Noah Petherbridge
07cefb6499
* New and completed widgets: Menu, MenuButton and MenuBar. * MenuButton is a kind of Button that opens a popup Menu when clicked. * MenuBar is a container of buttons designed to be attached to the top of an application window ("File, Edit, View, Help") * Supervisor manages the popup menus with its new concept of a Modal Widget. Modal widgets take exclusive event priority for all mouse and key events. The pop-up menu is a modal window, which means you must click an option inside the menu OR clicking outside the menu will close it and eat your click event (widgets outside the modal don't receive events, but the modal itself gets an event that you've done this).
196 lines
4.9 KiB
Go
196 lines
4.9 KiB
Go
package ui
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import (
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"fmt"
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"git.kirsle.net/go/render"
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"git.kirsle.net/go/ui/theme"
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)
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// MenuButton is a button that opens a menu when clicked.
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//
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// After creating a MenuButton, call AddItem() to add options and callback
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// functions to fill out the menu. When the MenuButton is clicked, its menu
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// will be drawn and take modal priority in the Supervisor.
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type MenuButton struct {
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Button
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name string
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supervisor *Supervisor
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menu *Menu
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}
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// NewMenuButton creates a new MenuButton (labels recommended).
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//
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// If the child is a Label, this function will set some sensible padding on
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// its font if the Label does not already have non-zero padding set.
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func NewMenuButton(name string, child Widget) *MenuButton {
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w := &MenuButton{
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name: name,
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}
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w.Button.child = child
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// If it's a Label (most common), set sensible default padding.
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if label, ok := child.(*Label); ok {
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if label.Font.Padding == 0 && label.Font.PadX == 0 && label.Font.PadY == 0 {
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label.Font.PadX = 8
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label.Font.PadY = 4
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}
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}
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w.IDFunc(func() string {
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return fmt.Sprintf("MenuButton<%s>", name)
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})
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w.setup()
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return w
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}
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// Supervise the MenuButton. This is necessary for the pop-up menu to work
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// when the button is clicked.
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func (w *MenuButton) Supervise(s *Supervisor) {
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w.initMenu()
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w.supervisor = s
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w.menu.Supervise(s)
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}
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// AddItem adds a new option to the MenuButton's menu.
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func (w *MenuButton) AddItem(label string, f func()) {
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w.initMenu()
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w.menu.AddItem(label, f)
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}
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// AddItemAccel adds a new menu option with hotkey text.
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func (w *MenuButton) AddItemAccel(label string, accelerator string, f func()) *MenuItem {
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w.initMenu()
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return w.menu.AddItemAccel(label, accelerator, f)
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}
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// AddSeparator adds a separator to the menu.
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func (w *MenuButton) AddSeparator() {
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w.initMenu()
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w.menu.AddSeparator()
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}
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// Compute to re-evaluate the button state (in the case of radio buttons where
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// a different button will affect the state of this one when clicked).
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func (w *MenuButton) Compute(e render.Engine) {
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if w.menu != nil {
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w.menu.Compute(e)
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w.positionMenu(e)
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}
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}
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// positionMenu sets the position where the pop-up menu will appear when
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// the button is clicked. Usually, the menu appears below and to the right of
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// the button. But if the menu will hit a window boundary, its position will
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// be adjusted to fit the window while trying not to overlap its own button.
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func (w *MenuButton) positionMenu(e render.Engine) {
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var (
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// Position and size of the MenuButton button.
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buttonPoint = w.Point()
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buttonSize = w.Size()
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// Size of the actual desktop window.
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Width, Height = e.WindowSize()
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)
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// Ideal location: below and to the right of the button.
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w.menu.MoveTo(render.Point{
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X: buttonPoint.X,
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Y: buttonPoint.Y + buttonSize.H + w.BoxThickness(2),
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})
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var (
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// Size of the menu.
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menuPoint = w.menu.Point()
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menuSize = w.menu.Rect()
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margin = 8 // keep away from directly touching window edges
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topMargin = 32 // keep room for standard Menu Bar
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)
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// Will we clip out the bottom of the window?
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if menuPoint.Y+menuSize.H+margin > Height {
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// Put us above the button instead, with the bottom of the
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// menu touching the top of the button.
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menuPoint = render.Point{
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X: buttonPoint.X,
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Y: buttonPoint.Y - menuSize.H - w.BoxThickness(2),
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}
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// If this would put us over the TOP edge of the window now,
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// cap the movement so the top of the menu is visible. We can't
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// avoid overlapping the button with the menu so might as well
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// start now.
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if menuPoint.Y < topMargin {
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menuPoint.Y = topMargin
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}
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w.menu.MoveTo(menuPoint)
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}
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// Will we clip out the right of the window?
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if menuPoint.X+menuSize.W > Width {
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// Move us in from the right side of the window.
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var delta = Width - menuSize.W - margin
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w.menu.MoveTo(render.Point{
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X: delta,
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Y: menuPoint.Y,
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})
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}
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_ = Width
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}
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// setup the common things between checkboxes and radioboxes.
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func (w *MenuButton) setup() {
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w.Configure(Config{
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BorderSize: 1,
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BorderStyle: BorderSolid,
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Background: theme.ButtonBackgroundColor,
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})
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w.Handle(MouseOver, func(ed EventData) error {
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w.hovering = true
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w.SetBorderStyle(BorderRaised)
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return nil
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})
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w.Handle(MouseOut, func(ed EventData) error {
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w.hovering = false
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w.SetBorderStyle(BorderSolid)
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return nil
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})
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w.Handle(MouseDown, func(ed EventData) error {
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w.clicked = true
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w.SetBorderStyle(BorderSunken)
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return nil
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})
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w.Handle(MouseUp, func(ed EventData) error {
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w.clicked = false
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return nil
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})
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w.Handle(Click, func(ed EventData) error {
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// Are we properly configured?
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if w.supervisor != nil && w.menu != nil {
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w.menu.Show()
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w.supervisor.PushModal(w.menu)
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}
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return nil
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})
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}
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// initialize the Menu widget.
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func (w *MenuButton) initMenu() {
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if w.menu == nil {
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w.menu = NewMenu(w.name + ":Menu")
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w.menu.Hide()
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// Handle closing the menu when clicked outside.
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w.menu.Handle(CloseModal, func(ed EventData) error {
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ed.Supervisor.PopModal(w.menu)
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return nil
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})
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}
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}
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