_MOUSEINPUT - mkilgore/QB64pe GitHub Wiki

The _MOUSEINPUT function is used to monitor any new mouse positions, button presses or movements of the scroll wheel. Must be called before other mouse information becomes available.

Syntax

infoExists%% = _MOUSEINPUT

Description

  • Returns -1 if new mouse information is available, otherwise it returns 0.
  • Must be called before reading any of the other mouse functions. The function will not miss any mouse input even during an INPUT entry.
  • Use in a loop to monitor the mouse buttons, scroll wheel and coordinate positions.
  • To clear all previous mouse data, use _MOUSEINPUT in a loop until it returns 0.

Examples

Example 1: Mouse coordinate, click and scroll events are returned sequentially inside of a _MOUSEINPUT loop. 

 '' ''
DO
  DO...LOOP WHILE _MOUSEINPUT '      Check the mouse status
    PRINT _MOUSEX, _MOUSEY, _MOUSEBUTTON(1), _MOUSEWHEEL
  LOOP
LOOP UNTIL INKEY$ <> "" '' ''
Explanation: The latest mouse function status can be read after the loop. _LIMIT and _DELAY loops will slow returns down.
Example 2: How to use a _MOUSEINPUT loop to locate PSET positions on a screen using a right mouse button click. 
DO...LOOP ' main program loop

  ' your program code

  DO...LOOP WHILE _MOUSEINPUT'mouse status changes only
    x = _MOUSEX
    y = _MOUSEY
    IF...THEN x > 0 AND (boolean) x < 640 AND (boolean) y > 0 AND (boolean) y < 480 THEN
      IF...THEN _MOUSEBUTTON(2) THEN
        PSET (x, y), 15
        LOCATE 1, 1: PRINT x, y
      END IF
    END IF
  LOOP 

  ' your program code

LOOP UNTIL INKEY$ = CHR$(27) '' ''

Example 3: Clearing any mouse data read before or during an INPUT entry. Press "I" to enter input: 

PRINT "Press I to enter input! Press Q to quit"
DO...LOOP 
  K$ = UCASE$(INKEY$) 
  DO...LOOP  
    IF...THEN _MOUSEBUTTON(1) = -1 THEN PRINT "*"    'indicates a mouse click event
  LOOP WHILE _MOUSEINPUT
  IF...THEN K$ = "Q" THEN END 
  IF...THEN K$ = "I" THEN                                          'press I to enter text
    INPUT "Click the mouse and enter something: ", entry$   'enter some text 
    GOSUB Clickcheck                                        'clear mouse data
  END IF 
LOOP 

END 

Clickcheck: 
count = 0 
DO...LOOP  
  count = count + 1 
LOOP WHILE _MOUSEINPUT
PRINT count        'returns the number of loops before mouse data is cleared
RETURN '' ''
Explanation: Click the mouse a few times while entering INPUT text. When Enter is pressed, the number of loops are displayed.

See also

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