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image/font: expose caret slope

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Change-Id: I775224dd3fc7e5b6c2fc5c4a7d3db83bb36d047d
Reviewed-on: https://go-review.googlesource.com/136255
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
This commit is contained in:
Elias Naur 2018-09-19 13:48:13 +02:00 committed by Nigel Tao
parent e1a1ede689
commit 991ec62608
8 changed files with 61 additions and 34 deletions
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11
font/basicfont/basicfont.go
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@ -77,11 +77,12 @@ func (f *Face) Kern(r0, r1 rune) fixed.Int26_6 { return 0 }
func (f *Face) Metrics() font.Metrics {
return font.Metrics{
Height: fixed.I(f.Height),
Ascent: fixed.I(f.Ascent),
Descent: fixed.I(f.Descent),
XHeight: fixed.I(f.Ascent),
CapHeight: fixed.I(f.Ascent),
Height: fixed.I(f.Height),
Ascent: fixed.I(f.Ascent),
Descent: fixed.I(f.Descent),
XHeight: fixed.I(f.Ascent),
CapHeight: fixed.I(f.Ascent),
CaretSlope: image.Point{X: 0, Y: 1},
}
}

3
font/basicfont/basicfont_test.go
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@ -5,13 +5,14 @@
package basicfont
import (
"image"
"testing"
"golang.org/x/image/font"
)
func TestMetrics(t *testing.T) {
want := font.Metrics{Height: 832, Ascent: 704, Descent: 128, XHeight: 704, CapHeight: 704}
want := font.Metrics{Height: 832, Ascent: 704, Descent: 128, XHeight: 704, CapHeight: 704, CaretSlope: image.Point{X: 0, Y: 1}}
if got := Face7x13.Metrics(); got != want {
t.Errorf("Face7x13: Metrics: got %v want %v", got, want)
}

4
font/font.go
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@ -94,6 +94,10 @@ type Metrics struct {
// CapHeight is the distance from the top of uppercase letters to the
// baseline.
CapHeight fixed.Int26_6
// CaretSlope is the slope of a caret as a vector with the Y axis pointing up.
// The slope {0, 1} is the vertical caret.
CaretSlope image.Point
}
// Drawer draws text on a destination image.

4
font/opentype/face_test.go
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@ -5,6 +5,7 @@
package opentype
import (
"image"
"testing"
"golang.org/x/image/font"
@ -82,7 +83,8 @@ func TestFaceKern(t *testing.T) {
}
func TestFaceMetrics(t *testing.T) {
want := font.Metrics{Height: 888, Ascent: 726, Descent: 162, XHeight: 407, CapHeight: 555}
want := font.Metrics{Height: 888, Ascent: 726, Descent: 162, XHeight: 407, CapHeight: 555,
CaretSlope: image.Point{X: 0, Y: 1}}
got := regular.Metrics()
if got != want {
t.Fatalf("metrics failed. got=%#v. want=%#v", got, want)

22
font/plan9font/plan9font.go
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@ -67,11 +67,12 @@ func (f *subface) Metrics() font.Metrics {
// The same applies to CapHeight, using the uppercase 'H'.
hbounds, _, _ := f.GlyphBounds('H')
return font.Metrics{
Height: fixed.I(f.height),
Ascent: fixed.I(f.ascent),
Descent: fixed.I(f.height - f.ascent),
XHeight: -xbounds.Min.Y,
CapHeight: -hbounds.Min.Y,
Height: fixed.I(f.height),
Ascent: fixed.I(f.ascent),
Descent: fixed.I(f.height - f.ascent),
XHeight: -xbounds.Min.Y,
CapHeight: -hbounds.Min.Y,
CaretSlope: image.Point{X: 0, Y: 1},
}
}
@ -153,11 +154,12 @@ func (f *face) Metrics() font.Metrics {
xbounds, _, _ := f.GlyphBounds('x')
hbounds, _, _ := f.GlyphBounds('H')
return font.Metrics{
Height: fixed.I(f.height),
Ascent: fixed.I(f.ascent),
Descent: fixed.I(f.height - f.ascent),
XHeight: -xbounds.Min.Y,
CapHeight: -hbounds.Min.Y,
Height: fixed.I(f.height),
Ascent: fixed.I(f.ascent),
Descent: fixed.I(f.height - f.ascent),
XHeight: -xbounds.Min.Y,
CapHeight: -hbounds.Min.Y,
CaretSlope: image.Point{X: 0, Y: 1},
}
}

