Terminal-based user interface toolkit
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 

360 lines
11 KiB

package cview
import (
"github.com/gdamore/tcell"
)
// Box implements Primitive with a background and optional elements such as a
// border and a title. Most subclasses keep their content contained in the box
// but don't necessarily have to.
//
// Note that all classes which subclass from Box will also have access to its
// functions.
//
// See https://git.sr.ht/~tslocum/cview/wiki/Box for an example.
type Box struct {
// The position of the rect.
x, y, width, height int
// The inner rect reserved for the box's content.
innerX, innerY, innerWidth, innerHeight int
// Border padding.
paddingTop, paddingBottom, paddingLeft, paddingRight int
// The box's background color.
backgroundColor tcell.Color
// Whether or not a border is drawn, reducing the box's space for content by
// two in width and height.
border bool
// The color of the border.
borderColor tcell.Color
// The style attributes of the border.
borderAttributes tcell.AttrMask
// The title. Only visible if there is a border, too.
title string
// The color of the title.
titleColor tcell.Color
// The alignment of the title.
titleAlign int
// Provides a way to find out if this box has focus. We always go through
// this interface because it may be overridden by implementing classes.
focus Focusable
// Whether or not this box has focus.
hasFocus bool
// An optional capture function which receives a key event and returns the
// event to be forwarded to the primitive's default input handler (nil if
// nothing should be forwarded).
inputCapture func(event *tcell.EventKey) *tcell.EventKey
// An optional function which is called before the box is drawn.
draw func(screen tcell.Screen, x, y, width, height int) (int, int, int, int)
}
// NewBox returns a Box without a border.
func NewBox() *Box {
b := &Box{
width: 15,
height: 10,
innerX: -1, // Mark as uninitialized.
backgroundColor: Styles.PrimitiveBackgroundColor,
borderColor: Styles.BorderColor,
titleColor: Styles.TitleColor,
titleAlign: AlignCenter,
}
b.focus = b
return b
}
// SetBorderPadding sets the size of the borders around the box content.
func (b *Box) SetBorderPadding(top, bottom, left, right int) *Box {
b.paddingTop, b.paddingBottom, b.paddingLeft, b.paddingRight = top, bottom, left, right
return b
}
// GetRect returns the current position of the rectangle, x, y, width, and
// height.
func (b *Box) GetRect() (int, int, int, int) {
return b.x, b.y, b.width, b.height
}
// GetInnerRect returns the position of the inner rectangle (x, y, width,
// height), without the border and without any padding. Width and height values
// will clamp to 0 and thus never be negative.
func (b *Box) GetInnerRect() (int, int, int, int) {
if b.innerX >= 0 {
return b.innerX, b.innerY, b.innerWidth, b.innerHeight
}
x, y, width, height := b.GetRect()
if b.border {
x++
y++
width -= 2
height -= 2
}
x, y, width, height = x+b.paddingLeft,
y+b.paddingTop,
width-b.paddingLeft-b.paddingRight,
height-b.paddingTop-b.paddingBottom
if width < 0 {
width = 0
}
if height < 0 {
height = 0
}
return x, y, width, height
}
// SetRect sets a new position of the primitive. Note that this has no effect
// if this primitive is part of a layout (e.g. Flex, Grid) or if it was added
// like this:
//
// application.SetRoot(b, true)
func (b *Box) SetRect(x, y, width, height int) {
b.x = x
b.y = y
b.width = width
b.height = height
b.innerX = -1 // Mark inner rect as uninitialized.
}
// SetDrawFunc sets a callback function which is invoked after the box primitive
// has been drawn. This allows you to add a more individual style to the box
// (and all primitives which extend it).
//
// The function is provided with the box's dimensions (set via SetRect()). It
// must return the box's inner dimensions (x, y, width, height) which will be
// returned by GetInnerRect(), used by descendent primitives to draw their own
// content.
func (b *Box) SetDrawFunc(handler func(screen tcell.Screen, x, y, width, height int) (int, int, int, int)) *Box {
b.draw = handler
return b
}
// GetDrawFunc returns the callback function which was installed with
// SetDrawFunc() or nil if no such function has been installed.
func (b *Box) GetDrawFunc() func(screen tcell.Screen, x, y, width, height int) (int, int, int, int) {
return b.draw
}
// WrapInputHandler wraps an input handler (see InputHandler()) with the
// functionality to capture input (see SetInputCapture()) before passing it
// on to the provided (default) input handler.
//
// This is only meant to be used by subclassing primitives.
func (b *Box) WrapInputHandler(inputHandler func(*tcell.EventKey, func(p Primitive))) func(*tcell.EventKey, func(p Primitive)) {
return func(event *tcell.EventKey, setFocus func(p Primitive)) {
if b.inputCapture != nil {
event = b.inputCapture(event)
}
if event != nil && inputHandler != nil {
inputHandler(event, setFocus)
}
}
}
// InputHandler returns nil.
func (b *Box) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) {
return b.WrapInputHandler(nil)
}
// SetInputCapture installs a function which captures key events before they are
// forwarded to the primitive's default key event handler. This function can
// then choose to forward that key event (or a different one) to the default
// handler by returning it. If nil is returned, the default handler will not
// be called.
//
// Providing a nil handler will remove a previously existing handler.
