feat(misc): rotate wheel beta labels

internal/modules/misc/handlers_test.go

@@ -386,13 +386,32 @@ func TestWheelOfNamesBeta_DrawsOptionLabelsInsideSlices(t *testing.T) {
 	segment := 2 * math.Pi / float64(len(options))
 	angle := rotation + segment/2
 	centerX := wheelBetaSize/2 + int(math.Round(math.Cos(angle)*float64(wheelBetaSliceLabelRadius)))
-	baselineY := wheelBetaSize/2 + int(math.Round(math.Sin(angle)*float64(wheelBetaSliceLabelRadius))) + wheelBetaSliceLabelBaselineOffset
-	bounds := image.Rect(centerX-28, baselineY-14, centerX+28, baselineY+2)
+	centerY := wheelBetaSize/2 + int(math.Round(math.Sin(angle)*float64(wheelBetaSliceLabelRadius)))
+	bounds := image.Rect(centerX-28, centerY-28, centerX+28, centerY+28)
 	if got := countColorIndex(img, bounds, 1); got == 0 {
 		t.Fatalf("slice label dark pixels = %d, want > 0", got)
 	}
 }
 
+func TestWheelOfNamesBeta_RotatesOptionLabelsWithSlices(t *testing.T) {
+	options := []string{"Rotate", "Teacher", "Parent", "Staff"}
+	rotation := -3 * math.Pi / 4
+	img := renderWheelBetaFrame(options, 0, rotation, false)
+
+	segment := 2 * math.Pi / float64(len(options))
+	angle := rotation + segment/2
+	centerX := wheelBetaSize/2 + int(math.Round(math.Cos(angle)*float64(wheelBetaSliceLabelRadius)))
+	centerY := wheelBetaSize/2 + int(math.Round(math.Sin(angle)*float64(wheelBetaSliceLabelRadius)))
+	searchBounds := image.Rect(centerX-28, centerY-32, centerX+28, centerY+32)
+	labelBounds, ok := colorIndexBounds(img, searchBounds, wheelBetaInkColorIndex)
+	if !ok {
+		t.Fatalf("slice label dark pixels missing in %v", searchBounds)
+	}
+	if labelBounds.Dy() <= labelBounds.Dx() {
+		t.Fatalf("slice label bounds = %v, want taller than wide for rotated label", labelBounds)
+	}
+}
+
 func countColorIndex(img *image.Paletted, bounds image.Rectangle, colorIndex byte) int {
 	bounds = bounds.Intersect(img.Bounds())
 	count := 0
@@ -406,6 +425,37 @@ func countColorIndex(img *image.Paletted, bounds image.Rectangle, colorIndex byt
 	return count
 }
 
+func colorIndexBounds(img *image.Paletted, bounds image.Rectangle, colorIndex byte) (image.Rectangle, bool) {
+	bounds = bounds.Intersect(img.Bounds())
+	minX, minY := bounds.Max.X, bounds.Max.Y
+	maxX, maxY := bounds.Min.X, bounds.Min.Y
+	found := false
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		for x := bounds.Min.X; x < bounds.Max.X; x++ {
+			if img.ColorIndexAt(x, y) != colorIndex {
+				continue
+			}
+			found = true
+			if x < minX {
+				minX = x
+			}
+			if y < minY {
+				minY = y
+			}
+			if x+1 > maxX {
+				maxX = x + 1
+			}
+			if y+1 > maxY {
+				maxY = y + 1
+			}
+		}
+	}
+	if !found {
+		return image.Rectangle{}, false
+	}
+	return image.Rect(minX, minY, maxX, maxY), true
+}
+
 func TestWheelOfNamesBeta_SendsAnimationWithoutSpoilingCaption(t *testing.T) {
 	rb, _ := installMisc(t, 999)
 	rb.Bot.ProcessUpdate(context.Background(), testutil.NewPrivateMessage(7, "/wheelofnamesbeta Alice"))

internal/modules/misc/wheelofnames_beta_drawing.go

@@ -2,6 +2,7 @@ package misc
 
 import (
 	"image"
+	"image/color"
 	"math"
 	"strings"
 
@@ -11,8 +12,7 @@ import (
 )
 
 const (
-	wheelBetaSliceLabelRadius         = 64
-	wheelBetaSliceLabelBaselineOffset = 5
+	wheelBetaSliceLabelRadius = 64
 )
 
 func drawWheelSliceLabels(img *image.Paletted, options []string, rotation float64) {
@@ -25,10 +25,10 @@ func drawWheelSliceLabels(img *image.Paletted, options []string, rotation float6
 	for idx, option := range options {
 		angle := rotation + (float64(idx)+0.5)*segment
 		centerX := cx + int(math.Round(math.Cos(angle)*float64(wheelBetaSliceLabelRadius)))
-		baselineY := cy + int(math.Round(math.Sin(angle)*float64(wheelBetaSliceLabelRadius))) + wheelBetaSliceLabelBaselineOffset
+		centerY := cy + int(math.Round(math.Sin(angle)*float64(wheelBetaSliceLabelRadius)))
 		text := asciiWheelText(option, limit)
-		drawCenteredTextAt(img, text, centerX+1, baselineY+1, 2)
-		drawCenteredTextAt(img, text, centerX, baselineY, 1)
+		drawRotatedCenteredTextAt(img, text, centerX+1, centerY+1, angle, wheelBetaPaperColorIndex)
+		drawRotatedCenteredTextAt(img, text, centerX, centerY, angle, wheelBetaInkColorIndex)
 	}
 }
 
@@ -215,6 +215,38 @@ func drawCenteredTextAt(img *image.Paletted, text string, centerX, baselineY int
 	drawer.DrawString(text)
 }
 
+func drawRotatedCenteredTextAt(img *image.Paletted, text string, centerX, centerY int, angle float64, colorIndex byte) {
+	face := basicfont.Face7x13
+	padding := 2
+	metrics := face.Metrics()
+	textWidth := font.MeasureString(face, text).Ceil()
+	textHeight := metrics.Height.Ceil()
+	mask := image.NewAlpha(image.Rect(0, 0, textWidth+padding*2, textHeight+padding*2))
+	drawer := font.Drawer{
+		Dst:  mask,
+		Src:  image.NewUniform(color.Alpha{A: 255}),
+		Face: face,
+		Dot:  fixed.P(padding, padding+metrics.Ascent.Ceil()),
+	}
+	drawer.DrawString(text)
+
+	sourceCenterX := float64(mask.Bounds().Dx()-1) / 2
+	sourceCenterY := float64(mask.Bounds().Dy()-1) / 2
+	sin, cos := math.Sin(angle), math.Cos(angle)
+	for y := mask.Bounds().Min.Y; y < mask.Bounds().Max.Y; y++ {
+		for x := mask.Bounds().Min.X; x < mask.Bounds().Max.X; x++ {
+			if mask.AlphaAt(x, y).A == 0 {
+				continue
+			}
+			localX := float64(x) - sourceCenterX
+			localY := float64(y) - sourceCenterY
+			targetX := centerX + int(math.Round(localX*cos-localY*sin))
+			targetY := centerY + int(math.Round(localX*sin+localY*cos))
+			setWheelBetaPixel(img, targetX, targetY, colorIndex)
+		}
+	}
+}
+
 func asciiWheelText(s string, limit int) string {
 	var b strings.Builder
 	for _, r := range s {