// 画一个带有text的图片
func (this *Signer) DrawStringImage(text string) (image.Image, error) {
fg, bg := image.Black, image.Transparent
rgba := image.NewRGBA(image.Rect(0, 0, this.signPoint.X, this.signPoint.Y))
draw.Draw(rgba, rgba.Bounds(), bg, image.ZP, draw.Src)
c := freetype.NewContext()
c.SetDPI(this.Dpi)
c.SetFont(this.font)
c.SetFontSize(this.FontSize)
c.SetClip(rgba.Bounds())
c.SetDst(rgba)
c.SetSrc(fg)
// Draw the text.
pt := freetype.Pt(10, 10+int(c.PointToFix32(12)>>8))
limit := c.PointToFix32(100) - raster.Fix32(10<<8) - raster.Fix32(10<<8)
for _, s := range strings.Split(text, "\r\n") {
_, err := c.DrawString(s, pt, limit)
if err != nil {
fmt.Println("c.DrawString(%s) error(%v)", s, err)
return nil, err
}
pt.Y += c.PointToFix32(12 * 1.5)
}
// fff, _ := os.Create("aaa.png")
// defer fff.Close()
// png.Encode(fff, rgba)
return rgba, nil
}
func BenchmarkFreetypeNonZeroWinding(b *testing.B) {
var p Path
p.LineTo(10, 190)
draw2dbase.TraceCubic(&p, []float64{10, 190, 10, 10, 190, 10, 190, 190}, 0.5)
poly := Polygon(p.points)
color := color.RGBA{0, 0, 0, 0xff}
for i := 0; i < b.N; i++ {
img := image.NewRGBA(image.Rect(0, 0, 200, 200))
rasterizer := raster.NewRasterizer(200, 200)
rasterizer.UseNonZeroWinding = true
rasterizer.Start(raster.Point{
X: raster.Fix32(10 * 256),
Y: raster.Fix32(190 * 256)})
for j := 0; j < len(poly); j = j + 2 {
rasterizer.Add1(raster.Point{
X: raster.Fix32(poly[j] * 256),
Y: raster.Fix32(poly[j+1] * 256)})
}
painter := raster.NewRGBAPainter(img)
painter.SetColor(color)
rasterizer.Rasterize(painter)
}
}
func p(n node) raster.Point {
x, y := 20+n.x/4, 380-n.y/4
return raster.Point{
X: raster.Fix32(x * 256),
Y: raster.Fix32(y * 256),
}
}
// DrawString draws s at p and returns p advanced by the text extent. The text
// is placed so that the left edge of the em square of the first character of s
// and the baseline intersect at p. The majority of the affected pixels will be
// above and to the right of the point, but some may be below or to the left.
// For example, drawing a string that starts with a 'J' in an italic font may
// affect pixels below and left of the point.
// p is a raster.Point and can therefore represent sub-pixel positions.
func (c *Context) DrawString(s string, p raster.Point) (raster.Point, error) {
if c.font == nil {
return raster.Point{}, errors.New("freetype: DrawText called with a nil font")
}
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := c.font.Index(rune)
if hasPrev {
kern := raster.Fix32(c.font.Kerning(c.scale, prev, index)) << 2
if c.hinting != NoHinting {
kern = (kern + 128) &^ 255
}
p.X += kern
}
advanceWidth, mask, offset, err := c.glyph(index, p)
if err != nil {
return raster.Point{}, err
}
p.X += advanceWidth
glyphRect := mask.Bounds().Add(offset)
dr := c.clip.Intersect(glyphRect)
if !dr.Empty() {
mp := image.Point{0, dr.Min.Y - glyphRect.Min.Y}
draw.DrawMask(c.dst, dr, c.src, image.ZP, mask, mp, draw.Over)
}
prev, hasPrev = index, true
}
return p, nil
}
// drawContour draws the given closed contour with the given offset.
func (p *glyphPage) drawContour(ps []truetype.Point, dx, dy raster.Fix32) {
if len(ps) == 0 {
return
}
rast := p.rast
resolution := p.resolution
// ps[0] is a truetype.Point measured in FUnits and positive Y going upwards.
