Fix Windows masked cursor blending with GPU encoders

[cgutman]

Description

Blending of masked color and monochrome cursors was broken when using GPU accelerated encoding on Windows. Color masked cursors would be rendered completely transparently (no cursor at all) and monochrome masked cursors would not be blended with the display contents at all (using fixed colors instead).

This fixes the I-beam cursor when using High DPI (which is a masked color cursor) and the inverted cursor style (which uses monochrome cursors with inversion masks).

Screenshot

Issues Fixed or Closed

Fixes #513

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

Branch Updates

LizardByte requires that branches be up-to-date before merging. This means that after any PR is merged, this branch
must be updated before it can be merged. You must also
Allow edits from maintainers.

• I want maintainers to keep my branch updated

[psyke83]

I tested on Windows 10 and, comparing to the host screen, can't identify any problems with the colour/transparency reproduction for masked or inverted cursors. Seems good to me.