//
// Note that this function will not have an effect on primitives composed of
// other primitives, such as Form, Flex, or Grid. Key events are only captured
// by the primitives that have focus (e.g. InputField) and only one primitive
// can have focus at a time. Composing primitives such as Form pass the focus on
// to their contained primitives and thus never receive any key events
// themselves. Therefore, they cannot intercept key events.
func (b *Box) SetInputCapture(capture func(event *tcell.EventKey) *tcell.EventKey) *Box {
b.inputCapture = capture
return b
}
// GetInputCapture returns the function installed with SetInputCapture() or nil
// if no such function has been installed.
func (b *Box) GetInputCapture() func(event *tcell.EventKey) *tcell.EventKey {
return b.inputCapture
}
// SetBackgroundColor sets the box's background color.
func (b *Box) SetBackgroundColor(color tcell.Color) *Box {
b.backgroundColor = color
return b
}
// SetBorder sets the flag indicating whether or not the box should have a
// border.
func (b *Box) SetBorder(show bool) *Box {
b.border = show
return b
}
// SetBorderColor sets the box's border color.
func (b *Box) SetBorderColor(color tcell.Color) *Box {
b.borderColor = color
return b
}
// SetBorderAttributes sets the border's style attributes. You can combine
// different attributes using bitmask operations:
//
// box.SetBorderAttributes(tcell.AttrUnderline | tcell.AttrBold)
func (b *Box) SetBorderAttributes(attr tcell.AttrMask) *Box {
b.borderAttributes = attr
return b
}
// SetTitle sets the box's title.
func (b *Box) SetTitle(title string) *Box {
b.title = title
return b
}
// GetTitle returns the box's current title.
func (b *Box) GetTitle() string {
return b.title
}
// SetTitleColor sets the box's title color.
func (b *Box) SetTitleColor(color tcell.Color) *Box {
b.titleColor = color
return b
}
// SetTitleAlign sets the alignment of the title, one of AlignLeft, AlignCenter,
// or AlignRight.
func (b *Box) SetTitleAlign(align int) *Box {
b.titleAlign = align
return b
}
// Draw draws this primitive onto the screen.
func (b *Box) Draw(screen tcell.Screen) {
// Don't draw anything if there is no space.
if b.width <= 0 || b.height <= 0 {
return
}
def := tcell.StyleDefault
// Fill background.
background := def.Background(b.backgroundColor)
if b.backgroundColor != tcell.ColorDefault {
for y := b.y; y < b.y+b.height; y++ {
for x := b.x; x < b.x+b.width; x++ {
screen.SetContent(x, y, ' ', nil, background)
}
}
}
// Draw border.
if b.border && b.width >= 2 && b.height >= 2 {
border := background.Foreground(b.borderColor) | tcell.Style(b.borderAttributes)
var vertical, horizontal, topLeft, topRight, bottomLeft, bottomRight rune
if b.focus.HasFocus() {
horizontal = Borders.HorizontalFocus
vertical = Borders.VerticalFocus
topLeft = Borders.TopLeftFocus
topRight = Borders.TopRightFocus
bottomLeft = Borders.BottomLeftFocus
bottomRight = Borders.BottomRightFocus
} else {
horizontal = Borders.Horizontal
vertical = Borders.Vertical
topLeft = Borders.TopLeft
topRight = Borders.TopRight
bottomLeft = Borders.BottomLeft
bottomRight = Borders.BottomRight
}
for x := b.x + 1; x < b.x+b.width-1; x++ {
screen.SetContent(x, b.y, horizontal, nil, border)
screen.SetContent(x, b.y+b.height-1, horizontal, nil, border)
}
for y := b.y + 1; y < b.y+b.height-1; y++ {
screen.SetContent(b.x, y, vertical, nil, border)
screen.SetContent(b.x+b.width-1, y, vertical, nil, border)
}
screen.SetContent(b.x, b.y, topLeft, nil, border)
screen.SetContent(b.x+b.width-1, b.y, topRight, nil, border)
screen.SetContent(b.x, b.y+b.height-1, bottomLeft, nil, border)
screen.SetContent(b.x+b.width-1, b.y+b.height-1, bottomRight, nil, border)
// Draw title.
if b.title != "" && b.width >= 4 {
printed, _ := Print(screen, b.title, b.x+1, b.y, b.width-2, b.titleAlign, b.titleColor)
if len(b.title)-printed > 0 && printed > 0 {
_, _, style, _ := screen.GetContent(b.x+b.width-2, b.y)
fg, _, _ := style.Decompose()
Print(screen, string(SemigraphicsHorizontalEllipsis), b.x+b.width-2, b.y, 1, AlignLeft, fg)
}
}
}
// Call custom draw function.
if b.draw != nil {
b.innerX, b.innerY, b.innerWidth, b.innerHeight = b.draw(screen, b.x, b.y, b.width, b.height)
} else {
// Remember the inner rect.
b.innerX = -1
b.innerX, b.innerY, b.innerWidth, b.innerHeight = b.GetInnerRect()
}
// Clamp inner rect to screen.
width, height := screen.Size()
if b.innerX < 0 {
b.innerWidth += b.innerX
b.innerX = 0
}
if b.innerX+b.innerWidth >= width {
b.innerWidth = width - b.innerX
}
if b.innerY+b.innerHeight >= height {
b.innerHeight = height - b.innerY
}
if b.innerY < 0 {
b.innerHeight += b.innerY
b.innerY = 0
}
if b.innerWidth < 0 {
b.innerWidth = 0
}
if b.innerHeight < 0 {
b.innerHeight = 0
}
}
// Focus is called when this primitive receives focus.
func (b *Box) Focus(delegate func(p Primitive)) {
b.hasFocus = true
}
// Blur is called when this primitive loses focus.
func (b *Box) Blur() {
b.hasFocus = false
}
// HasFocus returns whether or not this primitive has focus.
func (b *Box) HasFocus() bool {
return b.hasFocus
}
// GetFocusable returns the item's Focusable.
func (b *Box) GetFocusable() Focusable {
return b.focus
}