// rasterize returns the advance width, glyph mask and integer-pixel offset
// to render the given glyph at the given sub-pixel offsets.
// The 26.6 fixed point arguments fx and fy must be in the range [0, 1).
func (c *Context) rasterize(glyph truetype.Index, fx, fy fixed.Int26_6) (
fixed.Int26_6, *image.Alpha, image.Point, error) {
if err := c.glyphBuf.Load(c.f, c.scale, glyph, c.hinting); err != nil {
return 0, nil, image.Point{}, err
}
// Calculate the integer-pixel bounds for the glyph.
xmin := int(fx+c.glyphBuf.Bounds.Min.X) >> 6
ymin := int(fy-c.glyphBuf.Bounds.Max.Y) >> 6
xmax := int(fx+c.glyphBuf.Bounds.Max.X+0x3f) >> 6
ymax := int(fy-c.glyphBuf.Bounds.Min.Y+0x3f) >> 6
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 -= fixed.Int26_6(xmin << 6)
fy -= fixed.Int26_6(ymin << 6)
// Rasterize the glyph's vectors.
c.r.Clear()
e0 := 0
for _, e1 := range c.glyphBuf.Ends {
c.drawContour(c.glyphBuf.Points[e0:e1], fx, fy)
e0 = e1
}
a := image.NewAlpha(image.Rect(0, 0, xmax-xmin, ymax-ymin))
c.r.Rasterize(raster.NewAlphaSrcPainter(a))
return c.glyphBuf.AdvanceWidth, a, image.Point{xmin, ymin}, nil
}
func TestNewFontFaceItalic(t *testing.T) {
base, _ := NewFontWithName("Verdana")
defer base.Close()
face := base.Face(text.FaceData{
Size: 20.0,
Style: font.StyleItalic,
})
defer face.Close()
if data := face.Data(); data != (text.FaceData{
Size: 20.0,
DPI: 72.0,
Hinting: font.HintingNone,
Stretch: font.StretchNormal,
Style: font.StyleItalic,
Weight: font.WeightNormal,
}) {
t.Error("invalid font face data:", data)
}
if metrics := face.Metrics(); metrics != (font.Metrics{
Height: fixed.Int26_6((24 << 6) | 18),
Ascent: fixed.Int26_6((20 << 6) | 6),
Descent: fixed.Int26_6((4 << 6) | 12),
}) {
t.Error("invalid font face metrics:", metrics)
}
if s := fmt.Sprint(face); s != "Verdana Italic { size: 20, DPI: 72 }" {
t.Error("invalid face representation:", s)
}
}
func p(n node) fixed.Point26_6 {
x, y := 20+n.x/4, 380-n.y/4
return fixed.Point26_6{
X: fixed.Int26_6(x << 6),
Y: fixed.Int26_6(y << 6),
}
}
// pRot45CCW returns the vector p rotated counter-clockwise by 45 degrees.
//
// Note that the Y-axis grows downwards, so {1, 0}.Rot45CCW is {1/√2, -1/√2}.
func pRot45CCW(p fixed.Point26_6) fixed.Point26_6 {
// 181/256 is approximately 1/√2, or sin(π/4).
px, py := int64(p.X), int64(p.Y)
qx := (+px + py) * 181 / 256
qy := (-px + py) * 181 / 256
return fixed.Point26_6{fixed.Int26_6(qx), fixed.Int26_6(qy)}
}
// unscaledVMetric returns the unscaled vertical metrics for the glyph with
// the given index. yMax is the top of the glyph's bounding box.
func (f *Font) unscaledVMetric(i Index, yMax fixed.Int26_6) (v VMetric) {
j := int(i)
if j < 0 || f.nGlyph <= j {
return VMetric{}
}
if 4*j+4 <= len(f.vmtx) {
return VMetric{
AdvanceHeight: fixed.Int26_6(u16(f.vmtx, 4*j)),
TopSideBearing: fixed.Int26_6(int16(u16(f.vmtx, 4*j+2))),
}
}
// The OS/2 table has grown over time.
// https://developer.apple.com/fonts/TTRefMan/RM06/Chap6OS2.html
// says that it was originally 68 bytes. Optional fields, including
// the ascender and descender, are described at
// http://www.microsoft.com/typography/otspec/os2.htm
if len(f.os2) >= 72 {
sTypoAscender := fixed.Int26_6(int16(u16(f.os2, 68)))
sTypoDescender := fixed.Int26_6(int16(u16(f.os2, 70)))
return VMetric{
AdvanceHeight: sTypoAscender - sTypoDescender,
TopSideBearing: sTypoAscender - yMax,
}
}
return VMetric{
AdvanceHeight: fixed.Int26_6(f.fUnitsPerEm),
TopSideBearing: 0,
}
}
// GetStringBounds returns the approximate pixel bounds of the string s at x, y.
