THotPDF.RenderColorimetricLuminosityMasks

Controls how loaded-page rendering converts the colours of a luminosity soft mask into mask values

Declaration

property RenderColorimetricLuminosityMasks: boolean read FRenderColorimetricLuminosityMasks write FRenderColorimetricLuminosityMasks default false;

Remarks

With the property false (the default), a luminosity mask weights the resolved red, green, and blue values of its group as 0.30, 0.59, and 0.11, whatever blending space the group uses. A mid-grey therefore masks roughly half, which is how widespread PDF viewers draw drop shadows and fades

With the property true and the mask group carrying a CIE-based blending space (CalGray, CalRGB, Lab, or ICCBased), the mask takes the CIE 1931 Y component as set out in ISO 32000-1 section 11.5.3. Y is measured on a linear scale, so the same mid-grey masks only about a fifth and shadows come out lighter than in widespread viewers

Groups in device spaces are unaffected. The /BC backdrop colour of the mask is converted in the same way as the paint inside the group

The setting takes part in memory and disk render-cache identity, so bitmaps rendered under one setting are never handed back for the other

Example

Doc.RenderColorimetricLuminosityMasks:= true;
Bitmap:= Doc.RenderLoadedPageToBitmap(0, 150);