Package gradient provides linear and radial gradient images.



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    type Gradient

    type Gradient struct {
    	Shape  Shape
    	Spread Spread
    	// Pix2Grad transforms coordinates from pixel space (the arguments to the
    	// Image.At method) to gradient space. Gradient space is where a linear
    	// gradient ranges from x == 0 to x == 1, and a radial gradient has center
    	// (0, 0) and radius 1.
    	// This is an affine transform, so it can represent elliptical gradients in
    	// pixel space, including non-axis-aligned ellipses.
    	// For a linear gradient, the bottom row is ignored.
    	Pix2Grad f64.Aff3
    	Ranges []Range
    	// First and Last are the first and last stop's colors.
    	First, Last color.RGBA64

      Gradient is a very large image.Image (the same size as an image.Uniform) whose colors form a gradient.

      func (*Gradient) At

      func (g *Gradient) At(x, y int) color.Color

        At satisfies the image.Image interface.

        func (*Gradient) Bounds

        func (g *Gradient) Bounds() image.Rectangle

          Bounds satisfies the image.Image interface.

          func (*Gradient) ColorModel

          func (g *Gradient) ColorModel() color.Model

            ColorModel satisfies the image.Image interface.

            func (*Gradient) Init

            func (g *Gradient) Init(shape Shape, spread Spread, pix2Grad f64.Aff3, stops []Stop)

              Init initializes g to a gradient whose geometry is defined by shape and pix2Grad and whose colors are defined by spread and stops.

              type Range

              type Range struct {
              	Offset0 float64
              	Offset1 float64
              	Width   float64
              	R0      float64
              	R1      float64
              	G0      float64
              	G1      float64
              	B0      float64
              	B1      float64
              	A0      float64
              	A1      float64

                Range is the range between two stops.

                func AppendRanges

                func AppendRanges(a []Range, stops []Stop) []Range

                  AppendRanges appends to a the ranges defined by a's implicit final stop (if any exist) and stops.

                  func MakeRange

                  func MakeRange(s0, s1 Stop) Range

                    MakeRange returns the range between two stops.

                    type Shape

                    type Shape uint8

                      Shape is the gradient shape.

                      const (
                      	ShapeLinear Shape = iota

                      type Spread

                      type Spread uint8

                        Spread is the gradient spread, or how to spread a gradient past its nominal bounds (from offset being 0.0 to offset being 1.0).

                        const (
                        	// SpreadNone means that offsets outside of the [0, 1] range map to
                        	// transparent black.
                        	SpreadNone Spread = iota
                        	// SpreadPad means that offsets below 0 and above 1 map to the colors that
                        	// 0 and 1 would map to.
                        	// SpreadReflect means that the offset mapping is reflected start-to-end,
                        	// end-to-start, start-to-end, etc.
                        	// SpreadRepeat means that the offset mapping is repeated start-to-end,
                        	// start-to-end, start-to-end, etc.

                        func (Spread) Clamp

                        func (s Spread) Clamp(x float64) float64

                          Clamp clamps x to the range [0, 1]. If x is outside that range, it is converted to a value in that range according to s's semantics. It returns -1 if s is SpreadNone and x is outside the range [0, 1].

                          type Stop

                          type Stop struct {
                          	Offset float64
                          	RGBA64 color.RGBA64

                            Stop is an offset and color.

                            Source Files