package tview import ( "github.com/gdamore/tcell/v2" ) // Box implements the Primitive interface with an empty background and optional // elements such as a border and a title. Box itself does not hold any content // but serves as the superclass of all other primitives. Subclasses add their // own content, typically (but not necessarily) keeping their content within the // box's rectangle. // // Box provides a number of utility functions available to all primitives. // // See https://github.com/rivo/tview/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 // If set to true, the background of this box is not cleared while drawing. dontClear bool // Whether or not a border is drawn, reducing the box's space for content by // two in width and height. border bool // The border style. borderStyle tcell.Style // 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 // Whether or not this box has focus. This is typically ignored for // container primitives (e.g. Flex, Grid, Pages), as they will delegate // focus to their children. hasFocus bool // Optional callback functions invoked when the primitive receives or loses // focus. focus, blur func() // 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) // An optional capture function which receives a mouse event and returns the // event to be forwarded to the primitive's default mouse event handler (at // least one nil if nothing should be forwarded). mouseCapture func(action MouseAction, event *tcell.EventMouse) (MouseAction, *tcell.EventMouse) } // NewBox returns a Box without a border. func NewBox() *Box { b := &Box{ width: 15, height: 10, innerX: -1, // Mark as uninitialized. backgroundColor: Styles.PrimitiveBackgroundColor, borderStyle: tcell.StyleDefault.Foreground(Styles.BorderColor).Background(Styles.PrimitiveBackgroundColor), titleColor: Styles.TitleColor, titleAlign: AlignCenter, } 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(p, 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 [Box.InputHandler]) with the // functionality to capture input (see [Box.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. Box has no default input handling. func (b *Box) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) { return b.WrapInputHandler(nil) } // WrapPasteHandler wraps a paste handler (see [Box.PasteHandler]). func (b *Box) WrapPasteHandler(pasteHandler func(string, func(p Primitive))) func(string, func(p Primitive)) { return func(text string, setFocus func(p Primitive)) { if pasteHandler != nil { pasteHandler(text, setFocus) } } } // PasteHandler returns nil. Box has no default paste handling. func (b *Box) PasteHandler() func(pastedText string, setFocus func(p Primitive)) { return b.WrapPasteHandler(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. // // This function can also be used on container primitives (like Flex, Grid, or // Form) as keyboard events will be handed down until they are handled. // // Pasted key events are not forwarded to the input capture function if pasting // is enabled (see [Application.EnablePaste]). 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 } // WrapMouseHandler wraps a mouse event handler (see [Box.MouseHandler]) with the // functionality to capture mouse events (see [Box.SetMouseCapture]) before passing // them on to the provided (default) event handler. // // This is only meant to be used by subclassing primitives. func (b *Box) WrapMouseHandler(mouseHandler func(MouseAction, *tcell.EventMouse, func(p Primitive)) (bool, Primitive)) func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { return func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { if b.mouseCapture != nil { action, event = b.mouseCapture(action, event) } if event == nil { if action == MouseConsumed { consumed = true } } else if mouseHandler != nil { consumed, capture = mouseHandler(action, event, setFocus) } return } } // MouseHandler returns nil. Box has no default mouse handling. func (b *Box) MouseHandler() func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { return b.WrapMouseHandler(func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { if action == MouseLeftDown && b.InRect(event.Position()) { setFocus(b) consumed = true } return }) } // SetMouseCapture sets a function which captures mouse events (consisting of // the original tcell mouse event and the semantic mouse action) before they are // forwarded to the primitive's default mouse event handler. This function can // then choose to forward that event (or a different one) by returning it or // returning a nil mouse event, in which case the default handler will not be // called. // // When a nil event is returned, the returned mouse action value may be set to // [MouseConsumed] to indicate that the event was consumed and the screen should // be redrawn. Any other value will not cause a redraw. // // Providing a nil handler will remove a previously existing handler. // // Note that mouse events are ignored completely