dither_test.go

package xtx_test

import (
	"image"
	"image/color"
	"testing"

	"github.com/phrozen/xtx"
)

func TestDitherParse(t *testing.T) {
	tests := []struct {
		name string
		want xtx.DitherAlgorithm
	}{
		{"floyd-steinberg", xtx.DitherFloydSteinberg},
		{"atkinson", xtx.DitherAtkinson},
		{"sierra", xtx.DitherSierra},
		{"stucki", xtx.DitherStucki},
		{"unknown-xyz", xtx.DitherFloydSteinberg}, // fallbacks
	}

	for _, tt := range tests {
		algo, _ := xtx.ParseDitherAlgorithm(tt.name)
		if algo.Name != tt.want.Name {
			t.Errorf("ParseDitherAlgorithm(%q).Name = %q, want %q", tt.name, algo.Name, tt.want.Name)
		}
	}
}

func TestDither_Bounds(t *testing.T) {
	// 4x4 grayscale image
	src := image.NewGray(image.Rect(0, 0, 4, 4))
	for y := 0; y < 4; y++ {
		for x := 0; x < 4; x++ {
			src.SetGray(x, y, color.Gray{Y: uint8(x*64 + y*64)})
		}
	}

	dst := xtx.NewMonochrome(image.Rect(0, 0, 4, 4))

	ditherer := xtx.Dither{Algo: xtx.DitherAtkinson}
	ditherer.Draw(dst, dst.Bounds(), src, image.Point{0, 0})

	// If it doesn't panic out of bounds on the error buffer, we're good.
}