Use 65535 as scale factor for color-values on NS

Use 65535 as scale factor for color-values on NS

[Mattias Engdegård]

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Alan, it seems that only NS uses 65280 as scale factor for 'color-values'; all other back-ends use 65535. Do you know if there is any reason for keeping it this way? Otherwise, I propose we change it (see patch).

It is probably just a relic from when colour components were scaled from 8 to 16 bits by multiplication with 256 instead of 257; this seems to have been fixed everywhere else.


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From fba2c0d5f93c05db580b3aa7c8eda7a282411796 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Sat, 6 Jun 2020 11:23:48 +0200
Subject: [PATCH] Use 65535 as color-values scale value in the NS backend

* src/nsfns.m (Fxw_color_values): Scale with 65535 instead of 65280, for
uniformity with other backends.
* lisp/faces.el (color-values): Update doc string.
* doc/lispref/frames.texi (Color Names): Update examples.
---
 doc/lispref/frames.texi | 6 +++---
 lisp/faces.el           | 2 +-
 src/nsfns.m             | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index 6bf5db2aa1..966f620558 100644
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -3975,11 +3975,11 @@ Color Names
 (color-values "black")
      @result{} (0 0 0)
 (color-values "white")
-     @result{} (65280 65280 65280)
+     @result{} (65535 65535 65535)
 (color-values "red")
-     @result{} (65280 0 0)
+     @result{} (65535 0 0)
 (color-values "pink")
-     @result{} (65280 49152 51968)
+     @result{} (65535 49344 52171)
 (color-values "hungry")
      @result{} nil
 @end example
diff --git a/lisp/faces.el b/lisp/faces.el
index e707f6f4b6..f4a9dedd79 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1822,7 +1822,7 @@ color-values
 string specifying a color's RGB components (e.g. \"#ff12ec\").
 
 Return a list of three integers, (RED GREEN BLUE), each between 0
-and either 65280 or 65535 (the maximum depends on the system).
+and 65535 inclusive.
 Use `color-name-to-rgb' if you want RGB floating-point values
 normalized to 1.0.
 
diff --git a/src/nsfns.m b/src/nsfns.m
index 273fb5f759..5e8d572d8f 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -2329,8 +2329,8 @@ Frames are listed from topmost (first) to bottommost (last).  */)
   [[col colorUsingDefaultColorSpace]
         getRed: &red green: &green blue: &blue alpha: &alpha];
   unblock_input ();
-  return list3i (lrint (red * 65280), lrint (green * 65280),
-		 lrint (blue * 65280));
+  return list3i (lrint (red * 65335), lrint (green * 65535),
+		 lrint (blue * 65535));
 }
 
 
-- 
2.21.1 (Apple Git-122.3)

Re: Use 65535 as scale factor for color-values on NS

[Mattias Engdegård]

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> <0001-Use-65535-as-color-values-scale-value-in-the-NS-back.patch>

That patch contained a typo (65335 instead of 65535); corrected below. Sorry.


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From 38a7e4cce4ae9fb807f82e9efb4d6848668ab547 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Sat, 6 Jun 2020 11:23:48 +0200
Subject: [PATCH] Use 65535 as color-values scale value in the NS backend

* src/nsfns.m (Fxw_color_values): Scale with 65535 instead of 65280, for
uniformity with other backends.
* lisp/faces.el (color-values): Update doc string.
* doc/lispref/frames.texi (Color Names): Update examples.
---
 doc/lispref/frames.texi | 6 +++---
 lisp/faces.el           | 2 +-
 src/nsfns.m             | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index 6bf5db2aa1..966f620558 100644
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -3975,11 +3975,11 @@ Color Names
 (color-values "black")
      @result{} (0 0 0)
 (color-values "white")
-     @result{} (65280 65280 65280)
+     @result{} (65535 65535 65535)
 (color-values "red")
-     @result{} (65280 0 0)
+     @result{} (65535 0 0)
 (color-values "pink")
-     @result{} (65280 49152 51968)
+     @result{} (65535 49344 52171)
 (color-values "hungry")
      @result{} nil
 @end example
diff --git a/lisp/faces.el b/lisp/faces.el
index e707f6f4b6..f4a9dedd79 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1822,7 +1822,7 @@ color-values
 string specifying a color's RGB components (e.g. \"#ff12ec\").
 
 Return a list of three integers, (RED GREEN BLUE), each between 0
-and either 65280 or 65535 (the maximum depends on the system).
+and 65535 inclusive.
 Use `color-name-to-rgb' if you want RGB floating-point values
 normalized to 1.0.
 
diff --git a/src/nsfns.m b/src/nsfns.m
index 273fb5f759..628233ea0d 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -2329,8 +2329,8 @@ Frames are listed from topmost (first) to bottommost (last).  */)
   [[col colorUsingDefaultColorSpace]
         getRed: &red green: &green blue: &blue alpha: &alpha];
   unblock_input ();
-  return list3i (lrint (red * 65280), lrint (green * 65280),
-		 lrint (blue * 65280));
+  return list3i (lrint (red * 65535), lrint (green * 65535),
+		 lrint (blue * 65535));
 }
 
 
-- 
2.21.1 (Apple Git-122.3)

Re: Use 65535 as scale factor for color-values on NS

[Alan Third]

On Sat, Jun 06, 2020 at 11:57:03AM +0200, Mattias Engdegård wrote:
> Alan, it seems that only NS uses 65280 as scale factor for
> 'color-values'; all other back-ends use 65535. Do you know if there
> is any reason for keeping it this way? Otherwise, I propose we
> change it (see patch).
> 
> It is probably just a relic from when colour components were scaled
> from 8 to 16 bits by multiplication with 256 instead of 257; this
> seems to have been fixed everywhere else.

I'm not aware of any reason for this, and I don't see any immediate
problems with your (second) patch applied.
-- 
Alan Third

Re: Use 65535 as scale factor for color-values on NS

[Mattias Engdegård]

6 juni 2020 kl. 20.57 skrev Alan Third <alan@idiocy.org>:

> I'm not aware of any reason for this, and I don't see any immediate
> problems with your (second) patch applied.

Thank you! Pushed to master.