paint

Documentation

Overview

Package paint provides drawing operations for 2D graphics.

The PaintOp operation fills the current clip with the current brush, taking the current transformation into account. Drawing outside the current clip area is ignored.

The current brush is set by either a ColorOp for a constant color, or ImageOp for an image, or LinearGradientOp for gradients.

All color.NRGBA values are in the sRGB color space.

Index

• func Fill(ops *op.Ops, c color.NRGBA)
• func FillShape(ops *op.Ops, c color.NRGBA, shape clip.Op)
• type ColorOp
  • func (c ColorOp) Add(o *op.Ops)
• type ImageFilter
• type ImageOp
  • func NewImageOp(src image.Image) ImageOp
  • func (i ImageOp) Add(o *op.Ops)
  • func (i ImageOp) Size() image.Point
• type LinearGradientOp
  • func (c LinearGradientOp) Add(o *op.Ops)
• type OpacityStack
  • func PushOpacity(o *op.Ops, opacity float32) OpacityStack
  • func (t OpacityStack) Pop()
• type PaintOp
  • func (d PaintOp) Add(o *op.Ops)

Functions

func Fill

func Fill(ops *op.Ops, c color.NRGBA)

Fill paints an infinitely large plane with the provided color. It is intended to be used with a clip.Op already in place to limit the painted area. Use FillShape unless you need to paint several times within the same clip.Op.

func FillShape

func FillShape(ops *op.Ops, c color.NRGBA, shape clip.Op)

FillShape fills the clip shape with a color.

Types

type ColorOp

type ColorOp struct {
	Color color.NRGBA
}

ColorOp sets the brush to a constant color.

func (ColorOp) Add

func (c ColorOp) Add(o *op.Ops)

type ImageFilter

type ImageFilter byte

ImageFilter is the scaling filter for images.

const (
	// FilterLinear uses linear interpolation for scaling.
	FilterLinear ImageFilter = iota
	// FilterNearest uses nearest neighbor interpolation for scaling.
	FilterNearest
)

type ImageOp

type ImageOp struct {
	Filter ImageFilter
	// contains filtered or unexported fields
}

ImageOp sets the brush to an image.

func NewImageOp

func NewImageOp(src image.Image) ImageOp

NewImageOp creates an ImageOp backed by src.

NewImageOp assumes the backing image is immutable, and may cache a copy of its contents in a GPU-friendly way. Create new ImageOps to ensure that changes to an image is reflected in the display of it.

func (ImageOp) Add

func (i ImageOp) Add(o *op.Ops)

func (ImageOp) Size

func (i ImageOp) Size() image.Point

type LinearGradientOp

type LinearGradientOp struct {
	Stop1  f32.Point
	Color1 color.NRGBA
	Stop2  f32.Point
	Color2 color.NRGBA
}

LinearGradientOp sets the brush to a gradient starting at stop1 with color1 and ending at stop2 with color2.

func (LinearGradientOp) Add

func (c LinearGradientOp) Add(o *op.Ops)

type OpacityStack

type OpacityStack struct {
	// contains filtered or unexported fields
}

OpacityStack represents an opacity applied to all painting operations until Pop is called.

func PushOpacity

func PushOpacity(o *op.Ops, opacity float32) OpacityStack

PushOpacity creates a drawing layer with an opacity in the range [0;1]. The layer includes every subsequent drawing operation until OpacityStack.Pop is called.

The layer is drawn in two steps. First, the layer operations are drawn to a separate image. Then, the image is blended on top of the frame, with the opacity used as the blending factor.

func (OpacityStack) Pop

func (t OpacityStack) Pop()

type PaintOp

type PaintOp struct {
}

PaintOp fills the current clip area with the current brush.

func (PaintOp) Add

func (d PaintOp) Add(o *op.Ops)