NSTextInputClient Protocol Reference

Adopted by
Framework
/System/Library/Frameworks/AppKit.framework
Availability
Available in OS X v10.5 and later.
Declared in
NSTextInputClient.h
Related sample code

Overview

The NSTextInputClient protocol defines the methods that Cocoa text views must implement in order to interact properly with the text input management system. To create another text view class, you can either subclass NSTextView (and not NSText, for historical reasons), or subclass NSView and implement the NSTextInputClient protocol

Tasks

Handling Marked Text

Storing Text

Getting Character Coordinates

Binding Keystrokes

Optional Methods

Instance Methods

attributedString

Returns an attributed string representing the receiver's text storage.

- (NSAttributedString *)attributedString
Return Value

The attributed string of the receiver’s text storage.

Discussion

Implementation of this method is optional. A class adopting the NSTextInputClient protocol can implement this interface if it can be done efficiently to enable callers of this interface to access arbitrary portions of the receiver's content more efficiently.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h

attributedSubstringForProposedRange:actualRange:

Returns an attributed string derived from the given range in the receiver's text storage. (required)

- (NSAttributedString *)attributedSubstringForProposedRange:(NSRange)aRange actualRange:(NSRangePointer)actualRange
Parameters
aRange

The range in the text storage from which to create the returned string.

actualRange

The actual range of the returned string if it was adjusted, for example, to a grapheme cluster boundary or for performance or other reasons. NULL if range was not adjusted.

Return Value

The string created from the given range. May return nil.

Discussion

An implementation of this method should be prepared for aRange to be out of bounds. For example, the InkWell text input service can ask for the contents of the text input client that extends beyond the document’s range. In this case, you should return the intersection of the document’s range and aRange. If the location of aRange is completely outside of the document’s range, return nil.

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

baselineDeltaForCharacterAtIndex:

Returns the baseline position of a given character relative to the origin of rectangle returned by firstRectForCharacterRange:actualRange:.

- (CGFloat)baselineDeltaForCharacterAtIndex:(NSUInteger)anIndex
Parameters
anIndex

Index of the character whose baseline is tested.

Return Value

The vertical distance, in points, between the baseline of the character at anIndex and the rectangle origin.

Discussion

Implementation of this method is optional. This information allows the caller to determine finer-grained character positioning within the text storage of the text view adopting NSTextInputClient.

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

characterIndexForPoint:

Returns the index of the character whose bounding rectangle includes the given point. (required)

- (NSUInteger)characterIndexForPoint:(NSPoint)aPoint
Parameters
aPoint

The point to test, in screen coordinates.

Return Value

The character index, measured from the start of the receiver’s text storage, of the character containing the given point. Returns NSNotFound if the cursor is not within a character’s bounding rectangle.

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

doCommandBySelector:

Invokes the action specified by the given selector. (required)

- (void)doCommandBySelector:(SEL)aSelector
Parameters
aSelector

The selector to invoke.

Discussion

If aSelector cannot be invoked, then doCommandBySelector: should not pass this message up the responder chain. NSResponder also implements this method, and it does forward uninvokable commands up the responder chain, but a text view should not. A text view implementing the NSTextInputClient protocol inherits from NSView, which inherits from NSResponder, so your implementation of this method will override the one in NSResponder. It should not call super.

Availability
  • Available in OS X v10.5 and later.
See Also
Declared In
NSTextInputClient.h

drawsVerticallyForCharacterAtIndex:

Informs the text input management system whether the protocol-conforming client renders the character at the given index vertically.

- (BOOL)drawsVerticallyForCharacterAtIndex:(NSUInteger)charIndex
Parameters
charIndex

The index of the character to test.

Return Value

YES if the character is rendered vertically; otherwise NO.

Availability
  • Available in OS X v10.6 and later.
Declared In
NSTextInputClient.h

firstRectForCharacterRange:actualRange:

Returns the first logical boundary rectangle for characters in the given range. (required)

- (NSRect)firstRectForCharacterRange:(NSRange)aRange actualRange:(NSRangePointer)actualRange
Parameters
aRange

The character range whose boundary rectangle is returned.

actualRange

If non-NULL, contains the character range corresponding to the returned area if it was adjusted, for example, to a grapheme cluster boundary or characters in the first line fragment.

Return Value

The boundary rectangle for the given range of characters, in screen coordinates. The rectangle’s size value can be negative if the text flows to the left.

Discussion

If aRange spans multiple lines of text in the text view, the rectangle returned is the one surrounding the characters in the first line. In that case actualRange contains the range covered by the first rect, so you can query all line fragments by invoking this method repeatedly. If the length of aRange is 0 (as it would be if there is nothing selected at the insertion point), the rectangle coincides with the insertion point, and its width is 0.