// start is the same thing measured in fixed point units and positive Y
// going downwards, and offset by (dx, dy)
start := raster.Point{
X: dx + raster.Fix32(int64(ps[0].X)*int64(resolution)>>14),
Y: dy - raster.Fix32(int64(ps[0].Y)*int64(resolution)>>14),
}
rast.Start(start)
q0, on0 := start, true
for _, p := range ps[1:] {
q := raster.Point{
X: dx + raster.Fix32(int64(p.X)*int64(resolution)>>14),
Y: dy - raster.Fix32(int64(p.Y)*int64(resolution)>>14),
}
on := p.Flags&0x01 != 0
if on {
if on0 {
rast.Add1(q)
} else {
rast.Add2(q0, q)
}
} else {
if on0 {
// No-op.
} else {
mid := raster.Point{
X: (q0.X + q.X) / 2,
Y: (q0.Y + q.Y) / 2,
}
rast.Add2(q0, mid)
}
}
q0, on0 = q, on
}
// Close the curve.
if on0 {
rast.Add1(start)
} else {
rast.Add2(q0, start)
}
}
func (p *glyphPage) add(rune rune, g *glyph) bool {
if _, found := p.offsets[rune]; found {
panic("Glyph already added to glyph page")
}
w, h := g.size(p.resolution).WH()
x, y := p.nextPoint.X, p.nextPoint.Y
if x+w > p.size.W {
// Row full, start new line
x = 0
y += p.rowHeight + glyphPadding
p.rowHeight = 0
}
if y+h > p.size.H {
return false // Page full
}
// Build the raster contours
p.rast.Clear()
fx := -raster.Fix32((int64(g.B.XMin) * int64(p.resolution)) >> 14)
fy := +raster.Fix32((int64(g.B.YMax) * int64(p.resolution)) >> 14)
e0 := 0
for _, e1 := range g.End {
p.drawContour(g.Point[e0:e1], fx, fy)
e0 = e1
}
// Perform the rasterization
a := &image.Alpha{
Pix: p.image.Pix[x+y*p.image.Stride:],
Stride: p.image.Stride,
Rect: image.Rect(0, 0, w, h),
}
p.rast.Rasterize(raster.NewAlphaSrcPainter(a))
p.offsets[rune] = math.Point{X: x, Y: y}
p.nextPoint = math.Point{X: x + w + glyphPadding, Y: y}
if h > p.rowHeight {
p.rowHeight = h
}
p.tex = nil
return true
}
// rasterize returns the advance width, glyph mask and integer-pixel offset
// to render the given glyph at the given sub-pixel offsets.
// The 24.8 fixed point arguments fx and fy must be in the range [0, 1).
func (c *Context) rasterize(glyph truetype.Index, fx, fy raster.Fix32) (
raster.Fix32, *image.Alpha, image.Point, error) {
if err := c.glyphBuf.Load(c.font, c.scale, glyph, truetype.Hinting(c.hinting)); err != nil {
return 0, nil, image.Point{}, err
}
// Calculate the integer-pixel bounds for the glyph.
xmin := int(fx+raster.Fix32(c.glyphBuf.B.XMin<<2)) >> 8
ymin := int(fy-raster.Fix32(c.glyphBuf.B.YMax<<2)) >> 8
xmax := int(fx+raster.Fix32(c.glyphBuf.B.XMax<<2)+0xff) >> 8
ymax := int(fy-raster.Fix32(c.glyphBuf.B.YMin<<2)+0xff) >> 8
if xmin > xmax || ymin > ymax {
return 0, nil, image.Point{}, errors.New("freetype: negative sized glyph")
}
// A TrueType's glyph's nodes can have negative co-ordinates, but the
// rasterizer clips anything left of x=0 or above y=0. xmin and ymin
// are the pixel offsets, based on the font's FUnit metrics, that let
// a negative co-ordinate in TrueType space be non-negative in
// rasterizer space. xmin and ymin are typically <= 0.
