doodle/pkg/level/palette.go

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package level
import (
"encoding/json"
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"errors"
"fmt"
"os"
"git.kirsle.net/go/render"
)
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// Palettes are limited to uint8 in length, to aid image compression.
const PaletteSizeLimit = 256
// DefaultPalette returns a sensible default palette.
func DefaultPalette() *Palette {
return &Palette{
Swatches: []*Swatch{
&Swatch{
Name: "solid",
Color: render.Black,
Solid: true,
},
&Swatch{
Name: "decoration",
Color: render.Grey,
},
&Swatch{
Name: "fire",
Color: render.Red,
Fire: true,
},
&Swatch{
Name: "water",
Color: render.RGBA(0, 0, 255, 180),
Water: true,
},
},
}
}
// NewBlueprintPalette returns the blueprint theme's color palette.
// DEPRECATED in favor of DefaultPalettes.
func NewBlueprintPalette() *Palette {
return &Palette{
Swatches: []*Swatch{
&Swatch{
Name: "solid",
Color: render.RGBA(254, 254, 254, 255),
Solid: true,
},
&Swatch{
Name: "decoration",
Color: render.Grey,
},
&Swatch{
Name: "fire",
Color: render.RGBA(255, 80, 0, 255),
Fire: true,
},
&Swatch{
Name: "water",
Color: render.RGBA(0, 153, 255, 255),
Water: true,
},
&Swatch{
Name: "electric",
Color: render.RGBA(255, 255, 0, 255),
Solid: true,
},
},
}
}
// NewPalette initializes a blank palette.
func NewPalette() *Palette {
return &Palette{
Swatches: []*Swatch{},
byName: map[string]int{},
}
}
// LoadPaletteFromFile reads a list of Swatches from a palette.json file.
func LoadPaletteFromFile(filename string) (*Palette, error) {
var (
pal = NewPalette()
bin, err = os.ReadFile(filename)
)
if err != nil {
return nil, err
}
err = json.Unmarshal(bin, &pal.Swatches)
pal.update()
return pal, err
}
// Palette holds an index of colors used in a drawing.
type Palette struct {
Swatches []*Swatch `json:"swatches"`
// Private runtime values
ActiveSwatch *Swatch `json:"-"` // name of the actively selected color
byName map[string]int // Cache map of swatches by name
}
// Inflate the palette swatch caches. Always call this method after you have
// initialized the palette (i.e. loaded it from JSON); this will update the
// "color by name" cache and assign the index numbers to each swatch.
func (p *Palette) Inflate() {
p.update()
}
// FlushCaches if you have modified the swatches, especially if you have
// changed the name of an existing color. This invalidates the "by name"
// cache and rebuilds it from scratch.
func (p *Palette) FlushCaches() {
p.byName = nil
p.update()
}
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// NewSwatch adds a new swatch to the palette.
func (p *Palette) NewSwatch() (*Swatch, error) {
p.update()
var (
index = len(p.Swatches)
name = fmt.Sprintf("color %d", len(p.Swatches))
)
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if index > PaletteSizeLimit {
return nil, errors.New("only 256 colors are supported in a palette")
}
p.Swatches = append(p.Swatches, &Swatch{
Name: name,
Color: render.Magenta,
index: index,
})
p.byName[name] = index
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return p.Swatches[index], nil
}
// AddSwatch adds a new swatch to the palette.
func (p *Palette) AddSwatch(swatch *Swatch) error {
p.update()
var index = len(p.Swatches)
if len(p.Swatches) > PaletteSizeLimit {
return errors.New("only 256 colors are supported in a palette")
}
swatch.index = index
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p.Swatches = append(p.Swatches, swatch)
p.byName[swatch.Name] = index
return nil
}
// Get a swatch by name.
func (p *Palette) Get(name string) (result *Swatch, exists bool) {
p.update()
if index, ok := p.byName[name]; ok && index < len(p.Swatches) {
result = p.Swatches[index]
exists = true
}
return
}
// update the internal caches and such.
func (p *Palette) update() {
// Initialize the name cache if nil or if the size disagrees with the
// length of the swatches available.
if p.byName == nil || len(p.byName) != len(p.Swatches) {
// Initialize the name cache.
p.byName = map[string]int{}
for i, swatch := range p.Swatches {
swatch.index = i
p.byName[swatch.Name] = i
}
}
}
// ReplacePalette installs a new palette into your level.
// Your existing level colors, by index, are replaced by the incoming
// palette. If the new palette is smaller, extraneous indices are
// left alone.
func (l *Level) ReplacePalette(pal *Palette) {
for i, swatch := range pal.Swatches {
if i >= len(l.Palette.Swatches) {
l.Palette.Swatches = append(l.Palette.Swatches, swatch)
continue
}
// Ugly code, but can't just replace the swatch
// wholesale -- the inflated level data means existing
// pixels already have refs to their Swatch and they
// will keep those refs until you fully save and exit
// out of the editor.
l.Palette.Swatches[i].Name = swatch.Name
l.Palette.Swatches[i].Color = swatch.Color
l.Palette.Swatches[i].Pattern = swatch.Pattern
l.Palette.Swatches[i].Solid = swatch.Solid
l.Palette.Swatches[i].Fire = swatch.Fire
l.Palette.Swatches[i].Water = swatch.Water
}
}