// The the left edge of the em square of the first character of s
// and the baseline intersect at 0, 0 in the returned coordinates.
// Therefore the top and left coordinates may well be negative.
func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom float64) {
font, err := gc.loadCurrentFont()
if err != nil {
log.Println(err)
return 0, 0, 0, 0
}
top, left, bottom, right = 10e6, 10e6, -10e6, -10e6
cursor := 0.0
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := font.Index(rune)
if hasPrev {
cursor += fUnitsToFloat64(int32(font.Kern(fixed.Int26_6(gc.Current.Scale), prev, index)))
}
if err := gc.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), index, expfont.HintingNone); err != nil {
log.Println(err)
return 0, 0, 0, 0
}
e0 := 0
for _, e1 := range gc.glyphBuf.End {
ps := gc.glyphBuf.Point[e0:e1]
for _, p := range ps {
x, y := pointToF64Point(p)
top = math.Min(top, y)
bottom = math.Max(bottom, y)
left = math.Min(left, x+cursor)
right = math.Max(right, x+cursor)
}
}
cursor += fUnitsToFloat64(int32(font.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth))
prev, hasPrev = index, true
}
return left, top, right, bottom
}
func TestGlyphBounds(t *testing.T) {
base, _ := NewFontWithName("Verdana")
defer base.Close()
face := base.Face(text.FaceData{
Size: 20.0,
})
defer face.Close()
bounds, advance, ok := face.GlyphBounds('A')
if !ok {
t.Error("failed to get glyph bounds for 'A'")
return
}
if advance != fixed.Int26_6((13<<6)|43) {
t.Error("invalid glyph advance for 'A':", advance)
return
}
if bounds != (fixed.Rectangle26_6{
Min: fixed.Point26_6{
X: fixed.Int26_6((0 << 6) | 16),
Y: fixed.Int26_6(0),
},
Max: fixed.Point26_6{
X: fixed.Int26_6((13 << 6) | 26),
Y: fixed.Int26_6((14 << 6) | 34),
},
}) {
t.Error("invalid glyph bounds for 'A':", bounds)
}
}
// TestParse tests that the luxisr.ttf metrics and glyphs are parsed correctly.
// The numerical values can be manually verified by examining luxisr.ttx.
func TestParse(t *testing.T) {
f, _, err := parseTestdataFont("luxisr")
if err != nil {
t.Fatal(err)
}
if got, want := f.FUnitsPerEm(), int32(2048); got != want {
t.Errorf("FUnitsPerEm: got %v, want %v", got, want)
}
fupe := fixed.Int26_6(f.FUnitsPerEm())
if got, want := f.Bounds(fupe), mkBounds(-441, -432, 2024, 2033); got != want {
t.Errorf("Bounds: got %v, want %v", got, want)
}
i0 := f.Index('A')
i1 := f.Index('V')
if i0 != 36 || i1 != 57 {
t.Fatalf("Index: i0, i1 = %d, %d, want 36, 57", i0, i1)
}
if got, want := f.HMetric(fupe, i0), (HMetric{1366, 19}); got != want {
t.Errorf("HMetric: got %v, want %v", got, want)
}
if got, want := f.VMetric(fupe, i0), (VMetric{2465, 553}); got != want {
t.Errorf("VMetric: got %v, want %v", got, want)
}
if got, want := f.Kern(fupe, i0, i1), fixed.Int26_6(-144); got != want {
t.Errorf("Kern: got %v, want %v", got, want)
}
g := &GlyphBuf{}
err = g.Load(f, fupe, i0, font.HintingNone)
if err != nil {
t.Fatalf("Load: %v", err)
}
g0 := &GlyphBuf{
Bounds: g.Bounds,
Points: g.Points,
Ends: g.Ends,
}
g1 := &GlyphBuf{
Bounds: mkBounds(19, 0, 1342, 1480),
Points: []Point{
{19, 0, 51},
{581, 1480, 1},
{789, 1480, 51},
{1342, 0, 1},
{1116, 0, 35},
{962, 410, 3},
{368, 410, 33},
{214, 0, 3},
{428, 566, 19},
{904, 566, 33},
{667, 1200, 3},
},
Ends: []int{8, 11},
}
if got, want := fmt.Sprint(g0), fmt.Sprint(g1); got != want {
t.Errorf("GlyphBuf:\ngot %v\nwant %v", got, want)
}
}
// scale returns x divided by f.fUnitsPerEm, rounded to the nearest integer.