fx += raster.Fix32(-xmin << 8)
fy += raster.Fix32(-ymin << 8)
// Rasterize the glyph's vectors.
c.r.Clear()
e0 := 0
for _, e1 := range c.glyphBuf.End {
c.drawContour(c.glyphBuf.Point[e0:e1], fx, fy)
e0 = e1
}
a := image.NewAlpha(image.Rect(0, 0, xmax-xmin, ymax-ymin))
c.r.Rasterize(raster.NewAlphaSrcPainter(a))
return raster.Fix32(c.glyphBuf.AdvanceWidth << 2), a, image.Point{xmin, ymin}, nil
}
func TestFreetypeNonZeroWinding(t *testing.T) {
var p Path
p.LineTo(10, 190)
draw2dbase.TraceCubic(&p, []float64{10, 190, 10, 10, 190, 10, 190, 190}, 0.5)
poly := Polygon(p.points)
color := color.RGBA{0, 0, 0, 0xff}
img := image.NewRGBA(image.Rect(0, 0, 200, 200))
rasterizer := raster.NewRasterizer(200, 200)
rasterizer.UseNonZeroWinding = true
rasterizer.Start(raster.Point{
X: raster.Fix32(10 * 256),
Y: raster.Fix32(190 * 256)})
for j := 0; j < len(poly); j = j + 2 {
rasterizer.Add1(raster.Point{
X: raster.Fix32(poly[j] * 256),
Y: raster.Fix32(poly[j+1] * 256)})
}
painter := raster.NewRGBAPainter(img)
painter.SetColor(color)
rasterizer.Rasterize(painter)
draw2dimg.SaveToPngFile("../output/raster/TestFreetypeNonZeroWinding.png", img)
}
// PointToFix32 converts the given number of points (as in ``a 12 point font'')
// into fixed point units.
func (c *Context) PointToFix32(x float64) raster.Fix32 {
return raster.Fix32(x * float64(c.dpi) * (256.0 / 72.0))
}
// Pt converts from a co-ordinate pair measured in pixels to a raster.Point
// co-ordinate pair measured in raster.Fix32 units.
func Pt(x, y int) raster.Point {
return raster.Point{
X: raster.Fix32(x << 8),
Y: raster.Fix32(y << 8),
}
}
// drawContour draws the given closed contour with the given offset.
func (c *Context) drawContour(ps []truetype.Point, dx, dy raster.Fix32) {
if len(ps) == 0 {
return
}
// The low bit of each point's Flags value is whether the point is on the
// curve. Truetype fonts only have quadratic Bézier curves, not cubics.
// Thus, two consecutive off-curve points imply an on-curve point in the
// middle of those two.
//
// See http://chanae.walon.org/pub/ttf/ttf_glyphs.htm for more details.
// ps[0] is a truetype.Point measured in FUnits and positive Y going
// upwards. start is the same thing measured in fixed point units and
// positive Y going downwards, and offset by (dx, dy).
start := raster.Point{
X: dx + raster.Fix32(ps[0].X<<2),
Y: dy - raster.Fix32(ps[0].Y<<2),
}
others := []truetype.Point(nil)
if ps[0].Flags&0x01 != 0 {
others = ps[1:]
} else {
last := raster.Point{
X: dx + raster.Fix32(ps[len(ps)-1].X<<2),
Y: dy - raster.Fix32(ps[len(ps)-1].Y<<2),
}
if ps[len(ps)-1].Flags&0x01 != 0 {
start = last
others = ps[:len(ps)-1]
} else {
start = raster.Point{
X: (start.X + last.X) / 2,
Y: (start.Y + last.Y) / 2,
}
others = ps
}
}
c.r.Start(start)
q0, on0 := start, true
for _, p := range others {
q := raster.Point{
X: dx + raster.Fix32(p.X<<2),
Y: dy - raster.Fix32(p.Y<<2),
}
on := p.Flags&0x01 != 0
if on {
if on0 {
c.r.Add1(q)
} else {
c.r.Add2(q0, q)
}
} else {
if on0 {
// No-op.
