all: update comment URLs from HTTP to HTTPS, where possible

Each URL was manually verified to ensure it did not serve up incorrect
content.

Change-Id: I4dc846227af95a73ee9a3074d0c379ff0fa955df
Reviewed-on: https://go-review.googlesource.com/115798
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

6 files changed, 14 insertions, 14 deletions

diff --git a/src/image/color/palette/gen.go b/src/image/color/palette/gen.go
index d55e2d285a..f8587db8f3 100644
--- a/src/image/color/palette/gen.go
+++ b/src/image/color/palette/gen.go
@@ -111,7 +111,7 @@ func printWebSafe(w io.Writer) {
 	fmt.Fprintln(w, "// WebSafe is a 216-color palette that was popularized by early versions")
 	fmt.Fprintln(w, "// of Netscape Navigator. It is also known as the Netscape Color Cube.")
 	fmt.Fprintln(w, "//")
-	fmt.Fprintln(w, "// See http://en.wikipedia.org/wiki/Web_colors#Web-safe_colors for details.")
+	fmt.Fprintln(w, "// See https://en.wikipedia.org/wiki/Web_colors#Web-safe_colors for details.")
 	fmt.Fprintln(w, "var WebSafe = []color.Color{")
 	for _, line := range lines {
 		fmt.Fprintln(w, line)
diff --git a/src/image/color/palette/palette.go b/src/image/color/palette/palette.go
index 07d60d2fb0..2a4cdcb7df 100644
--- a/src/image/color/palette/palette.go
+++ b/src/image/color/palette/palette.go
@@ -282,7 +282,7 @@ var Plan9 = []color.Color{
 // WebSafe is a 216-color palette that was popularized by early versions
 // of Netscape Navigator. It is also known as the Netscape Color Cube.
 //
-// See http://en.wikipedia.org/wiki/Web_colors#Web-safe_colors for details.
+// See https://en.wikipedia.org/wiki/Web_colors#Web-safe_colors for details.
 var WebSafe = []color.Color{
 	color.RGBA{0x00, 0x00, 0x00, 0xff},
 	color.RGBA{0x00, 0x00, 0x33, 0xff},
diff --git a/src/image/color/ycbcr.go b/src/image/color/ycbcr.go
index fd2443078c..8b6d508588 100644
--- a/src/image/color/ycbcr.go
+++ b/src/image/color/ycbcr.go
@@ -10,7 +10,7 @@ func RGBToYCbCr(r, g, b uint8) (uint8, uint8, uint8) {
 	//	Y' =  0.2990*R + 0.5870*G + 0.1140*B
 	//	Cb = -0.1687*R - 0.3313*G + 0.5000*B + 128
 	//	Cr =  0.5000*R - 0.4187*G - 0.0813*B + 128
-	// http://www.w3.org/Graphics/JPEG/jfif3.pdf says Y but means Y'.
+	// https://www.w3.org/Graphics/JPEG/jfif3.pdf says Y but means Y'.
 
 	r1 := int32(r)
 	g1 := int32(g)
@@ -60,7 +60,7 @@ func YCbCrToRGB(y, cb, cr uint8) (uint8, uint8, uint8) {
 	//	R = Y' + 1.40200*(Cr-128)
 	//	G = Y' - 0.34414*(Cb-128) - 0.71414*(Cr-128)
 	//	B = Y' + 1.77200*(Cb-128)
-	// http://www.w3.org/Graphics/JPEG/jfif3.pdf says Y but means Y'.
+	// https://www.w3.org/Graphics/JPEG/jfif3.pdf says Y but means Y'.
 	//
 	// Those formulae use non-integer multiplication factors. When computing,
 	// integer math is generally faster than floating point math. We multiply
@@ -163,7 +163,7 @@ func YCbCrToRGB(y, cb, cr uint8) (uint8, uint8, uint8) {
 //
 // Conversion between RGB and Y'CbCr is lossy and there are multiple, slightly
 // different formulae for converting between the two. This package follows
-// the JFIF specification at http://www.w3.org/Graphics/JPEG/jfif3.pdf.
+// the JFIF specification at https://www.w3.org/Graphics/JPEG/jfif3.pdf.
 type YCbCr struct {
 	Y, Cb, Cr uint8
 }
diff --git a/src/image/gif/reader.go b/src/image/gif/reader.go
index 7ae1ba9b41..e580ab049e 100644
--- a/src/image/gif/reader.go
+++ b/src/image/gif/reader.go
@@ -4,7 +4,7 @@
 