4
font/plan9font/plan9font_test.go
View File

@ -5,6 +5,7 @@
package plan9font
import (
"image"
"io/ioutil"
"path"
"path/filepath"
@ -25,7 +26,8 @@ func TestMetrics(t *testing.T) {
if err != nil {
t.Fatal(err)
}
want := font.Metrics{Height: 832, Ascent: 704, Descent: 128, XHeight: 704, CapHeight: 704}
want := font.Metrics{Height: 832, Ascent: 704, Descent: 128, XHeight: 704, CapHeight: 704,
CaretSlope: image.Point{X: 0, Y: 1}}
if got := face.Metrics(); got != want {
t.Errorf("unicode.7x13.font: Metrics: got %v, want %v", got, want)
}

40
font/sfnt/sfnt.go
View File

@ -21,6 +21,7 @@ package sfnt // import "golang.org/x/image/font/sfnt"
import (
"errors"
"image"
"io"
"golang.org/x/image/font"
@ -579,6 +580,7 @@ type Font struct {
lineGap int32
numHMetrics int32
postTableVersion uint32
slope [2]int32
unitsPerEm Units
xHeight int32
}
@ -627,7 +629,7 @@ func (f *Font) initialize(offset int, isDfont bool) error {
if err != nil {
return err
}
buf, ascent, descent, lineGap, numHMetrics, err := f.parseHhea(buf, numGlyphs)
buf, ascent, descent, lineGap, run, rise, numHMetrics, err := f.parseHhea(buf, numGlyphs)
if err != nil {
return err
}
@ -658,6 +660,7 @@ func (f *Font) initialize(offset int, isDfont bool) error {
f.cached.lineGap = lineGap
f.cached.numHMetrics = numHMetrics
f.cached.postTableVersion = postTableVersion
f.cached.slope = [2]int32{run, rise}
f.cached.unitsPerEm = unitsPerEm
f.cached.xHeight = xHeight
@ -853,32 +856,40 @@ func (f *Font) parseHead(buf []byte) (buf1 []byte, bounds [4]int16, indexToLocFo
return buf, bounds, indexToLocFormat, unitsPerEm, nil
}
func (f *Font) parseHhea(buf []byte, numGlyphs int32) (buf1 []byte, ascent, descent, lineGap, numHMetrics int32, err error) {
func (f *Font) parseHhea(buf []byte, numGlyphs int32) (buf1 []byte, ascent, descent, lineGap, run, rise, numHMetrics int32, err error) {
// https://www.microsoft.com/typography/OTSPEC/hhea.htm
if f.hhea.length != 36 {
return nil, 0, 0, 0, 0, errInvalidHheaTable
return nil, 0, 0, 0, 0, 0, 0, errInvalidHheaTable
}
u, err := f.src.u16(buf, f.hhea, 34)
if err != nil {
return nil, 0, 0, 0, 0, err
return nil, 0, 0, 0, 0, 0, 0, err
}
if int32(u) > numGlyphs || u == 0 {
return nil, 0, 0, 0, 0, errInvalidHheaTable
return nil, 0, 0, 0, 0, 0, 0, errInvalidHheaTable
}
a, err := f.src.u16(buf, f.hhea, 4)
if err != nil {
return nil, 0, 0, 0, 0, err
return nil, 0, 0, 0, 0, 0, 0, err
}
d, err := f.src.u16(buf, f.hhea, 6)
if err != nil {
return nil, 0, 0, 0, 0, err
return nil, 0, 0, 0, 0, 0, 0, err
}
l, err := f.src.u16(buf, f.hhea, 8)
if err != nil {
return nil, 0, 0, 0, 0, err
