ttc fonts supported

internal/painter/font.go

@@ -71,10 +71,17 @@ func lookupRuneFont(r rune, family string, aspect font.Aspect) *font.Face {
 func lookupFaces(theme, fallback, emoji fyne.Resource, family string, style fyne.TextStyle) (faces *dynamicFontMap) {
 	f1 := loadMeasureFont(theme)
 	if theme == fallback {
+		if f1 == nil {
+			return nil
+		}
 		faces = &dynamicFontMap{family: family, faces: []*font.Face{f1}}
 	} else {
 		f2 := loadMeasureFont(fallback)
-		faces = &dynamicFontMap{family: family, faces: []*font.Face{f1, f2}}
+		if f1 == nil {
+			faces = &dynamicFontMap{family: family, faces: []*font.Face{f2}}
+		} else {
+			faces = &dynamicFontMap{family: family, faces: []*font.Face{f1, f2}}
+		}
 	}
 
 	aspect := font.Aspect{Style: font.StyleNormal}
@@ -152,6 +159,9 @@ func CachedFontFace(style fyne.TextStyle, source fyne.Resource, o fyne.CanvasObj
 		default:
 			faces = lookupFaces(font1, theme.DefaultTextFont(), emoji, fontscan.SansSerif, style)
 		}
+		if faces == nil {
+			return nil
+		}
 
 		val = &FontCacheItem{Fonts: faces}
 		fontCache.Store(cacheID{style: style, scope: scope}, val)
@@ -192,13 +202,13 @@ func DrawString(dst draw.Image, s string, color color.Color, f shaping.Fontmap,
 }
 
 func loadMeasureFont(data fyne.Resource) *font.Face {
-	loaded, err := font.ParseTTF(bytes.NewReader(data.Content()))
+	loaded, err := font.ParseTTC(bytes.NewReader(data.Content()))
 	if err != nil {
 		fyne.LogError("font load error", err)
 		return nil
 	}
 
-	return loaded
+	return loaded[0]
 }
 
 // MeasureString returns how far dot would advance by drawing s with f.
@@ -230,6 +240,9 @@ func float32ToFixed266(f float32) fixed.Int26_6 {
 
 func measureText(text string, fontSize float32, style fyne.TextStyle, source fyne.Resource) (fyne.Size, float32) {
 	face := CachedFontFace(style, source, nil)
+	if face == nil {
+		return fyne.NewSize(0, 0), 0
+	}
 	return MeasureString(face.Fonts, text, fontSize, style)
 }
 

internal/painter/font_test.go

@@ -28,6 +28,7 @@ func TestCachedFontFace(t *testing.T) {
 	} {
 		t.Run(name, func(t *testing.T) {
 			got := painter.CachedFontFace(tt.style, nil, nil)
+			assert.NotNil(t, got, "Font not loaded")
 			for _, r := range tt.runes {
 				f := got.Fonts.ResolveFace(r)
 				assert.NotNil(t, f, "symbol Font should include: %c", r)
@@ -78,6 +79,7 @@ func TestDrawString(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			img := image.NewNRGBA(image.Rect(0, 0, 300, 100))
 			f := painter.CachedFontFace(tt.style, nil, nil)
+			assert.NotNil(t, f, "Font not loaded")
 
 			fontMap := &intTest.FontMap{f.Fonts.ResolveFace(' ')} // first (ascii) font
 			painter.DrawString(img, tt.string, tt.color, fontMap, tt.size, 1, fyne.TextStyle{TabWidth: tt.tabWidth})
@@ -118,6 +120,7 @@ func TestMeasureString(t *testing.T) {
 	} {
 		t.Run(name, func(t *testing.T) {
 			faces := painter.CachedFontFace(tt.style, nil, nil)
+			assert.NotNil(t, faces, "Font not loaded")
 			fontMap := &intTest.FontMap{faces.Fonts.ResolveFace(' ')} // first (ascii) font
 			got, _ := painter.MeasureString(fontMap, tt.string, tt.size, fyne.TextStyle{TabWidth: tt.tabWidth})
 			assert.Equal(t, tt.want, got.Width)

internal/painter/gl/texture.go

@@ -172,8 +172,9 @@ func (p *painter) newGlTextTexture(obj fyne.CanvasObject) Texture {
 	height := int(math.Ceil(float64(p.textureScale(bounds.Height))))
 	img := image.NewNRGBA(image.Rect(0, 0, width, height))
 
