API changes to support future functionality

layout.go

@@ -111,7 +111,7 @@ type LineLayout struct {
 // wrap is set to true, this function will stop processing words once maxWidth
 // is crossed. The word which would have crossed over the limit will not be
 // processed.
-func DoLine (text []rune, face font.Face, wrap bool, maxWidth fixed.Int26_6) (line LineLayout, remaining []rune) {
+func DoLine (text []rune, face font.Face, wrap bool, width fixed.Int26_6) (line LineLayout, remaining []rune) {
 	remaining    = text
 	x           := fixed.Int26_6(0)
 	lastWord    := WordLayout { }
@@ -122,9 +122,9 @@ func DoLine (text []rune, face font.Face, wrap bool, maxWidth fixed.Int26_6) (li
 		word.X = x
 		x += word.Width
 
-		// if we have gone over the maximum width, stop processing
+		// if we have gone over the preferred width, stop processing
 		// words (if wrap is enabled)
-		if !isFirstWord && wrap && x > maxWidth {
+		if !isFirstWord && wrap && x > width {
 			break
 		}
 
@@ -149,9 +149,13 @@ func DoLine (text []rune, face font.Face, wrap bool, maxWidth fixed.Int26_6) (li
 	}
 
 	// set the width of the line's content.
-	line.Width        = maxWidth
 	line.ContentWidth = lastWord.X + lastWord.Width
-	line.SpaceAfter   = lastWord.SpaceAfter
+	if wrap {
+		line.Width = width
+	} else {
+		line.Width = line.ContentWidth
+	}
+	line.SpaceAfter = lastWord.SpaceAfter
 	return
 }
 

setter.go

@@ -34,23 +34,15 @@ func (setter *TypeSetter) needLayout () {
 	setter.layoutBounds      = image.Rectangle { }
 	setter.layoutBoundsSpace = image.Rectangle { }
 	setter.minWidth          = 0
-	if len(setter.text) == 0 { return }
 	if setter.face  == nil { return }
 
 	horizontalExtent      := fixed.Int26_6(0)
 	horizontalExtentSpace := fixed.Int26_6(0)
-
-	metrics   := setter.face.Metrics()
-	remaining := setter.text
-	y         := fixed.Int26_6(0)
-	for len(remaining) > 0 {
-		// process one line
-		line, remainingFromLine := DoLine (
-			remaining, setter.face, setter.wrap,
-			fixed.I(setter.maxWidth))
-		remaining = remainingFromLine
-
-		// add the line
+	metrics               := setter.face.Metrics()
+	remaining             := setter.text
+	y                     := fixed.Int26_6(0)
+	
+	addLine := func (line LineLayout) {
 		line.Y = y
 		y += metrics.Height
 		if line.ContentWidth > horizontalExtent {
@@ -62,10 +54,27 @@ func (setter *TypeSetter) needLayout () {
 		}
 		setter.lines = append(setter.lines, line)
 	}
-	setter.minWidth = horizontalExtentSpace
 
-	setter.layoutBounds.Max.X      = setter.maxWidth
-	setter.layoutBoundsSpace.Max.X = setter.maxWidth
+	// process every line until there are no more remaining runes
+	for len(remaining) > 0 {
+		line, remainingFromLine := DoLine (
+			remaining, setter.face, setter.wrap,
+			fixed.I(setter.maxWidth))
+		remaining = remainingFromLine
+		addLine(line)
+	}
+
+	// if there were no lines processed or the last line has a break after
+	// it, add a blank line at the end
+	needBlankLine :=
+		len(setter.lines) == 0 ||
+		setter.lines[len(setter.lines) - 1].BreakAfter
+	if needBlankLine { addLine(LineLayout { }) }
+
+	// calculate layout boundaries
+	setter.minWidth = horizontalExtentSpace
+	setter.layoutBounds.Max.X      = horizontalExtent.Round()
+	setter.layoutBoundsSpace.Max.X = horizontalExtentSpace.Round()
 
 	y -= metrics.Height
 	if setter.maxHeight == 0 {
@@ -90,8 +99,11 @@ func (setter *TypeSetter) needAlignedLayout () {
 
 	for index := range setter.lines {
 		align := setter.align
-		if index == len(setter.lines) - 1 && align == AlignJustify {
-			align = AlignLeft
+		if align == AlignJustify {
+			except :=
+				index == len(setter.lines) - 1 ||
+				setter.lines[index].BreakAfter
+			if except { align = AlignLeft }
 		}
 		setter.lines[index].Align(align)
 	}
@@ -105,10 +117,10 @@ func (setter *TypeSetter) SetWrap (wrap bool) {
 }
 
 // SetAlign sets the alignment method of the typesetter.
-func (setter *TypeSetter) SetAlign (align Align) {
-	if setter.align == align { return }
+func (setter *TypeSetter) SetAlign (horizontal, vertical Align) {
+	if setter.align == horizontal { return }
 	setter.alignClean = false
-	setter.align = align
+	setter.align = horizontal
 }
 
 // SetText sets the text content of the typesetter.
@@ -126,18 +138,19 @@ func (setter *TypeSetter) SetFace (face font.Face) {
 	setter.face = face
 }
 
-// SetMaxWidth sets the maximum width of the typesetter.
-func (setter *TypeSetter) SetMaxWidth (width int) {
+// SetWidth sets the width of the typesetter. Text will still be able
+// to overflow outside of this width if wrapping is disabled.
+func (setter *TypeSetter) SetWidth (width int) {
 	if setter.maxWidth == width { return }
 	setter.layoutClean = false
 	setter.alignClean  = false
 	setter.maxWidth = width
 }
 
-// SetMaxHeight sets the maximum height of the typesetter. If the maximum height
-// is greater than zero, no lines will be laid out past that point. If the
-// maximum height is zero, the text's maximum height will not be constrained.
-func (setter *TypeSetter) SetMaxHeight (heignt int) {
+// SetHeight sets the height of the typesetter. If the height is greater than
+// zero, no lines will be laid out past it. If the height is zero, the text's
+// maximum height will not be constrained.
+func (setter *TypeSetter) SetHeight (heignt int) {
 	if setter.maxHeight == heignt { return }
 	setter.layoutClean = false
 	setter.alignClean  = false
@@ -158,14 +171,13 @@ func (setter *TypeSetter) LineHeight () fixed.Int26_6 {
 	return setter.face.Metrics().Height
 }
 
-// MaxWidth returns the maximum width of the typesetter as set by SetMaxWidth.
-func (setter *TypeSetter) MaxWidth () int {
+// Width returns the height of the typesetter as set by SetWidth.
+func (setter *TypeSetter) Width () int {
 	return setter.maxWidth
 }
 
-// MaxHeight returns the maximum height of the typesetter as set by
-// SetMaxHeight.
-func (setter *TypeSetter) MaxHeight () int {
+// Height returns the height of the typesetter as set by SetHeight.
+func (setter *TypeSetter) Height () int {
 	return setter.maxHeight
 }