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image/draw: add RGBA64Image fast path

name               old time/op  new time/op  delta
GenericOver-4      15.0ms ± 1%   2.9ms ± 1%  -80.56%  (p=0.008 n=5+5)
GenericMaskOver-4  7.82ms ± 4%  1.69ms ± 2%  -78.38%  (p=0.008 n=5+5)
GenericSrc-4       6.13ms ± 3%  1.66ms ± 1%  -72.90%  (p=0.008 n=5+5)
GenericMaskSrc-4   11.5ms ± 1%   2.0ms ± 0%  -82.77%  (p=0.008 n=5+5)

Updates #44808.

Change-Id: I131cf6fad01708540390a8012d8f2a21e849fe9d
Reviewed-on: https://go-review.googlesource.com/c/go/+/340049
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Nigel Tao <nigeltao@golang.org>
This commit is contained in:
Nigel Tao 2021-08-05 16:11:28 +10:00
parent 065f380815
commit 9f69a44308
3 changed files with 272 additions and 23 deletions

View File

@ -83,6 +83,19 @@ Do not send CLs removing the interior tags from such phrases.
TODO: complete this section
</p>
<dl id="image/draw"><dt><a href="/pkg/image/draw/">image/draw</a></dt>
<dd>
<p><!-- CL 340049 -->
The <code>Draw</code> and <code>DrawMask</code> fallback implementations
(used when the arguments are not the most common image types) are now
faster when those arguments implement the optional
<a href="/pkg/image/draw/#RGBA64Image"><code>draw.RGBA64Image</code></a>
and <a href="/pkg/image/#RGBA64Image"><code>image.RGBA64Image</code></a>
interfaces that were added in Go 1.17.
</p>
</dd>
</dl><!-- image/draw -->
<dl id="syscall"><dt><a href="/pkg/syscall/">syscall</a></dt>
<dd>
<p><!-- CL 336550 -->

View File

@ -119,7 +119,8 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
return
}
// Fast paths for special cases. If none of them apply, then we fall back to a general but slow implementation.
// Fast paths for special cases. If none of them apply, then we fall back
// to general but slower implementations.
switch dst0 := dst.(type) {
case *image.RGBA:
if op == Over {
@ -219,6 +220,84 @@ func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mas
y0, y1, dy = y1-1, y0-1, -1
}
// Try the draw.RGBA64Image and image.RGBA64Image interfaces, part of the
// standard library since Go 1.17. These are like the draw.Image and
// image.Image interfaces but they can avoid allocations from converting
// concrete color types to the color.Color interface type.
if dst0, _ := dst.(RGBA64Image); dst0 != nil {
if src0, _ := src.(image.RGBA64Image); src0 != nil {
if mask == nil {
sy := sp.Y + y0 - r.Min.Y
my := mp.Y + y0 - r.Min.Y
for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
sx := sp.X + x0 - r.Min.X
mx := mp.X + x0 - r.Min.X
for x := x0; x != x1; x, sx, mx = x+dx, sx+dx, mx+dx {
if op == Src {
dst0.SetRGBA64(x, y, src0.RGBA64At(sx, sy))
} else {
srgba := src0.RGBA64At(sx, sy)
a := m - uint32(srgba.A)
drgba := dst0.RGBA64At(x, y)
dst0.SetRGBA64(x, y, color.RGBA64{
R: uint16((uint32(drgba.R)*a)/m) + srgba.R,
G: uint16((uint32(drgba.G)*a)/m) + srgba.G,
B: uint16((uint32(drgba.B)*a)/m) + srgba.B,
A: uint16((uint32(drgba.A)*a)/m) + srgba.A,
})
}
}
}
return
} else if mask0, _ := mask.(image.RGBA64Image); mask0 != nil {
sy := sp.Y + y0 - r.Min.Y
my := mp.Y + y0 - r.Min.Y
for y := y0; y != y1; y, sy, my = y+dy, sy+dy, my+dy {
sx := sp.X + x0 - r.Min.X
mx := mp.X + x0 - r.Min.X
for x := x0; x != x1; x, sx, mx = x+dx, sx+dx, mx+dx {
ma := uint32(mask0.RGBA64At(mx, my).A)
switch {
case ma == 0:
if op == Over {
// No-op.
} else {
dst0.SetRGBA64(x, y, color.RGBA64{})
}
case ma == m && op == Src:
dst0.SetRGBA64(x, y, src0.RGBA64At(sx, sy))
default:
srgba := src0.RGBA64At(sx, sy)
if op == Over {
drgba := dst0.RGBA64At(x, y)
a := m - (uint32(srgba.A) * ma / m)
dst0.SetRGBA64(x, y, color.RGBA64{
R: uint16((uint32(drgba.R)*a + uint32(srgba.R)*ma) / m),
G: uint16((uint32(drgba.G)*a + uint32(srgba.G)*ma) / m),
B: uint16((uint32(drgba.B)*a + uint32(srgba.B)*ma) / m),
A: uint16((uint32(drgba.A)*a + uint32(srgba.A)*ma) / m),
})
} else {
dst0.SetRGBA64(x, y, color.RGBA64{
R: uint16(uint32(srgba.R) * ma / m),
G: uint16(uint32(srgba.G) * ma / m),
B: uint16(uint32(srgba.B) * ma / m),
A: uint16(uint32(srgba.A) * ma / m),
})
}
}
}
}
return
}
}
}
// If none of the faster code paths above apply, use the draw.Image and
// image.Image interfaces, part of the standard library since Go 1.0.
var out color.RGBA64
sy := sp.Y + y0 - r.Min.Y
my := mp.Y + y0 - r.Min.Y