-	face := paint.CachedFontFace(text.TextStyle, text.FontSource, text)
-	paint.DrawString(img, text.Text, color, face.Fonts, text.TextSize, p.pixScale, text.TextStyle)
+	if face := paint.CachedFontFace(text.TextStyle, text.FontSource, text); face != nil {
+		paint.DrawString(img, text.Text, color, face.Fonts, text.TextSize, p.pixScale, text.TextStyle)
+	}
 	return p.imgToTexture(img, canvas.ImageScaleSmooth)
 }
 

internal/painter/software/draw.go

@@ -142,8 +142,9 @@ func drawText(c fyne.Canvas, text *canvas.Text, pos fyne.Position, base *image.N
 		color = theme.Color(theme.ColorNameForeground)
 	}
 
-	face := painter.CachedFontFace(text.TextStyle, text.FontSource, text)
-	painter.DrawString(txtImg, text.Text, color, face.Fonts, text.TextSize, c.Scale(), text.TextStyle)
+	if face := painter.CachedFontFace(text.TextStyle, text.FontSource, text); face != nil {
+		painter.DrawString(txtImg, text.Text, color, face.Fonts, text.TextSize, c.Scale(), text.TextStyle)
+	}
 
 	size := text.Size()
 	offsetX := float32(0)

internal/test/util_test.go

@@ -25,10 +25,10 @@ func TestAssertImageMatches(t *testing.T) {
 	draw.Draw(img, bounds, image.NewUniform(color.White), image.Point{}, draw.Src)
 
 	txtImg := image.NewNRGBA(bounds)
-	face, err := font.ParseTTF(bytes.NewReader(theme.TextFont().Content()))
+	face, err := font.ParseTTC(bytes.NewReader(theme.TextFont().Content()))
 	assert.Nil(t, err)
 
-	painter.DrawString(txtImg, "Hello!", color.Black, &test.FontMap{face}, 25, 1, fyne.TextStyle{TabWidth: 4})
+	painter.DrawString(txtImg, "Hello!", color.Black, &test.FontMap{face[0]}, 25, 1, fyne.TextStyle{TabWidth: 4})
 	draw.Draw(img, bounds, txtImg, image.Point{}, draw.Over)
 
 	tt := &testing.T{}

internal/theme/theme.go

@@ -1,9 +1,11 @@
 package theme
 
 import (
+	"bytes"
 	"image/color"
 
 	"fyne.io/fyne/v2"
+	"github.com/go-text/typesetting/font"
 )
 
 // Primary color names.
@@ -91,3 +93,10 @@ func PrimaryColorNamed(name string) color.Color {
 	// There is no need to have it in the switch above.
 	return colorLightPrimaryBlue
 }
+
+// CheckFontParsable checks whether a resource is a valid font.
+// It mimics internal/painter.loadMeasureFont
+func CheckFontParsable(data fyne.Resource) error {
+	_, err := font.ParseTTC(bytes.NewReader(data.Content()))
+	return err
+}

theme/theme.go

@@ -204,6 +204,11 @@ func CurrentForWidget(w fyne.CanvasObject) fyne.Theme {
 	return Current()
 }
 
+// CheckFontParsable checks whether a resource is a valid font.
+func CheckFontParsable(data fyne.Resource) error {
+	return internaltheme.CheckFontParsable(data)
+}
+
 func currentVariant() fyne.ThemeVariant {
 	if std, ok := Current().(*builtinTheme); ok {
 		if std.variant != internaltheme.VariantNameUserPreference {

theme/theme_test.go

@@ -107,3 +107,25 @@ func (e *emptyTheme) Icon(n fyne.ThemeIconName) fyne.Resource {
 func (e *emptyTheme) Size(n fyne.ThemeSizeName) float32 {
 	return 0
 }
+
+func TestCheckFontParsable(t *testing.T) {
+	for name, tt := range map[string]struct {
+		fn string
+		ok bool
+	}{
+		"ttf": {"./testdata/NotoMono-Regular.ttf", true},
+		"ttc": {"./testdata/Sitka.ttc", true},
+		"otf": {"./testdata/teamviewer14.otf", true},
+		"fon": {"./testdata/smaller.fon", false},
+	} {
+		t.Run(name, func(t *testing.T) {
+			res, err := fyne.LoadResourceFromPath(tt.fn)
+			assert.Nil(t, err)
+			checkFunc := assert.Nil
+			if !tt.ok {
+				checkFunc = assert.NotNil
+			}
+			checkFunc(t, theme.CheckFontParsable(res))
+		})
+	}
+}

widget/richtext.go

@@ -1113,6 +1113,9 @@ func splitLines(seg *TextSegment) []rowBoundary {
 
 func truncateLimit(s string, text *canvas.Text, limit int, ellipsis []rune) (int, bool) {
 	face := paint.CachedFontFace(text.TextStyle, text.FontSource, text)
+	if face == nil {
+		return 0, true
+	}
 
 	runes := []rune(s)
 	in := shaping.Input{