зеркало из https://github.com/golang/image.git
font/opentype: merge face.go into opentype.go
There's no need for two .go files if one of them is just a placeholder. If we're only going to have one, it might as well have the same name as the package. Change-Id: I0eb639d00e84f0d942adca49b1391987ae77bd7b Reviewed-on: https://go-review.googlesource.com/c/image/+/257538 Reviewed-by: Hajime Hoshi <hajimehoshi@gmail.com> Trust: Nigel Tao <nigeltao@golang.org>
This commit is contained in:
Nigel Tao
Родитель
2fd4ef34c9
Коммит
a67d67e093
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@ -1,217 +0,0 @@
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// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package opentype
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import (
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"image"
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"image/draw"
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"golang.org/x/image/font"
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"golang.org/x/image/font/sfnt"
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"golang.org/x/image/math/fixed"
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"golang.org/x/image/vector"
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)
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// FaceOptions describes the possible options given to NewFace when
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// creating a new font.Face from a sfnt.Font.
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type FaceOptions struct {
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Size float64 // Size is the font size in points
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DPI float64 // DPI is the dots per inch resolution
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Hinting font.Hinting // Hinting selects how to quantize a vector font's glyph nodes
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}
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func defaultFaceOptions() *FaceOptions {
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return &FaceOptions{
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Size: 12,
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DPI: 72,
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Hinting: font.HintingNone,
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}
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}
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// Face implements the font.Face interface for sfnt.Font values.
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type Face struct {
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f *sfnt.Font
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hinting font.Hinting
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scale fixed.Int26_6
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metrics font.Metrics
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metricsSet bool
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buf sfnt.Buffer
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rast vector.Rasterizer
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mask image.Alpha
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}
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// NewFace returns a new font.Face for the given sfnt.Font.
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// if opts is nil, sensible defaults will be used.
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func NewFace(f *sfnt.Font, opts *FaceOptions) (font.Face, error) {
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if opts == nil {
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opts = defaultFaceOptions()
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}
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face := &Face{
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f: f,
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hinting: opts.Hinting,
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scale: fixed.Int26_6(0.5 + (opts.Size * opts.DPI * 64 / 72)),
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}
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return face, nil
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}
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// Close satisfies the font.Face interface.
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func (f *Face) Close() error {
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return nil
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}
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// Metrics satisfies the font.Face interface.
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func (f *Face) Metrics() font.Metrics {
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if !f.metricsSet {
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var err error
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f.metrics, err = f.f.Metrics(&f.buf, f.scale, f.hinting)
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if err != nil {
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f.metrics = font.Metrics{}
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}
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f.metricsSet = true
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}
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return f.metrics
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}
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// Kern satisfies the font.Face interface.
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func (f *Face) Kern(r0, r1 rune) fixed.Int26_6 {
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x0 := f.index(r0)
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x1 := f.index(r1)
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k, err := f.f.Kern(&f.buf, x0, x1, fixed.Int26_6(f.f.UnitsPerEm()), f.hinting)
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if err != nil {
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return 0
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}
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return k
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}
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// Glyph satisfies the font.Face interface.
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func (f *Face) Glyph(dot fixed.Point26_6, r rune) (dr image.Rectangle, mask image.Image, maskp image.Point, advance fixed.Int26_6, ok bool) {
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x, err := f.f.GlyphIndex(&f.buf, r)
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if err != nil {
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return image.Rectangle{}, nil, image.Point{}, 0, false
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}
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// Call f.f.GlyphAdvance before f.f.LoadGlyph because the LoadGlyph docs
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// say this about the &f.buf argument: the segments become invalid to use
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// once [the buffer] is re-used.
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advance, err = f.f.GlyphAdvance(&f.buf, x, f.scale, f.hinting)
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if err != nil {
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return image.Rectangle{}, nil, image.Point{}, 0, false
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}
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segments, err := f.f.LoadGlyph(&f.buf, x, f.scale, nil)
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if err != nil {
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return image.Rectangle{}, nil, image.Point{}, 0, false
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}
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// Numerical notation used below:
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// - 2 is an integer, "two"
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// - 2:16 is a 26.6 fixed point number, "two and a quarter"
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// - 2.5 is a float32 number, "two and a half"
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// Using 26.6 fixed point numbers means that there are 64 sub-pixel units
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// in 1 integer pixel unit.
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// Translate the sub-pixel bounding box from glyph space (where the glyph
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// origin is at (0:00, 0:00)) to dst space (where the glyph origin is at
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// the dot). dst space is the coordinate space that contains both the dot
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// (a sub-pixel position) and dr (an integer-pixel rectangle).
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dBounds := segments.Bounds().Add(dot)
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// Quantize the sub-pixel bounds (dBounds) to integer-pixel bounds (dr).
