NSTextInputClient Protocol Reference
| Adopted by | |
| Framework | /System/Library/Frameworks/AppKit.framework |
| Availability | Available in OS X v10.5 and later. |
| Declared in | NSTextInputClient.h |
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
-
– hasMarkedTextrequired method -
– markedRangerequired method -
– selectedRangerequired method -
– setMarkedText:selectedRange:replacementRange:required method -
– unmarkTextrequired method -
– validAttributesForMarkedTextrequired method
Storing Text
-
– attributedSubstringForProposedRange:actualRange:required method -
– insertText:replacementRange:required method
Getting Character Coordinates
-
– characterIndexForPoint:required method -
– firstRectForCharacterRange:actualRange:required method
Binding Keystrokes
-
– doCommandBySelector:required method
Optional Methods
Instance Methods
attributedString
Returns an attributed string representing the receiver's text storage.
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.
Declared In
NSTextInputClient.hattributedSubstringForProposedRange:actualRange:
Returns an attributed string derived from the given range in the receiver's text storage. (required)
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.
NULLif 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.hbaselineDeltaForCharacterAtIndex:
Returns the baseline position of a given character relative to the origin of rectangle returned by firstRectForCharacterRange:actualRange:.
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.hcharacterIndexForPoint:
Returns the index of the character whose bounding rectangle includes the given point. (required)
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.hdoCommandBySelector:
Invokes the action specified by the given selector. (required)
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
-
interpretKeyEvents:(NSResponder) -
doCommandBySelector:(NSResponder)
Declared In
NSTextInputClient.hdrawsVerticallyForCharacterAtIndex:
Informs the text input management system whether the protocol-conforming client renders the character at the given index vertically.
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.hfirstRectForCharacterRange:actualRange:
Returns the first logical boundary rectangle for characters in the given range. (required)
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.hfractionOfDistanceThroughGlyphForPoint:
Returns the fraction of the distance from the left side of the character to the right side that a given point lies.
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.hhasMarkedText
Returns a Boolean value indicating whether the receiver has marked text. (required)
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.
See Also
Declared In
NSTextInputClient.hinsertText:replacementRange:
Inserts the given string into the receiver, replacing the specified content. (required)
Parameters
- aString
The text to insert, either an
NSStringorNSAttributedStringinstance.- 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.hmarkedRange
Returns the range of the marked text. (required)
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.
Declared In
NSTextInputClient.hselectedRange
Returns the range of selected text. (required)
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.
Declared In
NSTextInputClient.hsetMarkedText:selectedRange:replacementRange:
Replaces a specified range in the receiver’s text storage with the given string and sets the selection. (required)
Parameters
- aString
The string to insert. Can be either an
NSStringorNSAttributedStringinstance.- 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.
See Also
Declared In
NSTextInputClient.hunmarkText
Unmarks the marked text. (required)
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.
Declared In
NSTextInputClient.hvalidAttributesForMarkedText
Returns an array of attribute names recognized by the receiver. (required)
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 Application Kit Additions Reference for the set of string constants representing standard attributes.
Availability
- Available in OS X v10.5 and later.
Declared In
NSTextInputClient.hwindowLevel
Returns the window level of the receiver.
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.
Declared In
NSTextInputClient.h© 2009 Apple Inc. All Rights Reserved. (Last updated: 2009-05-04)