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all: use color.NRGBA in public API

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color.RGBA has two problems with regards to using it.

First the color values need to be premultiplied, whereas most APIs
have non-premultiplied values. This is mainly to preserve color components
with low alpha values.

Second there are two ways to premultiply with sRGB. One is to premultiply
after sRGB conversion, the other is before. This makes using the API more
confusing.

Using color.NRGBA in sRGB makes it align with CSS.e

Signed-off-by: Egon Elbre <egonelbre@gmail.com>
This commit is contained in:
Egon Elbre
2020-11-18 20:21:26 +02:00
committed by Elias Naur
parent 9469d18907
commit 21ef492cc9
23 changed files with 200 additions and 157 deletions
Download Patch File Download Diff File Expand all files Collapse all files
internal/rendertest/render_test.go
+24 -24
View File
@@ -25,12 +25,12 @@ func TestTransformMacro(t *testing.T) {
// render the first Stacked item
m1 := op.Record(o)
dr := image.Rect(0, 0, 128, 50)
paint.FillShape(o, colornames.Black, clip.Rect(dr).Op())
paint.FillShape(o, black, clip.Rect(dr).Op())
c1 := m1.Stop()
// Render the second stacked item
m2 := op.Record(o)
paint.ColorOp{Color: colornames.Red}.Add(o)
paint.ColorOp{Color: red}.Add(o)
// Simulate a draw text call
stack := op.Push(o)
op.Offset(f32.Pt(0, 10)).Add(o)
@@ -62,7 +62,7 @@ func TestTransformMacro(t *testing.T) {
func TestRepeatedPaintsZ(t *testing.T) {
run(t, func(o *op.Ops) {
// Draw a rectangle
paint.FillShape(o, colornames.Black, clip.Rect(image.Rect(0, 0, 128, 50)).Op())
paint.FillShape(o, black, clip.Rect(image.Rect(0, 0, 128, 50)).Op())
builder := clip.Path{}
builder.Begin(o)
@@ -72,7 +72,7 @@ func TestRepeatedPaintsZ(t *testing.T) {
builder.Line(f32.Pt(-10, 0))
builder.Line(f32.Pt(0, -10))
builder.Outline().Add(o)
paint.Fill(o, colornames.Red)
paint.Fill(o, red)
}, func(r result) {
r.expect(5, 5, colornames.Red)
r.expect(11, 15, colornames.Black)
@@ -86,11 +86,11 @@ func TestNoClipFromPaint(t *testing.T) {
run(t, func(o *op.Ops) {
a := f32.Affine2D{}.Rotate(f32.Pt(20, 20), math.Pi/4)
op.Affine(a).Add(o)
paint.FillShape(o, colornames.Red, clip.Rect(image.Rect(10, 10, 30, 30)).Op())
paint.FillShape(o, red, clip.Rect(image.Rect(10, 10, 30, 30)).Op())
a = f32.Affine2D{}.Rotate(f32.Pt(20, 20), -math.Pi/4)
op.Affine(a).Add(o)
paint.FillShape(o, colornames.Black, clip.Rect(image.Rect(0, 0, 50, 50)).Op())
paint.FillShape(o, black, clip.Rect(image.Rect(0, 0, 50, 50)).Op())
}, func(r result) {
r.expect(1, 1, colornames.Black)
r.expect(20, 20, colornames.Black)
@@ -195,16 +195,16 @@ func TestNegativeOverlaps(t *testing.T) {
}
type Gradient struct {
From, To color.RGBA
From, To color.NRGBA
}
var gradients = []Gradient{
{From: color.RGBA{R: 0x00, G: 0x00, B: 0x00, A: 0xFF}, To: color.RGBA{R: 0xFF, G: 0xFF, B: 0xFF, A: 0xFF}},
