Merge pull request fyne-io#4906 from andydotxyz/feature/textfont

Add support for setting a custom resource as the font source for text

canvas/text.go

@@ -21,6 +21,13 @@ type Text struct {
 	Text      string         // The string content of this Text
 	TextSize  float32        // Size of the text - if the Canvas scale is 1.0 this will be equivalent to point size
 	TextStyle fyne.TextStyle // The style of the text content
+
+	// FontSource defines a resource that can be used instead of the theme for looking up the font.
+	// When a font source is set the `TextStyle` may not be effective, as it will be limited to the styles
+	// present in the data provided.
+	//
+	// Since: 2.5
+	FontSource fyne.Resource
 }
 
 // Hide will set this text to not be visible
@@ -33,7 +40,8 @@ func (t *Text) Hide() {
 // MinSize returns the minimum size of this text object based on its font size and content.
 // This is normally determined by the render implementation.
 func (t *Text) MinSize() fyne.Size {
-	return fyne.MeasureText(t.Text, t.TextSize, t.TextStyle)
+	s, _ := fyne.CurrentApp().Driver().RenderedTextSize(t.Text, t.TextSize, t.TextStyle, t.FontSource)
+	return s
 }
 
 // Move the text to a new position, relative to its parent / canvas

canvas/text_test.go

@@ -1,6 +1,7 @@
 package canvas_test
 
 import (
+	"image"
 	"image/color"
 	"testing"
 
@@ -12,6 +13,22 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestText_FontSource(t *testing.T) {
+	text := canvas.NewText("Test", color.NRGBA{0, 0, 0, 0xff})
+	c := test.NewWindow(text).Canvas()
+
+	text.FontSource = test.Theme().Font(fyne.TextStyle{Bold: true})
+	img1 := c.Capture()
+	text.FontSource = test.Theme().Font(fyne.TextStyle{Italic: true})
+	img2 := c.Capture()
+	assert.NotEqual(t, img1.(*image.NRGBA).Pix, img2.(*image.NRGBA).Pix)
+
+	text.FontSource = fyne.NewStaticResource("corrupt", []byte{})
+	assert.NotPanics(t, func() {
+		test.NewWindow(text).Canvas().Capture()
+	})
+}
+
 func TestText_MinSize(t *testing.T) {
 	text := canvas.NewText("Test", color.NRGBA{0, 0, 0, 0xff})
 	min := text.MinSize()

driver.go

@@ -12,7 +12,8 @@ type Driver interface {
 
 	// RenderedTextSize returns the size required to render the given string of specified
 	// font size and style. It also returns the height to text baseline, measured from the top.
-	RenderedTextSize(text string, fontSize float32, style TextStyle) (size Size, baseline float32)
+	// If the source is specified it will be used, otherwise the current theme will be asked for the font.
+	RenderedTextSize(text string, fontSize float32, style TextStyle, source Resource) (size Size, baseline float32)
 
 	// CanvasForObject returns the canvas that is associated with a given CanvasObject.
 	CanvasForObject(CanvasObject) Canvas

internal/cache/text.go

@@ -19,14 +19,19 @@ type fontMetric struct {
 }
 
 type fontSizeEntry struct {
-	text  string
-	size  float32
-	style fyne.TextStyle
+	text   string
+	size   float32
+	style  fyne.TextStyle
+	custom string
 }
 
 // GetFontMetrics looks up a calculated size and baseline required for the specified text parameters.
-func GetFontMetrics(text string, fontSize float32, style fyne.TextStyle) (size fyne.Size, base float32) {
-	ent := fontSizeEntry{text, fontSize, style}
+func GetFontMetrics(text string, fontSize float32, style fyne.TextStyle, source fyne.Resource) (size fyne.Size, base float32) {
+	name := ""
+	if source != nil {
+		name = source.Name()
+	}
+	ent := fontSizeEntry{text, fontSize, style, name}
 	fontSizeLock.RLock()
 	ret, ok := fontSizeCache[ent]
 	fontSizeLock.RUnlock()
@@ -38,8 +43,12 @@ func GetFontMetrics(text string, fontSize float32, style fyne.TextStyle) (size f
 }
 