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dr.Min.X = dBounds.Min.X.Floor()
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dr.Min.Y = dBounds.Min.Y.Floor()
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dr.Max.X = dBounds.Max.X.Ceil()
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dr.Max.Y = dBounds.Max.Y.Ceil()
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width := dr.Dx()
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height := dr.Dy()
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if width < 0 || height < 0 {
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return image.Rectangle{}, nil, image.Point{}, 0, false
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}
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// Calculate the sub-pixel bias to convert from glyph space to rasterizer
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// space. In glyph space, the segments may be to the left or right and
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// above or below the glyph origin. In rasterizer space, the segments
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// should only be right and below (or equal to) the top-left corner (0.0,
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// 0.0). They should also be left and above (or equal to) the bottom-right
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// corner (width, height), as the rasterizer should enclose the glyph
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// bounding box.
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//
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// For example, suppose that dot.X was at the sub-pixel position 25:48,
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// three quarters of the way into the 26th pixel, and that bounds.Min.X was
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// 1:20. We then have dBounds.Min.X = 1:20 + 25:48 = 27:04, dr.Min.X = 27
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// and biasX = 25:48 - 27:00 = -1:16. A vertical stroke at 1:20 in glyph
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// space becomes (1:20 + -1:16) = 0:04 in rasterizer space. 0:04 as a
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// fixed.Int26_6 value is float32(4)/64.0 = 0.0625 as a float32 value.
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biasX := dot.X - fixed.Int26_6(dr.Min.X<<6)
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biasY := dot.Y - fixed.Int26_6(dr.Min.Y<<6)
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// Configure the mask image, re-allocating its buffer if necessary.
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nPixels := width * height
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if cap(f.mask.Pix) < nPixels {
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f.mask.Pix = make([]uint8, 2*nPixels)
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}
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f.mask.Pix = f.mask.Pix[:nPixels]
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f.mask.Stride = width
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f.mask.Rect.Min.X = 0
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f.mask.Rect.Min.Y = 0
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f.mask.Rect.Max.X = width
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f.mask.Rect.Max.Y = height
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// Rasterize the biased segments, converting from fixed.Int26_6 to float32.
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f.rast.Reset(width, height)
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f.rast.DrawOp = draw.Src
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for _, seg := range segments {
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switch seg.Op {
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case sfnt.SegmentOpMoveTo:
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f.rast.MoveTo(
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float32(seg.Args[0].X+biasX)/64,
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float32(seg.Args[0].Y+biasY)/64,
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)
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case sfnt.SegmentOpLineTo:
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f.rast.LineTo(
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float32(seg.Args[0].X+biasX)/64,
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float32(seg.Args[0].Y+biasY)/64,
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)
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case sfnt.SegmentOpQuadTo:
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f.rast.QuadTo(
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float32(seg.Args[0].X+biasX)/64,
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float32(seg.Args[0].Y+biasY)/64,
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float32(seg.Args[1].X+biasX)/64,
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float32(seg.Args[1].Y+biasY)/64,
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)
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case sfnt.SegmentOpCubeTo:
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f.rast.CubeTo(
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float32(seg.Args[0].X+biasX)/64,
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float32(seg.Args[0].Y+biasY)/64,
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float32(seg.Args[1].X+biasX)/64,
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float32(seg.Args[1].Y+biasY)/64,
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float32(seg.Args[2].X+biasX)/64,
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float32(seg.Args[2].Y+biasY)/64,
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)
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}
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}
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f.rast.Draw(&f.mask, f.mask.Bounds(), image.Opaque, image.Point{})
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return dr, &f.mask, f.mask.Rect.Min, advance, true
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}
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// GlyphBounds satisfies the font.Face interface.
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func (f *Face) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) {
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bounds, advance, err := f.f.GlyphBounds(&f.buf, f.index(r), f.scale, f.hinting)
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return bounds, advance, err == nil
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}
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// GlyphAdvance satisfies the font.Face interface.
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func (f *Face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
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advance, err := f.f.GlyphAdvance(&f.buf, f.index(r), f.scale, f.hinting)
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return advance, err == nil
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}
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func (f *Face) index(r rune) sfnt.GlyphIndex {
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x, _ := f.f.GlyphIndex(&f.buf, r)
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return x
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}
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@ -5,3 +5,215 @@
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// Package opentype implements the font.Face interface based on SFNT
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// font file formats.
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package opentype // import "golang.org/x/image/font/opentype"
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import (
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"image"
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"image/draw"
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"golang.org/x/image/font"
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"golang.org/x/image/font/sfnt"
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"golang.org/x/image/math/fixed"
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"golang.org/x/image/vector"
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)
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// FaceOptions describes the possible options given to NewFace when
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// creating a new font.Face from a sfnt.Font.
