Hochwasser/render/pattern.go

145 lines
3.6 KiB
Go

package render
import (
"image"
"image/color"
"math"
"golang.org/x/image/draw"
)
// Pattern provides infinite algorithmically generated Patterns and implements
// the image.Image interface.
type Pattern struct {
Size image.Point
}
// Image interface
func (c *Pattern) ColorModel() color.Model { return color.NRGBAModel }
func (c *Pattern) At(x, y int) color.Color { return color.Transparent }
func (c *Pattern) Bounds() image.Rectangle {
return image.Rectangle{image.Point{-1e9, -1e9}, image.Point{1e9, 1e9}}
}
func (p *Pattern) ToFixedImage(bounds image.Rectangle) *image.NRGBA {
img := image.NewNRGBA(bounds)
// TODO: allow setting a mask?
// override size for pattern?
p.Size = bounds.Size() // override size for this Pattern
draw.Draw(img, bounds, p, image.Point{}, draw.Src)
return img
}
type StripePattern struct {
Pattern
Palette color.Palette
}
func (c *StripePattern) At(x, y int) color.Color {
n := len(c.Palette)
if n == 0 {
return color.Transparent
}
pxPerStripe := c.Size.Y / n
if pxPerStripe <= 0 {
pxPerStripe = 1
}
stripeIndex := y / pxPerStripe % n // FIXME: y - c.Size? -> negative modulo fix
return c.Palette[stripeIndex]
}
func NewPrideImage(p color.Palette, bounds image.Rectangle) image.Image {
Pattern := StripePattern{Palette: p}
return Pattern.ToFixedImage(bounds)
}
var PrideFlags = map[string]color.Palette{
"lgbti": color.Palette{
color.NRGBA{0xe4, 0x03, 0x03, 0xff},
color.NRGBA{0xff, 0x8c, 0x00, 0xff},
color.NRGBA{0xff, 0xed, 0x00, 0xff},
color.NRGBA{0x00, 0x80, 0x26, 0xff},
color.NRGBA{0x00, 0x4d, 0xff, 0xff},
color.NRGBA{0x75, 0x07, 0x87, 0xff},
},
"nonbinary": color.Palette{
color.NRGBA{0x9c, 0x5c, 0xd4, 0xff},
color.NRGBA{0xfc, 0xfc, 0xfc, 0xff},
color.NRGBA{0xfc, 0xf4, 0x34, 0xff},
color.NRGBA{0x2c, 0x2c, 0x2c, 0xff},
},
"trans": color.Palette{
color.NRGBA{0x5b, 0xde, 0xfa, 0xff},
color.NRGBA{0xf5, 0xa9, 0xb8, 0xff},
color.NRGBA{0xff, 0xff, 0xff, 0xff},
color.NRGBA{0xf5, 0xa9, 0xb8, 0xff},
color.NRGBA{0x5b, 0xde, 0xfa, 0xff},
},
}
type DynamicPattern struct {
Pattern
Color func(x, y int, p *DynamicPattern) (float64, float64, float64) // should return rgb in [0,1] range
Luma float64 // color parameter
Freq float64 // frequency parameter
Phase float64 // phase parameter
Brightness float64 // additive base brightness
ColFactor float64 // Pattern intensity
}
func (c *DynamicPattern) At(x, y int) color.Color {
col := color.NRGBA{}
if c.ColFactor == 0.0 && c.Brightness == 0.0 {
c.ColFactor = 1.0
}
if c.Color != nil {
r, g, b := c.Color(x, y, c)
col.R = uint8(r * c.ColFactor * 255)
col.G = uint8(g * c.ColFactor * 255)
col.B = uint8(b * c.ColFactor * 255)
}
if c.Freq == 0.0 {
c.Freq = 1.0
}
col.R = col.R + uint8(255*c.Brightness)
col.G = col.G + uint8(255*c.Brightness)
col.B = col.B + uint8(255*c.Brightness)
col.A = 0xff
return col
}
var DynPatterns = map[string]image.Image{
"rbow": &DynamicPattern{
Color: func(x, y int, p *DynamicPattern) (float64, float64, float64) {
xx := float64(x) / 26.0 // TODO: dynamic sizing
yy := float64(y) / 13.0
r := 0.5 + 0.5*math.Cos(xx+p.Phase)
g := 0.5 + 0.5*math.Sin(yy+p.Phase)
b := 0.5 + 0.5*math.Sin(xx+p.Phase)*math.Cos(yy+p.Phase)
return r, g, b
},
},
"pastel": &DynamicPattern{
Brightness: 0.5, // TODO: expose these params?
ColFactor: 0.5,
Freq: 5.0,
Color: func(x, y int, p *DynamicPattern) (float64, float64, float64) {
offset := 0.0
v := math.Atan2(float64(x)-offset, float64(y)-offset) + p.Phase
r := 0.5 + 0.5*math.Sin(v*p.Freq)
g := 0.5 + 0.5*math.Cos(v*p.Freq)
b := 0.5 + 0.5*math.Sin(v*p.Freq+6.28318/p.Luma)
return r, g, b
},
},
}