Fix wrong maximized window offset on non primary monitors

[dsafa]

Summary of the Pull Request

Fixes the calculation of the margins when the non client island window is maximized on non primary monitors

References

#1055

PR Checklist

• Closes Left side of text is cut off when maximizing windows terminal on non-primary monitor #1055
• CLA signed. If not, go over here and sign the CLA
• Tests added/passed
• Requires documentation to be updated
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

Detailed Description of the Pull Request / Additional comments

The overhang of a maximized window is currently calculated with this:

auto offset = 0;
if (rcMaximum.left == 0)
{
    offset = windowPos->x;
}
else if (rcMaximum.top == 0)
{
    offset = windowPos->y;
}

This always works on the primary monitor but on a non primary monitor, it isn't always the case that left or top can be 0. Examples are when you offset a monitor. In those cases, offset will be 0 and the window will be cut off.

Instead I've changed the calculation to calculate the width of the windows frame which is how much it would overhang. Admittedly, the old calculation could be kept and take into consideration the current monitor.

Also I see a lot of work on the non client window so maybe we won't even need to do this later?

Validation Steps Performed

Manually tested on primary and non primary monitors and the same offset is given: 8 pixels on all sides at 100% scaling. Also tested with different dpi and the margins are the same as using the old method.

[zadjii-msft]

This seems reasonable to me. I was poking around at this just recently, but hadn't identified that this was the real issue here. Good work on the find!

Even with my other nonclient changes, I think this will still work as the right fix.

[zadjii-msft]

@dsafa (also make sure to runformat before submitting code, so that it's formatted correctly)

[dsafa]

Whoops, thanks for the reminder. I've read up on the tools now and ran runformat.

[DHowett-MSFT]

Thanks!

[DHowett-MSFT]

@msftbot merge this in 2 hours

[ghost]

Hello @DHowett-MSFT!

Because you've given me some instructions on how to help merge this pull request, I'll be modifying my merge approach. Here's how I understand your requirements for merging this pull request:

• I won't merge this pull request until after the UTC date Thu, 11 Jul 2019 18:58:59 GMT, which is in 2 hours

If this doesn't seem right to you, you can tell me to cancel these instructions and use the auto-merge policy that has been configured for this repository. Try telling me "forget everything I just told you".

[miniksa]

Beautiful. Thank you.

[ghost]

🎉Windows Terminal Preview v0.3.2142.0 has been released which incorporates this pull request.:tada:

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