Re: Question about scale in nested frames

[Khushal Sagar]

+Graphics-dev +Sunny Sachanandani

Adding Sunny for the raster scale details.

On Sun, Feb 23, 2025 at 11:46 PM Maksim Sisov <msi...@igalia.com> wrote:

Hi!

I have some questions about
https://chromium-review.googlesource.com/c/chromium/src/+/5030933

Basically, we're dealing with the following bug in electron
https://github.com/electron/electron/issues/44227

Looking at the issue, it turned out to be a raster issue, which does
nothing with capturePage, which is implemented via copy output request.
Basically, after the 5030933, the webview started to be rendered with
lower transform scale that it used to be. It was noticed that
PictureLayerImpl[1],
started to use the scale factor of the <webview>, which is set as
transform: scale(0.5) in our specific case.

This scale factor started to be set in [2]. As
`is_for_nested_main_fram`e started to be true and is set [3]. Is it
expected behavior?

[1]
https://source.chromium.org/chromium/chromium/src/+/main:cc/layers/picture_layer_impl.cc;l=1955
[2]
https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/co[…]ame%2Fweb_frame_widget_impl.cc&ss=chromium%2Fchromium%2Fsrc
[3]
https://chromium-review.googlesource.com/c/chromium/src/+/5030933/8/content/browser/renderer_host/render_frame_host_impl.cc#3373

--
Best Regards,
Maksim Sisov
* Usual work time - 08:00-16:00 (EET).