979973 - Aligning to tile boundaries is incorrect when the resolution is about to change

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[Chris Lord [:cwiiis]]

It would appear, though I've yet to deeply investigate, that when we change the zoom level, we don't also set a new displayport. This is pretty bad, as when you zoom in far, we end up with a *much* larger displayport than we intend, and can easily blow through available RAM.

This sounds to me like a relatively easy fix, so I'll be looking at this tomorrow.

Comment 1

[Chris Lord [:cwiiis]]

erk, so this is the fault of my code :) LayersPixelsPerCSSPixel() is wrong when the resolution is about to change as the resolution/cumulative resolution aren't updated, so the align to tile boundaries ends up making the displayport much bigger when zooming in. It also won't be at all aligned to tiles when zooming in/out either, which isn't fantastic...

Pretty easy fix, thankfully, patch incoming.

Comment 2

[Chris Lord [:cwiiis]]

Attachment: Fix displayport tile-alignment when zooming

Comment 3

[Botond Ballo [:botond]]

Comment on attachment 8386702 [details] [diff] [review]
Fix displayport tile-alignment when zooming

Review of attachment 8386702 [details] [diff] [review]:
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Good catch!

Comment 4

[Chris Lord [:cwiiis]]

Pushed to inbound: https://hg.mozilla.org/integration/mozilla-inbound/rev/5de7483b01d2

Comment 5

[Timothy Nikkel (:tnikkel)]

It would be nice if there was a clean separation of which fields/properties on a FrameMetrics are up to date and which are outdated so bugs like this don't crop up.

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/5de7483b01d2