Selections in Text (HI Guide)

Inside Macintosh: Macintosh Human Interface Guidelines / Part 2 - The Interface Elements: Chapter 10 - Behaviors / Selecting

Selections in Text

In most applications, the user is required at some point to edit text. The principle of consistency (both within and among applications) requires that text be selected and edited in a consistent way, regardless of where it appears.

A block of text is a string of characters. A text selection is a substring of this string, which can have any length from zero characters to the whole block. Each of the text selection methods selects a different kind of substring.
Figure 10-19 shows different kinds of text selections.

Figure 10-19 Text selections

The insertion point is a zero-length text selection. The user establishes
the location of the insertion point by clicking somewhere in the text. The insertion point then appears at the nearest character boundary. If the user clicks anywhere to the right of the last character on a line, the insertion point appears immediately after the last character. If the user clicks to the left
of the first character on a line, the insertion point appears immediately
before the first character.

The insertion point shows where text will be inserted when the user begins typing, or where the contents of the Clipboard will be pasted. As each character is typed, the insertion point is moved to the right of that character.

Selecting With the Mouse

The range selection method can be applied to text. The user selects a range of text by dragging through the range. A range can be a range of characters, words, lines, or paragraphs, as defined by the application. If the user extends the range, the way the range is extended depends on what kind of range it is. If it's a range of individual characters, it can be extended one character at a time. If it's a range of words (including a single word), it's extended only by whole words.

The user selects a whole word by double-clicking somewhere within that word. If the user begins a double-click sequence, but then drags the mouse between the mouse-down and the mouse-up of the second click, the selection becomes a range of words. As the pointer moves, the application highlights or unhighlights whole words at a time.

Selecting Ranges

A word or range of words can also be selected in the same way as any
other range; whether this type of selection is treated as a range of characters or as a range of words depends on the operation. For example, in a word processor, a range of individual characters that coincides with a range of words is treated like characters for purposes of extending a selection, but is treated like words for purposes of "intelligent cut and paste" (described in the section "Intelligent Cut and Paste" on page 299).

The following definition of a word applies in the United States and Canada and in some other countries. In many countries, the definition differs to reflect local formats for numbers, dates, and currency. A word is defined as any continuous string that contains any of the following characters:

a letter
a digit
a nonbreaking space (Option-space or Command-space)
a currency symbol ($, , , or )
a percent sign
a comma between digits
a period before a digit
an apostrophe between letters or digits
a hyphen, but not Option-hyphen (-) or Option-Shift-hyphen (--)

If the user double-clicks any character not on this list, only that character
is selected.

These are examples of words:

$123,456.78
shouldn't
3 1/2 (with a nonbreaking space)
.5%

These are examples of strings treated as more than one word:

7/10/6
blue cheese (with a breaking space)
"Wow!" (The quotation marks and exclamation point aren't part of
the word.)

In some contexts--in a programming language, for example--it may be appropriate to allow users to select both the left and right parentheses in a pair, as well as all the characters between them, by double-clicking either one of them. The same feature could be implemented for braces and brackets. This would mean that the user could select the entire expression

[x+y-(4*3)^(n-1)]

simply by double-clicking [ or ].

Selecting With the Arrow Keys

To use arrow keys to make a text selection, the user holds down Shift while pressing an arrow key. If it's important that your Macintosh application makes use of the numeric keypad, you shouldn't use these Shift-arrow key combinations. This is because the keypad's codes for the four Shift-arrow
key combinations are the same as those for the keypad's +, *, /, and = keys.
If the use of a Shift-arrow key combination for making selections is more important to your application than is the numeric keypad, the following paragraphs describe how it should work.

When a Shift-arrow key combination is pressed, the active end of the selection moves and the range over which it moves becomes selected. If both the Shift key and another modifier key are held down, the end of the selection moves as defined for the particular modifier key, and the range over which
it moves becomes selected. For example, Option-Shift-Left Arrow selects the whole word that contains the character to the left of the insertion point (just like double-clicking a word).

A selection made by using the mouse is no different from one made by using arrow keys. A selection started with the mouse can be extended by using
Shift and Left Arrow or Right Arrow.

In a text application, pressing Shift and either Left Arrow or Right Arrow selects a single character. If the Left Arrow key is used, the anchor point of the selection is on the right side of the selection, the active end on the left. Each subsequent Shift-Left Arrow adds another character to the left side
of the selection. In many applications, a Shift-Right Arrow at this point shrinks the selection. In some applications, a Shift-Right Arrow at this
point extends the selection, making the right side of the selection the active end (see the description of the addition and fixed-point methods for extending text selections in "Changing a Selection With Shift-Click" beginning on page 288). In this case, each subsequent Shift-Right Arrow
adds another character to the right side of the selection.

Figure 10-20 summarizes these two different series of steps.

Figure 10-20 Selecting with Shift and arrow keys

Pressing Option-Shift and either Left Arrow or Right Arrow (in a text application) selects the entire word containing the character to the left or right of the insertion point. Assuming Left Arrow is pressed, the anchor point is at the right end of the word, the active end at the left. Each subsequent Option-Shift-Left Arrow adds another word to the left end of the selection,
as shown in Figure 10-21.

Figure 10-21 Selecting with Option-Shift and arrow keys

When a block of text is selected, either with a pointing device or with arrow keys, pressing either Left Arrow, Right Arrow, Up Arrow, or Down Arrow deselects the range. If Left Arrow is pressed, the insertion point goes to the beginning of what had been the selection. If Right Arrow is pressed, the insertion point goes to the end of what had been the selection.