{From: color.RGBA{R: 0x19, G: 0xFF, B: 0x19, A: 0xFF}, To: color.RGBA{R: 0xFF, G: 0x19, B: 0x19, A: 0xFF}},
{From: color.RGBA{R: 0xFF, G: 0x19, B: 0x19, A: 0xFF}, To: color.RGBA{R: 0x19, G: 0x19, B: 0xFF, A: 0xFF}},
{From: color.RGBA{R: 0x19, G: 0x19, B: 0xFF, A: 0xFF}, To: color.RGBA{R: 0x19, G: 0xFF, B: 0x19, A: 0xFF}},
{From: color.RGBA{R: 0x19, G: 0xFF, B: 0xFF, A: 0xFF}, To: color.RGBA{R: 0xFF, G: 0x19, B: 0x19, A: 0xFF}},
{From: color.RGBA{R: 0xFF, G: 0xFF, B: 0x19, A: 0xFF}, To: color.RGBA{R: 0x19, G: 0x19, B: 0xFF, A: 0xFF}},
{From: color.NRGBA{R: 0x00, G: 0x00, B: 0x00, A: 0xFF}, To: color.NRGBA{R: 0xFF, G: 0xFF, B: 0xFF, A: 0xFF}},
{From: color.NRGBA{R: 0x19, G: 0xFF, B: 0x19, A: 0xFF}, To: color.NRGBA{R: 0xFF, G: 0x19, B: 0x19, A: 0xFF}},
{From: color.NRGBA{R: 0xFF, G: 0x19, B: 0x19, A: 0xFF}, To: color.NRGBA{R: 0x19, G: 0x19, B: 0xFF, A: 0xFF}},
{From: color.NRGBA{R: 0x19, G: 0x19, B: 0xFF, A: 0xFF}, To: color.NRGBA{R: 0x19, G: 0xFF, B: 0x19, A: 0xFF}},
{From: color.NRGBA{R: 0x19, G: 0xFF, B: 0xFF, A: 0xFF}, To: color.NRGBA{R: 0xFF, G: 0x19, B: 0x19, A: 0xFF}},
{From: color.NRGBA{R: 0xFF, G: 0xFF, B: 0x19, A: 0xFF}, To: color.NRGBA{R: 0x19, G: 0x19, B: 0xFF, A: 0xFF}},
}
func TestLinearGradient(t *testing.T) {
@@ -236,11 +236,11 @@ func TestLinearGradient(t *testing.T) {
}, func(r result) {
gr := pixelAligned
for _, g := range gradients {
from := f32color.RGBAFromSRGB(g.From)
to := f32color.RGBAFromSRGB(g.To)
from := f32color.LinearFromSRGB(g.From)
to := f32color.LinearFromSRGB(g.To)
for _, p := range samples {
exp := lerp(from, to, float32(p)/float32(r.img.Bounds().Dx()-1))
r.expect(p, int(gr.Min.Y+gradienth/2), exp.SRGB())
r.expect(p, int(gr.Min.Y+gradienth/2), f32color.NRGBAToRGBA(exp.SRGB()))
}
gr = gr.Add(f32.Pt(0, gradienth))
}
@@ -251,9 +251,9 @@ func TestLinearGradientAngled(t *testing.T) {
run(t, func(ops *op.Ops) {
paint.LinearGradientOp{
Stop1: f32.Pt(64, 64),
Color1: colornames.Black,
Color1: black,
Stop2: f32.Pt(0, 0),
Color2: colornames.Red,
Color2: red,
}.Add(ops)
st := op.Push(ops)
clip.Rect(image.Rect(0, 0, 64, 64)).Add(ops)
@@ -262,9 +262,9 @@ func TestLinearGradientAngled(t *testing.T) {
paint.LinearGradientOp{
Stop1: f32.Pt(64, 64),
Color1: colornames.White,
Color1: white,
Stop2: f32.Pt(128, 0),
Color2: colornames.Green,
Color2: green,
}.Add(ops)
st = op.Push(ops)
clip.Rect(image.Rect(64, 0, 128, 64)).Add(ops)
@@ -273,9 +273,9 @@ func TestLinearGradientAngled(t *testing.T) {
paint.LinearGradientOp{
Stop1: f32.Pt(64, 64),
Color1: colornames.Black,
Color1: black,
Stop2: f32.Pt(128, 128),
Color2: colornames.Blue,
Color2: blue,
}.Add(ops)
st = op.Push(ops)
clip.Rect(image.Rect(64, 64, 128, 128)).Add(ops)
@@ -284,9 +284,9 @@ func TestLinearGradientAngled(t *testing.T) {
paint.LinearGradientOp{
Stop1: f32.Pt(64, 64),
Color1: colornames.White,
Color1: white,
Stop2: f32.Pt(0, 128),
Color2: colornames.Magenta,
Color2: magenta,
}.Add(ops)
st = op.Push(ops)
clip.Rect(image.Rect(0, 64, 64, 128)).Add(ops)