Fix text selection with hdpi screens (#15229)

[calixteman]

No description provided.

[Snuffleupagus]

Given that we have a couple of other measureText-usages in the code-base, are any of those similarly affected?
If so that can, and maybe even should, be handled in follow-up patches.

Also, I'm assuming that there's no particularly good way to test this?

[Snuffleupagus]

To prevent issues in non-browser environments, please change this to:

Suggested change

	this._devicePixelRatio = window.devicePixelRatio;
	this._devicePixelRatio = globalThis.devicePixelRatio || 1;

[calixteman]

Given that we have a couple of other measureText-usages in the code-base, are any of those similarly affected? If so that can, and maybe even should, be handled in follow-up patches.

Yep, I'm in favor of follow-up patches.

Also, I'm assuming that there's no particularly good way to test this?

I have no idea on how to do that.
Here's a screenshot from my HDPI screen (pixelRatio == 1.5):

For people having a pixel ratio equals to 1, it should be impactless and for the other it cannot be worst than it is right now.
I tested with different pixelRatio settings in the Windows parameters stuff (System > Display > Scale & Layout > Scale), and everything is ok.

[Snuffleupagus]

/botio test

[pdfjsbot]

From: Bot.io (Windows)

---

Received

Command cmd_test from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.193.163.58:8877/abdfec01cf95c38/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

---

Received

Command cmd_test from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.241.84.105:8877/465981514c8de28/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

---

Failed

Full output at http://54.241.84.105:8877/465981514c8de28/output.txt

Total script time: 25.92 mins

• Font tests: Passed
• Unit tests: Passed
• Integration Tests: Passed
• Regression tests: FAILED

  different ref/snapshot: 4

Image differences available at: http://54.241.84.105:8877/465981514c8de28/reftest-analyzer.html#web=eq.log

[pdfjsbot]

From: Bot.io (Windows)

---

Failed

Full output at http://54.193.163.58:8877/abdfec01cf95c38/output.txt

Total script time: 28.79 mins

• Font tests: Passed
• Unit tests: Passed
• Integration Tests: FAILED
• Regression tests: Passed

[Snuffleupagus]

/botio-linux preview

[pdfjsbot]

From: Bot.io (Linux m4)

---

Received

Command cmd_preview from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.241.84.105:8877/df81b472a512af7/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

---

Success

Full output at http://54.241.84.105:8877/df81b472a512af7/output.txt

Total script time: 2.43 mins

Published

• Viewer: http://54.241.84.105:8877/df81b472a512af7/web/viewer.html
• Viewer (legacy): http://54.241.84.105:8877/df81b472a512af7/legacy/web/viewer.html