View File

@ -13,6 +13,138 @@ import (
"testing/quick"
)
// slowestRGBA is a draw.Image like image.RGBA but it is a different type and
// therefore does not trigger the draw.go fastest code paths.
//
// Unlike slowerRGBA, it does not implement the draw.RGBA64Image interface.
type slowestRGBA struct {
Pix []uint8
Stride int
Rect image.Rectangle
}
func (p *slowestRGBA) ColorModel() color.Model { return color.RGBAModel }
func (p *slowestRGBA) Bounds() image.Rectangle { return p.Rect }
func (p *slowestRGBA) At(x, y int) color.Color {
return p.RGBA64At(x, y)
}
func (p *slowestRGBA) RGBA64At(x, y int) color.RGBA64 {
if !(image.Point{x, y}.In(p.Rect)) {
return color.RGBA64{}
}
i := p.PixOffset(x, y)
s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
r := uint16(s[0])
g := uint16(s[1])
b := uint16(s[2])
a := uint16(s[3])
return color.RGBA64{
(r << 8) | r,
(g << 8) | g,
(b << 8) | b,
(a << 8) | a,
}
}
func (p *slowestRGBA) Set(x, y int, c color.Color) {
if !(image.Point{x, y}.In(p.Rect)) {
return
}
i := p.PixOffset(x, y)
c1 := color.RGBAModel.Convert(c).(color.RGBA)
s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
s[0] = c1.R
s[1] = c1.G
s[2] = c1.B
s[3] = c1.A
}
func (p *slowestRGBA) PixOffset(x, y int) int {
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
}
func init() {
var p interface{} = (*slowestRGBA)(nil)
if _, ok := p.(RGBA64Image); ok {
panic("slowestRGBA should not be an RGBA64Image")
}
}
// slowerRGBA is a draw.Image like image.RGBA but it is a different type and
// therefore does not trigger the draw.go fastest code paths.
//
// Unlike slowestRGBA, it still implements the draw.RGBA64Image interface.
type slowerRGBA struct {
Pix []uint8
Stride int
Rect image.Rectangle
}
func (p *slowerRGBA) ColorModel() color.Model { return color.RGBAModel }
func (p *slowerRGBA) Bounds() image.Rectangle { return p.Rect }
func (p *slowerRGBA) At(x, y int) color.Color {
return p.RGBA64At(x, y)
}
func (p *slowerRGBA) RGBA64At(x, y int) color.RGBA64 {
if !(image.Point{x, y}.In(p.Rect)) {
return color.RGBA64{}
}
i := p.PixOffset(x, y)
s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
r := uint16(s[0])
g := uint16(s[1])
b := uint16(s[2])
a := uint16(s[3])
return color.RGBA64{
(r << 8) | r,
(g << 8) | g,
(b << 8) | b,
(a << 8) | a,
}
}
func (p *slowerRGBA) Set(x, y int, c color.Color) {
if !(image.Point{x, y}.In(p.Rect)) {
return
}
i := p.PixOffset(x, y)
c1 := color.RGBAModel.Convert(c).(color.RGBA)
s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
s[0] = c1.R
s[1] = c1.G
s[2] = c1.B
s[3] = c1.A
}
func (p *slowerRGBA) SetRGBA64(x, y int, c color.RGBA64) {
if !(image.Point{x, y}.In(p.Rect)) {
return
}
i := p.PixOffset(x, y)
s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
s[0] = uint8(c.R >> 8)
s[1] = uint8(c.G >> 8)
s[2] = uint8(c.B >> 8)
s[3] = uint8(c.A >> 8)
}
func (p *slowerRGBA) PixOffset(x, y int) int {
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
}
func init() {
var p interface{} = (*slowerRGBA)(nil)
