More intelligent text editing with new textmanip system

elements/basic/textbox.go

@@ -4,6 +4,7 @@ import "image"
 import "git.tebibyte.media/sashakoshka/tomo"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
+import "git.tebibyte.media/sashakoshka/tomo/textmanip"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
 type TextBox struct {
@@ -15,7 +16,7 @@ type TextBox struct {
 
 	cursor int
 	placeholder string
-	text        string
+	text        []rune
 	placeholderDrawer artist.TextDrawer
 	valueDrawer       artist.TextDrawer
 }
@@ -50,14 +51,51 @@ func (element *TextBox) HandleKeyDown (
 	modifiers tomo.Modifiers,
 	repeated bool,
 ) {
+	altered := true
 	switch {
 	case key == tomo.KeyBackspace:
 		if len(element.text) < 1 { break }
-		element.cursor --
-		element.SetText(element.text[:len(element.text) - 1])
+		element.text, element.cursor = textmanip.Backspace (
+			element.text,
+			element.cursor,
+			modifiers.Control)
+			
+	case key == tomo.KeyDelete:
+		if len(element.text) < 1 { break }
+		element.text, element.cursor = textmanip.Delete (
+			element.text,
+			element.cursor,
+			modifiers.Control)
+			
+	case key == tomo.KeyLeft:
+		element.cursor = textmanip.MoveLeft (
+			element.text,
+			element.cursor,
+			modifiers.Control)
+			
+	case key == tomo.KeyRight:
+		element.cursor = textmanip.MoveRight (
+			element.text,
+			element.cursor,
+			modifiers.Control)
+		
 	case key.Printable():
-		element.cursor ++
-		element.SetText(element.text + string(rune(key)))
+		element.text, element.cursor = textmanip.Type (
+			element.text,
+			element.cursor,
+			rune(key))
+			
+	default:
+		altered = false
+	}
+
+	if altered {
+		element.valueDrawer.SetText(element.text)
+	}
+	
+	if altered && element.core.HasImage () {
+		element.draw()
+		element.core.PushAll()
 	}
 }
 
@@ -130,10 +168,10 @@ func (element *TextBox) updateMinimumSize () {
 }
 
 func (element *TextBox) SetText (text string) {
-	if element.text == text { return }
+	// if element.text == text { return }
 
-	element.text = text
-	element.valueDrawer.SetText([]rune(text))
+	element.text = []rune(text)
+	element.valueDrawer.SetText(element.text)
 	if element.cursor > element.valueDrawer.Length() {
 		element.cursor = element.valueDrawer.Length()
 	}
@@ -160,7 +198,7 @@ func (element *TextBox) draw () {
 	innerBounds.Max.X -= theme.Padding()
 	innerBounds.Max.Y -= theme.Padding()
 
-	if element.text == "" && !element.selected {
+	if element.text == nil && !element.selected {
 		// draw placeholder
 		textBounds := element.placeholderDrawer.LayoutBounds()
 		offset := image.Point {

textmanip/textmanip.go

@@ -0,0 +1,99 @@
+package textmanip
+
+import "unicode"
+
+func WordToLeft (text []rune, cursor int) (length int) {
+	if cursor < 1 { return }
+	if cursor > len(text) { cursor = len(text) }
+
+	index := cursor - 1
+	for index >= 0 && unicode.IsSpace(text[index]) {
+		length ++
+		index --
+	}
+	for index >= 0 && !unicode.IsSpace(text[index]) {
+		length ++
+		index --
+	}
+	return
+}
+
+func WordToRight (text []rune, cursor int) (length int) {
+	if cursor < 0 { return }
+	if cursor > len(text) { cursor = len(text) }
+
+	index := cursor
+	for index < len(text) && unicode.IsSpace(text[index]) {
+		length ++
+		index ++
+	}
+	for index < len(text) && !unicode.IsSpace(text[index]) {
+		length ++
+		index ++
+	}
+	return
+}
+
+func Backspace (text []rune, cursor int, word bool) (result []rune, moved int) {
+	if cursor < 1         { return text, cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToLeft(text, cursor)
+	}
+	result = append(result, text[:cursor - moved]...)
+	result = append(result, text[cursor:]...)
+	moved = cursor - moved
+	return
+}
+
+func Delete (text []rune, cursor int, word bool) (result []rune, moved int) {
+	if cursor < 0         { return text, cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToRight(text, cursor)
+	}
+	result = append(result, text[:cursor]...)
+	result = append(result, text[cursor + moved:]...)
+	moved = cursor
+	return
+}
+
+func Type (text []rune, cursor int, character rune) (result []rune, moved int) {
+	if cursor < 0         { cursor = 0 }
+	if cursor > len(text) { cursor = len(text) }
+	result = append(result, text[:cursor]...)
+	result = append(result, character)
+	if cursor < len(text) {
+		result = append(result, text[cursor:]...)
+	}
+	moved = cursor + 1
+	return
+}
+
+func MoveLeft (text []rune, cursor int, word bool) (moved int) {
+	if cursor < 1         { return cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToLeft(text, cursor)
+	}
+	moved = cursor - moved
+	return
+}
+
+func MoveRight (text []rune, cursor int, word bool) (moved int) {
+	if cursor < 0         { return cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToRight(text, cursor)
+	}
+	moved = cursor + moved
+	return
+}