User can now select text with the mouse

event.go

@@ -306,6 +306,7 @@ func (window *window) handleMotionNotify (
 	if window.hasModal { return }
 	
 	motionEvent := window.compressMotionNotify(*event.MotionNotifyEvent)
+	window.updateMousePosition(motionEvent.EventX, motionEvent.EventY)
 	x := int(motionEvent.EventX)
 	y := int(motionEvent.EventY)
 

textbox.go

@@ -3,10 +3,11 @@ package x
 import "image"
 import "image/color"
 import "golang.org/x/image/font"
-import "golang.org/x/image/math/fixed"
 import "git.tebibyte.media/tomo/tomo"
+import "golang.org/x/image/math/fixed"
 import "git.tebibyte.media/tomo/typeset"
 import "git.tebibyte.media/tomo/tomo/text"
+import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/tomo/canvas"
 
@@ -24,6 +25,8 @@ type textBox struct {
 	hAlign    tomo.Align
 
 	selectable  bool
+	selecting   bool
+	selectStart int
 	dot         text.Dot
 	dotColor    color.Color
 	
@@ -228,6 +231,38 @@ func (this *textBox) handleFocusLeave () {
 	this.box.handleFocusLeave()
 }
 
+func (this *textBox) handleMouseDown (button input.Button) {
+	if button == input.ButtonLeft {
+		index           := this.runeUnderMouse()
+		this.selectStart = index
+		this.selecting   = true
+		this.Select(text.Dot { Start: this.selectStart, End: index })
+	}
+	this.box.handleMouseDown(button)
+}
+
+func (this *textBox) handleMouseUp (button input.Button) {
+	if button == input.ButtonLeft && this.selecting {
+		index         := this.runeUnderMouse()
+		this.selecting = false
+		this.Select(text.Dot { Start: this.selectStart, End: index })
+	}
+	this.box.handleMouseUp(button)
+}
+
+func (this *textBox) handleMouseMove () {
+	if this.selecting {
+		index := this.runeUnderMouse()
+		this.Select(text.Dot { Start: this.selectStart, End: index })
+	}
+	this.box.handleMouseMove()
+}
+
+func (this *textBox) runeUnderMouse () int {
+	position := this.MousePosition().Sub(this.textOffset())
+	return this.drawer.AtPosition(fixPt(position))
+}
+
 func (this *textBox) normalizedLayoutBoundsSpace () image.Rectangle {
 	bounds := this.drawer.LayoutBoundsSpace()
 	return bounds.Sub(bounds.Min)

window.go

@@ -117,8 +117,8 @@ func (backend *Backend) newWindow (
 		Connect(backend.x, window.xWindow.Id)
 	xevent.ButtonReleaseFun(window.handleButtonRelease).
 		Connect(backend.x, window.xWindow.Id)
-	// xevent.MotionNotifyFun(window.handleMotionNotify).
-		// Connect(backend.x, window.xWindow.Id)
+	xevent.MotionNotifyFun(window.handleMotionNotify).
+		Connect(backend.x, window.xWindow.Id)
 	// xevent.SelectionNotifyFun(window.handleSelectionNotify).
 		// Connect(backend.x, window.xWindow.Id)
 	// xevent.PropertyNotifyFun(window.handlePropertyNotify).