func (f *Font) scale(x fixed.Int26_6) fixed.Int26_6 {
if x >= 0 {
x += fixed.Int26_6(f.fUnitsPerEm) / 2
} else {
x -= fixed.Int26_6(f.fUnitsPerEm) / 2
}
return x / fixed.Int26_6(f.fUnitsPerEm)
}
// Metrics satisfies the font.Face interface.
func (a *face) Metrics() font.Metrics {
scale := float64(a.scale)
fupe := float64(a.f.FUnitsPerEm())
return font.Metrics{
Height: a.scale,
Ascent: fixed.Int26_6(math.Ceil(scale * float64(+a.f.ascent) / fupe)),
Descent: fixed.Int26_6(math.Ceil(scale * float64(-a.f.descent) / fupe)),
}
}
// pNorm returns the vector p normalized to the given length, or zero if p is
// degenerate.
func pNorm(p fixed.Point26_6, length fixed.Int26_6) fixed.Point26_6 {
d := pLen(p)
if d == 0 {
return fixed.Point26_6{}
}
s, t := int64(length), int64(d)
x := int64(p.X) * s / t
y := int64(p.Y) * s / t
return fixed.Point26_6{fixed.Int26_6(x), fixed.Int26_6(y)}
}
func (s *Sparkline) scale(idx int, n, min, max float32, dx, dy int) fixed.Point26_6 {
// 26.6 format, so shift by 6
x := float32(idx) / float32(s.items) * float32(dx)
y := (1.0 - ((n - min) / max)) * float32(dy)
p := fixed.Point26_6{
X: fixed.Int26_6(x)<<6 | (fixed.Int26_6(x*64) & (1<<6 - 1)),
Y: fixed.Int26_6(y)<<6 | (fixed.Int26_6(y*64) & (1<<6 - 1)),
}
return p
}
// NewFace returns a new font.Face for the given Font.
func NewFace(f *Font, opts *Options) font.Face {
a := &face{
f: f,
hinting: opts.hinting(),
scale: fixed.Int26_6(0.5 + (opts.size() * opts.dpi() * 64 / 72)),
glyphCache: make([]glyphCacheEntry, opts.glyphCacheEntries()),
}
a.subPixelX, a.subPixelBiasX, a.subPixelMaskX = opts.subPixelsX()
a.subPixelY, a.subPixelBiasY, a.subPixelMaskY = opts.subPixelsY()
// Fill the cache with invalid entries. Valid glyph cache entries have fx
// and fy in the range [0, 64). Valid index cache entries have rune >= 0.
for i := range a.glyphCache {
a.glyphCache[i].key.fy = 0xff
}
for i := range a.indexCache {
a.indexCache[i].rune = -1
}
// Set the rasterizer's bounds to be big enough to handle the largest glyph.
b := f.Bounds(a.scale)
xmin := +int(b.Min.X) >> 6
ymin := -int(b.Max.Y) >> 6
xmax := +int(b.Max.X+63) >> 6
ymax := -int(b.Min.Y-63) >> 6
a.maxw = xmax - xmin
a.maxh = ymax - ymin
a.masks = image.NewAlpha(image.Rect(0, 0, a.maxw, a.maxh*len(a.glyphCache)))
a.r.SetBounds(a.maxw, a.maxh)
a.p = facePainter{a}
return a
}
// Width returns width of a string when drawn using the font.