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type FaceOptions struct {
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Size float64 // Size is the font size in points
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DPI float64 // DPI is the dots per inch resolution
|
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Hinting font.Hinting // Hinting selects how to quantize a vector font's glyph nodes
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}
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|
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func defaultFaceOptions() *FaceOptions {
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return &FaceOptions{
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Size: 12,
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DPI: 72,
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Hinting: font.HintingNone,
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}
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}
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// Face implements the font.Face interface for sfnt.Font values.
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type Face struct {
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f *sfnt.Font
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hinting font.Hinting
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scale fixed.Int26_6
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metrics font.Metrics
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metricsSet bool
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buf sfnt.Buffer
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rast vector.Rasterizer
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mask image.Alpha
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}
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// NewFace returns a new font.Face for the given sfnt.Font.
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// if opts is nil, sensible defaults will be used.
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func NewFace(f *sfnt.Font, opts *FaceOptions) (font.Face, error) {
|
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if opts == nil {
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opts = defaultFaceOptions()
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}
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face := &Face{
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f: f,
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hinting: opts.Hinting,
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scale: fixed.Int26_6(0.5 + (opts.Size * opts.DPI * 64 / 72)),
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}
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return face, nil
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}
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// Close satisfies the font.Face interface.
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func (f *Face) Close() error {
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return nil
|
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}
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|
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// Metrics satisfies the font.Face interface.
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func (f *Face) Metrics() font.Metrics {
|
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if !f.metricsSet {
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var err error
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f.metrics, err = f.f.Metrics(&f.buf, f.scale, f.hinting)
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if err != nil {
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f.metrics = font.Metrics{}
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}
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f.metricsSet = true
|
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}
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return f.metrics
|
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}
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|
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// Kern satisfies the font.Face interface.
|
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func (f *Face) Kern(r0, r1 rune) fixed.Int26_6 {
|
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x0 := f.index(r0)
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x1 := f.index(r1)
|
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k, err := f.f.Kern(&f.buf, x0, x1, fixed.Int26_6(f.f.UnitsPerEm()), f.hinting)
|
||||
if err != nil {
|
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return 0
|
||||
}
|
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return k
|
||||
}
|
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|
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// Glyph satisfies the font.Face interface.
|
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func (f *Face) Glyph(dot fixed.Point26_6, r rune) (dr image.Rectangle, mask image.Image, maskp image.Point, advance fixed.Int26_6, ok bool) {
|
||||
x, err := f.f.GlyphIndex(&f.buf, r)
|
||||
if err != nil {
|
||||
return image.Rectangle{}, nil, image.Point{}, 0, false
|
||||
}
|
||||
|
||||
// Call f.f.GlyphAdvance before f.f.LoadGlyph because the LoadGlyph docs
|
||||
// say this about the &f.buf argument: the segments become invalid to use
|
||||
// once [the buffer] is re-used.
|
||||
|
||||
advance, err = f.f.GlyphAdvance(&f.buf, x, f.scale, f.hinting)
|
||||
if err != nil {
|
||||
return image.Rectangle{}, nil, image.Point{}, 0, false
|
||||
}
|
||||
|
||||
segments, err := f.f.LoadGlyph(&f.buf, x, f.scale, nil)
|
||||
if err != nil {
|
||||
return image.Rectangle{}, nil, image.Point{}, 0, false
|
||||
}
|
||||
|
||||
// Numerical notation used below:
|
||||
// - 2 is an integer, "two"
|
||||
// - 2:16 is a 26.6 fixed point number, "two and a quarter"
|
||||
// - 2.5 is a float32 number, "two and a half"
|
||||
// Using 26.6 fixed point numbers means that there are 64 sub-pixel units
|
||||
// in 1 integer pixel unit.
|
||||
|
||||
// Translate the sub-pixel bounding box from glyph space (where the glyph
|
||||
// origin is at (0:00, 0:00)) to dst space (where the glyph origin is at
|
||||
// the dot). dst space is the coordinate space that contains both the dot
|
||||
// (a sub-pixel position) and dr (an integer-pixel rectangle).
|
||||
dBounds := segments.Bounds().Add(dot)
|
||||
|
||||
// Quantize the sub-pixel bounds (dBounds) to integer-pixel bounds (dr).