 // SetFontMetrics stores a calculated font size and baseline for parameters that were missing from the cache.
-func SetFontMetrics(text string, fontSize float32, style fyne.TextStyle, size fyne.Size, base float32) {
-	ent := fontSizeEntry{text, fontSize, style}
+func SetFontMetrics(text string, fontSize float32, style fyne.TextStyle, source fyne.Resource, size fyne.Size, base float32) {
+	name := ""
+	if source != nil {
+		name = source.Name()
+	}
+	ent := fontSizeEntry{text, fontSize, style, name}
 	metric := &fontMetric{size: size, baseLine: base}
 	metric.setAlive()
 	fontSizeLock.Lock()

internal/cache/text_test.go

@@ -11,14 +11,14 @@ func TestTextCacheGet(t *testing.T) {
 	ResetThemeCaches()
 	assert.Equal(t, 0, len(fontSizeCache))
 
-	bound, base := GetFontMetrics("hi", 10, fyne.TextStyle{})
+	bound, base := GetFontMetrics("hi", 10, fyne.TextStyle{}, nil)
 	assert.True(t, bound.IsZero())
 	assert.Equal(t, float32(0), base)
 
-	SetFontMetrics("hi", 10, fyne.TextStyle{}, fyne.NewSize(10, 10), 8)
+	SetFontMetrics("hi", 10, fyne.TextStyle{}, nil, fyne.NewSize(10, 10), 8)
 	assert.Equal(t, 1, len(fontSizeCache))
 
-	bound, base = GetFontMetrics("hi", 10, fyne.TextStyle{})
+	bound, base = GetFontMetrics("hi", 10, fyne.TextStyle{}, nil)
 	assert.Equal(t, fyne.NewSize(10, 10), bound)
 	assert.Equal(t, float32(8), base)
 }

internal/driver/glfw/driver.go

@@ -72,8 +72,8 @@ func toOSIcon(icon []byte) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-func (d *gLDriver) RenderedTextSize(text string, textSize float32, style fyne.TextStyle) (size fyne.Size, baseline float32) {
-	return painter.RenderedTextSize(text, textSize, style)
+func (d *gLDriver) RenderedTextSize(text string, textSize float32, style fyne.TextStyle, source fyne.Resource) (size fyne.Size, baseline float32) {
+	return painter.RenderedTextSize(text, textSize, style, source)
 }
 
 func (d *gLDriver) CanvasForObject(obj fyne.CanvasObject) fyne.Canvas {

internal/driver/mobile/driver.go

@@ -100,8 +100,8 @@ func (d *driver) currentWindow() *window {
 	return last
 }
 
-func (d *driver) RenderedTextSize(text string, textSize float32, style fyne.TextStyle) (size fyne.Size, baseline float32) {
-	return painter.RenderedTextSize(text, textSize, style)
+func (d *driver) RenderedTextSize(text string, textSize float32, style fyne.TextStyle, source fyne.Resource) (size fyne.Size, baseline float32) {
+	return painter.RenderedTextSize(text, textSize, style, source)
 }
 
 func (d *driver) CanvasForObject(obj fyne.CanvasObject) fyne.Canvas {

internal/painter/font.go

@@ -95,10 +95,26 @@ func lookupFaces(theme, fallback fyne.Resource, family string, style fyne.TextSt
 }
 
 // CachedFontFace returns a Font face held in memory. These are loaded from the current theme.
-func CachedFontFace(style fyne.TextStyle, fontDP float32, texScale float32) *FontCacheItem {
+func CachedFontFace(style fyne.TextStyle, source fyne.Resource, fontDP float32, texScale float32) *FontCacheItem {
+	if source != nil {
+		val, ok := fontCustomCache.Load(source)
+		if !ok {
+			face := loadMeasureFont(source)
+			if face == nil {
+				face = loadMeasureFont(theme.TextFont())
+			}
+			faces := &dynamicFontMap{family: source.Name(), faces: []font.Face{face}}
+
+			val = &FontCacheItem{Fonts: faces}
+			fontCustomCache.Store(source, val)
+		}
+		return val.(*FontCacheItem)
+	}
+
 	val, ok := fontCache.Load(style)
 	if !ok {
 		var faces *dynamicFontMap
+
 		switch {
 		case style.Monospace:
 			faces = lookupFaces(theme.TextMonospaceFont(), theme.DefaultTextMonospaceFont(), fontscan.Monospace, style)
@@ -137,8 +153,8 @@ func CachedFontFace(style fyne.TextStyle, fontDP float32, texScale float32) *Fon
 