func (f *Font) Width(s string) Length {
// scale converts truetype.FUnit to float64
scale := f.Size / Points(float64(f.font.FUnitsPerEm()))
width := 0
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := f.font.Index(rune)
if hasPrev {
width += int(f.font.Kern(fixed.Int26_6(f.font.FUnitsPerEm()), prev, index))
}
width += int(f.font.HMetric(fixed.Int26_6(f.font.FUnitsPerEm()), index).AdvanceWidth)
prev, hasPrev = index, true
}
return Points(float64(width)) * scale
}
func (f *face) Glyph(dot fixed.Point26_6, r rune) (
newDot fixed.Point26_6, dr image.Rectangle, mask image.Image, maskp image.Point, ok bool) {
r -= f.firstRune
if r < 0 || f.n <= int(r) {
return fixed.Point26_6{}, image.Rectangle{}, nil, image.Point{}, false
}
i := &f.fontchars[r+0]
j := &f.fontchars[r+1]
newDot = fixed.Point26_6{
X: dot.X + fixed.Int26_6(i.width)<<6,
Y: dot.Y,
}
minX := int(dot.X+32)>>6 + int(i.left)
minY := int(dot.Y+32)>>6 + int(i.top) - f.ascent
dr = image.Rectangle{
Min: image.Point{
X: minX,
Y: minY,
},
Max: image.Point{
X: minX + int(j.x-i.x),
Y: minY + int(i.bottom) - int(i.top),
},
}
return newDot, dr, f.img, image.Point{int(i.x), int(i.top)}, true
}
func Measure(r io.RuneReader, f font.Face) (size fixed.Point26_6, err error) {
var char rune
var prev rune
w := fixed.Int26_6(0)
m := f.Metrics()
size.Y = m.Height + m.Descent
for {
if char, _, err = r.ReadRune(); err != nil {
if err == io.EOF {
err = nil
}
size.X = maxInt26_6(size.X, w)
return
}
if char == '\n' {
size.X = maxInt26_6(size.X, w)
size.Y += m.Height
w, prev = 0, 0
continue
}
if prev != 0 {
w += f.Kern(prev, char)
}
w += advance(f, char)
prev = char
}
}
// dotProduct returns the dot product of [x, y] and q. It is almost the same as
// px := int64(x)
// py := int64(y)
// qx := int64(q[0])
// qy := int64(q[1])
// return fixed.Int26_6((px*qx + py*qy + 1<<13) >> 14)
// except that the computation is done with 32-bit integers to produce exactly
// the same rounding behavior as C Freetype.
func dotProduct(x, y fixed.Int26_6, q [2]f2dot14) fixed.Int26_6 {
// Compute x*q[0] as 64-bit value.
l := uint32((int32(x) & 0xFFFF) * int32(q[0]))
m := (int32(x) >> 16) * int32(q[0])
lo1 := l + (uint32(m) << 16)
hi1 := (m >> 16) + (int32(l) >> 31) + bool2int32(lo1 < l)
// Compute y*q[1] as 64-bit value.
l = uint32((int32(y) & 0xFFFF) * int32(q[1]))
m = (int32(y) >> 16) * int32(q[1])
lo2 := l + (uint32(m) << 16)
hi2 := (m >> 16) + (int32(l) >> 31) + bool2int32(lo2 < l)
// Add them.
lo := lo1 + lo2
hi := hi1 + hi2 + bool2int32(lo < lo1)
// Divide the result by 2^14 with rounding.
s := hi >> 31
l = lo + uint32(s)
hi += s + bool2int32(l < lo)
lo = l
l = lo + 0x2000
hi += bool2int32(l < lo)
return fixed.Int26_6((uint32(hi) << 18) | (l >> 14))
}
func main() {
flag.Parse()
fmt.Printf("Loading fontfile %q\n", *fontfile)
b, err := ioutil.ReadFile(*fontfile)
if err != nil {
log.Println(err)
return
}
f, err := truetype.Parse(b)
if err != nil {
log.Println(err)
return
}
fupe := fixed.Int26_6(f.FUnitsPerEm())
printBounds(f.Bounds(fupe))
fmt.Printf("FUnitsPerEm:%d\n\n", fupe)
c0, c1 := 'A', 'V'
i0 := f.Index(c0)
hm := f.HMetric(fupe, i0)
g := &truetype.GlyphBuf{}
err = g.Load(f, fupe, i0, font.HintingNone)
if err != nil {
log.Println(err)
return
}
fmt.Printf("'%c' glyph\n", c0)
fmt.Printf("AdvanceWidth:%d LeftSideBearing:%d\n", hm.AdvanceWidth, hm.LeftSideBearing)
printGlyph(g)
i1 := f.Index(c1)
fmt.Printf("\n'%c', '%c' Kern:%d\n", c0, c1, f.Kern(fupe, i0, i1))
}
func (f *subface) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
r -= f.firstRune
if r < 0 || f.n <= int(r) {
return 0, false
}
return fixed.Int26_6(f.fontchars[r].width) << 6, true
}
// https://code.google.com/p/plotinum/source/browse/vg/font.go#160
func widthOfString(font *truetype.Font, size float64, s string) float64 {
// scale converts truetype.FUnit to float64
scale := size / float64(font.FUnitsPerEm())
width := 0
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := font.Index(rune)
if hasPrev {
width += int(font.Kern(fixed.Int26_6(font.FUnitsPerEm()), prev, index))
}
width += int(font.HMetric(fixed.Int26_6(font.FUnitsPerEm()), index).AdvanceWidth)
prev, hasPrev = index, true
}
return float64(width) * scale
}
// unscaledHMetric returns the unscaled horizontal metrics for the glyph with
// the given index.
