Remove shift limitation
Removes the [-180,180] limitation from the hue shift and adds additional test cases for -540, -360, -350, 350, 360, 540, -480 (golden), 480 (golden).
diff --git a/adjust.go b/adjust.go
index 31bb5e6..29caea6 100644
--- a/adjust.go
+++ b/adjust.go
@@ -81,8 +81,7 @@
}
// AdjustHue changes the hue of the image using the shift parameter (measured in degrees) and returns the adjusted image.
-// The shift must be in the range (-180, 180).
-// The shift = 0 gives the original image.
+// The shift = 0 (or 360 / -360 / etc.) gives the original image.
// The shift = 180 (or -180) corresponds to a 180° degree rotation of the color wheel and thus gives the image with its hue inverted for each pixel.
//
// Examples:
@@ -94,13 +93,16 @@
return Clone(img)
}
- shift = math.Min(math.Max(shift, -180), 180)
summand := shift / 360
return AdjustFunc(img, func(c color.NRGBA) color.NRGBA {
h, s, l := rgbToHSL(c.R, c.G, c.B)
h += summand
- h = math.Mod(h, 1.0)
+ h = math.Mod(h, 1)
+ //Adding 1 because Golang's Modulo function behaves differently to similar operators in most other languages.
+ if h < 0 {
+ h++
+ }
r, g, b := hslToRGB(h, s, l)
return color.NRGBA{r, g, b, c.A}
})
diff --git a/adjust_test.go b/adjust_test.go
index 9128200..c928676 100644
--- a/adjust_test.go
+++ b/adjust_test.go
@@ -255,7 +255,7 @@
want *image.NRGBA
}{
{
- "AdjustHue 3x3 -10",
+ "AdjustHue 3x3 -540",
&image.NRGBA{
Rect: image.Rect(-1, -1, 2, 2),
Stride: 3 * 4,
@@ -265,13 +265,57 @@
0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
},
},
- -10,
+ -540,
&image.NRGBA{
Rect: image.Rect(0, 0, 3, 3),
Stride: 3 * 4,
Pix: []uint8{
- 0xcc, 0x00, 0x22, 0x01, 0x22, 0xcc, 0x00, 0x02, 0x00, 0x22, 0xcc, 0x03,
- 0x11, 0x28, 0x33, 0xff, 0x33, 0x1c, 0x11, 0xff, 0x93, 0x33, 0xbb, 0xff,
+ 0x00, 0xcc, 0xcc, 0x01, 0xcc, 0x00, 0xcc, 0x02, 0xcc, 0xcc, 0x00, 0x03,
+ 0x33, 0x22, 0x11, 0xff, 0x11, 0x22, 0x33, 0xff, 0x44, 0xbb, 0x33, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ },
+ {
+ "AdjustHue 3x3 -360",
+ &image.NRGBA{
+ Rect: image.Rect(-1, -1, 2, 2),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ -360,
+ &image.NRGBA{
+ Rect: image.Rect(0, 0, 3, 3),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ },
+ {
+ "AdjustHue 3x3 -350",
+ &image.NRGBA{
+ Rect: image.Rect(-1, -1, 2, 2),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ -350,
+ &image.NRGBA{
+ Rect: image.Rect(0, 0, 3, 3),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x22, 0x00, 0x01, 0x00, 0xcc, 0x22, 0x02, 0x22, 0x00, 0xcc, 0x03,
+ 0x11, 0x1c, 0x33, 0xff, 0x33, 0x28, 0x11, 0xff, 0xbb, 0x33, 0xb5, 0xff,
0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
},
},
@@ -299,6 +343,50 @@
},
},
{
+ "AdjustHue 3x3 -10",
+ &image.NRGBA{
+ Rect: image.Rect(-1, -1, 2, 2),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ -10,
+ &image.NRGBA{
+ Rect: image.Rect(0, 0, 3, 3),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x22, 0x01, 0x22, 0xcc, 0x00, 0x02, 0x00, 0x22, 0xcc, 0x03,
+ 0x11, 0x28, 0x33, 0xff, 0x33, 0x1c, 0x11, 0xff, 0x93, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ },
+ {
+ "AdjustHue 3x3 0",
+ &image.NRGBA{
+ Rect: image.Rect(-1, -1, 2, 2),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ 0,
+ &image.NRGBA{
+ Rect: image.Rect(0, 0, 3, 3),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ },
+ {
"AdjustHue 3x3 10",
&image.NRGBA{
Rect: image.Rect(-1, -1, 2, 2),
@@ -343,7 +431,7 @@
},
},
{
- "AdjustHue 3x3 0",
+ "AdjustHue 3x3 350",
&image.NRGBA{
Rect: image.Rect(-1, -1, 2, 2),
Stride: 3 * 4,
@@ -353,7 +441,29 @@
0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
},
},
- 0,
+ 350,
+ &image.NRGBA{
+ Rect: image.Rect(0, 0, 3, 3),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x22, 0x01, 0x22, 0xcc, 0x00, 0x02, 0x00, 0x22, 0xcc, 0x03,
+ 0x11, 0x28, 0x33, 0xff, 0x33, 0x1c, 0x11, 0xff, 0x93, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ },
+ {
+ "AdjustHue 3x3 360",
+ &image.NRGBA{
+ Rect: image.Rect(-1, -1, 2, 2),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ 360,
&image.NRGBA{
Rect: image.Rect(0, 0, 3, 3),
Stride: 3 * 4,
@@ -364,6 +474,28 @@
},
},
},
+ {
+ "AdjustHue 3x3 540",
+ &image.NRGBA{
+ Rect: image.Rect(-1, -1, 2, 2),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+ 0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ 540,
+ &image.NRGBA{
+ Rect: image.Rect(0, 0, 3, 3),
+ Stride: 3 * 4,
+ Pix: []uint8{
+ 0x00, 0xcc, 0xcc, 0x01, 0xcc, 0x00, 0xcc, 0x02, 0xcc, 0xcc, 0x00, 0x03,
+ 0x33, 0x22, 0x11, 0xff, 0x11, 0x22, 0x33, 0xff, 0x44, 0xbb, 0x33, 0xff,
+ 0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+ },
+ },
+ },
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
@@ -377,10 +509,12 @@
func TestAdjustHueGolden(t *testing.T) {
for name, p := range map[string]float64{
+ "out_hue_m480.png": -480,
"out_hue_m120.png": -120,
"out_hue_m60.png": -60,
"out_hue_p60.png": 60,
"out_hue_p120.png": 120,
+ "out_hue_p480.png": 480,
} {
got := AdjustHue(testdataFlowersSmallPNG, p)
want, err := Open("testdata/" + name)
diff --git a/testdata/out_hue_m480.png b/testdata/out_hue_m480.png
new file mode 100644
index 0000000..32b2b37
--- /dev/null
+++ b/testdata/out_hue_m480.png
Binary files differ
diff --git a/testdata/out_hue_p480.png b/testdata/out_hue_p480.png
new file mode 100644
index 0000000..28d4c55
--- /dev/null
+++ b/testdata/out_hue_p480.png
Binary files differ
