Heat map for «Out of gamut» visualization

This feature compares the currently opened PDF page based on its actual or assigned source color space/output intent profile against a color converted version of that page in an out of gamut heat map view. 

Understand the UI:

  1. The feature offers views that can be toggled between different specialised views like the original color space image, target color space image, overlay with heat map and regular page view.
  2. For each pixel, the color distance (in delta E) is computed and the result is represented as a pixel image where each pixel represents that distance by using a certain color (the ‘heat map image’); the colors range from yellow over red to pink
  3. Threshold distance: Pixels below a threshold distance of e.g. 2.5 delta E shall be transparent
  4. The current “color state” is the ‘current document color space’
  5. The “color state” that results from color converting the PDF page is the ‘target color space’
  6. Delta E methods: Delta E 2000 OR Delta E 1976
    • Toggle between current and target view manually by clicking the switch view button
    • Turn heat map view on and off manually by clicking the show/hide heat map button
    • Continuously toggle between the two views
  8. To find out what the color difference is in a given position, delta E value and matching color patch are shown for current mouse position
    • If delta E at mouse position is below threshold, the color patch is shown using black
    • If mouse position is outside of page area, delta E is shown as “–“, and the color patch is shown using black
  • The heat map image is placed on top of the current page view