func (f *Font) unscaledHMetric(i Index) (h HMetric) {
j := int(i)
if j < 0 || f.nGlyph <= j {
return HMetric{}
}
if j >= f.nHMetric {
p := 4 * (f.nHMetric - 1)
return HMetric{
AdvanceWidth: fixed.Int26_6(u16(f.hmtx, p)),
LeftSideBearing: fixed.Int26_6(int16(u16(f.hmtx, p+2*(j-f.nHMetric)+4))),
}
}
return HMetric{
AdvanceWidth: fixed.Int26_6(u16(f.hmtx, 4*j)),
LeftSideBearing: fixed.Int26_6(int16(u16(f.hmtx, 4*j+2))),
}
}
// Add2 adds a quadratic segment to the current curve.
func (r *Rasterizer) Add2(b, c fixed.Point26_6) {
// Calculate nSplit (the number of recursive decompositions) based on how
// 'curvy' it is. Specifically, how much the middle point b deviates from
// (a+c)/2.
dev := maxAbs(r.a.X-2*b.X+c.X, r.a.Y-2*b.Y+c.Y) / fixed.Int26_6(r.splitScale2)
nsplit := 0
for dev > 0 {
dev /= 4
nsplit++
}
// dev is 32-bit, and nsplit++ every time we shift off 2 bits, so maxNsplit
// is 16.
const maxNsplit = 16
if nsplit > maxNsplit {
panic("freetype/raster: Add2 nsplit too large: " + strconv.Itoa(nsplit))
}
// Recursively decompose the curve nSplit levels deep.
var (
pStack [2*maxNsplit + 3]fixed.Point26_6
sStack [maxNsplit + 1]int
i int
)
sStack[0] = nsplit
pStack[0] = c
pStack[1] = b
pStack[2] = r.a
for i >= 0 {
s := sStack[i]
p := pStack[2*i:]
if s > 0 {
// Split the quadratic curve p[:3] into an equivalent set of two
// shorter curves: p[:3] and p[2:5]. The new p[4] is the old p[2],
// and p[0] is unchanged.
mx := p[1].X
p[4].X = p[2].X
p[3].X = (p[4].X + mx) / 2
p[1].X = (p[0].X + mx) / 2
p[2].X = (p[1].X + p[3].X) / 2
my := p[1].Y
p[4].Y = p[2].Y
p[3].Y = (p[4].Y + my) / 2
p[1].Y = (p[0].Y + my) / 2
p[2].Y = (p[1].Y + p[3].Y) / 2
// The two shorter curves have one less split to do.
sStack[i] = s - 1
sStack[i+1] = s - 1
i++
} else {
// Replace the level-0 quadratic with a two-linear-piece
// approximation.
midx := (p[0].X + 2*p[1].X + p[2].X) / 4
midy := (p[0].Y + 2*p[1].Y + p[2].Y) / 4
r.Add1(fixed.Point26_6{midx, midy})
r.Add1(p[0])
i--
}
}
}
// Extents returns the FontExtents for a font.
// TODO needs to read this https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/Chap2.html#intro
func Extents(font *truetype.Font, size float64) FontExtents {
bounds := font.Bounds(fixed.Int26_6(font.FUnitsPerEm()))
scale := size / float64(font.FUnitsPerEm())
return FontExtents{
Ascent: float64(bounds.YMax) * scale,
Descent: float64(bounds.YMin) * scale,
Height: float64(bounds.YMax-bounds.YMin) * scale,
}
}
// Extents returns the FontExtents for a font.
