gpu/headless: move package app/headless

Package headless is more about rendering that windows. Move it
accordingly.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/headless/headless_test.go

@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package headless
+
+import (
+	"image"
+	"image/color"
+	"testing"
+
+	"gioui.org/f32"
+	"gioui.org/internal/f32color"
+	"gioui.org/op"
+	"gioui.org/op/clip"
+	"gioui.org/op/paint"
+)
+
+func TestHeadless(t *testing.T) {
+	w, release := newTestWindow(t)
+	defer release()
+
+	sz := w.size
+	col := color.NRGBA{A: 0xff, R: 0xca, G: 0xfe}
+	var ops op.Ops
+	paint.ColorOp{Color: col}.Add(&ops)
+	// Paint only part of the screen to avoid the glClear optimization.
+	paint.FillShape(&ops, col, clip.Rect(image.Rect(0, 0, sz.X-100, sz.Y-100)).Op())
+	if err := w.Frame(&ops); err != nil {
+		t.Fatal(err)
+	}
+
+	img, err := w.Screenshot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if isz := img.Bounds().Size(); isz != sz {
+		t.Errorf("got %v screenshot, expected %v", isz, sz)
+	}
+	if got := img.RGBAAt(0, 0); got != f32color.NRGBAToRGBA(col) {
+		t.Errorf("got color %v, expected %v", got, f32color.NRGBAToRGBA(col))
+	}
+}
+
+func TestClipping(t *testing.T) {
+	w, release := newTestWindow(t)
+	defer release()
+
+	col := color.NRGBA{A: 0xff, R: 0xca, G: 0xfe}
+	col2 := color.NRGBA{A: 0xff, R: 0x00, G: 0xfe}
+	var ops op.Ops
+	paint.ColorOp{Color: col}.Add(&ops)
+	clip.RRect{
+		Rect: f32.Rectangle{
+			Min: f32.Point{X: 50, Y: 50},
+			Max: f32.Point{X: 250, Y: 250},
+		},
+		SE: 75,
+	}.Add(&ops)
+	paint.PaintOp{}.Add(&ops)
+	paint.ColorOp{Color: col2}.Add(&ops)
+	clip.RRect{
+		Rect: f32.Rectangle{
+			Min: f32.Point{X: 100, Y: 100},
+			Max: f32.Point{X: 350, Y: 350},
+		},
+		NW: 75,
+	}.Add(&ops)
+	paint.PaintOp{}.Add(&ops)
+	if err := w.Frame(&ops); err != nil {
+		t.Fatal(err)
+	}
+
+	img, err := w.Screenshot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if *dumpImages {
+		if err := saveImage("clip.png", img); err != nil {
+			t.Fatal(err)
+		}
+	}
+	bg := color.NRGBA{A: 0xff, R: 0xff, G: 0xff, B: 0xff}
+	tests := []struct {
+		x, y  int
+		color color.NRGBA
+	}{
+		{120, 120, col},
+		{130, 130, col2},
+		{210, 210, col2},
+		{230, 230, bg},
+	}
+	for _, test := range tests {
+		if got := img.RGBAAt(test.x, test.y); got != f32color.NRGBAToRGBA(test.color) {
+			t.Errorf("(%d,%d): got color %v, expected %v", test.x, test.y, got, f32color.NRGBAToRGBA(test.color))
+		}
+	}
+}
+
+func TestDepth(t *testing.T) {
+	w, release := newTestWindow(t)
+	defer release()
+	var ops op.Ops
+
+	blue := color.NRGBA{B: 0xFF, A: 0xFF}
+	paint.FillShape(&ops, blue, clip.Rect(image.Rect(0, 0, 50, 100)).Op())
+	red := color.NRGBA{R: 0xFF, A: 0xFF}
+	paint.FillShape(&ops, red, clip.Rect(image.Rect(0, 0, 100, 50)).Op())
+	if err := w.Frame(&ops); err != nil {
+		t.Fatal(err)
+	}
+
+	img, err := w.Screenshot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if *dumpImages {
+		if err := saveImage("depth.png", img); err != nil {
+			t.Fatal(err)
+		}
+	}
+	tests := []struct {
+		x, y  int
+		color color.NRGBA
+	}{
+		{25, 25, red},
+		{75, 25, red},
+		{25, 75, blue},
+	}
+	for _, test := range tests {
+		if got := img.RGBAAt(test.x, test.y); got != f32color.NRGBAToRGBA(test.color) {
+			t.Errorf("(%d,%d): got color %v, expected %v", test.x, test.y, got, f32color.NRGBAToRGBA(test.color))
+		}
+	}
+}
+
+func newTestWindow(t *testing.T) (*Window, func()) {
+	t.Helper()
+	sz := image.Point{X: 800, Y: 600}
+	w, err := NewWindow(sz.X, sz.Y)
+	if err != nil {
+		t.Skipf("headless windows not supported: %v", err)
+	}
+	return w, func() {
+		w.Release()
+	}
+}