From 472a1f9c91650448e2f3a5bdb235972e505774e6 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sun, 8 May 2022 11:06:18 +0200
Subject: [PATCH] Ignore `pageColors` when the background/foreground is
identical (PR 14874 follow-up)
If the computed background/foreground colors are identical, the `canvas` would be rendered mostly blank with only images visible. Hence it seems reasonable to also ignore the `pageColors`-option in this case.
Also, the patch tries to *briefly* outline the various cases in which we ignore the `pageColors`-option in a comment.
---
src/display/canvas.js | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/src/display/canvas.js b/src/display/canvas.js
index b34aba22e..469cc588b 100644
--- a/src/display/canvas.js
+++ b/src/display/canvas.js
@@ -1302,7 +1302,19 @@ class CanvasGraphics {
typeof defaultBg === "string" && /^#[0-9A-Fa-f]{6}$/.test(defaultBg);
}
- if ((fg === "#000000" && bg === "#ffffff") || !isValidDefaultBg) {
+ if (
+ (fg === "#000000" && bg === "#ffffff") ||
+ fg === bg ||
+ !isValidDefaultBg
+ ) {
+ // Ignore the `pageColors`-option when:
+ // - The computed background/foreground colors have their default
+ // values, i.e. white/black.
+ // - The computed background/foreground colors are identical,
+ // since that'd render the `canvas` mostly blank.
+ // - The `background`-option has a value that's incompatible with
+ // the `pageColors`-values.
+ //
this.foregroundColor = this.backgroundColor = null;
} else {
// https://developer.mozilla.org/en-US/docs/Web/Accessibility/Understanding_Colors_and_Luminance