Improve mouse handling in editable views

gui.go

@@ -1327,23 +1327,48 @@ func (g *Gui) onKey(ev *GocuiEvent) error {
 			}
 		}
 
+		// newCx and newCy are relative to the view port, i.e. to the visible area of the view
 		newCx := mx - v.x0 - 1
 		newCy := my - v.y0 - 1
-		// if view  is editable don't go further than the furthest character for that line
-		if v.Editable && newCy >= 0 && newCy <= len(v.lines)-1 {
-			lastCharForLine := len(v.lines[newCy])
-			if lastCharForLine < newCx {
-				newCx = lastCharForLine
+		// newX and newY are relative to the view's content, independent of its scroll position
+		newX := newCx + v.ox
+		newY := newCy + v.oy
+		// if view is editable don't go further than the furthest character for that line
+		if v.Editable {
+			if newY < 0 {
+				newY = 0
+				newCy = -v.oy
+			} else if newY >= len(v.lines) {
+				newY = len(v.lines) - 1
+				newCy = newY - v.oy
+			}
+
+			lastCharForLine := len(v.lines[newY])
+			for lastCharForLine > 0 && v.lines[newY][lastCharForLine-1].chr == 0 {
+				lastCharForLine--
+			}
+			if lastCharForLine < newX {
+				newX = lastCharForLine
+				newCx = lastCharForLine - v.ox
 			}
 		}
 		if !IsMouseScrollKey(ev.Key) {
 			if err := v.SetCursor(newCx, newCy); err != nil {
 				return err
 			}
+			if v.Editable {
+				v.TextArea.SetCursor2D(newX, newY)
+
+				// SetCursor2D might have adjusted the text area's cursor to the
+				// left to move left from a soft line break, so we need to
+				// update the view's cursor to match the text area's cursor.
+				cX, _ := v.TextArea.GetCursorXY()
+				v.SetCursorX(cX)
+			}
 		}
 
 		if IsMouseKey(ev.Key) {
-			opts := ViewMouseBindingOpts{X: newCx + v.ox, Y: newCy + v.oy}
+			opts := ViewMouseBindingOpts{X: newX, Y: newY}
 			matched, err := g.execMouseKeybindings(v, ev, opts)
 			if err != nil {
 				return err

text_area.go

@@ -282,13 +282,7 @@ func (self *TextArea) GoToEndOfLine() {
 
 	self.cursor = self.closestNewlineOnRight()
 
-	// If the end of line is a soft line break, we need to move left by one so
-	// that we end up at the last whitespace before the line break. Otherwise
-	// we'd be at the start of the next line, since the newline character
-	// doesn't really exist in the real content.
-	if self.cursor < len(self.content) && self.content[self.cursor] != '\n' {
-		self.cursor--
-	}
+	self.moveLeftFromSoftLineBreak()
 }
 
 func (self *TextArea) closestNewlineOnRight() int {
@@ -303,6 +297,16 @@ func (self *TextArea) closestNewlineOnRight() int {
 	return len(self.content)
 }
 
+func (self *TextArea) moveLeftFromSoftLineBreak() {
+	// If the end of line is a soft line break, we need to move left by one so
+	// that we end up at the last whitespace before the line break. Otherwise
+	// we'd be at the start of the next line, since the newline character
+	// doesn't really exist in the real content.
+	if self.cursor < len(self.content) && self.content[self.cursor] != '\n' {
+		self.cursor--
+	}
+}
+
 func (self *TextArea) atLineStart() bool {
 	return self.cursor == 0 ||
 		(len(self.content) > self.cursor-1 && self.content[self.cursor-1] == '\n')
@@ -420,12 +424,16 @@ func (self *TextArea) SetCursor2D(x int, y int) {
 	for _, r := range self.wrappedContent {
 		if x <= 0 && y == 0 {
 			self.cursor = self.wrappedCursorToOrigCursor(newCursor)
+			if self.wrappedContent[newCursor] == '\n' {
+				self.moveLeftFromSoftLineBreak()
+			}
 			return
 		}
 
 		if r == '\n' {
 			if y == 0 {
 				self.cursor = self.wrappedCursorToOrigCursor(newCursor)
+				self.moveLeftFromSoftLineBreak()
 				return
 			}
 			y--