package ui import ( "fmt" "strings" "git.kirsle.net/go/render" ) func init() { precomputeArrows() } // Tooltip attaches a mouse-over popup to another widget. type Tooltip struct { BaseWidget // Configurable attributes. Text string // Text to show in the tooltip. TextVariable *string // String pointer instead of text. Edge Edge // side to display tooltip on target Widget lineHeight int font render.Text } // Constants for tooltips. const ( tooltipArrowSize = 5 ) // NewTooltip creates a new tooltip attached to a widget. func NewTooltip(target Widget, tt Tooltip) *Tooltip { w := &Tooltip{ Text: tt.Text, TextVariable: tt.TextVariable, Edge: tt.Edge, target: target, } // Default style. w.Hide() w.SetBackground(render.RGBA(0, 0, 0, 230)) w.font = render.Text{ Size: 10, Color: render.White, Padding: 4, } // Add event bindings to the target widget. // - Show the tooltip on MouseOver // - Hide it on MouseOut // - Compute the tooltip when the parent widget Computes // - Present the tooltip when the parent widget Presents target.Handle(MouseOver, func(ed EventData) { w.Show() }) target.Handle(MouseOut, func(ed EventData) { w.Hide() }) target.Handle(Compute, func(ed EventData) { w.Compute(ed.Engine) }) target.Handle(Present, func(ed EventData) { w.Present(ed.Engine, w.Point()) }) w.IDFunc(func() string { return fmt.Sprintf(`Tooltip<"%s">`, w.Value()) }) return w } // Value returns the current text displayed in the tooltop, whether from the // configured Text or the TextVariable pointer. func (w *Tooltip) Value() string { return w.text().Text } // text returns the raw render.Text holding the current value to be displayed // in the tooltip, either from Text or TextVariable. func (w *Tooltip) text() render.Text { if w.TextVariable != nil { w.font.Text = *w.TextVariable } else { w.font.Text = w.Text } return w.font } // Compute the size of the tooltip. func (w *Tooltip) Compute(e render.Engine) { // Compute the size based on the text. w.computeText(e) // Compute the position based on the Edge and the target widget. var ( size = w.Size() target = w.target tSize = target.Size() tPoint = AbsolutePosition(target) moveTo render.Point ) switch w.Edge { case Top: moveTo.Y = tPoint.Y - size.H - tooltipArrowSize moveTo.X = tPoint.X + (tSize.W / 2) - (size.W / 2) case Left: moveTo.X = tPoint.X - size.W - tooltipArrowSize moveTo.Y = tPoint.Y + (tSize.H / 2) - (size.H / 2) case Right: moveTo.X = tPoint.X + tSize.W + tooltipArrowSize moveTo.Y = tPoint.Y + (tSize.H / 2) - (size.H / 2) case Bottom: moveTo.Y = tPoint.Y + tSize.H + tooltipArrowSize moveTo.X = tPoint.X + (tSize.W / 2) - (size.W / 2) } // Adjust to keep the tooltip from clipping outside the window boundaries. { width, height := e.WindowSize() if moveTo.X < 0 { moveTo.X = 0 } else if moveTo.X+size.W > width { moveTo.X = width - size.W } if moveTo.Y < 0 { moveTo.Y = 0 } else if moveTo.Y+size.H > height { moveTo.Y = height - size.H } } w.MoveTo(moveTo) } // computeText handles the text compute, very similar to Label.Compute. func (w *Tooltip) computeText(e render.Engine) { text := w.text() lines := strings.Split(text.Text, "\n") // Max rect to encompass all lines of text. var maxRect = render.Rect{} for _, line := range lines { if line == "" { line = "" } text.Text = line // only this line at this time. rect, err := e.ComputeTextRect(text) if err != nil { panic(fmt.Sprintf("%s: failed to compute text rect: %s", w, err)) // TODO return an error } if rect.W > maxRect.W { maxRect.W = rect.W } maxRect.H += rect.H w.lineHeight = int(rect.H) } var ( padX = w.font.Padding + w.font.PadX padY = w.font.Padding + w.font.PadY ) w.Resize(render.Rect{ W: maxRect.W + (padX * 2), H: maxRect.H + (padY * 2), }) } // Present the tooltip. func (w *Tooltip) Present(e render.Engine, P render.Point) { if w.Hidden() { return } // Draw the text. w.presentText(e, P) // Draw the arrow. w.presentArrow(e, P) } // presentText draws the text similar to Label. func (w *Tooltip) presentText(e render.Engine, P render.Point) { var ( text = w.text() padX = w.font.Padding + w.font.PadX padY = w.font.Padding + w.font.PadY ) w.DrawBox(e, P) for i, line := range strings.Split(text.Text, "\n") { text.Text = line e.DrawText(text, render.Point{ X: P.X + padX, Y: P.Y + padY + (i * w.lineHeight), }) } } // presentArrow draws the arrow between the tooltip and its target widget. func (w *Tooltip) presentArrow(e render.Engine, P render.Point) { var ( // size = w.Size() target = w.target tSize = target.Size() tPoint = AbsolutePosition(target) drawAt render.Point arrow [][]render.Point ) switch w.Edge { case Top: arrow = arrowDown drawAt = render.Point{ X: tPoint.X + (tSize.W / 2) - tooltipArrowSize, Y: tPoint.Y - tooltipArrowSize, } case Bottom: arrow = arrowUp drawAt = render.Point{ X: tPoint.X + (tSize.W / 2) - tooltipArrowSize, Y: tPoint.Y + tSize.H, } case Left: arrow = arrowRight drawAt = render.Point{ X: tPoint.X - tooltipArrowSize, Y: tPoint.Y + (tSize.H / 2) - tooltipArrowSize, } case Right: arrow = arrowLeft drawAt = render.Point{ X: tPoint.X + tSize.W, Y: tPoint.Y + (tSize.H / 2) - tooltipArrowSize, } } drawArrow(e, w.Background(), drawAt, arrow) } // Draw an arrow at a given top/left coordinate. func drawArrow(e render.Engine, color render.Color, p render.Point, arrow [][]render.Point) { for _, row := range arrow { if len(row) == 1 { point := render.NewPoint(row[0].X, row[0].Y) point.Add(p) e.DrawPoint(color, point) } else { start := render.NewPoint(row[0].X, row[0].Y) end := render.NewPoint(row[1].X, row[1].Y) start.Add(p) end.Add(p) e.DrawLine(color, start, end) } } } // Arrows for the tooltip widget. var ( arrowDown [][]render.Point arrowUp [][]render.Point arrowLeft [][]render.Point arrowRight [][]render.Point ) func precomputeArrows() { arrowDown = [][]render.Point{ {render.NewPoint(0, 0), render.NewPoint(10, 0)}, {render.NewPoint(1, 1), render.NewPoint(9, 1)}, {render.NewPoint(2, 2), render.NewPoint(8, 2)}, {render.NewPoint(3, 3), render.NewPoint(7, 3)}, {render.NewPoint(4, 4), render.NewPoint(6, 4)}, {render.NewPoint(5, 5)}, } arrowUp = [][]render.Point{ {render.NewPoint(5, 0)}, {render.NewPoint(4, 1), render.NewPoint(6, 1)}, {render.NewPoint(3, 2), render.NewPoint(7, 2)}, {render.NewPoint(2, 3), render.NewPoint(8, 3)}, {render.NewPoint(1, 4), render.NewPoint(9, 4)}, // {render.NewPoint(0, 5), render.NewPoint(10, 5)}, } arrowLeft = [][]render.Point{ {render.NewPoint(0, 5)}, {render.NewPoint(1, 4), render.NewPoint(1, 6)}, {render.NewPoint(2, 3), render.NewPoint(2, 7)}, {render.NewPoint(3, 2), render.NewPoint(3, 8)}, {render.NewPoint(4, 1), render.NewPoint(4, 9)}, // {render.NewPoint(5, 0), render.NewPoint(5, 10)}, } arrowRight = [][]render.Point{ {render.NewPoint(0, 0), render.NewPoint(0, 10)}, {render.NewPoint(1, 1), render.NewPoint(1, 9)}, {render.NewPoint(2, 2), render.NewPoint(2, 8)}, {render.NewPoint(3, 3), render.NewPoint(3, 7)}, {render.NewPoint(4, 4), render.NewPoint(4, 6)}, {render.NewPoint(5, 5)}, } }