|
||||
dr.Min.X = dBounds.Min.X.Floor()
|
||||
dr.Min.Y = dBounds.Min.Y.Floor()
|
||||
dr.Max.X = dBounds.Max.X.Ceil()
|
||||
dr.Max.Y = dBounds.Max.Y.Ceil()
|
||||
width := dr.Dx()
|
||||
height := dr.Dy()
|
||||
if width < 0 || height < 0 {
|
||||
return image.Rectangle{}, nil, image.Point{}, 0, false
|
||||
}
|
||||
|
||||
// Calculate the sub-pixel bias to convert from glyph space to rasterizer
|
||||
// space. In glyph space, the segments may be to the left or right and
|
||||
// above or below the glyph origin. In rasterizer space, the segments
|
||||
// should only be right and below (or equal to) the top-left corner (0.0,
|
||||
// 0.0). They should also be left and above (or equal to) the bottom-right
|
||||
// corner (width, height), as the rasterizer should enclose the glyph
|
||||
// bounding box.
|
||||
//
|
||||
// For example, suppose that dot.X was at the sub-pixel position 25:48,
|
||||
// three quarters of the way into the 26th pixel, and that bounds.Min.X was
|
||||
// 1:20. We then have dBounds.Min.X = 1:20 + 25:48 = 27:04, dr.Min.X = 27
|
||||
// and biasX = 25:48 - 27:00 = -1:16. A vertical stroke at 1:20 in glyph
|
||||
// space becomes (1:20 + -1:16) = 0:04 in rasterizer space. 0:04 as a
|
||||
// fixed.Int26_6 value is float32(4)/64.0 = 0.0625 as a float32 value.
|
||||
biasX := dot.X - fixed.Int26_6(dr.Min.X<<6)
|
||||
biasY := dot.Y - fixed.Int26_6(dr.Min.Y<<6)
|
||||
|
||||
// Configure the mask image, re-allocating its buffer if necessary.
|
||||
nPixels := width * height
|
||||
if cap(f.mask.Pix) < nPixels {
|
||||
f.mask.Pix = make([]uint8, 2*nPixels)
|
||||
}
|
||||
f.mask.Pix = f.mask.Pix[:nPixels]
|
||||
f.mask.Stride = width
|
||||
f.mask.Rect.Min.X = 0
|
||||
f.mask.Rect.Min.Y = 0
|
||||
f.mask.Rect.Max.X = width
|
||||
f.mask.Rect.Max.Y = height
|
||||
|
||||
// Rasterize the biased segments, converting from fixed.Int26_6 to float32.
|
||||
f.rast.Reset(width, height)
|
||||
f.rast.DrawOp = draw.Src
|
||||
for _, seg := range segments {
|
||||
switch seg.Op {
|
||||
case sfnt.SegmentOpMoveTo:
|
||||
f.rast.MoveTo(
|
||||
float32(seg.Args[0].X+biasX)/64,
|
||||
float32(seg.Args[0].Y+biasY)/64,
|
||||
)
|
||||
case sfnt.SegmentOpLineTo:
|
||||
f.rast.LineTo(
|
||||
float32(seg.Args[0].X+biasX)/64,
|
||||
float32(seg.Args[0].Y+biasY)/64,
|
||||
)
|
||||
case sfnt.SegmentOpQuadTo:
|
||||
f.rast.QuadTo(
|
||||
float32(seg.Args[0].X+biasX)/64,
|
||||
float32(seg.Args[0].Y+biasY)/64,
|
||||
float32(seg.Args[1].X+biasX)/64,
|
||||
float32(seg.Args[1].Y+biasY)/64,
|
||||
)
|
||||
case sfnt.SegmentOpCubeTo:
|
||||
f.rast.CubeTo(
|
||||
float32(seg.Args[0].X+biasX)/64,
|
||||
float32(seg.Args[0].Y+biasY)/64,
|
||||
float32(seg.Args[1].X+biasX)/64,
|
||||
float32(seg.Args[1].Y+biasY)/64,
|
||||
float32(seg.Args[2].X+biasX)/64,
|
||||
float32(seg.Args[2].Y+biasY)/64,
|
||||
)
|
||||
}
|
||||
}
|
||||
f.rast.Draw(&f.mask, f.mask.Bounds(), image.Opaque, image.Point{})
|
||||
|
||||
return dr, &f.mask, f.mask.Rect.Min, advance, true
|
||||
}
|
||||
|
||||
// GlyphBounds satisfies the font.Face interface.
|
||||
func (f *Face) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) {
|
||||
bounds, advance, err := f.f.GlyphBounds(&f.buf, f.index(r), f.scale, f.hinting)
|
||||
return bounds, advance, err == nil
|
||||
}
|
||||
|
||||
// GlyphAdvance satisfies the font.Face interface.
|
||||
func (f *Face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
|
||||
advance, err := f.f.GlyphAdvance(&f.buf, f.index(r), f.scale, f.hinting)
|
||||
return advance, err == nil
|
||||
}
|
||||
|
||||
func (f *Face) index(r rune) sfnt.GlyphIndex {
|
||||
x, _ := f.f.GlyphIndex(&f.buf, r)
|
||||
return x
|
||||
}
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче