If you are looking to have high resolution dynamic icons on any Windows machine screen size you should take a look at the TSVGIconImageList component set from developer carloBarazzetta over on GitHub. The component set is open source using the Apache 2.0 license and supports both VCL and FMX. SVGs are vector based graphics which are drawn at runtime which means you get the best quality graphic for the screen size you are using. The components only support Windows for now and does not support Android, IOS, OSX, or Linux. However, it does allow you to create crisp clean icons for your Windows applications using Delphi 10.4 FireMonkey which look great eat any resolution. It can probably be used in C++Builder as well. Here are some of the most recent release notes at the time of this writing.
RELEASE NOTES: 26 Aug 2020: version 2.0 (VCL+FMX)
Added factory to choose engine
Added interface to use alternative Third-party SVG engine
Redesigned component editor to support Categories for icons
New support for native VirtualImageList (from D10.3)
StoreAsText icons to dfm by default (and unique mode)
Fixed many issues (from #35 to #72) Take care of TSVGIconVirtualImageList.Collection renamed to SVGIconVirtualImageList.ImageCollection.
17 Aug 2020: version 1.9 (VCL+FMX)
FixedColor changed from TSVGColor to TColor
Fixed assign FixedColor to icon in component editor
Updated component editor to use TColorBox
13 Aug 2020: version 1.8 (VCL+FMX)
Complete refactoring for full support of High-DPI
New SVGIconImageCollection component
New SVGIconVirtualImageList component
Redesign of SVGIconImageList component and Component Editor
Demo updated to test multi-monitor with different DPI
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