_MOUSEBUTTON

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The _MOUSEBUTTON function returns the button status of a specified mouse button when read after _MOUSEINPUT.


Syntax

buttonStatus%% = _MOUSEBUTTON(buttoNumber)


Parameters

  • INTEGER buttoNumber designates the mouse button to read (See _DEVICES for more than 3).
    • 1 = Left mouse button
    • 2 = Right mouse button
    • 3 = Center or scroll button


Description

  • Returns -1 if the corresponding buttoNumber is pressed or zero when released.
  • Read _MOUSEINPUT first to return the current button up or down status. (See Example 2)
  • Button clicks and mouse movements will be remembered and should be cleared after an INPUT statement or other interruption.
  • To clear unread mouse input, use a _MOUSEINPUT loop that loops until it returns 0.
  • Use _DEVICE$ to find the "[MOUSE]" _DEVICES number to find the number of buttons available using _LASTBUTTON.
  • Note: The center mouse button can also be read as _BUTTON(2) on _DEVICEINPUT(2) when a mouse is present.


Examples

Example 1: Finding the number of mouse buttons available in QB64. This could also be used for other controller devices.

FOR d = 1 TO _DEVICES 'number of input devices found dev$ = _DEVICE$(d) IF INSTR(dev$, "[MOUSE]") THEN buttons = _LASTBUTTON(d): EXIT FOR NEXT PRINT buttons; "mouse buttons available"


Example 2: How to monitor when a button is down or wait until a mouse button is not held down.

PRINT "Hold down the left mouse button until you want to quit!" DO i = _MOUSEINPUT ' read #1 IF _MOUSEBUTTON(1) THEN PRINT "Left button down!": EXIT DO LOOP DO ' need to wait i = _MOUSEINPUT ' read #2 until the mouse LOOP UNTIL NOT _MOUSEBUTTON(1) ' button is released PRINT "DONE!"


Example 3: Checking for a click or a double-click by the user.

DO 'main program loop DO WHILE _MOUSEINPUT 'check mouse status buttondown = _MOUSEBUTTON(1) LOOP DO WHILE buttondown 'check for button release i = _MOUSEINPUT buttondown = _MOUSEBUTTON(1) Click = 1 LOOP IF Click = 1 THEN 'if button was pressed and released t = TIMER + .3 DO WHILE TIMER < t 'check for a second press within .3 seconds i = _MOUSEINPUT IF _MOUSEBUTTON(1) THEN Click = 2: EXIT DO LOOP IF Click = 2 THEN PRINT "Double click" ELSE PRINT "Click" END IF Click = 0: buttondown = 0 'reset where needed LOOP UNTIL INKEY$ = CHR$(27)

Explanation: To find the current button status read _MOUSEINPUT repeatedly. The TIMER loop looks for a second click.


Example 4: Verifying that a user clicked and released a mouse button on a program button.

SCREEN 12 LINE (250, 250)-(300, 300), 14, BF DO Mouser mx, my, mb IF mb THEN IF mx >= 250 AND my >= 250 AND mx <= 300 AND my <= 300 THEN 'button down DO WHILE mb 'wait for button release Mouser mx, my, mb LOOP 'verify mouse still in box area IF mx >= 250 AND my >= 250 AND mx <= 300 AND my <= 300 THEN PRINT "Click verified on yellow box!" END IF END IF LOOP SUB Mouser (x, y, b) mi = _MOUSEINPUT b = _MOUSEBUTTON(1) x = _MOUSEX y = _MOUSEY END SUB

Explanation: The mouse SUB has no internal _MOUSEINPUT loop so that no button presses, releases or moves are missed.
If the above read procedure goes to another one, it may be advisable to skip over unread input in a _MOUSEINPUT only loop.

SUB Catchup DO WHILE _MOUSEINPUT: LOOP END SUB

The above procedure can be used to catch up after INPUT, LINE INPUT or INPUT$ delays when mouse input may accumulate.


Example 5: Combining mouse button or keyboard selections in a menu or test:

DO 'main program loop in demo only LOCATE 10, 10: PRINT "A" 'position A, B & C in same position on every question LOCATE 12, 10: PRINT "B" LOCATE 14, 10: PRINT "C" 'demo only DO: _LIMIT 10 'get user answer loop DO WHILE _MOUSEINPUT: LOOP 'read mouse K$ = UCASE$(INKEY$) 'read keypresses also x% = _MOUSEX y% = _MOUSEY Lclick = _MOUSEBUTTON(1) LOCATE 20, 10: PRINT x%, y%, Lclick 'only used to find mouse coordinates IF x% = 10 AND y% = 10 AND Lclick THEN 'position clicked DO i = _MOUSEINPUT x% = _MOUSEX y% = _MOUSEY LOOP WHILE _MOUSEBUTTON(1) IF x% = 10 AND y% = 10 THEN K$ = "A" 'position released END IF IF x% = 10 AND y% = 12 AND Lclick THEN 'position clicked DO i = _MOUSEINPUT x% = _MOUSEX y% = _MOUSEY LOOP WHILE _MOUSEBUTTON(1) IF x% = 10 AND y% = 12 THEN K$ = "B" 'position released END IF IF x% = 10 AND y% = 14 AND Lclick THEN 'position clicked DO i = _MOUSEINPUT x% = _MOUSEX y% = _MOUSEY LOOP WHILE _MOUSEBUTTON(1) IF x% = 10 AND y% = 14 THEN K$ = "C" 'position released END IF LOOP UNTIL K$ = "A" OR K$ = "B" OR K$ = "C" 'GOTO next question IF LEN(K$) THEN 'DEMO ONLY LOCATE 22, 35: PRINT " Answer = "; K$ 'display user answer at location _DELAY 2 'allow time for user to view answer LOCATE 22, 35: PRINT "SELECT AGAIN" K$ = "" 'reset K$ END IF LOOP 'DEMO only loop use red X box to quit

Code by Ted Weissgerber
Explanation: User can cancel letter selection by moving pointer off letter before releasing the left mouse button.


See also



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