go-chart/drawing/painter.go

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2016-07-09 02:57:14 +02:00
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)
}