TextBox has double-click to select word

elements/file/file.go

@@ -130,8 +130,7 @@ func (element *File) HandleMouseDown (x, y int, button input.Button) {
 func (element *File) HandleMouseUp (x, y int, button input.Button) {
 	if button != input.ButtonLeft { return }
 	element.pressed = false
-	within := image.Point { x, y }.
-		In(element.Bounds())
+	within := image.Point { x, y }.In(element.Bounds())
 	if time.Since(element.lastClick) < element.config.DoubleClickDelay() {
 		if element.Enabled() && within && element.onChoose != nil {
 			element.onChoose()

elements/textbox.go

@@ -1,6 +1,7 @@
 package elements
 
 import "io"
+import "time"
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo"
 import "git.tebibyte.media/sashakoshka/tomo/data"
@@ -22,7 +23,8 @@ type TextBox struct {
 	core core.CoreControl
 	focusableControl core.FocusableCoreControl
 
-	dragging bool
+	lastClick   time.Time
+	dragging    int
 	dot         textmanip.Dot
 	scroll      int
 	placeholder string
@@ -81,23 +83,50 @@ func (element *TextBox) HandleMouseDown (x, y int, button input.Button) {
 
 	if button == input.ButtonLeft {
 		runeIndex := element.atPosition(image.Pt(x, y))
-		element.dragging = true
-		if runeIndex > -1 {
+		if runeIndex == -1 { return }
+		
+		if time.Since(element.lastClick) < element.config.DoubleClickDelay() {
+			element.dragging = 2
+			element.dot = textmanip.WordAround(element.text, runeIndex)
+		} else {
+			element.dragging = 1
 			element.dot = textmanip.EmptyDot(runeIndex)
-			element.redo()
+			element.lastClick = time.Now()
 		}
+		
+		element.redo()
 	}
 }
 
 func (element *TextBox) HandleMotion (x, y int) {
 	if !element.Enabled() { return }
 
-	if element.dragging {
+	switch element.dragging {
+	case 1:
 		runeIndex := element.atPosition(image.Pt(x, y))
 		if runeIndex > -1 {
 			element.dot.End = runeIndex
 			element.redo()
 		}
+		
+	case 2:
+		runeIndex := element.atPosition(image.Pt(x, y))
+		if runeIndex > -1 {
+			if runeIndex < element.dot.Start {
+				element.dot.End =
+					runeIndex -
+					textmanip.WordToLeft (
+						element.text,
+						runeIndex)
+			} else {
+				element.dot.End =
+					runeIndex +
+					textmanip.WordToRight (
+						element.text,
+						runeIndex)
+			}
+			element.redo()
+		}
 	}
 }
 
@@ -120,7 +149,7 @@ func (element *TextBox) atPosition (position image.Point) int {
 
 func (element *TextBox) HandleMouseUp (x, y int, button input.Button) {
 	if button == input.ButtonLeft {
-		element.dragging = false
+		element.dragging = 0
 	}
 }
 

textmanip/textmanip.go

@@ -13,7 +13,7 @@ func EmptyDot (position int) Dot {
 
 // Canon places the lesser value at the start, and the greater value at the end.
 // Note that a canonized dot does not in all cases correspond directly to the
-// original.
+// original, because there is a semantic value to the start and end positions.
 func (dot Dot) Canon () Dot {
 	if dot.Start > dot.End {
 		return Dot { dot.End, dot.Start }
@@ -35,7 +35,7 @@ func (dot Dot) Add (delta int) Dot {
 	}
 }
 
-// Add shifts the dot to the left by the specified amount.
+// Sub shifts the dot to the left by the specified amount.
 func (dot Dot) Sub (delta int) Dot {
 	return Dot {
 		dot.Start - delta,
@@ -103,8 +103,8 @@ func WordToRight (text []rune, position int) (length int) {
 // WordAround returns a dot that surrounds the word at the specified position.
 func WordAround (text []rune, position int) (around Dot) {
 	return Dot {
-		WordToLeft(text, position),
-		WordToRight(text, position),
+		position - WordToLeft(text, position),
+		position + WordToRight(text, position),
 	}
 }