fix(examples): font loading on different os

Author: fumiama

.github/workflows/ci.yml

@@ -61,6 +61,13 @@ jobs:
           find . -name "*.cpp" -type f -delete
         shell: bash
 
+      - name: Install Microsoft core fonts
+        if: runner.os == 'Linux'
+        run: |
+          echo ttf-mscorefonts-installer msttcorefonts/accepted-mscorefonts-eula select true | sudo debconf-set-selections
+          sudo apt-get update -q
+          sudo apt-get install -y ttf-mscorefonts-installer
+
       - name: Run examples
         shell: bash
         run: go test -v -count=1 ./...

examples/fonts_test.go

@@ -0,0 +1,38 @@
+package main
+
+import "runtime"
+
+// fontPath returns the OS-specific file path for a given font name.
+// Supported names: "Impact", "Arial", "Arial Bold".
+func fontPath(name string) string {
+	switch runtime.GOOS {
+	case "windows":
+		switch name {
+		case "Impact":
+			return `C:\Windows\Fonts\impact.ttf`
+		case "Arial":
+			return `C:\Windows\Fonts\arial.ttf`
+		case "Arial Bold":
+			return `C:\Windows\Fonts\arialbd.ttf`
+		}
+	case "darwin":
+		switch name {
+		case "Impact":
+			return "/System/Library/Fonts/Supplemental/Impact.ttf"
+		case "Arial":
+			return "/System/Library/Fonts/Supplemental/Arial.ttf"
+		case "Arial Bold":
+			return "/System/Library/Fonts/Supplemental/Arial Bold.ttf"
+		}
+	default: // linux, freebsd, etc.
+		switch name {
+		case "Impact":
+			return "/usr/share/fonts/truetype/msttcorefonts/Impact.ttf"
+		case "Arial":
+			return "/usr/share/fonts/truetype/msttcorefonts/Arial.ttf"
+		case "Arial Bold":
+			return "/usr/share/fonts/truetype/msttcorefonts/Arial_Bold.ttf"
+		}
+	}
+	return name
+}

examples/gradient-text_test.go

@@ -16,7 +16,7 @@ func TestGT(*testing.T) {
 
 	// draw text
 	dc.SetRGB(0, 0, 0)
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Impact.ttf", 128); err != nil {
+	if err := dc.LoadFontFace(fontPath("Impact"), 128); err != nil {
 		panic(err)
 	}
 	dc.DrawStringAnchored("Gradient Text", W/2, H/2, 0.5, 0.5)

examples/meme_test.go

@@ -11,7 +11,7 @@ func TestMeme(*testing.T) {
 	dc := gg.NewContext(S, S)
 	dc.SetRGB(1, 1, 1)
 	dc.Clear()
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Impact.ttf", 96); err != nil {
+	if err := dc.LoadFontFace(fontPath("Impact"), 96); err != nil {
 		panic(err)
 	}
 	dc.SetRGB(0, 0, 0)

examples/quadratic_test.go

@@ -50,7 +50,7 @@ func TestQuadratic(*testing.T) {
 	dc.SetLineWidth(4)
 	dc.Stroke()
 
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Arial.ttf", 200); err != nil {
+	if err := dc.LoadFontFace(fontPath("Arial"), 200); err != nil {
 		panic(err)
 	}
 	dc.DrawStringAnchored("g", -5, 5, 0.5, 0.5)

examples/scatter_test.go

@@ -55,11 +55,11 @@ func TestScatter(*testing.T) {
 	// draw text
 	dc.Identity()
 	dc.SetRGB(0, 0, 0)
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Arial Bold.ttf", 24); err != nil {
+	if err := dc.LoadFontFace(fontPath("Arial Bold"), 24); err != nil {
 		panic(err)
 	}
 	dc.DrawStringAnchored("Chart Title", S/2, P/2, 0.5, 0.5)
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Arial.ttf", 18); err != nil {
+	if err := dc.LoadFontFace(fontPath("Arial"), 18); err != nil {
 		panic(err)
 	}
 	dc.DrawStringAnchored("X Axis Title", S/2, S-P/2, 0.5, 0.5)

examples/text_test.go

@@ -13,7 +13,7 @@ func TestText(*testing.T) {
 	dc.Clear()
 	dc.SetRGB(0, 0, 0)
 	// 字体路径
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Arial.ttf", 96); err != nil {
+	if err := dc.LoadFontFace(fontPath("Arial"), 96); err != nil {
 		panic(err)
 	}
 	dc.DrawStringAnchored("Hello, world!", S/2, S/2, 0.5, 0.5)

examples/unicode_test.go

@@ -14,7 +14,7 @@ func TestUnicode(*testing.T) {
 	dc.SetRGB(1, 1, 1)
 	dc.Clear()
 	dc.SetRGB(0, 0, 0)
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Impact.ttf", F); err != nil {
+	if err := dc.LoadFontFace(fontPath("Impact"), F); err != nil {
 		panic(err)
 	}
 	for r := range 256 {

examples/wrap_test.go

@@ -22,7 +22,7 @@ func TestWrap(*testing.T) {
 	dc.SetLineWidth(3)
 	dc.Stroke()
 	dc.SetRGB(0, 0, 0)
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Arial Bold.ttf", 18); err != nil {
+	if err := dc.LoadFontFace(fontPath("Arial Bold"), 18); err != nil {
 		panic(err)
 	}
 	dc.DrawStringWrapped("UPPER LEFT", P, P, 0, 0, 0, 1.5, gg.AlignLeft)
@@ -33,7 +33,7 @@ func TestWrap(*testing.T) {
 	dc.DrawStringWrapped("LOWER MIDDLE", W/2, H-P, 0.5, 1, 0, 1.5, gg.AlignCenter)
 	dc.DrawStringWrapped("LEFT MIDDLE", P, H/2, 0, 0.5, 0, 1.5, gg.AlignLeft)
 	dc.DrawStringWrapped("RIGHT MIDDLE", W-P, H/2, 1, 0.5, 0, 1.5, gg.AlignRight)
-	if err := dc.LoadFontFace("/System/Library/Fonts/Supplemental/Arial.ttf", 12); err != nil {
+	if err := dc.LoadFontFace(fontPath("Arial"), 12); err != nil {
 		panic(err)
 	}
 	dc.DrawStringWrapped(TEXT, W/2-P, H/2-P, 1, 1, W/3, 1.75, gg.AlignLeft)