Move font helpers to fonts.go

fonts.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"io/ioutil"
+	"log"
+
+	"github.com/flopp/go-findfont"
+	"github.com/golang/freetype"
+	"github.com/golang/freetype/truetype"
+	"golang.org/x/image/font"
+)
+
+var (
+	ttfFont     *truetype.Font
+	ttfThinFont *truetype.Font
+	ttfBoldFont *truetype.Font
+)
+
+// maxPointSize returns the maximum point size we can use to fit text inside width and height
+// as well as the resulting text-width in pixels.
+func maxPointSize(text string, c *freetype.Context, width, height int) (float64, int) {
+	// never let the font size exceed the requested height
+	fontsize := 72.0
+	for c.PointToFixed(fontsize).Round() > height {
+		fontsize -= 1
+	}
+
+	// offset initial loop iteration
+	fontsize += 1
+
+	// find the biggest matching font size for the requested width
+	var actwidth int
+	for actwidth = width + 1; actwidth > width; fontsize -= 1 {
+		c.SetFontSize(fontsize)
+
+		textExtent, err := c.DrawString(text, freetype.Pt(0, 0))
+		if err != nil {
+			return 0, 0
+		}
+
+		actwidth = textExtent.X.Round()
+	}
+
+	return fontsize, actwidth
+}
+
+func fontByName(font string) *truetype.Font {
+	switch font {
+	case "thin":
+		return ttfThinFont
+	case "regular":
+		return ttfFont
+	case "bold":
+		return ttfBoldFont
+	default:
+		return ttfFont
+	}
+}
+
+func ftContext(img *image.RGBA, ttf *truetype.Font, fontsize float64) *freetype.Context {
+	c := freetype.NewContext()
+	c.SetDPI(float64(dev.DPI))
+	c.SetFont(ttf)
+	c.SetSrc(image.NewUniform(color.RGBA{0, 0, 0, 0}))
+	c.SetDst(img)
+	c.SetClip(img.Bounds())
+	c.SetHinting(font.HintingFull)
+	c.SetFontSize(fontsize)
+
+	return c
+}
+
+func loadFont(name string) (*truetype.Font, error) {
+	fontPath, err := findfont.Find(name)
+	if err != nil {
+		return nil, err
+	}
+
+	ttf, err := ioutil.ReadFile(fontPath)
+	if err != nil {
+		return nil, err
+	}
+
+	return freetype.ParseFont(ttf)
+}
+
+func init() {
+	var err error
+	ttfFont, err = loadFont("Roboto-Regular.ttf")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	ttfThinFont, err = loadFont("Roboto-Thin.ttf")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	ttfBoldFont, err = loadFont("Roboto-Bold.ttf")
+	if err != nil {
+		log.Fatal(err)
+	}
+}

widget.go

@@ -4,23 +4,14 @@ import (
 	"image"
 	"image/color"
 	"image/draw"
-	"io/ioutil"
 	"log"
 	"os"
 	"strconv"
 
-	"github.com/flopp/go-findfont"
 	"github.com/golang/freetype"
 	"github.com/golang/freetype/truetype"
 	"github.com/muesli/streamdeck"
 	"github.com/nfnt/resize"
-	"golang.org/x/image/font"
-)
-
-var (
-	ttfFont     *truetype.Font
-	ttfThinFont *truetype.Font
-	ttfBoldFont *truetype.Font
 )
 
 type Widget interface {
@@ -167,35 +158,3 @@ func drawString(img *image.RGBA, bounds image.Rectangle, ttf *truetype.Font, tex
 		log.Fatal(err)
 	}
 }
-
-func loadFont(name string) (*truetype.Font, error) {
-	fontPath, err := findfont.Find(name)
-	if err != nil {
-		return nil, err
-	}
-
-	ttf, err := ioutil.ReadFile(fontPath)
-	if err != nil {
-		return nil, err
-	}
-
-	return freetype.ParseFont(ttf)
-}
-
-func init() {
-	var err error
-	ttfFont, err = loadFont("Roboto-Regular.ttf")
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	ttfThinFont, err = loadFont("Roboto-Thin.ttf")
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	ttfBoldFont, err = loadFont("Roboto-Bold.ttf")
-	if err != nil {
-		log.Fatal(err)
-	}
-}