XnView Software

XnViewMP 1.8.2 64bit
Windows11 (24H2), display resolution 3840x2160, win scaling 150%

Viewer - png
there is no full support (view/save/edit) of png 'cheap alpha' transparency (via tRNS values), which is inconvenient
test files


Suggestion

• add save/edit support for all transparency variations via tRNS chunk
  • save
  • edit
    - add visualization of alpha value on index map (eg same as in TweakPNG)

ref
https://www.w3.org/TR/png-3/#11transinfo
http://www.libpng.org/pub/png/book/chap ... ch08.div.5
http://www.libpng.org/pub/png/spec/1.2/ ... C.Anc-trns




Example

• tweakPNG

  

Related

• issues
  1.8.2 - view - png - tRNS transparency - viewing issues
  - todo -
  1.7.1 - viewer - high zoom quality - border at the edge of transparent png
  - fixed -
  1.8.0 - viewer - change color depth - 32bit result when converting 8 to 24 (1.8.1)
  1.6.5 - view - transparent index visible when zooming (1.8.1)
  1.7.2 - viewer - Show alpha became disabled (1.8.0)
  1.4.0 - viewer / batch convert - Change color depth to 8bit + Filter = mess (feature)

• suggestions
  Viewer - png - tRNS transparency - add save/edit for all variations (current post)
  - done -
  App UI - menu structure - View - improve channel commands (1.9.0)