663023 - Cache system dpi

Status: RESOLVED FIXED

(Firefox for Android Graveyard :: General, defect)

Description

[Wesley Johnston (:wesj)]

Attachment: Patch

I've been implementing touch events, and noticed 3 or 4 getDPI calls coming across the AndroidBridge for every tap. Since this shouldn't ever change, we might as well cache it.

Comment 1

[Matt Brubeck (:mbrubeck)]

Comment on attachment 538165 [details] [diff] [review]
Patch

># HG changeset patch
># Parent b9354cf9282d8b4f8fae3bf43144e3bcf0e6c592
>
>+++ b/mobile/chrome/content/Util.js

>+  get displayDPI() function() {
>+    delete this.displayDPI;
>+    return this.displayDPI = this.getWindowUtils(window).displayDPI;
>   }
> };

Perhaps add a comment that this will only work in the parent process.

>+++ b/mobile/chrome/content/browser.js
>@@ -1112,7 +1112,7 @@
>     if (prefValue > 0)
>       return prefValue / 100;
> 
>+    let dpi = Utils.displayDPI;
>     if (dpi < 200) // Includes desktop displays, and LDPI and MDPI Android devices
>       return 1;

s/Utils/Util/

>   updateCanCancel: function(aX, aY) {
>+    let dpi = Utils.displayDPI;
> 
>     const kSafetyX = Services.prefs.getIntPref("dom.w3c_touch_events.safetyX") / 240 * dpi;
>     const kSafetyY = Services.prefs.getIntPref("dom.w3c_touch_events.safetyY") / 240 * dpi;

here too

Comment 2

[Mounir Lamouri (:mounir)]

http://hg.mozilla.org/mozilla-central/rev/3e9a4e14f6c6

Comment 3

[Wesley Johnston (:wesj)]

backed out due to general bustage;

http://hg.mozilla.org/mozilla-central/rev/46dbe6bfd8fe

Comment 4

[Wesley Johnston (:wesj)]

Attachment: Patch v2

Sorry about that. This fixes the errors (missed Utils->Util and getter returning a function). I've been browsing around with this for a bit and things that depend on dpi adjustments seem to be working fine.

Comment 5

[(no longer active)]

http://hg.mozilla.org/mozilla-central/rev/b36ae2b20ae1