 // Package gif implements a GIF image decoder and encoder.
 //
-// The GIF specification is at http://www.w3.org/Graphics/GIF/spec-gif89a.txt.
+// The GIF specification is at https://www.w3.org/Graphics/GIF/spec-gif89a.txt.
 package gif
 
 import (
diff --git a/src/image/jpeg/reader.go b/src/image/jpeg/reader.go
index a915e96a4c..26b312cfd2 100644
--- a/src/image/jpeg/reader.go
+++ b/src/image/jpeg/reader.go
@@ -4,7 +4,7 @@
 
 // Package jpeg implements a JPEG image decoder and encoder.
 //
-// JPEG is defined in ITU-T T.81: http://www.w3.org/Graphics/JPEG/itu-t81.pdf.
+// JPEG is defined in ITU-T T.81: https://www.w3.org/Graphics/JPEG/itu-t81.pdf.
 package jpeg
 
 import (
@@ -62,13 +62,13 @@ const (
 	comMarker  = 0xfe // COMment.
 	// "APPlication specific" markers aren't part of the JPEG spec per se,
 	// but in practice, their use is described at
-	// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html
+	// https://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html
 	app0Marker  = 0xe0
 	app14Marker = 0xee
 	app15Marker = 0xef
 )
 
-// See http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
+// See https://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
 const (
 	adobeTransformUnknown = 0
 	adobeTransformYCbCr   = 1
@@ -684,7 +684,7 @@ func (d *decoder) applyBlack() (image.Image, error) {
 
 	// If the 4-component JPEG image isn't explicitly marked as "Unknown (RGB
 	// or CMYK)" as per
-	// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
+	// https://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
 	// we assume that it is YCbCrK. This matches libjpeg's jdapimin.c.
 	if d.adobeTransform != adobeTransformUnknown {
 		// Convert the YCbCr part of the YCbCrK to RGB, invert the RGB to get
@@ -747,7 +747,7 @@ func (d *decoder) isRGB() bool {
 		return false
 	}
 	if d.adobeTransformValid && d.adobeTransform == adobeTransformUnknown {
-		// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
+		// https://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe
 		// says that 0 means Unknown (and in practice RGB) and 1 means YCbCr.
 		return true
 	}
diff --git a/src/image/png/reader.go b/src/image/png/reader.go
index 4fbcef84b7..53fbf3e00a 100644
--- a/src/image/png/reader.go
+++ b/src/image/png/reader.go
@@ -4,7 +4,7 @@
 
 // Package png implements a PNG image decoder and encoder.
 //
-// The PNG specification is at http://www.w3.org/TR/PNG/.
+// The PNG specification is at https://www.w3.org/TR/PNG/.
 package png
 
 import (
@@ -73,7 +73,7 @@ type interlaceScan struct {
 }
 
 // interlacing defines Adam7 interlacing, with 7 passes of reduced images.
-// See http://www.w3.org/TR/PNG/#8Interlace
+// See https://www.w3.org/TR/PNG/#8Interlace
 var interlacing = []interlaceScan{
 	{8, 8, 0, 0},
 	{8, 8, 4, 0},
@@ -89,7 +89,7 @@ var interlacing = []interlaceScan{
 // present), IDAT and IEND chunks must appear in that order. There may be
 // multiple IDAT chunks, and IDAT chunks must be sequential (i.e. they may not
 // have any other chunks between them).
-// http://www.w3.org/TR/PNG/#5ChunkOrdering
+// https://www.w3.org/TR/PNG/#5ChunkOrdering
 const (
 	dsStart = iota
 	dsSeenIHDR