if the application has not been // enabled for mouse events (see [Application.EnableMouse]), which is the // default. func (b *Box) SetMouseCapture(capture func(action MouseAction, event *tcell.EventMouse) (MouseAction, *tcell.EventMouse)) *Box { b.mouseCapture = capture return b } // InRect returns true if the given coordinate is within the bounds of the box's // rectangle. func (b *Box) InRect(x, y int) bool { rectX, rectY, width, height := b.GetRect() return x >= rectX && x < rectX+width && y >= rectY && y < rectY+height } // InInnerRect returns true if the given coordinate is within the bounds of the // box's inner rectangle (within the border and padding). func (b *Box) InInnerRect(x, y int) bool { rectX, rectY, width, height := b.GetInnerRect() return x >= rectX && x < rectX+width && y >= rectY && y < rectY+height } // GetMouseCapture returns the function installed with SetMouseCapture() or nil // if no such function has been installed. func (b *Box) GetMouseCapture() func(action MouseAction, event *tcell.EventMouse) (MouseAction, *tcell.EventMouse) { return b.mouseCapture } // SetBackgroundColor sets the box's background color. func (b *Box) SetBackgroundColor(color tcell.Color) *Box { b.backgroundColor = color b.borderStyle = b.borderStyle.Background(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 } // SetBorderStyle sets the box's border style. func (b *Box) SetBorderStyle(style tcell.Style) *Box { b.borderStyle = style return b } // SetBorderColor sets the box's border color. func (b *Box) SetBorderColor(color tcell.Color) *Box { b.borderStyle = b.borderStyle.Foreground(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.borderStyle = b.borderStyle.Attributes(attr) return b } // GetBorderAttributes returns the border's style attributes. func (b *Box) GetBorderAttributes() tcell.AttrMask { _, _, attr := b.borderStyle.Decompose() return attr } // GetBorderColor returns the box's border color. func (b *Box) GetBorderColor() tcell.Color { color, _, _ := b.borderStyle.Decompose() return color } // GetBackgroundColor returns the box's background color. func (b *Box) GetBackgroundColor() tcell.Color { return b.backgroundColor } // 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) { b.DrawForSubclass(screen, b) } // DrawForSubclass draws this box under the assumption that primitive p is a // subclass of this box. This is needed e.g. to draw proper box frames which // depend on the subclass's focus. // // Only call this function from your own custom primitives. It is not needed in // applications that have no custom primitives. func (b *Box) DrawForSubclass(screen tcell.Screen, p Primitive) { // Don't draw anything if there is no space. if b.width <= 0 || b.height <= 0 { return } // Fill background. background := tcell.StyleDefault.Background(b.backgroundColor) if !b.dontClear { 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 { var vertical, horizontal, topLeft, topRight, bottomLeft, bottomRight rune if p.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, b.borderStyle) screen.SetContent(x, b.y+b.height-1, horizontal, nil, b.borderStyle) } for y := b.y + 1; y < b.y+b.height-1; y++ { screen.SetContent(b.x, y, vertical, nil, b.borderStyle) screen.SetContent(b.x+b.width-1, y, vertical, nil, b.borderStyle) } screen.SetContent(b.x, b.y, topLeft, nil, b.borderStyle) screen.SetContent(b.x+b.width-1, b.y, topRight, nil, b.borderStyle) screen.SetContent(b.x, b.y+b.height-1, bottomLeft, nil, b.borderStyle) screen.SetContent(b.x+b.width-1, b.y+b.height-1, bottomRight, nil, b.borderStyle) // 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 { xEllipsis := b.x + b.width - 2 if b.titleAlign == AlignRight { xEllipsis = b.x + 1 } _, _, style, _ := screen.GetContent(xEllipsis, b.y) fg, _, _ := style.Decompose() Print(screen, string(SemigraphicsHorizontalEllipsis), xEllipsis, 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() } } // SetFocusFunc sets a callback function which is invoked when this primitive // receives focus. Container primitives such as [Flex] or [Grid] may not be // notified if one of their descendents receive focus directly. // // Set to nil to remove the callback function. func (b *Box) SetFocusFunc(callback func()) *Box { b.focus = callback return b } // SetBlurFunc sets a callback function which is invoked when this primitive // loses focus. This does not apply to container primitives such as [Flex] or // [Grid]. // // Set to nil to remove the callback function. func (b *Box) SetBlurFunc(callback func()) *Box { b.blur = callback return b } // Focus is called when this primitive receives focus. func (b *Box) Focus(delegate func(p Primitive)) { b.hasFocus = true if b.focus != nil { b.focus() } } // Blur is called when this primitive loses focus. func (b *Box) Blur() { if b.blur != nil { b.blur() } b.hasFocus = false } // HasFocus returns whether or not this primitive has focus. func (b *Box) HasFocus() bool { return b.hasFocus }