func (f *Font) Extents() FontExtents {
bounds := f.font.Bounds(fixed.Int26_6(f.Font().FUnitsPerEm()))
scale := f.Size / Points(float64(f.Font().FUnitsPerEm()))
return FontExtents{
Ascent: Points(float64(bounds.Max.Y)) * scale,
Descent: Points(float64(bounds.Min.Y)) * scale,
Height: Points(float64(bounds.Max.Y-bounds.Min.Y)) * scale,
}
}
func (f *Font) parseHead() error {
if len(f.head) != 54 {
return FormatError(fmt.Sprintf("bad head length: %d", len(f.head)))
}
f.fUnitsPerEm = int32(u16(f.head, 18))
f.bounds.Min.X = fixed.Int26_6(int16(u16(f.head, 36)))
f.bounds.Min.Y = fixed.Int26_6(int16(u16(f.head, 38)))
f.bounds.Max.X = fixed.Int26_6(int16(u16(f.head, 40)))
f.bounds.Max.Y = fixed.Int26_6(int16(u16(f.head, 42)))
switch i := u16(f.head, 50); i {
case 0:
f.locaOffsetFormat = locaOffsetFormatShort
case 1:
f.locaOffsetFormat = locaOffsetFormatLong
default:
return FormatError(fmt.Sprintf("bad indexToLocFormat: %d", i))
}
return nil
}
func (gc *GraphicContext) drawGlyph(glyph truetype.Index, dx, dy float64) error {
if err := gc.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), glyph, expfont.HintingNone); err != nil {
return err
}
e0 := 0
for _, e1 := range gc.glyphBuf.End {
DrawContour(gc, gc.glyphBuf.Point[e0:e1], dx, dy)
e0 = e1
}
return nil
}
func (f *Font) TextDimensions(text string) (int, int, int) {
fnt := f.ttf
size := f.Size
var (
totalWidth = fixed.Int26_6(0)
totalHeight = fixed.Int26_6(size)
maxYBearing = fixed.Int26_6(0)
)
fupe := fixed.Int26_6(fnt.FUnitsPerEm())
for _, char := range text {
idx := fnt.Index(char)
hm := fnt.HMetric(fupe, idx)
vm := fnt.VMetric(fupe, idx)
g := truetype.GlyphBuf{}
err := g.Load(fnt, fupe, idx, font.HintingNone)
if err != nil {
log.Println(err)
return 0, 0, 0
}
totalWidth += hm.AdvanceWidth
yB := (vm.TopSideBearing * fixed.Int26_6(size)) / fupe
if yB > maxYBearing {
maxYBearing = yB
}
}
// Scale to actual pixel size
totalWidth *= fixed.Int26_6(size)
totalWidth /= fupe
return int(totalWidth), int(totalHeight), int(maxYBearing)
}
// CreateStringPath creates a path from the string s at x, y, and returns the string width.
// The text is placed so that the left edge of the em square of the first character of s
// and the baseline intersect at x, y. 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.
func (gc *GraphicContext) CreateStringPath(s string, x, y float64) float64 {
font, err := gc.loadCurrentFont()
if err != nil {
log.Println(err)
return 0.0
}
startx := x
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := font.Index(rune)
if hasPrev {
x += fUnitsToFloat64(int32(font.Kern(fixed.Int26_6(gc.Current.Scale), prev, index)))
}
err := gc.drawGlyph(index, x, y)
if err != nil {
log.Println(err)
return startx - x
}
x += fUnitsToFloat64(int32(font.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth))
prev, hasPrev = index, true
}
return x - startx
}
func TestKern(t *testing.T) {
base, _ := NewFontWithName("Verdana")
defer base.Close()
face := base.Face(text.FaceData{
Size: 20.0,
DPI: 144,
})
defer face.Close()
if kern := face.Kern('W', '\\'); kern != -fixed.Int26_6(12) {
t.Error("invalid kerning for characters 'W' and '\\':", kern)
}
}
func (h *hinter) move(p *Point, distance fixed.Int26_6, touch bool) {
fvx := int64(h.gs.fv[0])
pvx := int64(h.gs.pv[0])
if fvx == 0x4000 && pvx == 0x4000 {
p.X += fixed.Int26_6(distance)
if touch {
p.Flags |= flagTouchedX
}
return
}
fvy := int64(h.gs.fv[1])
pvy := int64(h.gs.pv[1])
if fvy == 0x4000 && pvy == 0x4000 {
p.Y += fixed.Int26_6(distance)
if touch {
p.Flags |= flagTouchedY
}
return
}
fvDotPv := (fvx*pvx + fvy*pvy) >> 14
if fvx != 0 {
p.X += fixed.Int26_6(mulDiv(fvx, int64(distance), fvDotPv))
if touch {
p.Flags |= flagTouchedX
}
}
if fvy != 0 {
p.Y += fixed.Int26_6(mulDiv(fvy, int64(distance), fvDotPv))
if touch {
p.Flags |= flagTouchedY
}
}
}