return nil, 0, 0, 0, 0, 0, 0, err
}
return buf, int32(int16(a)), int32(int16(d)), int32(int16(l)), int32(u), nil
ru, err := f.src.u16(buf, f.hhea, 20)
if err != nil {
return nil, 0, 0, 0, 0, 0, 0, err
}
ri, err := f.src.u16(buf, f.hhea, 18)
if err != nil {
return nil, 0, 0, 0, 0, 0, 0, err
}
return buf, int32(int16(a)), int32(int16(d)), int32(int16(l)), int32(int16(ru)), int32(int16(ri)), int32(u), nil
}
func (f *Font) parseHmtx(buf []byte, numGlyphs, numHMetrics int32) (buf1 []byte, err error) {
@ -1384,11 +1395,12 @@ func (f *Font) Kern(b *Buffer, x0, x1 GlyphIndex, ppem fixed.Int26_6, h font.Hin
// Metrics returns the metrics of this font.
func (f *Font) Metrics(b *Buffer, ppem fixed.Int26_6, h font.Hinting) (font.Metrics, error) {
m := font.Metrics{
Height: scale(fixed.Int26_6(f.cached.ascent-f.cached.descent+f.cached.lineGap)*ppem, f.cached.unitsPerEm),
Ascent: +scale(fixed.Int26_6(f.cached.ascent)*ppem, f.cached.unitsPerEm),
Descent: -scale(fixed.Int26_6(f.cached.descent)*ppem, f.cached.unitsPerEm),
XHeight: scale(fixed.Int26_6(f.cached.xHeight)*ppem, f.cached.unitsPerEm),
CapHeight: scale(fixed.Int26_6(f.cached.capHeight)*ppem, f.cached.unitsPerEm),
Height: scale(fixed.Int26_6(f.cached.ascent-f.cached.descent+f.cached.lineGap)*ppem, f.cached.unitsPerEm),
Ascent: +scale(fixed.Int26_6(f.cached.ascent)*ppem, f.cached.unitsPerEm),
Descent: -scale(fixed.Int26_6(f.cached.descent)*ppem, f.cached.unitsPerEm),
XHeight: scale(fixed.Int26_6(f.cached.xHeight)*ppem, f.cached.unitsPerEm),
CapHeight: scale(fixed.Int26_6(f.cached.capHeight)*ppem, f.cached.unitsPerEm),
CaretSlope: image.Point{X: int(f.cached.slope[0]), Y: int(f.cached.slope[1])},
}
if h == font.HintingFull {
// Quantize up to a whole pixel.

7
font/sfnt/sfnt_test.go
View File

@ -7,6 +7,7 @@ package sfnt
import (
"bytes"
"fmt"
"image"
"io/ioutil"
"path/filepath"
"testing"
@ -223,9 +224,11 @@ func TestMetrics(t *testing.T) {
font []byte
want font.Metrics
}{
"goregular": {goregular.TTF, font.Metrics{Height: 2367, Ascent: 1935, Descent: 432, XHeight: 1086, CapHeight: 1480}},
"goregular": {goregular.TTF, font.Metrics{Height: 2367, Ascent: 1935, Descent: 432, XHeight: 1086, CapHeight: 1480,
CaretSlope: image.Point{X: 0, Y: 1}}},
// cmapTest.ttf has a non-zero lineGap.
"cmapTest": {cmapFont, font.Metrics{Height: 1549, Ascent: 1365, Descent: 0, XHeight: 800, CapHeight: 800}},
"cmapTest": {cmapFont, font.Metrics{Height: 1549, Ascent: 1365, Descent: 0, XHeight: 800, CapHeight: 800,
CaretSlope: image.Point{X: 20, Y: 100}}},
}
var b Buffer
for name, tc := range testCases {