From QB64 Wiki
The _MOUSEBUTTON Function returns the button status of a specified mouse button when read after _MOUSEINPUT.
- buttonstatus% = _MOUSEBUTTON(button_number)
- 1 = Left mouse button
- 2 = Right mouse button
- 3 = Center or scroll button
- Returns -1 if the corresponding numbered button is pressed and zero when released.
- The button parameter is 1 for the Left button, 2 for the right and 3 for the center button. Other buttons are currently not available.
- 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.
Example 1: Finding the number of mouse buttons available in QB64. This could also be used for other controller devices.
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$(27)
- Explanation: To find the current button status read _MOUSEINPUT repeatedly. The TIMER loop looks for a second click.
Example 4: Verifying that a user clicked and released a mouse button on a program button.
SCREEN 12 LINE (250, 250)-(300, 300), 14, BF DO Mouser mx, my, mb IF mb THEN IF mx >= 250 AND my >= 250 AND mx <= 300 AND my <= 300 THEN 'button down DO WHILE mb 'wait for button release Mouser mx, my, mb LOOP 'verify mouse still in box area IF mx >= 250 AND my >= 250 AND mx <= 300 AND my <= 300 THEN PRINT "Click verified on yellow box!" END IF END IF LOOP SUB Mouser (x, y, b) mi = _MOUSEINPUT b = _MOUSEBUTTON(1) x = _MOUSEX y = _MOUSEY END SUB
- Explanation: The mouse SUB has no internal _MOUSEINPUT loop so that no button presses, releases or moves are missed.
- If the above read procedure goes to another one, it may be advisable to skip over unread input in a _MOUSEINPUT only loop.
- The above procedure can be used to catch up after INPUT, LINE INPUT or INPUT$ 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
- Explanation: User can cancel letter selection by moving pointer off letter before releasing the left mouse button.
- _MOUSEX, _MOUSEY, _MOUSEWHEEL
- _MOUSEINPUT, _MOUSEMOVE
- _MOUSESHOW, _MOUSEHIDE
- _DEVICES, _DEVICE$, _LASTBUTTON
- _BUTTON, _BUTTONCHANGE (devices)
- SDL Mouse Button Down Library