 // ClearFontCache is used to remove cached fonts in the case that we wish to re-load Font faces
 func ClearFontCache() {
-
 	fontCache = &sync.Map{}
+	fontCustomCache = &sync.Map{}
 }
 
 // DrawString draws a string into an image.
@@ -184,14 +200,14 @@ func MeasureString(f shaping.Fontmap, s string, textSize float32, style fyne.Tex
 
 // RenderedTextSize looks up how big a string would be if drawn on screen.
 // It also returns the distance from top to the text baseline.
-func RenderedTextSize(text string, fontSize float32, style fyne.TextStyle) (size fyne.Size, baseline float32) {
-	size, base := cache.GetFontMetrics(text, fontSize, style)
+func RenderedTextSize(text string, fontSize float32, style fyne.TextStyle, source fyne.Resource) (size fyne.Size, baseline float32) {
+	size, base := cache.GetFontMetrics(text, fontSize, style, source)
 	if base != 0 {
 		return size, base
 	}
 
-	size, base = measureText(text, fontSize, style)
-	cache.SetFontMetrics(text, fontSize, style, size, base)
+	size, base = measureText(text, fontSize, style, source)
+	cache.SetFontMetrics(text, fontSize, style, source, size, base)
 	return size, base
 }
 
@@ -203,8 +219,8 @@ func float32ToFixed266(f float32) fixed.Int26_6 {
 	return fixed.Int26_6(float64(f) * (1 << 6))
 }
 
-func measureText(text string, fontSize float32, style fyne.TextStyle) (fyne.Size, float32) {
-	face := CachedFontFace(style, fontSize, 1)
+func measureText(text string, fontSize float32, style fyne.TextStyle, source fyne.Resource) (fyne.Size, float32) {
+	face := CachedFontFace(style, source, fontSize, 1)
 	return MeasureString(face.Fonts, text, fontSize, style)
 }
 
@@ -313,7 +329,8 @@ type FontCacheItem struct {
 	Fonts shaping.Fontmap
 }
 
-var fontCache = &sync.Map{} // map[fyne.TextStyle]*FontCacheItem
+var fontCache = &sync.Map{}       // map[fyne.TextStyle]*FontCacheItem
+var fontCustomCache = &sync.Map{} // map[string]*FontCacheItem for custom resources
 
 type noopLogger struct{}
 

internal/painter/font_test.go

@@ -27,7 +27,7 @@ func TestCachedFontFace(t *testing.T) {
 		},
 	} {
 		t.Run(name, func(t *testing.T) {
-			got := painter.CachedFontFace(tt.style, 14, 1)
+			got := painter.CachedFontFace(tt.style, nil, 14, 1)
 			for _, r := range tt.runes {
 				f := got.Fonts.ResolveFace(r)
 				assert.NotNil(t, f, "symbol Font should include: %c", r)
@@ -77,7 +77,7 @@ 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, tt.size, 1)
+			f := painter.CachedFontFace(tt.style, nil, tt.size, 1)
 
 			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})
@@ -117,7 +117,7 @@ func TestMeasureString(t *testing.T) {
 		},
 	} {
 		t.Run(name, func(t *testing.T) {
-			faces := painter.CachedFontFace(tt.style, tt.size, 1)
+			faces := painter.CachedFontFace(tt.style, nil, tt.size, 1)
 			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)
@@ -126,8 +126,8 @@ func TestMeasureString(t *testing.T) {
 }
 
