device.(w|h): use screen.(width|height) instead of (innerWidth|innerHeight)

[justadreamer]

Type of issue

enhancement

Description

The proposed change is to replace these lines in src/fpd/enrichment.js:

      const w = win.innerWidth || win.document.documentElement.clientWidth || win.document.body.clientWidth;
      const h = win.innerHeight || win.document.documentElement.clientHeight || win.document.body.clientHeight;

with

      const w = window.screen.width;
      const h = window.screen.height;

• screen API docs

Motivation

1. Consistency, DRYness. Many adapters already do this anyway overriding the fpd implementation (f.e. see ixBidAdapter, adplusBidAdapter, adxcgAnalyticsAdapter, adxpremiumAnalyticsAdapter, brightMountainMediaBidAdapter, sharethroughBidAdapter, saambaaBidAdapter)
2. Following the standard. oRTB spec actually prescribes that device.(w|h) is the physical size of the screen in pixels, not browser window size
   

Alternative

Remove this code from the src/fpd/enrichment.js completely and let FPD module / RTD submodules take care of this.

Other considerations

(can be extracted into a separate issue)

Given oRTB spec literally says "physical size of the screen in pixels" - perhaps it makes more sense to set it in physical pixels, not logical aka CSS pixels? Then it would be:

      const pxratio = window.devicePixelRatio || 1;
      const w = window.screen.width * pxratio;
      const h = window.screen.height * pxratio;

devicePixelRatio is usually more than 1 on retina and HD displays. Thus it is desirable to either satisfy the spec or make it more precise if the industry expects device.(w|h) value to be expressed in CSS pixels.

cc: thanks @patmmccann and @BohdanVV for raising this point as part of this PR review comment #12005 (comment)

[patmmccann]

Interesting information from Safari as an aside

[patmmccann]

proposal extension: continue to pass inner height and width as device.ext.vpw and vph