Let me also vote for this feature. I hope to easily export each layer as PNG. Then my game dev tool can pack these as spritesheet (trimming the alpha, but maintaining relative position).
In case it helps anyone, let me share my workaround:
- Save the art to SVG from Affinity Designer.
- Call Inkscape (free/open source) command line to export individual symbol from SVG. inkscape "sourceFile.svg" -i symbolName -j -C -e "layer1.png" --without-gui. Quick explanation: "-i" - only export specific symbol, "-j" - only export symbol (all other content is hidden), "-C" - export entire page.