widget/material: allow configuring default typeface on theme

This commit introduces the material.Theme.Face field, which will automatically
populate the Font.Typeface in every text widget created using a constructor function
in package material.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>

widget/material/button.go

@@ -51,7 +51,7 @@ type IconButtonStyle struct {
 }
 
 func Button(th *Theme, button *widget.Clickable, txt string) ButtonStyle {
-	return ButtonStyle{
+	b := ButtonStyle{
 		Text:         txt,
 		Color:        th.Palette.ContrastFg,
 		CornerRadius: 4,
@@ -64,6 +64,8 @@ func Button(th *Theme, button *widget.Clickable, txt string) ButtonStyle {
 		Button: button,
 		shaper: th.Shaper,
 	}
+	b.Font.Typeface = th.Face
+	return b
 }
 
 func ButtonLayout(th *Theme, button *widget.Clickable) ButtonLayoutStyle {

widget/material/checkbox.go

@@ -14,7 +14,7 @@ type CheckBoxStyle struct {
 }
 
 func CheckBox(th *Theme, checkBox *widget.Bool, label string) CheckBoxStyle {
-	return CheckBoxStyle{
+	c := CheckBoxStyle{
 		CheckBox: checkBox,
 		checkable: checkable{
 			Label:              label,
@@ -27,6 +27,8 @@ func CheckBox(th *Theme, checkBox *widget.Bool, label string) CheckBoxStyle {
 			uncheckedStateIcon: th.Icon.CheckBoxUnchecked,
 		},
 	}
+	c.checkable.Font.Typeface = th.Face
+	return c
 }
 
 // Layout updates the checkBox and displays it.

widget/material/editor.go

@@ -33,7 +33,10 @@ type EditorStyle struct {
 
 func Editor(th *Theme, editor *widget.Editor, hint string) EditorStyle {
 	return EditorStyle{
-		Editor:         editor,
+		Editor: editor,
+		Font: font.Font{
+			Typeface: th.Face,
+		},
 		TextSize:       th.TextSize,
 		Color:          th.Palette.Fg,
 		shaper:         th.Shaper,

widget/material/label.go

@@ -105,13 +105,15 @@ func Overline(th *Theme, txt string) LabelStyle {
 }
 
 func Label(th *Theme, size unit.Sp, txt string) LabelStyle {
-	return LabelStyle{
+	l := LabelStyle{
 		Text:           txt,
 		Color:          th.Palette.Fg,
 		SelectionColor: f32color.MulAlpha(th.Palette.ContrastBg, 0x60),
 		TextSize:       size,
 		Shaper:         th.Shaper,
 	}
+	l.Font.Typeface = th.Face
+	return l
 }
 
 func (l LabelStyle) Layout(gtx layout.Context) layout.Dimensions {

widget/material/radiobutton.go

@@ -17,7 +17,7 @@ type RadioButtonStyle struct {
 // RadioButton returns a RadioButton with a label. The key specifies
 // the value for the Enum.
 func RadioButton(th *Theme, group *widget.Enum, key, label string) RadioButtonStyle {
-	return RadioButtonStyle{
+	r := RadioButtonStyle{
 		Group: group,
 		checkable: checkable{
 			Label: label,
@@ -32,6 +32,8 @@ func RadioButton(th *Theme, group *widget.Enum, key, label string) RadioButtonSt
 		},
 		Key: key,
 	}
+	r.checkable.Font.Typeface = th.Face
+	return r
 }
 
 // Layout updates enum and displays the radio button.

widget/material/theme.go

@@ -7,6 +7,7 @@ import (
 
 	"golang.org/x/exp/shiny/materialdesign/icons"
 
+	"gioui.org/font"
 	"gioui.org/text"
 	"gioui.org/unit"
 	"gioui.org/widget"
@@ -41,6 +42,8 @@ type Theme struct {
 		RadioChecked      *widget.Icon
 		RadioUnchecked    *widget.Icon
 	}
+	// Face selects the default typeface for text.
+	Face font.Typeface
 
 	// FingerSize is the minimum touch target size.
 	FingerSize unit.Dp