 func TestRenderedTextSize(t *testing.T) {
-	size1, baseline1 := painter.RenderedTextSize("Hello World!", 20, fyne.TextStyle{})
-	size2, baseline2 := painter.RenderedTextSize("\rH\re\rl\rl\ro\r \rW\ro\rr\rl\rd\r!\r", 20, fyne.TextStyle{})
+	size1, baseline1 := painter.RenderedTextSize("Hello World!", 20, fyne.TextStyle{}, nil)
+	size2, baseline2 := painter.RenderedTextSize("\rH\re\rl\rl\ro\r \rW\ro\rr\rl\rd\r!\r", 20, fyne.TextStyle{}, nil)
 	assert.Equal(t, int(size1.Width), int(size2.Width))
 	assert.Equal(t, size1.Height, size2.Height)
 	assert.Equal(t, baseline1, baseline2)

internal/painter/gl/texture.go

@@ -153,7 +153,7 @@ 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.TextSize*p.canvas.Scale(), p.texScale)
+	face := paint.CachedFontFace(text.TextStyle, text.FontSource, text.TextSize*p.canvas.Scale(), p.texScale)
 	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

@@ -142,7 +142,7 @@ func drawText(c fyne.Canvas, text *canvas.Text, pos fyne.Position, base *image.N
 		color = theme.ForegroundColor()
 	}
 
-	face := painter.CachedFontFace(text.TextStyle, text.TextSize*c.Scale(), 1)
+	face := painter.CachedFontFace(text.TextStyle, text.FontSource, text.TextSize*c.Scale(), 1)
 	painter.DrawString(txtImg, text.Text, color, face.Fonts, text.TextSize, c.Scale(), text.TextStyle)
 
 	size := text.Size()

test/driver.go

@@ -95,8 +95,8 @@ func (d *driver) Device() fyne.Device {
 }
 
 // RenderedTextSize looks up how bit a string would be if drawn on screen
-func (d *driver) RenderedTextSize(text string, size float32, style fyne.TextStyle) (fyne.Size, float32) {
-	return painter.RenderedTextSize(text, size, style)
+func (d *driver) RenderedTextSize(text string, size float32, style fyne.TextStyle, source fyne.Resource) (fyne.Size, float32) {
+	return painter.RenderedTextSize(text, size, style, source)
 }
 
 func (d *driver) Run() {

text.go

@@ -64,7 +64,8 @@ type TextStyle struct {
 }
 
 // MeasureText uses the current driver to calculate the size of text when rendered.
+// The font used will be read from the current app's theme.
 func MeasureText(text string, size float32, style TextStyle) Size {
-	s, _ := CurrentApp().Driver().RenderedTextSize(text, size, style)
+	s, _ := CurrentApp().Driver().RenderedTextSize(text, size, style, nil)
 	return s
 }

widget/richtext.go

@@ -787,7 +787,7 @@ func (r *textRenderer) layoutRow(texts []fyne.CanvasObject, align fyne.TextAlign
 	for i, text := range texts {
 		var size fyne.Size
 		if txt, ok := text.(*canvas.Text); ok {
-			s, base := fyne.CurrentApp().Driver().RenderedTextSize(txt.Text, txt.TextSize, txt.TextStyle)
+			s, base := fyne.CurrentApp().Driver().RenderedTextSize(txt.Text, txt.TextSize, txt.TextStyle, txt.FontSource)
 			if base > tallestBaseline {
 				if tallestBaseline > 0 {
 					realign = true
@@ -799,7 +799,7 @@ func (r *textRenderer) layoutRow(texts []fyne.CanvasObject, align fyne.TextAlign
 		} else if c, ok := text.(*fyne.Container); ok {
 			wid := c.Objects[0]
 			if link, ok := wid.(*Hyperlink); ok {
-				s, base := fyne.CurrentApp().Driver().RenderedTextSize(link.Text, textSize, link.TextStyle)
+				s, base := fyne.CurrentApp().Driver().RenderedTextSize(link.Text, textSize, link.TextStyle, nil)
 				if base > tallestBaseline {
 					if tallestBaseline > 0 {
 						realign = true
@@ -1110,7 +1110,7 @@ func splitLines(seg *TextSegment) []rowBoundary {
 }
 
 func truncateLimit(s string, text *canvas.Text, limit int, ellipsis []rune) (int, bool) {
-	face := paint.CachedFontFace(text.TextStyle, text.TextSize, 1.0)
+	face := paint.CachedFontFace(text.TextStyle, text.FontSource, text.TextSize, 1.0)
 
 	runes := []rune(s)
 	in := shaping.Input{