} else {
mid := raster.Point{
X: (q0.X + q.X) / 2,
Y: (q0.Y + q.Y) / 2,
}
c.r.Add2(q0, mid)
}
}
q0, on0 = q, on
}
// Close the curve.
if on0 {
c.r.Add1(start)
} else {
c.r.Add2(q0, start)
}
}
func int2fix(i int) raster.Fix32 {
return raster.Fix32(i << fixBits)
}
func main() {
const (
n = 17
r = 256 * 80
)
s := raster.Fix32(r * math.Sqrt(2) / 2)
t := raster.Fix32(r * math.Tan(math.Pi/8))
m := image.NewRGBA(image.Rect(0, 0, 800, 600))
draw.Draw(m, m.Bounds(), image.NewUniform(color.RGBA{63, 63, 63, 255}), image.ZP, draw.Src)
mp := raster.NewRGBAPainter(m)
mp.SetColor(image.Black)
z := raster.NewRasterizer(800, 600)
for i := 0; i < n; i++ {
cx := raster.Fix32(25600 + 51200*(i%4))
cy := raster.Fix32(2560 + 32000*(i/4))
c := raster.Point{X: cx, Y: cy}
theta := math.Pi * (0.5 + 0.5*float64(i)/(n-1))
dx := raster.Fix32(r * math.Cos(theta))
dy := raster.Fix32(r * math.Sin(theta))
d := raster.Point{X: dx, Y: dy}
// Draw a quarter-circle approximated by two quadratic segments,
// with each segment spanning 45 degrees.
z.Start(c)
z.Add1(c.Add(raster.Point{X: r, Y: 0}))
z.Add2(c.Add(raster.Point{X: r, Y: t}), c.Add(raster.Point{X: s, Y: s}))
z.Add2(c.Add(raster.Point{X: t, Y: r}), c.Add(raster.Point{X: 0, Y: r}))
// Add another quadratic segment whose angle ranges between 0 and 90 degrees.
// For an explanation of the magic constants 22, 150, 181 and 256, read the
// comments in the freetype/raster package.
dot := 256 * d.Dot(raster.Point{X: 0, Y: r}) / (r * r)
multiple := raster.Fix32(150 - 22*(dot-181)/(256-181))
z.Add2(c.Add(raster.Point{X: dx, Y: r + dy}.Mul(multiple)), c.Add(d))
// Close the curve.
z.Add1(c)
}
z.Rasterize(mp)
for i := 0; i < n; i++ {
cx := raster.Fix32(25600 + 51200*(i%4))
cy := raster.Fix32(2560 + 32000*(i/4))
for j := 0; j < n; j++ {
theta := math.Pi * float64(j) / (n - 1)
dx := raster.Fix32(r * math.Cos(theta))
dy := raster.Fix32(r * math.Sin(theta))
m.Set(int((cx+dx)/256), int((cy+dy)/256), color.RGBA{255, 255, 0, 255})
}
}
// 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, m)
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.")
}
func (obj *RasterItem) pt(p raster.Point) raster.Point {
return raster.Point{p.X + raster.Fix32(obj.rasterizer.Dx)<<fixBits, p.Y + raster.Fix32(obj.rasterizer.Dy)<<fixBits}
}
func float2fixed(f float64) raster.Fix32 {
if f < 0 {
return raster.Fix32(f*256 + 0.5)
}
return raster.Fix32(f*256 - 0.5)
}
func pixel2fixPoint(p image.Point) raster.Point {
return raster.Point{raster.Fix32(p.X << fixBits), raster.Fix32(p.Y << fixBits)}
}
func (c *Context) PixToFix32(p int) raster.Fix32 {
return raster.Fix32(p * 256)
}
func p(x, y int) raster.Point {
return raster.Point{
X: raster.Fix32(x * 256),
Y: raster.Fix32(y * 256),
}
}
func (liner FtLineBuilder) LineTo(x, y float64) {
liner.Adder.Add1(raster.Point{X: raster.Fix32(x * 256), Y: raster.Fix32(y * 256)})
}
func float2fix(f float64) raster.Fix32 {
return raster.Fix32(f*fixScale + 0.5)
}