Add SetHorizontal and SetVertical

These methods control how text is aligned within the field.

README.md

@@ -1,8 +1,9 @@
 # messeji
 [![GoDoc](https://code.rocketnine.space/tslocum/godoc-static/raw/branch/master/badge.svg)](https://docs.rocketnine.space/code.rocketnine.space/tslocum/messeji)
-[![Donate](https://img.shields.io/liberapay/receives/rocketnine.space.svg?logo=liberapay)](https://liberapay.com/rocketnine.space)
+[![Donate via LiberaPay](https://img.shields.io/liberapay/receives/rocketnine.space.svg?logo=liberapay)](https://liberapay.com/rocketnine.space)
+[![Donate via Patreon](https://img.shields.io/badge/dynamic/json?color=%23e85b46&label=Patreon&query=data.attributes.patron_count&suffix=%20patrons&url=https%3A%2F%2Fwww.patreon.com%2Fapi%2Fcampaigns%2F5252223)](https://www.patreon.com/rocketnine)
 
-Text widgets for [Ebiten](https://github.com/hajimehoshi/ebiten)
+Text widgets for [Ebitengine](https://github.com/hajimehoshi/ebiten)
 
 **Note:** [IME](https://en.wikipedia.org/wiki/Input_method) is not yet supported.
 

doc.go

@@ -1,4 +1,4 @@
 /*
-Package messeji provides text widgets for Ebiten.
+Package messeji provides text widgets for Ebitengine.
 */
 package messeji

examples/messeji/game/game.go

@@ -21,9 +21,10 @@ const initialText = `
 Welcome to the メッセージ (messeji) text widgets demo.
 This is a TextField, which can be used to display text.
 Below is an InputField, which accepts keyboard input.
-Press <Tab> to toggle word wrap.
-Press <Enter> to append input text.
-Press <Ctrl+M> to toggle multi-line.
+<Tab> to cycle horizontal alignment.
+<Enter> to append input text to buffer.
+<Ctrl+Tab> to toggle word wrap.
+<Ctrl+Enter> to toggle multi-line input.
 `
 
 var mplusNormalFont font.Face
@@ -36,7 +37,7 @@ func init() {
 
 	const dpi = 72
 	mplusNormalFont, err = opentype.NewFace(tt, &opentype.FaceOptions{
-		Size:    32,
+		Size:    28,
 		DPI:     dpi,
 		Hinting: font.HintingFull,
 	})
@@ -57,6 +58,8 @@ type game struct {
 	op *ebiten.DrawImageOptions
 
 	spinnerIndex int
+
+	horizontal messeji.Alignment
 }
 
 // NewDemoGame returns a new messeji demo game.
@@ -109,21 +112,26 @@ func (g *game) Layout(outsideWidth, outsideHeight int) (int, int) {
 }
 
 func (g *game) Update() error {
-	if inpututil.IsKeyJustPressed(ebiten.KeyEnter) && !g.input.Visible() {
+	if inpututil.IsKeyJustPressed(ebiten.KeyEnter) && ebiten.IsKeyPressed(ebiten.KeyControl) {
+		g.singleLine = !g.singleLine
+		g.input.SetSingleLine(g.singleLine)
+		return nil
+	} else if inpututil.IsKeyJustPressed(ebiten.KeyEnter) && !g.input.Visible() {
 		g.input.SetVisible(true)
 		return nil
 	}
 
-	if inpututil.IsKeyJustPressed(ebiten.KeyTab) {
+	if inpututil.IsKeyJustPressed(ebiten.KeyTab) && ebiten.IsKeyPressed(ebiten.KeyControl) {
 		wrap := g.buffer.WordWrap()
 		g.buffer.SetWordWrap(!wrap)
 		g.input.SetWordWrap(!wrap)
 		return nil
-	}
-
-	if inpututil.IsKeyJustPressed(ebiten.KeyM) && ebiten.IsKeyPressed(ebiten.KeyControl) {
-		g.singleLine = !g.singleLine
-		g.input.SetSingleLine(g.singleLine)
+	} else if inpututil.IsKeyJustPressed(ebiten.KeyTab) {
+		g.horizontal++
+		if g.horizontal > messeji.AlignEnd {
+			g.horizontal = messeji.AlignStart
+		}
+		g.buffer.SetHorizontal(g.horizontal)
 		return nil
 	}
 

textfield.go

@@ -13,8 +13,22 @@ import (
 	"golang.org/x/image/font"
 )
 
+// Alignment specifies how text is aligned within the field.
+type Alignment int
+
 const (
-	initialPadding     = 2
+	// AlignStart aligns text at the start of the field.
+	AlignStart Alignment = 0
+
+	// AlignCenter aligns text at the center of the field.
+	AlignCenter Alignment = 1
+
+	// AlignEnd aligns text at the end of the field.
+	AlignEnd Alignment = 2
+)
+
+const (
+	initialPadding     = 5
 	initialScrollWidth = 32
 )
 
@@ -51,9 +65,18 @@ type TextField struct {
 	// line mode is enabled,
 	bufferSize int
 
+	// lineWidths is the size (in pixels) of each line as it appears on the screen.
+	lineWidths []int
+
 	// singleLine is whether the field displays all text on a single line.
 	singleLine bool
 
+	// horizontal is the horizontal alignment of the text within field.
+	horizontal Alignment
+
+	// vertical is the vertical alignment of the text within field.
+	vertical Alignment
+
 	// face is the font face of the text within the field.
 	face font.Face
 
@@ -207,6 +230,32 @@ func (f *TextField) SetSingleLine(single bool) {
 	f.bufferModified()
 }
 
