mirror of
https://github.com/alecthomas/chroma.git
synced 2025-01-28 03:29:41 +02:00
92 lines
2.6 KiB
Go
92 lines
2.6 KiB
Go
package chroma
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import (
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"math"
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"testing"
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assert "github.com/alecthomas/assert/v2"
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)
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func TestColourRGB(t *testing.T) {
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colour := ParseColour("#8913af")
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assert.Equal(t, uint8(0x89), colour.Red())
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assert.Equal(t, uint8(0x13), colour.Green())
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assert.Equal(t, uint8(0xaf), colour.Blue())
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}
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func TestColourString(t *testing.T) {
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assert.Equal(t, "#8913af", ParseColour("#8913af").String())
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}
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func distance(a, b uint8) uint8 {
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if a < b {
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return b - a
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}
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return a - b
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}
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func TestColourBrighten(t *testing.T) {
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actual := NewColour(128, 128, 128).Brighten(0.5)
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// Closeish to what we expect is fine.
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assert.True(t, distance(192, actual.Red()) <= 2)
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assert.True(t, distance(192, actual.Blue()) <= 2)
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assert.True(t, distance(192, actual.Green()) <= 2)
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actual = NewColour(128, 128, 128).Brighten(-0.5)
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assert.True(t, distance(65, actual.Red()) <= 2)
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assert.True(t, distance(65, actual.Blue()) <= 2)
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assert.True(t, distance(65, actual.Green()) <= 2)
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}
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func TestColourBrightess(t *testing.T) {
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actual := NewColour(128, 128, 128).Brightness()
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assert.True(t, distance(128, uint8(actual*255.0)) <= 2)
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}
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// hue returns c's hue. See https://stackoverflow.com/a/23094494.
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func hue(c Colour) float64 {
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r := float64(c.Red()) / 255
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g := float64(c.Green()) / 255
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b := float64(c.Blue()) / 255
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min := math.Min(math.Min(r, g), b)
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max := math.Max(math.Max(r, g), b)
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switch {
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case r == min:
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return (g - b) / (max - min)
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case g == min:
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return 2 + (b-r)/(max-min)
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default:
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return 4 + (r-g)/(max-min)
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}
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}
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func TestColourClampBrightness(t *testing.T) {
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// Start with a colour with a brightness close to 0.5.
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initial := NewColour(0, 128, 255)
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br := initial.Brightness()
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assertInDelta(t, 0.5, br)
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// Passing a range that includes the colour's brightness should be a no-op.
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assert.Equal(t, initial.String(), initial.ClampBrightness(br-0.01, br+0.01).String())
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// Clamping to [0, 0] or [1, 1] should produce black or white, respectively.
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assert.Equal(t, "#000000", initial.ClampBrightness(0, 0).String())
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assert.Equal(t, "#ffffff", initial.ClampBrightness(1, 1).String())
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// Clamping to a brighter or darker range should produce the requested
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// brightness while preserving the colour's hue.
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brighter := initial.ClampBrightness(0.75, 1)
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assertInDelta(t, 0.75, brighter.Brightness())
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assertInDelta(t, hue(initial), hue(brighter))
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darker := initial.ClampBrightness(0, 0.25)
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assertInDelta(t, 0.25, darker.Brightness())
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assertInDelta(t, hue(initial), hue(darker))
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}
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func assertInDelta(t *testing.T, expected, actual float64) {
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const delta = 0.01 // used for brightness and hue comparisons
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assert.True(t, actual > (expected-delta) && actual < (expected+delta))
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}
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