Add TextView, improved Scrollbar

input.go

@@ -20,6 +20,7 @@ type TextInput struct {
 func NewTextInput (text string) *TextInput {
 	this := &TextInput { TextBox: tomo.NewTextBox() }
 	theme.Apply(this, theme.R("objects", "TextInput", ""))
+	this.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
 	this.SetText(text)
 	this.SetFocusable(true)
 	this.SetSelectable(true)
@@ -53,6 +54,9 @@ func (this *TextInput) handleKeyDown (key input.Key, numpad bool) {
 	sel       := modifiers.Shift
 	changed   := false
 
+	// TODO all this (except editing stuff) really should be moved into the
+	// backend
+
 	switch {
 	case key == input.KeyEnter:
 		this.on.enter.Broadcast()

label.go

@@ -15,4 +15,3 @@ func NewLabel (text string) *Label {
 	this.SetText(text)
 	return this
 }
-

scrollbar.go

@@ -173,15 +173,15 @@ func (this *Scrollbar) handleMouseDown (button input.Button) {
 		}
 	case input.ButtonMiddle:
 		if above {
-			this.SetValue(0)
+			this.scrollBy(-this.pageSize())
 		} else {
-			this.SetValue(1)
+			this.scrollBy(this.pageSize())
 		}
 	case input.ButtonRight:
 		if above {
-			this.SetValue(this.Value() - 0.05)
+			this.scrollBy(-this.stepSize())
 		} else {
-			this.SetValue(this.Value() + 0.05)
+			this.scrollBy(this.stepSize())
 		}
 	}
 }
@@ -229,6 +229,34 @@ func (this *Scrollbar) fallbackDragOffset () image.Point {
 	}
 }
 
+func (this *Scrollbar) pageSize () int {
+	if this.layout.linked == nil { return 0 }
+	viewport := this.layout.linked.InnerBounds()
+	if this.layout.vertical {
+		return viewport.Dy()
+	} else {
+		return viewport.Dx()
+	}
+}
+
+func (this *Scrollbar) stepSize () int {
+	// FIXME: this should not be hardcoded, need to get base font metrics
+	// from theme somehow. should be (emspace, lineheight)
+	return 16
+}
+
+func (this *Scrollbar) scrollBy (distance int) {
+	if this.layout.linked == nil { return }
+	var vector image.Point; if this.layout.vertical {
+		vector.Y = distance
+	} else {
+		vector.X = distance
+	}
+	this.layout.linked.ScrollTo (
+		this.layout.linked.ContentBounds().Min.
+		Add(vector))
+}
+
 type scrollbarCookie struct {
 	owner *Scrollbar
 	subCookies []event.Cookie

textview.go

@@ -0,0 +1,27 @@
+package objects
+
+import "image"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/theme"
+
+// TextView is an area for displaying a large amount of multi-line text.
+type TextView struct {
+	tomo.TextBox
+}
+
+// NewTextView creates a new text view.
+func NewTextView (text string) *TextView {
+	this := &TextView { TextBox: tomo.NewTextBox() }
+	theme.Apply(this, theme.R("objects", "TextView", ""))
+	this.SetFocusable(true)
+	this.SetSelectable(true)
+	this.SetText(text)
+	this.SetOverflow(false, true)
+	this.SetWrap(true)
+	this.OnScroll(this.handleScroll)
+	return this
+}
+
+func (this *TextView) handleScroll (x, y float64) {
+	this.ScrollTo(this.ContentBounds().Min.Add(image.Pt(int(x), int(y))))
+}