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--- responding_20to_20mouse_20double-clicks [2018/03/31 13:19] – external edit 127.0.0.1
+++ responding_20to_20mouse_20double-clicks [2024/01/05 00:21] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 =====Responding to mouse double-clicks=====
-//by Richard Russell, October 2015//\\ \\  By default the [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin6.html#onmouse|ON MOUSE]] event interrupt is activated by clicking one of the mouse buttons, but a **double-click** is not distinguishable from a single click. If you specifically want to respond to mouse double-clicks two steps are necessary; firstly you must enable them as follows:\\ \\
+//by Richard Russell, October 2015//\\ \\  By default the [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin6.html#onmouse|ON MOUSE]] event interrupt is activated by clicking one of the mouse buttons, but a **double-click** is not distinguishable from a single click. If you specifically want to respond to mouse double-clicks two steps are necessary; firstly you must enable them as follows:
+<code bb4w>
         SYS "GetClassLong", @hwnd%, GCL_STYLE TO wc%
         SYS "SetClassLong", @hwnd%, GCL_STYLE, wc% OR CS_DBLCLKS
-This code should be executed just once during the initialisation phase of your program (use the **Windows Constants utility** to add declarations for the GCL_STYLE and CS_DBLCLKS constants in the usual way).\\ \\  Secondly, you need to modify your ON MOUSE event handler to examine the **@msg%** system variable in order to discover whether the interrupt was caused by a single or double click. @msg% will have one of the following values:\\
+</code>
+This code should be executed just once during the initialisation phase of your program (use the **Windows Constants utility** to add declarations for the GCL_STYLE and CS_DBLCLKS constants in the usual way).\\ \\  Secondly, you need to modify your ON MOUSE event handler to examine the **@msg%** system variable in order to discover whether the interrupt was caused by a single or double click. @msg% will have one of the following values:
 | WM_LBUTTONDOWN\\ | Left button click\\ |
@@ Line 12: / Line 16: @@
 | WM_MBUTTONDBLCLK\\ | Middle button double-click\\ |
 | WM_RBUTTONDBLCLK\\ | Right button double-click\\ |
- There are various different approaches that may be adopted, but a simple asynchronous (polling) method is as follows:\\ \\
+There are various different approaches that may be adopted, but a simple asynchronous (polling) method is as follows:
+<code bb4w>
         REM. During initialisation:
         DIM Mouse%(2), mous%(2)
@@ Line 20: / Line 27: @@
         mous%() = 0
         SWAP mous%(), Mouse%()
-On receiving a mouse click **mous%(0)** will contain the **@msg%** value, **mous%(1)** will contain the **@wparam%** value (which contains information on whether the Shift and/or Control keys were pressed) and **mous%(2)** will contain the **@lparam%** value (which contains information on the position of the mouse when it was clicked). See the description of [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin6.html#onmouse|ON MOUSE]] in the main Help documentation for more details.\\ \\  If you prefer to use a synchronous method you can call a procedure when the interrupt occurs, as follows:\\ \\
+</code>
+On receiving a mouse click **mous%(0)** will contain the **@msg%** value, **mous%(1)** will contain the **@wparam%** value (which contains information on whether the Shift and/or Control keys were pressed) and **mous%(2)** will contain the **@lparam%** value (which contains information on the position of the mouse when it was clicked). See the description of [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin6.html#onmouse|ON MOUSE]] in the main Help documentation for more details.\\ \\  If you prefer to use a synchronous method you can call a procedure when the interrupt occurs, as follows:
+<code bb4w>
         ON MOUSE PROCmouse(@msg%, @wparam%, @lparam%) : RETURN
-\\  Note that when the user double-clicks the mouse you may well receive a 'single click' interrupt as well, and your program will need to cope with that.
+</code>
+Note that when the user double-clicks the mouse you may well receive a 'single click' interrupt as well, and your program will need to cope with that.