1957227 - Wrong translucent window painting when opaque region is all the way to the left of the window

Status: RESOLVED FIXED

(Core :: Widget: Win32, defect)

Description

[Emilio Cobos Álvarez (:emilio)]

STR:

• Enable mica.
• Apply this patch, which just makes the contents of the window invisible, except for a big red rectangle to the rect:

diff --git a/browser/themes/shared/browser-shared.css b/browser/themes/shared/browser-shared.css
index 0f0ed96da4494..0a6e9962327a3 100644
--- a/browser/themes/shared/browser-shared.css
+++ b/browser/themes/shared/browser-shared.css
@@ -148,6 +148,19 @@ body {
   margin: 0;
 }

+:root::after {
+  content: "";
+  width: 40px;
+  position: fixed;
+  left: 0;
+  inset-block: 0;
+  background-color: red;
+}
+
+#browser, #navigator-toolbox {
+  visibility: hidden
+}
+
 /* Toolbox and Toolbars */

 #navigator-toolbox {

ER:

• Mica backdrop as per usual, with the red bit to the left of the window.

AR:

• There's a strip of uncleared window area.

This affects thunderbird's spaces toolbar, see bug 1957211.

Just making the red not fully opaque fixes it, which confirms this is an issue of the widget opaque region handling.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1957227 - Fix client vs. window coordinate confusion in transparent window code. r=#win-reviewers!

The paint DC takes client coords, while we were providing window coords.

This means that the ComputeNonClientRegion() code was also clearing wrong
coords. Remove that, since it's disabled by default, and folks in bug 1935894
have confirmed that it's no longer needed after that and bug 1950441.

By the time this patch lands those should be in release already and we should
have two full cycles should any issue come up with those.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1957227 - Use prescontext scale to return opaque region in a test API. r=#layout,#win-reviewers

Test-only. The difference between the two scales is the OS text scale
factor. This just confused me a bit when using this API to debug this.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f58b871efb91
Use prescontext scale to return opaque region in a test API. r=dholbert

Comment 4

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/f58b871efb91

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7a12774d16a8
Fix client vs. window coordinate confusion in transparent window code. r=win-reviewers,handyman

Comment 6

[amarc]

https://hg.mozilla.org/mozilla-central/rev/7a12774d16a8