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#
# Bindings for Menubuttons.
#
# Menubuttons have three interaction modes:
#
# Pulldown: Press menubutton, drag over menu, release to activate menu entry
# Popdown: Click menubutton to post menu
# Keyboard: <Key-space> or accelerator key to post menu
#
# (In addition, when menu system is active, "dropdown" -- menu posts
# on mouse-over. Ttk menubuttons don't implement this).
#
# For keyboard and popdown mode, we hand off to tk_popup and let
# the built-in Tk bindings handle the rest of the interaction.
#
# ON X11:
#
# Standard Tk menubuttons use a global grab on the menubutton.
# This won't work for Ttk menubuttons in pulldown mode,
# since we need to process the final <ButtonRelease> event,
# and this might be delivered to the menu. So instead we
# rely on the passive grab that occurs on <ButtonPress> events,
# and transition to popdown mode when the mouse is released
# or dragged outside the menubutton.
#
# ON WINDOWS:
#
# I'm not sure what the hell is going on here. [$menu post] apparently
# sets up some kind of internal grab for native menus.
# On this platform, just use [tk_popup] for all menu actions.
#
# ON MACOS:
#
# Same probably applies here.
#
namespace eval ttk {
namespace eval menubutton {
variable State
array set State {
pulldown 0
oldcursor {}
}
}
}
bind TMenubutton <Enter> { %W instate !disabled {%W state active } }
bind TMenubutton <Leave> { %W state !active }
bind TMenubutton <Key-space> { ttk::menubutton::Popdown %W }
bind TMenubutton <<Invoke>> { ttk::menubutton::Popdown %W }
if {[tk windowingsystem] eq "x11"} {
bind TMenubutton <ButtonPress-1> { ttk::menubutton::Pulldown %W }
bind TMenubutton <ButtonRelease-1> { ttk::menubutton::TransferGrab %W }
bind TMenubutton <B1-Leave> { ttk::menubutton::TransferGrab %W }
} else {
bind TMenubutton <ButtonPress-1> \
{ %W state pressed ; ttk::menubutton::Popdown %W }
bind TMenubutton <ButtonRelease-1> \
{ if {[winfo exists %W]} { %W state !pressed } }
}
# PostPosition --
# Returns the x and y coordinates where the menu
# should be posted, based on the menubutton and menu size
# and -direction option.
#
# TODO: adjust menu width to be at least as wide as the button
# for -direction above, below.
#
proc ttk::menubutton::PostPosition {mb menu} {
set x [winfo rootx $mb]
set y [winfo rooty $mb]
set dir [$mb cget -direction]
set bw [winfo width $mb]
set bh [winfo height $mb]
set mw [winfo reqwidth $menu]
set mh [winfo reqheight $menu]
set sw [expr {[winfo screenwidth $menu] - $bw - $mw}]
set sh [expr {[winfo screenheight $menu] - $bh - $mh}]
switch -- $dir {
above { if {$y >= $mh} { incr y -$mh } { incr y $bh } }
below { if {$y <= $sh} { incr y $bh } { incr y -$mh } }
left { if {$x >= $mw} { incr x -$mw } { incr x $bw } }
right { if {$x <= $sw} { incr x $bw } { incr x -$mw } }
flush {
# post menu atop menubutton.
# If there's a menu entry whose label matches the
# menubutton -text, assume this is an optionmenu
# and place that entry over the menubutton.
set index [FindMenuEntry $menu [$mb cget -text]]
if {$index ne ""} {
incr y -[$menu yposition $index]
}
}
}
return [list $x $y]
}
# Popdown --
# Post the menu and set a grab on the menu.
#
proc ttk::menubutton::Popdown {mb} {
if {[$mb instate disabled] || [set menu [$mb cget -menu]] eq ""} {
return
}
foreach {x y} [PostPosition $mb $menu] { break }
tk_popup $menu $x $y
}
# Pulldown (X11 only) --
# Called when Button1 is pressed on a menubutton.
# Posts the menu; a subsequent ButtonRelease
# or Leave event will set a grab on the menu.
#
proc ttk::menubutton::Pulldown {mb} {
variable State
if {[$mb instate disabled] || [set menu [$mb cget -menu]] eq ""} {
return
}
foreach {x y} [PostPosition $mb $menu] { break }
set State(pulldown) 1
set State(oldcursor) [$mb cget -cursor]
$mb state pressed
$mb configure -cursor [$menu cget -cursor]
$menu post $x $y
tk_menuSetFocus $menu
}
# TransferGrab (X11 only) --
# Switch from pulldown mode (menubutton has an implicit grab)
# to popdown mode (menu has an explicit grab).
#
proc ttk::menubutton::TransferGrab {mb} {
variable State
if {$State(pulldown)} {
$mb configure -cursor $State(oldcursor)
$mb state {!pressed !active}
set State(pulldown) 0
set menu [$mb cget -menu]
tk_popup $menu [winfo rootx $menu] [winfo rooty $menu]
}
}
# FindMenuEntry --
# Hack to support tk_optionMenus.
# Returns the index of the menu entry with a matching -label,
# -1 if not found.
#
proc ttk::menubutton::FindMenuEntry {menu s} {
set last [$menu index last]
if {$last eq "none"} {
return ""
}
for {set i 0} {$i <= $last} {incr i} {
if {![catch {$menu entrycget $i -label} label]
&& ($label eq $s)} {
return $i
}
}
return ""
}
#*EOF*
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