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

fractionOfDistanceThroughGlyphForPoint:

Returns the fraction of the distance from the left side of the character to the right side that a given point lies.

- (CGFloat)fractionOfDistanceThroughGlyphForPoint:(NSPoint)aPoint
Parameters
aPoint

The point to test.

Return Value

The fraction of the distance aPoint is through the glyph in which it lies. May be 0 or 1 if aPoint is not within the bounding rectangle of a glyph (0 if the point is to the left or above the glyph; 1 if it's to the right or below).

Discussion

Implementation of this method is optional. This allows caller to perform precise selection handling.

For purposes such as dragging out a selection or placing the insertion point, a partial percentage less than or equal to 0.5 indicates that aPoint should be considered as falling before the glyph; a partial percentage greater than 0.5 indicates that it should be considered as falling after the glyph. If the nearest glyph doesn’t lie under aPoint at all (for example, if aPoint is beyond the beginning or end of a line), this ratio is 0 or 1.

For example, if the glyph stream contains the glyphs “A” and “b”, with the width of “A” being 13 points, and aPoint is 8 points from the left side of “A”, then the fraction of the distance is 8/13, or 0.615. In this case, the aPoint should be considered as falling between “A” and “b” for purposes such as dragging out a selection or placing the insertion point.

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

hasMarkedText

Returns a Boolean value indicating whether the receiver has marked text. (required)

- (BOOL)hasMarkedText
Return Value

YES if the receiver has marked text; otherwise NO.

Discussion

The text view itself may call this method to determine whether there currently is marked text. NSTextView, for example, disables the Edit > Copy menu item when this method returns YES.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h

insertText:replacementRange:

Inserts the given string into the receiver, replacing the specified content. (required)

- (void)insertText:(id)aString replacementRange:(NSRange)replacementRange
Parameters
aString

The text to insert, either an NSString or NSAttributedString instance.

replacementRange

The range of content to replace in the receiver’s text storage.

Discussion

This method is the entry point for inserting text typed by the user and is generally not suitable for other purposes. Programmatic modification of the text is best done by operating on the text storage directly. Because this method pertains to the actions of the user, the text view must be editable for the insertion to work.

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

markedRange

Returns the range of the marked text. (required)

- (NSRange)markedRange
Return Value

The range of marked text or {NSNotFound, 0} if there is no marked range.

Discussion

The returned range measures from the start of the receiver’s text storage. The return value’s location is NSNotFound and its length is 0 if and only if hasMarkedText returns NO.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h

selectedRange

Returns the range of selected text. (required)

- (NSRange)selectedRange
Return Value

The range of selected text or {NSNotFound, 0} if there is no selection.

Discussion

The returned range measures from the start of the receiver’s text storage, that is, from 0 to the document length.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h

setMarkedText:selectedRange:replacementRange:

Replaces a specified range in the receiver’s text storage with the given string and sets the selection. (required)

- (void)setMarkedText:(id)aString selectedRange:(NSRange)selectedRange replacementRange:(NSRange)replacementRange
Parameters
aString

The string to insert. Can be either an NSString or NSAttributedString instance.

selectedRange

The range to set as the selection, computed from the beginning of the inserted string.

replacementRange

The range to replace, computed from the beginning of the marked text.

Discussion

If there is no marked text, the current selection is replaced. If there is no selection, the string is inserted at the insertion point.

When aString is an NSString object, the receiver is expected to render the marked text with distinguishing appearance (for example, NSTextView renders with markedTextAttributes).

Availability
  • Available in OS X v10.5 and later.
Declared In
NSTextInputClient.h

unmarkText

Unmarks the marked text. (required)

- (void)unmarkText
Discussion

The receiver removes any marking from pending input text and disposes of the marked text as it wishes. The text view should accept the marked text as if it had been inserted normally. If there is no marked text, the invocation of this method has no effect.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h

validAttributesForMarkedText

Returns an array of attribute names recognized by the receiver. (required)

- (NSArray *)validAttributesForMarkedText
Return Value

An array of NSString objects representing names for the supported attributes.

Discussion

Returns an empty array if no attributes are supported. See NSAttributedString AppKit Additions Reference for the set of string constants representing standard attributes.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h

windowLevel

Returns the window level of the receiver.

- (NSInteger)windowLevel
Return Value

The window level of the receiver.

Discussion

Implementation of this method is optional. A class adopting NSTextInputClient can implement this interface to specify its window level if it is higher than NSFloatingWindowLevel.

Availability
  • Available in OS X v10.5 and later.
Related Sample Code
Declared In
NSTextInputClient.h