go-chart/drawing/painter.go
2016-07-08 17:57:14 -07:00

32 lines
837 B
Go

package drawing
import (
"image"
"image/color"
"golang.org/x/image/draw"
"golang.org/x/image/math/f64"
"github.com/golang/freetype/raster"
)
// Painter implements the freetype raster.Painter and has a SetColor method like the RGBAPainter
type Painter interface {
raster.Painter
SetColor(color color.Color)
}
// DrawImage draws an image into dest using an affine transformation matrix, an op and a filter
func DrawImage(src image.Image, dest draw.Image, tr Matrix, op draw.Op, filter ImageFilter) {
var transformer draw.Transformer
switch filter {
case LinearFilter:
transformer = draw.NearestNeighbor
case BilinearFilter:
transformer = draw.BiLinear
case BicubicFilter:
transformer = draw.CatmullRom
}
transformer.Transform(dest, f64.Aff3{tr[0], tr[1], tr[4], tr[2], tr[3], tr[5]}, src, src.Bounds(), op, nil)
}