First run at basic structure

internal/ui/hud/elements.go

@@ -0,0 +1,209 @@
+package hud
+
+import (
+	"fmt"
+	"image/color"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/text/v2"
+	"golang.org/x/image/font/basicfont"
+
+	"github.com/atridad/BigFeelings/internal/status"
+)
+
+var (
+	basicFace       = text.NewGoXFace(basicfont.Face7x13)
+	basicFaceAscent = basicFace.Metrics().HAscent
+)
+
+func drawHUDText(screen *ebiten.Image, txt string, clr color.Color, x, y int) {
+	if clr == nil {
+		clr = color.White
+	}
+	op := &text.DrawOptions{}
+	op.GeoM.Translate(float64(x), float64(y)-basicFaceAscent)
+	op.ColorScale.ScaleWithColor(clr)
+	text.Draw(screen, txt, basicFace, op)
+}
+
+// Drawable HUD chunk.
+type Element interface {
+	Draw(screen *ebiten.Image, x, y int) (width, height int)
+}
+
+// Plain text node.
+type Label struct {
+	Text  string
+	Color color.Color
+}
+
+func (l Label) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	if l.Color == nil {
+		l.Color = color.White
+	}
+	drawHUDText(screen, l.Text, l.Color, x, y)
+	width := len(l.Text) * 7 // approximate width for basicfont
+	return width, 13
+}
+
+// Percent readout node.
+type PercentageDisplay struct {
+	Meter status.Meter
+	Color color.Color
+}
+
+func (p PercentageDisplay) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	if p.Color == nil {
+		p.Color = color.White
+	}
+	txt := fmt.Sprintf("%3.0f%%", p.Meter.Level)
+	drawHUDText(screen, txt, p.Color, x, y)
+	return len(txt) * 7, 13
+}
+
+// Combined label and percent.
+type MeterLabel struct {
+	Meter status.Meter
+	Color color.Color
+}
+
+func (m MeterLabel) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	if m.Color == nil {
+		m.Color = color.White
+	}
+	txt := fmt.Sprintf("%s: %3.0f%%", m.Meter.Label, m.Meter.Level)
+	drawHUDText(screen, txt, m.Color, x, y)
+	return len(txt) * 7, 13
+}
+
+// Horizontal meter bar.
+type Bar struct {
+	Meter       status.Meter
+	MaxWidth    int
+	Height      int
+	BorderColor color.Color
+	ShowBorder  bool
+}
+
+func (b Bar) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	maxWidth := b.MaxWidth
+	if maxWidth <= 0 {
+		maxWidth = 180
+	}
+	height := b.Height
+	if height <= 0 {
+		height = 8
+	}
+
+	fillWidth := int((b.Meter.Level / 100.0) * float64(maxWidth))
+	if fillWidth < 0 {
+		fillWidth = 0
+	}
+	if fillWidth > maxWidth {
+		fillWidth = maxWidth
+	}
+
+	// Draw border if requested
+	if b.ShowBorder {
+		borderColor := b.BorderColor
+		if borderColor == nil {
+			borderColor = color.RGBA{R: 80, G: 80, B: 80, A: 255}
+		}
+		// Top border
+		drawRect(screen, x, y, maxWidth, 1, borderColor)
+		// Bottom border
+		drawRect(screen, x, y+height-1, maxWidth, 1, borderColor)
+		// Left border
+		drawRect(screen, x, y, 1, height, borderColor)
+		// Right border
+		drawRect(screen, x+maxWidth-1, y, 1, height, borderColor)
+	}
+
+	// Draw filled portion
+	if fillWidth > 0 {
+		drawRect(screen, x, y, fillWidth, height, b.Meter.Color)
+	}
+
+	return maxWidth, height
+}
+
+// Helper for filled rectangles.
+func drawRect(screen *ebiten.Image, x, y, width, height int, clr color.Color) {
+	if width <= 0 || height <= 0 {
+		return
+	}
+
+	// Create a small 1x1 pixel image and scale it
+	img := ebiten.NewImage(1, 1)
+	img.Fill(clr)
+
+	op := &ebiten.DrawImageOptions{}
+	op.GeoM.Scale(float64(width), float64(height))
+	op.GeoM.Translate(float64(x), float64(y))
+
+	screen.DrawImage(img, op)
+}
+
+// Empty padding block.
+type Spacer struct {
+	Width  int
+	Height int
+}
+
+func (s Spacer) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	return s.Width, s.Height
+}
+
+// Horizontal layout row.
+type Row struct {
+	Elements []Element
+	Spacing  int
+}
+
+func (r Row) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	totalWidth := 0
+	maxHeight := 0
+	currentX := x
+
+	for i, elem := range r.Elements {
+		w, h := elem.Draw(screen, currentX, y)
+		totalWidth += w
+		if h > maxHeight {
+			maxHeight = h
+		}
+		currentX += w
+		if i < len(r.Elements)-1 {
+			currentX += r.Spacing
+			totalWidth += r.Spacing
+		}
+	}
+
+	return totalWidth, maxHeight
+}
+
+// Vertical stack layout.
+type Column struct {
+	Elements []Element
+	Spacing  int
+}
+
+func (c Column) Draw(screen *ebiten.Image, x, y int) (int, int) {
+	maxWidth := 0
+	totalHeight := 0
+	currentY := y
+
+	for i, elem := range c.Elements {
+		w, h := elem.Draw(screen, x, currentY)
+		if w > maxWidth {
+			maxWidth = w
+		}
+		totalHeight += h
+		currentY += h
+		if i < len(c.Elements)-1 {
+			currentY += c.Spacing
+			totalHeight += c.Spacing
+		}
+	}
+
+	return maxWidth, totalHeight
+}

internal/ui/hud/hud.go

@@ -0,0 +1,52 @@
+package hud
+
+import (
+	"image/color"
+
+	"github.com/hajimehoshi/ebiten/v2"
+
+	"github.com/atridad/BigFeelings/internal/status"
+)
+
+// HUD overlay anchor.
+type Overlay struct {
+	X     int
+	Y     int
+	Color color.Color
+}
+
+// Paints the HUD overlay.
+func (o Overlay) Draw(screen *ebiten.Image, meters []status.Meter) {
+	if o.Color == nil {
+		o.Color = color.White
+	}
+
+	// Instruction text
+	instructions := Column{
+		Elements: []Element{
+			Label{Text: "Systems Prototype", Color: o.Color},
+			Label{Text: "Move with Arrow Keys / WASD", Color: o.Color},
+			Label{Text: "Track resource signals and plan ahead.", Color: o.Color},
+		},
+		Spacing: 7,
+	}
+	instructions.Draw(screen, 16, 16)
+
+	// Meter column
+	meterElements := make([]Element, 0, len(meters))
+	for _, meter := range meters {
+		meterElements = append(meterElements, Column{
+			Elements: []Element{
+				MeterLabel{Meter: meter, Color: o.Color},
+				Bar{Meter: meter, MaxWidth: 180, Height: 8, ShowBorder: false},
+			},
+			Spacing: 2,
+		})
+	}
+
+	meterPanel := Column{
+		Elements: meterElements,
+		Spacing:  16,
+	}
+	meterPanel.Draw(screen, o.X, o.Y)
+}