ebiten/text/v2/gotextseg.go

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// Copyright 2023 The Ebitengine Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package text
import (
"image"
"image/draw"
"math"
"github.com/go-text/typesetting/opentype/api"
"golang.org/x/image/math/fixed"
"golang.org/x/image/vector"
"github.com/hajimehoshi/ebiten/v2"
)
func segmentsToBounds(segs []api.Segment) fixed.Rectangle26_6 {
if len(segs) == 0 {
return fixed.Rectangle26_6{}
}
minX := float32(math.Inf(1))
minY := float32(math.Inf(1))
maxX := float32(math.Inf(-1))
maxY := float32(math.Inf(-1))
for _, seg := range segs {
n := 1
switch seg.Op {
case api.SegmentOpQuadTo:
n = 2
case api.SegmentOpCubeTo:
n = 3
}
for i := 0; i < n; i++ {
x := seg.Args[i].X
y := seg.Args[i].Y
if minX > x {
minX = x
}
if minY > y {
minY = y
}
if maxX < x {
maxX = x
}
if maxY < y {
maxY = y
}
}
}
return fixed.Rectangle26_6{
Min: fixed.Point26_6{
X: float32ToFixed26_6(minX),
Y: float32ToFixed26_6(minY),
},
Max: fixed.Point26_6{
X: float32ToFixed26_6(maxX),
Y: float32ToFixed26_6(maxY),
},
}
}
func segmentsToImage(segs []api.Segment, subpixelOffset fixed.Point26_6, glyphBounds fixed.Rectangle26_6) *ebiten.Image {
if len(segs) == 0 {
return nil
}
w, h := (glyphBounds.Max.X - glyphBounds.Min.X).Ceil(), (glyphBounds.Max.Y - glyphBounds.Min.Y).Ceil()
if w == 0 || h == 0 {
return nil
}
if glyphBounds.Min.X&((1<<6)-1) != 0 {
w++
}
if glyphBounds.Min.Y&((1<<6)-1) != 0 {
h++
}
biasX := fixed26_6ToFloat32(-glyphBounds.Min.X + subpixelOffset.X)
biasY := fixed26_6ToFloat32(-glyphBounds.Min.Y + subpixelOffset.Y)
rast := vector.NewRasterizer(w, h)
rast.DrawOp = draw.Src
for _, seg := range segs {
switch seg.Op {
case api.SegmentOpMoveTo:
rast.MoveTo(seg.Args[0].X+biasX, seg.Args[0].Y+biasY)
case api.SegmentOpLineTo:
rast.LineTo(seg.Args[0].X+biasX, seg.Args[0].Y+biasY)
case api.SegmentOpQuadTo:
rast.QuadTo(
seg.Args[0].X+biasX, seg.Args[0].Y+biasY,
seg.Args[1].X+biasX, seg.Args[1].Y+biasY,
)
case api.SegmentOpCubeTo:
rast.CubeTo(
seg.Args[0].X+biasX, seg.Args[0].Y+biasY,
seg.Args[1].X+biasX, seg.Args[1].Y+biasY,
seg.Args[2].X+biasX, seg.Args[2].Y+biasY,
)
}
}
dst := image.NewAlpha(image.Rect(0, 0, w, h))
rast.Draw(dst, dst.Bounds(), image.Opaque, image.Point{})
return ebiten.NewImageFromImage(dst)
}