package elements import "image" import "git.tebibyte.media/sashakoshka/tomo" import "git.tebibyte.media/sashakoshka/tomo/input" import "git.tebibyte.media/sashakoshka/tomo/canvas" import "git.tebibyte.media/sashakoshka/tomo/default/theme" import "git.tebibyte.media/sashakoshka/tomo/default/config" // Slider is a slider control with a floating point value between zero and one. type Slider struct { slider } // NewVSlider creates a new horizontal slider with the specified value. func NewVSlider (value float64) (element *Slider) { element = NewHSlider(value) element.vertical = true return } // NewHSlider creates a new horizontal slider with the specified value. func NewHSlider (value float64) (element *Slider) { element = &Slider { } element.value = value element.entity = tomo.NewEntity(element).(tomo.FocusableEntity) element.construct() return } type slider struct { entity tomo.FocusableEntity value float64 vertical bool dragging bool enabled bool dragOffset int track image.Rectangle bar image.Rectangle config config.Wrapped theme theme.Wrapped onSlide func () onRelease func () } func (element *slider) construct () { element.enabled = true if element.vertical { element.theme.Case = tomo.C("tomo", "sliderVertical") } else { element.theme.Case = tomo.C("tomo", "sliderHorizontal") } element.updateMinimumSize() } // Entity returns this element's entity. func (element *slider) Entity () tomo.Entity { return element.entity } // Draw causes the element to draw to the specified destination canvas. func (element *slider) Draw (destination canvas.Canvas) { bounds := element.entity.Bounds() element.track = element.theme.Padding(tomo.PatternGutter).Apply(bounds) if element.vertical { barSize := element.track.Dx() element.bar = image.Rect(0, 0, barSize, barSize).Add(element.track.Min) barOffset := float64(element.track.Dy() - barSize) * (1 - element.value) element.bar = element.bar.Add(image.Pt(0, int(barOffset))) } else { barSize := element.track.Dy() element.bar = image.Rect(0, 0, barSize, barSize).Add(element.track.Min) barOffset := float64(element.track.Dx() - barSize) * element.value element.bar = element.bar.Add(image.Pt(int(barOffset), 0)) } state := tomo.State { Disabled: !element.Enabled(), Focused: element.entity.Focused(), Pressed: element.dragging, } element.theme.Pattern(tomo.PatternGutter, state).Draw(destination, bounds) element.theme.Pattern(tomo.PatternHandle, state).Draw(destination, element.bar) } // Focus gives this element input focus. func (element *slider) Focus () { if !element.entity.Focused() { element.entity.Focus() } } // Enabled returns whether this slider can be dragged or not. func (element *slider) Enabled () bool { return element.enabled } // SetEnabled sets whether this slider can be dragged or not. func (element *slider) SetEnabled (enabled bool) { if element.enabled == enabled { return } element.enabled = enabled element.entity.Invalidate() } func (element *slider) HandleFocusChange () { element.entity.Invalidate() } func (element *slider) HandleMouseDown ( position image.Point, button input.Button, modifiers input.Modifiers, ) { if !element.Enabled() { return } element.Focus() if button == input.ButtonLeft { element.dragging = true element.value = element.valueFor(position.X, position.Y) if element.onSlide != nil { element.onSlide() } element.entity.Invalidate() } } func (element *slider) HandleMouseUp ( position image.Point, button input.Button, modifiers input.Modifiers, ) { if button != input.ButtonLeft || !element.dragging { return } element.dragging = false if element.onRelease != nil { element.onRelease() } element.entity.Invalidate() } func (element *slider) HandleMotion (position image.Point) { if element.dragging { element.dragging = true element.value = element.valueFor(position.X, position.Y) if element.onSlide != nil { element.onSlide() } element.entity.Invalidate() } } func (element *slider) HandleScroll ( position image.Point, deltaX, deltaY float64, modifiers input.Modifiers, ) { } func (element *slider) HandleKeyDown (key input.Key, modifiers input.Modifiers) { switch key { case input.KeyUp: element.changeValue(0.1) case input.KeyDown: element.changeValue(-0.1) case input.KeyRight: if element.vertical { element.changeValue(-0.1) } else { element.changeValue(0.1) } case input.KeyLeft: if element.vertical { element.changeValue(0.1) } else { element.changeValue(-0.1) } } } func (element *slider) HandleKeyUp (key input.Key, modifiers input.Modifiers) { } // Value returns the slider's value. func (element *slider) Value () (value float64) { return element.value } // SetValue sets the slider's value. func (element *slider) SetValue (value float64) { if value < 0 { value = 0 } if value > 1 { value = 1 } if element.value == value { return } element.value = value if element.onRelease != nil { element.onRelease() } element.entity.Invalidate() } // OnSlide sets a function to be called every time the slider handle changes // position while being dragged. func (element *slider) OnSlide (callback func ()) { element.onSlide = callback } // OnRelease sets a function to be called when the handle stops being dragged. func (element *slider) OnRelease (callback func ()) { element.onRelease = callback } // SetTheme sets the element's theme. func (element *slider) SetTheme (new tomo.Theme) { if new == element.theme.Theme { return } element.theme.Theme = new element.entity.Invalidate() } // SetConfig sets the element's configuration. func (element *slider) SetConfig (new tomo.Config) { if new == element.config.Config { return } element.config.Config = new element.updateMinimumSize() element.entity.Invalidate() } func (element *slider) changeValue (delta float64) { element.value += delta if element.value < 0 { element.value = 0 } if element.value > 1 { element.value = 1 } if element.onRelease != nil { element.onRelease() } element.entity.Invalidate() } func (element *slider) valueFor (x, y int) (value float64) { if element.vertical { value = float64(y - element.track.Min.Y - element.bar.Dy() / 2) / float64(element.track.Dy() - element.bar.Dy()) value = 1 - value } else { value = float64(x - element.track.Min.X - element.bar.Dx() / 2) / float64(element.track.Dx() - element.bar.Dx()) } if value < 0 { value = 0 } if value > 1 { value = 1 } return } func (element *slider) updateMinimumSize () { gutterPadding := element.theme.Padding(tomo.PatternGutter) handlePadding := element.theme.Padding(tomo.PatternHandle) if element.vertical { element.entity.SetMinimumSize ( gutterPadding.Horizontal() + handlePadding.Horizontal(), gutterPadding.Vertical() + handlePadding.Vertical() * 2) } else { element.entity.SetMinimumSize ( gutterPadding.Horizontal() + handlePadding.Horizontal() * 2, gutterPadding.Vertical() + handlePadding.Vertical()) } }