List of Affinity specific features

[ceocan]

Is there a list of features that are specific for Affinity (like the erase blend mode)? This would come in handy if I need to export files for a third party, so I know which parts of the design I need to convert or rasterise to keep the design as it needs to be if opened in another piece of software.

[thomaso]

I am not aware of a list of features that will cause rasterization on PDF export. It is not only influenced by the used blend modes but also by the hierarchical order of involved layers which are affected by transparency features.

For instance below: while the 4 blend modes do not require flattening on export they do if a shadow as a second feature gets applied. Then even the blend mode 'normal' can cause rasterization (group > shadow) for both involved objects (backdrop + source) whereas a different layer order (shadow > group) doesn't cause rasterization for 'normal'.

v1105 blend modes & rast_X4.pdf

I might be wrong with my limited maths skills but it appears that blend modes which require mathematical addition or subtraction when computing the resulting colour will cause rasterization while formulas which use multiplication only do not.

If wanted, this sources give more inside information about PDF specification regarding blend modes, transparency (opacity) and flattening (rasterization):

https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/pdfreference1.6.pdf  (-> chapter 7: Transparency)

https://help.autodesk.com/sfdcarticles/attachments/Adobe_Whitepaper_on_Transparency.pdf