+// SetHorizontal sets the horizontal alignment of the text within the field.
+func (f *TextField) SetHorizontal(h Alignment) {
+	f.Lock()
+	defer f.Unlock()
+
+	if f.horizontal == h {
+		return
+	}
+
+	f.horizontal = h
+	f.bufferModified()
+}
+
+// SetVertical sets the veritcal alignment of the text within the field.
+func (f *TextField) SetVertical(v Alignment) {
+	f.Lock()
+	defer f.Unlock()
+
+	if f.vertical == v {
+		return
+	}
+
+	f.vertical = v
+	f.bufferModified()
+}
+
 // LineHeight returns the line height for the field.
 func (f *TextField) LineHeight() int {
 	f.Lock()
@@ -467,10 +516,15 @@ func (f *TextField) setDefaultLineHeight() {
 }
 
 func (f *TextField) wrapContent(withScrollBar bool) {
+	f.lineWidths = f.lineWidths[:0]
 	buffer := f.prefix + f.buffer + f.suffix
 
 	if f.singleLine {
-		f.bufferWrapped = []string{strings.ReplaceAll(buffer, "\n", "")}
+		buffer = strings.ReplaceAll(buffer, "\n", "")
+		bounds := text.BoundString(f.face, buffer)
+
+		f.bufferWrapped = []string{buffer}
+		f.lineWidths = append(f.lineWidths, bounds.Dx())
 		return
 	}
 
@@ -483,8 +537,11 @@ func (f *TextField) wrapContent(withScrollBar bool) {
 		l := len(line)
 		var start int
 		var end int
+		var initialEnd int
 		for start < l {
 			for end = l; end > start; end-- {
+				initialEnd = end
+
 				bounds := text.BoundString(f.face, line[start:end])
 				if bounds.Dx() < w-(f.padding*2)-2 {
 					if f.wordWrap {
@@ -492,12 +549,21 @@ func (f *TextField) wrapContent(withScrollBar bool) {
 							for endOffset := 0; endOffset < end-start; endOffset++ {
 								if unicode.IsSpace(rune(line[end-endOffset])) {
 									end = end - endOffset
+									if end < l-1 {
+										end++
+									}
 									break
 								}
 							}
 						}
 					}
+
+					if end != initialEnd && f.horizontal != AlignStart {
+						bounds = text.BoundString(f.face, line[start:end])
+					}
+
 					f.bufferWrapped = append(f.bufferWrapped, line[start:end])
+					f.lineWidths = append(f.lineWidths, bounds.Dx())
 					break
 				}
 			}
@@ -510,12 +576,19 @@ func (f *TextField) wrapContent(withScrollBar bool) {
 func (f *TextField) drawContent() (overflow bool) {
 	f.img.Fill(f.backgroundColor)
 
+	fieldWidth := f.r.Dx()
+	fieldHeight := f.r.Dy()
+	if f.showScrollBar() {
+		fieldWidth -= f.scrollWidth
+	}
+	lines := len(f.bufferWrapped)
+
 	h := f.r.Dy()
 	lineHeight := f.overrideLineHeight
 	if lineHeight == 0 {
 		lineHeight = f.lineHeight
 	}
-	lineOffset := 7
+	lineOffset := lineHeight / 3
 	f.bufferSize = 0
 	for i, line := range f.bufferWrapped {
 		lineX := f.padding
@@ -545,6 +618,18 @@ func (f *TextField) drawContent() (overflow bool) {
 			lineY -= f.offset
 		}
 
+		if f.horizontal == AlignCenter {
+			lineX = (fieldWidth - f.lineWidths[i]) / 2
+		} else if f.horizontal == AlignEnd {
+			lineX = (fieldWidth - f.lineWidths[i]) - f.padding*2
+		}
+
+		if f.vertical == AlignCenter && lineHeight*lines <= h {
+			lineY = (fieldHeight-(lineHeight*lines))/2 + lineHeight*(i+1) - lineOffset
+		} else if f.vertical == AlignEnd && lineHeight*lines <= h {
+			lineY = (fieldHeight - lineHeight*i) - f.padding*2
+		}
+
 		text.Draw(f.img, line, f.face, lineX, lineY, f.textColor)
 	}
 
@@ -596,22 +681,20 @@ func (f *TextField) drawImage() {
 		f.drawContent()
 	}
 
-	scrollBarW := 32
-
 	// Draw scrollbar.
 	if f.showScrollBar() {
-		scrollAreaX, scrollAreaY := w-scrollBarW, 0
-		f.scrollRect = image.Rect(scrollAreaX, scrollAreaY, scrollAreaX+scrollBarW, h)
+		scrollAreaX, scrollAreaY := w-f.scrollWidth, 0
+		f.scrollRect = image.Rect(scrollAreaX, scrollAreaY, scrollAreaX+f.scrollWidth, h)
 
 		scrollBarH := f.scrollWidth / 2
 		if scrollBarH < 4 {
 			scrollBarH = 4
 		}
 
-		scrollX, scrollY := w-scrollBarW, 0
+		scrollX, scrollY := w-f.scrollWidth, 0
 		pct := float64(f.offset) / float64(f.bufferSize-h)
 		scrollY += int(float64(h-scrollBarH) * pct)
-		scrollBarRect := image.Rect(scrollX, scrollY, scrollX+scrollBarW, scrollY+scrollBarH)
+		scrollBarRect := image.Rect(scrollX, scrollY, scrollX+f.scrollWidth, scrollY+scrollBarH)
 
 		f.img.SubImage(f.scrollRect).(*ebiten.Image).Fill(color.RGBA{200, 200, 200, 255})
 		f.img.SubImage(scrollBarRect).(*ebiten.Image).Fill(color.RGBA{108, 108, 108, 255})