Difference between revisions of "Keyboard (Chili Framework)"

Revision as of 10:26, 14 July 2016

With Keyboard, you can get the current state of depressed keys, and you can pop key press and release events out of an Event queue contained in Keyboard. You can also turn autorepeat on/off. Whopee. (Note: the kbd object lives in MainWindow's belly.)

Members

KeyIsPressed

bool Keyboard::KeyIsPressed( unsigned char keycode ) const
Checks to see if a specific key is currently in the pressed state. The function parameter is the virtual key code of the key that you want to check.

ReadKey

Event Keyboard::ReadKey()
Pull a fresh Event object out of the key press/release event queue. Erases an event from the queue and returns a copy if there is a key press event in the queue. Returns an invalid Event object if the queue is empty.

KeyIsEmpty

bool Keyboard::KeyIsEmpty() const
Returns true if the key event queue is empty.

ReadChar

char Keyboard::ReadChar()
Pull a fresh character off of the character buffer. See also: #ReadKey vs. ReadChar.

CharIsEmpty

bool Keyboard::CharIsEmpty() const
Returns true if the character queue is empty.

Event

class Keyboard::Event

Key press and release events are held in a queue in Keyboard in the order they occurred. These events are modeled with their own class because they're precious fucking little snowflakes. They store the type of event (press or release) and the virtual key code of the associated key. You pull them out of the buffer with Keyboard::ReadKey().

Type

enum Keyboard::Event::Type

This represents the different types of events that can be recorded. The options are Press, Release, and Invalid.

IsPress

bool Keyboard::Event::IsPress() const

Returns true if the event is a press event.

IsRelease

bool Keyboard::Event::IsRelease() const

Returns true if the event is a release event.

IsValid

bool Keyboard::Event::IsValid() const

Returns true if the event is a valid event (reading from an empty buffer will return an invalid event object).

GetCode

char Keyboard::Event::GetCode() const

Gets the virtual key code of the key associated with the Event object.

Miscellaneous

Virtual Key Codes

The virtual key code for a standard alphanumeric key is just the char literal (capital if alphabetic), e.g. 'A' or '9'. Virtual key codes for other keys are defined with #define macros included with Windows.h. Some common ones are:

• VK_SPACE
• VK_SHIFT
• VK_ENTER
• VK_ESCAPE

ReadKey vs. ReadChar

There are two main differences between the events read with ReadKey() and the char values read with ReadChar():

1. Each key press and release sequence puts two events (press event and release event) into the ReadKey() queue, but the same sequence only puts one char value into the ReadChar() queue.
2. The char values read with ReadChar() have the shift modifier applied to them, whereas those read by ReadKey() are just the raw virtual key codes. For example, pressing the 'A' key puts 'a' into the ReadChar() queue when the shift key is not pressed and 'A' when it is pressed, but the virtual key code in either case is 'A' for ReadKey().

See also

• The Chili Framework