canvas

type AreaRect struct {
	MinX, MaxX, MinY, MaxY int
}

type DrawStringParams struct {
	Color   color.Color
	Size    int
	Width   int
	Height  int
	FontDPI int
	Text    string
	Font    *truetype.Font
}

type Matrix struct {
	XX, YX, XY, YY, X0, Y0 float64
}

type NRGBA interface {
	image.Image
	Get() *image.NRGBA
	DrawImage(img Palette, dotRect *PositionRect, posRect *AreaRect)
	DrawString(params *DrawStringParams, pt fixed.Point26_6) error
	CalcMarginBlankArea() *AreaRect
	Rotate(angle int, overCrop bool)
	Scale(zoomSize int, keepRatio, centerAlign bool)
	CropCircle(x, y, radius int)
	CropScaleCircle(x, y, radius int, zoomSize int)
	SubImage(r image.Rectangle)
}

type Palette interface {
	image.Image
	Get() *image.Paletted
	CalcMarginBlankArea() *AreaRect
	Rotate(angle int)
	Distort(amplude float64, period float64)
	DrawBeeline(point1 image.Point, point2 image.Point, lineColor color.RGBA)
	DrawCircle(x, y, radius int, c color.RGBA)
	DrawHorizLine(fromX, toX, y int, c color.RGBA)
	AngleSwapPoint(x, y, r, angle float64) (tarX, tarY float64)
	DrawString(params *DrawStringParams, pt fixed.Point26_6) error
}

type PositionRect struct {
	X, Y, Width, Height int
}