vector: add FillCircle and StrokeCircle

Updates #2387

ebitenutil/shapes.go

@@ -17,7 +17,6 @@ package ebitenutil
 import (
 	"image"
 	"image/color"
-	"math"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/vector"
@@ -53,20 +52,8 @@ func DrawRect(dst *ebiten.Image, x, y, width, height float64, clr color.Color) {
 // DrawCircle draws a circle on given destination dst.
 //
 // DrawCircle is intended to be used mainly for debugging or prototyping purpose.
+//
+// Deprecated: as of v2.5. Use vector.FillCircle instead.
 func DrawCircle(dst *ebiten.Image, cx, cy, r float64, clr color.Color) {
-	var path vector.Path
+	vector.FillCircle(dst, float32(cx), float32(cy), float32(r), clr)
-	rd, g, b, a := clr.RGBA()
-
-	path.Arc(float32(cx), float32(cy), float32(r), 0, 2*math.Pi, vector.Clockwise)
-
-	vertices, indices := path.AppendVerticesAndIndicesForFilling(nil, nil)
-	for i := range vertices {
-		vertices[i].SrcX = 1
-		vertices[i].SrcY = 1
-		vertices[i].ColorR = float32(rd) / 0xffff
-		vertices[i].ColorG = float32(g) / 0xffff
-		vertices[i].ColorB = float32(b) / 0xffff
-		vertices[i].ColorA = float32(a) / 0xffff
-	}
-	dst.DrawTriangles(vertices, indices, whiteSubImage, nil)
 }

examples/audio/main.go

@@ -343,9 +343,9 @@ func (p *Player) draw(screen *ebiten.Image) {
 
 	// Draw the cursor on the bar.
 	c := p.current
-	cx := float64(x) + float64(w)*float64(p.current)/float64(p.total)
+	cx := float32(x) + float32(w)*float32(p.current)/float32(p.total)
-	cy := float64(y) + float64(h)/2
+	cy := float32(y) + float32(h)/2
-	ebitenutil.DrawCircle(screen, cx, cy, 12, playerCurrentColor)
+	vector.FillCircle(screen, cx, cy, 12, playerCurrentColor)
 
 	// Compose the curren time text.
 	m := (c / time.Minute) % 100

examples/shapes/main.go

@@ -46,10 +46,13 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	cf := float32(g.count)
 	vector.StrokeLine(screen, 100, 100, 300, 100, 1, color.RGBA{0xff, 0xff, 0xff, 0xff})
 	vector.StrokeLine(screen, 50, 150, 50, 350, 1, color.RGBA{0xff, 0xff, 0x00, 0xff})
-	vector.StrokeLine(screen, 50, 100+float32(cf), 200+float32(cf), 250, 4, color.RGBA{0x00, 0xff, 0xff, 0xff})
+	vector.StrokeLine(screen, 50, 100+cf, 200+cf, 250, 4, color.RGBA{0x00, 0xff, 0xff, 0xff})
 
-	vector.FillRect(screen, 50+float32(cf), 50+float32(cf), 100+float32(cf), 100+float32(cf), color.RGBA{0x80, 0x80, 0x80, 0xff})
+	vector.FillRect(screen, 50+cf, 50+cf, 100+cf, 100+cf, color.RGBA{0x80, 0x80, 0x80, 0xc0})
-	vector.StrokeRect(screen, 300-float32(cf), 50, 120, 120, 10, color.RGBA{0x00, 0x80, 0x00, 0xff})
+	vector.StrokeRect(screen, 300-cf, 50, 120, 120, 10+cf/4, color.RGBA{0x00, 0x80, 0x00, 0xff})
+
+	vector.FillCircle(screen, 400, 400, 100, color.RGBA{0x80, 0x00, 0x80, 0x80})
+	vector.StrokeCircle(screen, 400, 400, 10+cf, 10+cf/2, color.RGBA{0xff, 0x80, 0xff, 0xff})
 
 	ebitenutil.DebugPrint(screen, fmt.Sprintf("TPS: %0.2f", ebiten.ActualTPS()))
 }

vector/util.go

@@ -17,6 +17,7 @@ package vector
 import (
 	"image"
 	"image/color"
+	"math"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
@@ -30,7 +31,7 @@ func init() {
 	whiteImage.Fill(color.White)
 }
 
-func updateVerticesForUtil(vs []ebiten.Vertex, clr color.Color) {
+func drawVerticesForUtil(dst *ebiten.Image, vs []ebiten.Vertex, is []uint16, clr color.Color) {
 	r, g, b, a := clr.RGBA()
 	for i := range vs {
 		vs[i].SrcX = 1
@@ -40,6 +41,11 @@ func updateVerticesForUtil(vs []ebiten.Vertex, clr color.Color) {
 		vs[i].ColorB = float32(b) / 0xffff
 		vs[i].ColorA = float32(a) / 0xffff
 	}
+
+	op := &ebiten.DrawTrianglesOptions{}
+	op.ColorScaleFormat = ebiten.ColorScaleFormatPremultipliedAlpha
+	op.AntiAlias = true
+	dst.DrawTriangles(vs, is, whiteSubImage, op)
 }
 
 // StrokeLine strokes a line (x0, y0)-(x1, y1) with the specified width and color.
@@ -51,12 +57,7 @@ func StrokeLine(dst *ebiten.Image, x0, y0, x1, y1 float32, strokeWidth float32,
 	strokeOp.Width = strokeWidth
 	vs, is := path.AppendVerticesAndIndicesForStroke(nil, nil, strokeOp)
 
-	updateVerticesForUtil(vs, clr)
+	drawVerticesForUtil(dst, vs, is, clr)
-
-	op := &ebiten.DrawTrianglesOptions{}
-	op.ColorScaleFormat = ebiten.ColorScaleFormatPremultipliedAlpha
-	op.AntiAlias = true
-	dst.DrawTriangles(vs, is, whiteSubImage, op)
 }
 
 // FillRect fills a rectangle with the specified width and color.
@@ -68,12 +69,7 @@ func FillRect(dst *ebiten.Image, x, y, width, height float32, clr color.Color) {
 	path.LineTo(x+width, y)
 	vs, is := path.AppendVerticesAndIndicesForFilling(nil, nil)
 
-	updateVerticesForUtil(vs, clr)
+	drawVerticesForUtil(dst, vs, is, clr)
-
-	op := &ebiten.DrawTrianglesOptions{}
-	op.ColorScaleFormat = ebiten.ColorScaleFormatPremultipliedAlpha
-	op.AntiAlias = true
-	dst.DrawTriangles(vs, is, whiteSubImage, op)
 }
 
 // StrokeRect strokes a rectangle with the specified width and color.
@@ -92,10 +88,29 @@ func StrokeRect(dst *ebiten.Image, x, y, width, height float32, strokeWidth floa
 	strokeOp.MiterLimit = 10
 	vs, is := path.AppendVerticesAndIndicesForStroke(nil, nil, strokeOp)
 
-	updateVerticesForUtil(vs, clr)
+	drawVerticesForUtil(dst, vs, is, clr)
-
+}
-	op := &ebiten.DrawTrianglesOptions{}
+
-	op.ColorScaleFormat = ebiten.ColorScaleFormatPremultipliedAlpha
+// FillCircle filles a circle with the specified center position (cx, cy), the radius (r), width and color.
-	op.AntiAlias = true
+func FillCircle(dst *ebiten.Image, cx, cy, r float32, clr color.Color) {
-	dst.DrawTriangles(vs, is, whiteSubImage, op)
+	var path Path
+	path.Arc(float32(cx), float32(cy), float32(r), 0, 2*math.Pi, Clockwise)
+	vs, is := path.AppendVerticesAndIndicesForFilling(nil, nil)
+
+	drawVerticesForUtil(dst, vs, is, clr)
+}
+
+// StrokeCircle strokes a circle with the specified center position (cx, cy), the radius (r), width and color.
+//
+// clr has be to be a solid (non-transparent) color.
+func StrokeCircle(dst *ebiten.Image, cx, cy, r float32, strokeWidth float32, clr color.Color) {
+	var path Path
+	path.Arc(float32(cx), float32(cy), float32(r), 0, 2*math.Pi, Clockwise)
+	path.Close()
+
+	strokeOp := &StrokeOptions{}
+	strokeOp.Width = strokeWidth
+	vs, is := path.AppendVerticesAndIndicesForStroke(nil, nil, strokeOp)
+
+	drawVerticesForUtil(dst, vs, is, clr)
 }