if _, ok := p.(RGBA64Image); !ok {
panic("slowerRGBA should be an RGBA64Image")
}
}
func eq(c0, c1 color.Color) bool {
r0, g0, b0, a0 := c0.RGBA()
r1, g1, b1, a1 := c1.RGBA()
@ -260,30 +392,55 @@ func TestDraw(t *testing.T) {
for _, r := range rr {
loop:
for _, test := range drawTests {
dst := hgradRed(255).(*image.RGBA).SubImage(r).(Image)
// Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
golden := makeGolden(dst, image.Rect(0, 0, 16, 16), test.src, image.ZP, test.mask, image.ZP, test.op)
b := dst.Bounds()
if !b.Eq(golden.Bounds()) {
t.Errorf("draw %v %s: bounds %v versus %v", r, test.desc, dst.Bounds(), golden.Bounds())
continue
}
// Draw the same combination onto the actual dst using the optimized DrawMask implementation.
DrawMask(dst, image.Rect(0, 0, 16, 16), test.src, image.ZP, test.mask, image.ZP, test.op)
if image.Pt(8, 8).In(r) {
// Check that the resultant pixel at (8, 8) matches what we expect
// (the expected value can be verified by hand).
if !eq(dst.At(8, 8), test.expected) {
t.Errorf("draw %v %s: at (8, 8) %v versus %v", r, test.desc, dst.At(8, 8), test.expected)
for i := 0; i < 3; i++ {
dst := hgradRed(255).(*image.RGBA).SubImage(r).(Image)
// For i != 0, substitute a different-typed dst that will take
// us off the fastest code paths. We should still get the same
// result, in terms of final pixel RGBA values.
switch i {
case 1:
d := dst.(*image.RGBA)
dst = &slowerRGBA{
Pix: d.Pix,
Stride: d.Stride,
Rect: d.Rect,
}
case 2:
d := dst.(*image.RGBA)
dst = &slowestRGBA{
Pix: d.Pix,
Stride: d.Stride,
Rect: d.Rect,
}
}
// Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
golden := makeGolden(dst, image.Rect(0, 0, 16, 16), test.src, image.ZP, test.mask, image.ZP, test.op)
b := dst.Bounds()
if !b.Eq(golden.Bounds()) {
t.Errorf("draw %v %s on %T: bounds %v versus %v",
r, test.desc, dst, dst.Bounds(), golden.Bounds())
continue
}
}
// Check that the resultant dst image matches the golden output.
for y := b.Min.Y; y < b.Max.Y; y++ {
for x := b.Min.X; x < b.Max.X; x++ {
if !eq(dst.At(x, y), golden.At(x, y)) {
t.Errorf("draw %v %s: at (%d, %d), %v versus golden %v", r, test.desc, x, y, dst.At(x, y), golden.At(x, y))
continue loop
// Draw the same combination onto the actual dst using the optimized DrawMask implementation.
DrawMask(dst, image.Rect(0, 0, 16, 16), test.src, image.ZP, test.mask, image.ZP, test.op)
if image.Pt(8, 8).In(r) {
// Check that the resultant pixel at (8, 8) matches what we expect
// (the expected value can be verified by hand).
if !eq(dst.At(8, 8), test.expected) {
t.Errorf("draw %v %s on %T: at (8, 8) %v versus %v",
r, test.desc, dst, dst.At(8, 8), test.expected)
continue
}
}
// Check that the resultant dst image matches the golden output.
for y := b.Min.Y; y < b.Max.Y; y++ {
for x := b.Min.X; x < b.Max.X; x++ {
if !eq(dst.At(x, y), golden.At(x, y)) {
t.Errorf("draw %v %s on %T: at (%d, %d), %v versus golden %v",
r, test.desc, dst, x, y, dst.At(x, y), golden.At(x, y))
continue loop
}
}
}
}