Changed the definition of KeyEvent to be positional. The implementation has not been written, and thus the package will not build yet.
This commit is contained in:
Pietro Gagliardi
parent
359462854b
commit
0d75303dc3
123
area.go
123
area.go
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@ -15,10 +15,11 @@ import (
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// See AreaHandler for details.
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//
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// Do not use an Area if you intend to read text.
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// Due to platform differences regarding text input,
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// keyboard events have beem compromised in
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// such a way that attempting to read Unicode data
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// in platform-native ways is painful.
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// Area reads keys based on their position on a standard
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// 101-key keyboard, and does no character processing.
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// Character processing methods differ across operating
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// systems; trying ot recreate these yourself is only going
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// to lead to trouble.
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// [Use TextArea instead, providing a TextAreaHandler.]
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//
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// To facilitate development and debugging, for the time being, Areas only work on GTK+.
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@ -106,15 +107,10 @@ func (e MouseEvent) HeldBits() (h uintptr) {
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// A KeyEvent represents a keypress in an Area.
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//
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// In a perfect world, KeyEvent would be 100% predictable.
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// Despite my best efforts to do this, however, the various
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// differences in input handling between each backend
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// environment makes this completely impossible (I can
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// work with two of the three identically, but not all three).
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// Keep this in mind, and remember that Areas are not ideal
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// for text. For more details, see areaplan.md and the linked
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// tweets at the end of that file. If you know a better solution
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// than the one I have chosen, please let me know.
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// Key presses are based on their positions on a standard
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// 101-key keyboard found on most computers. The
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// names chosen for keys here are based on their names
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// on US English QWERTY keyboards; see Key for details.
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//
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// When you are finished processing the incoming event,
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// return whether or not you did something in response
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@ -126,42 +122,39 @@ func (e MouseEvent) HeldBits() (h uintptr) {
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// unconditionally, which may result in unwanted behavior like
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// global task-switching keystrokes not being processed.)
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//
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// If a key is pressed that is not supported by ASCII, ExtKey,
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// If a key is pressed that is not supported by Key, ExtKey,
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// or Modifiers, no KeyEvent will be produced, and package
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// ui will act as if false was returned for handled.
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type KeyEvent struct {
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// ASCII is a byte representing the character pressed.
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// Despite my best efforts, this cannot be trivialized
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// to produce predictable input rules on all OSs, even if
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// I try to handle physical keys instead of equivalent
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// characters. Therefore, what happens when the user
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// inserts a non-ASCII character is undefined (some systems
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// will give package ui the underlying ASCII key and we
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// return it; other systems do not). This is especially important
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// if the given input method uses Modifiers to enter characters.
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// If the parenthesized rule cannot be followed and the user
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// enters a non-ASCII character, it will be ignored (package ui
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// will act as above regarding keys it cannot handle).
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// In general, alphanumeric characters, ',', '.', '+', '-', and the
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// (space) should be available on all keyboards. Other ASCII
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// whitespace keys mentioned below may be available, but
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// mind layout differences.
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// Whether or not alphabetic characters are uppercase or
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// lowercase is undefined, and cannot be determined solely
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// by examining Modifiers for Shift. Correct code should handle
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// both uppercase and lowercase identically.
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// In addition, ASCII will contain
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// Key is a byte representing a character pressed
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// in the typewriter section of the keyboard.
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// The value, which is independent of whether the
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// Shift key is held, is a constant with one of the
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// following (case-sensitive) values, drawn according
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// to the key's position on the keyboard.
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// ` 1 2 3 4 5 6 7 8 9 0 - =
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// q w e r t y u i o p [ ] \
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// a s d f g h j k l ; '
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// z x c v b n m , . /
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// The actual key entered will be the key at the respective
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// position on the user's keyboard, regardless of the actual
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// layout. (Some keyboards move \ to either the row above
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// or the row below but in roughly the same spot; this is
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// accounted for. Some keyboards have an additonal key
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// to the left of 'z' or additional keys to the right of '='; these
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// cannot be read.)
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// In addition, Key will contain
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// - ' ' (space) if the spacebar was pressed
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// - '\t' if Tab was pressed, regardless of Modifiers
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// - '\n' if any Enter/Return key was pressed, regardless of which
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// - '\n' if the typewriter Enter key was pressed
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// - '\b' if the typewriter Backspace key was pressed
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// If this value is zero, see ExtKey.
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ASCII byte
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Key byte
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// If ASCII is zero, ExtKey contains a predeclared identifier
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// If Key is zero, ExtKey contains a predeclared identifier
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// naming an extended key. See ExtKey for details.
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// If both ASCII and ExtKey are zero, a Modifier by itself
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// was pressed. ASCII and ExtKey will not both be nonzero.
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// If both Key and ExtKey are zero, a Modifier by itself
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// was pressed. Key and ExtKey will not both be nonzero.
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ExtKey ExtKey
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Modifiers Modifiers
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@ -175,8 +168,7 @@ type KeyEvent struct {
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Up bool
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}
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// ExtKey represents keys that do not have an ASCII representation.
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// There is no way to differentiate between left and right ExtKeys.
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// ExtKey represents keys that are not in the typewriter section of the keyboard.
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type ExtKey uintptr
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const (
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Escape ExtKey = iota + 1
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@ -190,7 +182,7 @@ const (
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Down
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Left
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Right
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F1 // no guarantee is made that Fn == F1+n in the future
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F1 // F1..F12 are guaranteed to be consecutive
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F2
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F3
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F4
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@ -202,9 +194,54 @@ const (
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F10
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F11
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F12
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N0 // numpad keys; independent of Num Lock state
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N1 // N0..N9 are guaranteed to be consecutive
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N2
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N3
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N4
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N5
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N6
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N7
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N8
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N9
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NDot
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NEnter
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NAdd
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NSubtract
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NMultiply
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NDivide
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_nextkeys // for sanity check
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)
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// EffectiveKey returns e.Key if it is set.
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// Otherwise, if e.ExtKey denotes a numpad key,
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// EffectiveKey returns the equivalent e.Key value
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// ('0'..'9', '.', '\n', '+', '-', '*', or '/').
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// Otherwise, EffectiveKey returns zero.
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func (e KeyEvent) EffectiveKey() byte {
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if e.Key != 0 {
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return e.Key
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}
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k := e.ExtKey
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switch {
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case k >= N0 && k <= N9:
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return byte(k - N0) + '0'
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case k == NDot:
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return '.'
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case k == NEnter:
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return '\n'
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case k == NAdd:
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return '+'
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case k == NSubtract:
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return '-'
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case k == NMultiply:
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return '*'
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case k == NDivide:
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return '/'
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}
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return 0
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}
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// Modifiers indicates modifier keys being held during an event.
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// There is no way to differentiate between left and right modifier keys.
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type Modifiers uintptr
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