예제 #1
0
// Text takes an image and, using the freetype package, writes text in the
// position specified on to the image. A color.Color, a font size and a font
// must also be specified.
// Finally, the (x, y) coordinate advanced by the text extents is returned.
//
// Note that the ParseFont helper function can be used to get a *truetype.Font
// value without having to import freetype-go directly.
//
// If you need more control over the 'context' used to draw text (like the DPI),
// then you'll need to ignore this convenience method and use your own.
func (im *Image) Text(x, y int, clr color.Color, fontSize float64,
	font *truetype.Font, text string) (int, int, error) {

	// Create a solid color image
	textClr := image.NewUniform(clr)

	// Set up the freetype context... mostly boiler plate
	c := ftContext(font, fontSize)
	c.SetClip(im.Bounds())
	c.SetDst(im)
	c.SetSrc(textClr)

	// Now let's actually draw the text...
	pt := freetype.Pt(x, y+int(c.PointToFix32(fontSize)>>8))
	newpt, err := c.DrawString(text, pt)
	if err != nil {
		return 0, 0, err
	}

	return int(newpt.X / 256), int(newpt.Y / 256), nil
}
예제 #2
0
func main() {
	flag.Parse()

	// Read the font data.
	fontBytes, err := ioutil.ReadFile(*fontfile)
	if err != nil {
		log.Println(err)
		return
	}
	font, err := freetype.ParseFont(fontBytes)
	if err != nil {
		log.Println(err)
		return
	}

	// Initialize the context.
	fg, bg := image.Black, image.White
	ruler := color.RGBA{0xdd, 0xdd, 0xdd, 0xff}
	if *wonb {
		fg, bg = image.White, image.Black
		ruler = color.RGBA{0x22, 0x22, 0x22, 0xff}
	}
	rgba := image.NewRGBA(image.Rect(0, 0, 640, 480))
	draw.Draw(rgba, rgba.Bounds(), bg, image.ZP, draw.Src)
	c := freetype.NewContext()
	c.SetDPI(*dpi)
	c.SetFont(font)
	c.SetFontSize(*size)
	c.SetClip(rgba.Bounds())
	c.SetDst(rgba)
	c.SetSrc(fg)

	// Draw the guidelines.
	for i := 0; i < 200; i++ {
		rgba.Set(10, 10+i, ruler)
		rgba.Set(10+i, 10, ruler)
	}

	// Draw the text.
	pt := freetype.Pt(10, 10+int(c.PointToFix32(*size)>>8))
	for _, s := range text {
		_, err = c.DrawString(s, pt)
		if err != nil {
			log.Println(err)
			return
		}
		pt.Y += c.PointToFix32(*size * *spacing)
	}

	// Save that RGBA image to disk.
	f, err := os.Create("out.png")
	if err != nil {
		log.Println(err)
		os.Exit(1)
	}
	defer f.Close()
	b := bufio.NewWriter(f)
	err = png.Encode(b, rgba)
	if err != nil {
		log.Println(err)
		os.Exit(1)
	}
	err = b.Flush()
	if err != nil {
		log.Println(err)
		os.Exit(1)
	}
	fmt.Println("Wrote out.png OK.")
}