53 lines
1.3 KiB
Go
53 lines
1.3 KiB
Go
package caption
|
|
|
|
import (
|
|
"image"
|
|
"image/color"
|
|
|
|
"github.com/golang/freetype/truetype"
|
|
"golang.org/x/image/draw"
|
|
"golang.org/x/image/font"
|
|
"golang.org/x/image/math/fixed"
|
|
)
|
|
|
|
type Line struct {
|
|
// collection of all text segments
|
|
Data []Segment `json:"data"`
|
|
// applies to all segments; avoid direct assignment and use SetFont instead
|
|
Font []byte `json:"font"`
|
|
// applies to all segments; avoid direct assignment and use SetFont instead
|
|
Options *truetype.Options `json:"options"`
|
|
|
|
// contains reference to parsed font, populated once per instance
|
|
face font.Face
|
|
}
|
|
|
|
// SetFont clears line font cache and sets the new font.
|
|
func (l *Line) SetFont(v []byte, opts *truetype.Options) { l.face = nil; l.Font = v; l.Options = opts }
|
|
|
|
type Segment struct {
|
|
Value string `json:"value"`
|
|
Color color.Color `json:"color"`
|
|
}
|
|
|
|
func (l *Line) Render(frame draw.Image, x, y int) error {
|
|
if l.face == nil {
|
|
if len(l.Font) == 0 {
|
|
l.SetFont(defaultFont, l.Options)
|
|
}
|
|
if f, err := truetype.Parse(l.Font); err != nil {
|
|
return err
|
|
} else {
|
|
l.face = truetype.NewFace(f, l.Options)
|
|
}
|
|
}
|
|
|
|
drawer := &font.Drawer{Dst: frame, Face: l.face, Dot: fixed.Point26_6{X: fixed.I(x), Y: fixed.I(y)}}
|
|
for _, seg := range l.Data {
|
|
drawer.Src = image.NewUniform(seg.Color)
|
|
drawer.DrawString(seg.Value)
|
|
}
|
|
|
|
return nil
|
|
}
|