widget/material: added support for Vertical axis to Slider

Adding an axis to the Float widget, allows positioning the Slider one not only horizontally but also vertically.
Also update the fill ops while there.

Signed-off-by: pierre <pierre.curto@gmail.com>

widget/material/slider.go

@@ -6,7 +6,6 @@ import (
 	"image"
 	"image/color"
 
-	"gioui.org/f32"
 	"gioui.org/internal/f32color"
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -36,34 +35,26 @@ type SliderStyle struct {
 }
 
 func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
-	thumbRadiusInt := gtx.Px(unit.Dp(6))
-	trackWidth := float32(gtx.Px(unit.Dp(2)))
-	thumbRadius := float32(thumbRadiusInt)
+	thumbRadius := gtx.Px(unit.Dp(6))
+	trackWidth := gtx.Px(unit.Dp(2))
 
-	size := gtx.Constraints.Min
+	axis := s.Float.Axis
 	// Keep a minimum length so that the track is always visible.
-	minLength := thumbRadiusInt + 3*thumbRadiusInt + thumbRadiusInt
-	if size.X < minLength {
-		size.X = minLength
-	}
-	size.Y = 2 * thumbRadiusInt
-
+	minLength := thumbRadius + 3*thumbRadius + thumbRadius
 	// Try to expand to finger size, but only if the constraints
 	// allow for it.
-	touchSizePx := gtx.Px(s.FingerSize)
-	if touchSizePx > gtx.Constraints.Max.Y {
-		touchSizePx = gtx.Constraints.Max.Y
-	}
-	if size.Y < touchSizePx {
-		size.Y = 2 * (touchSizePx / 2)
-	}
+	touchSizePx := min(gtx.Px(s.FingerSize), axis.Convert(gtx.Constraints.Max).Y)
+	sizeMain := max(axis.Convert(gtx.Constraints.Min).X, minLength)
+	sizeCross := max(2*thumbRadius, touchSizePx)
+	size := axis.Convert(image.Pt(sizeMain, sizeCross))
 
 	st := op.Save(gtx.Ops)
-	op.Offset(f32.Pt(thumbRadius, 0)).Add(gtx.Ops)
-	gtx.Constraints.Min = image.Pt(size.X-2*thumbRadiusInt, size.Y)
-	s.Float.Layout(gtx, thumbRadiusInt, s.Min, s.Max)
-	gtx.Constraints.Min.Y = size.Y
-	thumbPos := thumbRadius + s.Float.Pos()
+	o := axis.Convert(image.Pt(thumbRadius, 0))
+	op.Offset(layout.FPt(o)).Add(gtx.Ops)
+	gtx.Constraints.Min = axis.Convert(image.Pt(sizeMain-2*thumbRadius, sizeCross))
+	s.Float.Layout(gtx, thumbRadius, s.Min, s.Max)
+	gtx.Constraints.Min = gtx.Constraints.Min.Add(axis.Convert(image.Pt(0, sizeCross)))
+	thumbPos := thumbRadius + int(s.Float.Pos())
 	st.Load()
 
 	color := s.Color
@@ -73,50 +64,49 @@ func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
 
 	// Draw track before thumb.
 	st = op.Save(gtx.Ops)
-	track := f32.Rectangle{
-		Min: f32.Point{
-			X: thumbRadius,
-			Y: float32(size.Y/2) - trackWidth/2,
-		},
-		Max: f32.Point{
-			X: thumbPos,
-			Y: float32(size.Y/2) + trackWidth/2,
-		},
+	track := image.Rectangle{
+		Min: axis.Convert(image.Pt(thumbRadius, sizeCross/2-trackWidth/2)),
+		Max: axis.Convert(image.Pt(thumbPos, sizeCross/2+trackWidth/2)),
 	}
-	clip.RRect{Rect: track}.Add(gtx.Ops)
-	paint.ColorOp{Color: color}.Add(gtx.Ops)
-	paint.PaintOp{}.Add(gtx.Ops)
+	clip.Rect(track).Add(gtx.Ops)
+	paint.Fill(gtx.Ops, color)
 	st.Load()
 
 	// Draw track after thumb.
 	st = op.Save(gtx.Ops)
-	track.Min.X = thumbPos
-	track.Max.X = float32(size.X) - thumbRadius
-	clip.RRect{Rect: track}.Add(gtx.Ops)
-	paint.ColorOp{Color: f32color.MulAlpha(color, 96)}.Add(gtx.Ops)
-	paint.PaintOp{}.Add(gtx.Ops)
+	track = image.Rectangle{
+		Min: axis.Convert(image.Pt(thumbPos, axis.Convert(track.Min).Y)),
+		Max: axis.Convert(image.Pt(sizeMain-thumbRadius, axis.Convert(track.Max).Y)),
+	}
+	clip.Rect(track).Add(gtx.Ops)
+	paint.Fill(gtx.Ops, f32color.MulAlpha(color, 96))
 	st.Load()
 
 	// Draw thumb.
 	st = op.Save(gtx.Ops)
-	thumb := f32.Rectangle{
-		Min: f32.Point{
-			X: thumbPos - thumbRadius,
-			Y: float32(size.Y/2) - thumbRadius,
-		},
-		Max: f32.Point{
-			X: thumbPos + thumbRadius,
-			Y: float32(size.Y/2) + thumbRadius,
-		},
+	pt := axis.Convert(image.Pt(thumbPos, sizeCross/2))
+	rpt := image.Pt(thumbRadius, thumbRadius)
+	thumb := image.Rectangle{
+		Min: pt.Sub(rpt),
+		Max: pt.Add(rpt),
 	}
-	rr := thumbRadius
-	clip.RRect{
-		Rect: thumb,
-		NE:   rr, NW: rr, SE: rr, SW: rr,
-	}.Add(gtx.Ops)
-	paint.ColorOp{Color: color}.Add(gtx.Ops)
-	paint.PaintOp{}.Add(gtx.Ops)
+	clip.UniformRRect(layout.FRect(thumb), float32(thumbRadius)).Add(gtx.Ops)
+	paint.Fill(gtx.Ops, color)
 	st.Load()
 
 	return layout.Dimensions{Size: size}
 }
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}