Created
March 14, 2017 09:03
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Three ways of drawing text in go
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// Initialize an empty image | |
dest := image.NewRGBA(image.Rect(0, 0, 800, 300)) | |
// Draw a white background | |
draw.Draw(dest, dest.Bounds(), &image.Uniform{color.White}, image.ZP, draw.Src) | |
// Read the font | |
fontBytes, err := ioutil.ReadFile(exeDir + "/DejaVuSans.ttf") | |
if err != nil { | |
log.Fatal(err) | |
} | |
f, err := freetype.ParseFont(fontBytes) | |
if err != nil { | |
log.Fatal(err) | |
} | |
// Variant 1 (Freetype "high-level API") | |
ft := freetype.NewContext() | |
ft.SetDst(dest) | |
ft.SetFont(f) | |
ft.SetFontSize(8) | |
ft.SetDPI(96) | |
ft.SetClip(dest.Bounds()) | |
ft.SetSrc(image.Black) | |
ft.SetHinting(font.HintingNone) | |
ft.DrawString("some text", freetype.Pt(100, 100)) | |
// Variant 2 (Freetype/Go font API) | |
opts := &truetype.Options{} | |
opts.DPI = 96 | |
opts.Size = 8 | |
opts.Hinting = font.HintingNone | |
d := font.Drawer{} | |
d.Dst = dest | |
d.Src = image.Black | |
d.Face = truetype.NewFace(f, opts) | |
d.Dot = freetype.Pt(100, 120) | |
d.DrawString("some text") | |
// Variant 3 (draw2d) | |
gc := draw2dimg.NewGraphicContext(dest) | |
draw2d.RegisterFont(draw2dbase.DefaultFontData, f) | |
gc.SetFillColor(color.Black) | |
gc.SetFontSize(8) | |
gc.SetDPI(96) | |
gc.FillStringAt("some text", 100, 140) | |
// Write PNG | |
fd, err := os.Create(exeDir + "/image.png") | |
if err != nil { | |
log.Fatal(err) | |
} | |
defer fd.Close() | |
encoder := png.Encoder{} | |
encoder.CompressionLevel = png.DefaultCompression | |
encoder.Encode(fd, dest) |
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