)	- url

Instance Methods inherited from <NSObject>
(NSString *)	- description

(NSUInteger)	- hash

(BOOL)	- isEqual:

Instance Methods inherited from <NSKeyValueBindingCreation>
(void)	- bind:toObject:withKeyPath:options:

(NSArray *)	- exposedBindings

(NSDictionary *)	- infoForBinding:

(NSArray *)	- optionDescriptionsForBinding:

(void)	- unbind:

(Class)	- valueClassForBinding:

Instance Methods inherited from <NSCoding>
(void)	- encodeWithCoder:

(id)	- initWithCoder:

Class Methods
(BOOL)	+ scrollwheelInverted
	Return whether view zooms in or out for a given scrollwheel rotation direction. More...

(NSUInteger)	+ scrollwheelModifierKeyMask
	Return the default zoom key mask used by new instances of this class. More...

(BOOL)	+ scrollwheelZoomEnabled
	Return whether scroll-wheel zooming is enabled. More...

(void)	+ setScrollwheelInverted:
	Set whether view zooms in or out for a given scrollwheel rotation direction. More...

(void)	+ setScrollwheelModiferKeyMask:
	Set the modifier key(s) that will activate zooming using the scrollwheel. More...

(void)	+ setScrollwheelZoomEnabled:
	Set whether scroll-wheel zooming is enabled. More...

Class Methods inherited from NSObject
(id)	+ alloc

(Class)	+ class

(void)	+ initialize

(void)	+ load

(id)	+ new

Class Methods inherited from <NSKeyValueBindingCreation>
(void)	+ exposeBinding:

Detailed Description

This is a very general-purpose view class that provides some handy high-level methods for doing zooming.

This is a very general-purpose view class that provides some handy high-level methods for doing zooming. Simply hook up the action methods to suitable menu commands and away you go. The stuff you draw within drawRect: doesn't need to know or care abut the zoom of the view - you can just draw as usual and it works.

Note: this class doesn't bother to support NSCoding and thereby encoding the view zoom, because it usually isn't important for this value to persist. However, if your subclass wants to support coding, your initWithCoder method should reset _scale to 1.0. Otherwise it will get initialized to 0.0 and NOTHING WILL BE DRAWN.

Method Documentation

- (NSPoint) centredPointInDocView

Calculates the coordinates of the point that is visually centred in the view at the current scroll position and zoom.

Returns: the visually centred point

- (BOOL) isChangingScale

Returns whether the scale is being changed.

This property can be used to detect whether the user is rapidly changing the scale, for example using the scrollwheel. When a scrollwheel change starts, this is set to YES and a timer is run which is retriggered by further events. If it times out, this resets to NO. It can be used as one part of a drawing strategy where rapid changes temporarily use a lower quality drawing mechanism for performance, but reverts to a higher quality when things settle.

Returns: YES if the scale is changing, NO if not

- (CGFloat) maximumScale

Returns the maximum permitted view scale (zoom)

Returns: the maximum scale

- (CGFloat) minimumScale

Returns the minimum permitted view scale (zoom)

Returns: the minimum scale

- (CGFloat) scale

Returns the current view scale (zoom)

Returns: the current scale

- (void) scrollPointToCentre: (NSPoint) aPoint

Scrolls the view so that the point ends up visually centred.

Parameters

aPoint the desired centre point

+ (BOOL) scrollwheelInverted

Return whether view zooms in or out for a given scrollwheel rotation direction.

Default sense is to zoom in when scrollwheel is rotated towards the user. Some apps (e.g. Google Earth) use the opposite convention, which feels less natural but may become a defacto "standard".

Returns: whether scroll wheel inverted

+ (NSUInteger) scrollwheelModifierKeyMask

Return the default zoom key mask used by new instances of this class.

Reads the value from the prefs. If not set or set to zero, defaults to option key.

Returns: a modifier key mask value

+ (BOOL) scrollwheelZoomEnabled

Return whether scroll-wheel zooming is enabled.

Default is YES

Returns: YES to enable, NO to disable

- (void) setMaximumScale: (CGFloat) scmax

Sets the maximum permitted view scale (zoom)

Parameters

scmax the maximum scale

- (void) setMinimumScale: (CGFloat) scmin

Sets the minimum permitted view scale (zoom)

Parameters

scmin the minimum scale

- (void) setScale: (CGFloat) sc

Zooms the view to the given scale.

All zooms bottleneck through here. Scale passed is pinned within the min and max limits.

Parameters

sc	- the desired scale

+ (void) setScrollwheelInverted: (BOOL) inverted

Set whether view zooms in or out for a given scrollwheel rotation direction.

Default sense is to zoom in when scrollwheel is rotated towards the user. Some apps (e.g. Google Earth) use the opposite convention, which feels less natural but may become a defacto "standard".

+ (void) setScrollwheelModiferKeyMask: (NSUInteger) aMask

Set the modifier key(s) that will activate zooming using the scrollwheel.

Operating the given modifier keys along with the scroll wheel will zoom the view

Parameters

aMask a modifier key mask value

+ (void) setScrollwheelZoomEnabled: (BOOL) enable

Set whether scroll-wheel zooming is enabled.

Default is YES

Parameters

enable YES to enable, NO to disable

- (IBAction) zoomFitInWindow: (id) sender

Zoom so that the entire extent of the enclosing frame is visible.

Parameters