1-bit binary transparency

[XnTriq]

I would like to be able to view 1-bit monochrome images with transparency in such a way that transparent areas are actually displayed as transparent (= XnView's background color or the checkerboard pattern).

[xnview]

I would like to be able to view 1-bit monochrome images with transparency in such a way that transparent areas are actually displayed as transparent (= XnView's background color or the checkerboard pattern).

Ok, so as an option

[XnTriq]

We already have an option for that: Use transparent index (<=8bits).
This works for images with 16- and 256-color palettes, but not for monochrome images (2-color palettes):

• 
  [ z00m ]

BTW: How about combining the two separate settings (Use transparent index (<=8bits) & Use alpha channel) to a single option (Use transparency)?

[xnview]

We already have an option for that: Use transparent index (<=8bits).
This works for images with 16- and 256-color palettes, but not for monochrome images (2-color palettes):

B&W are not really a color palette picture!

[/list]BTW: How about combining the two separate settings (Use transparent index (<=8bits) & Use alpha channel) to a single option (Use transparency)?

Many users don't want a general setting for alpha & transparent index

[XnTriq]

We already have an option for that: Use transparent index (<=8bits).
This works for images with 16- and 256-color palettes, but not for monochrome images (2-color palettes):

B&W are not really a color palette picture!

I see. But why is transparency in “1-bit color graphics” or “binary images” ignored by XnView and handled differently than transparency in palette-based pictures?

Example of a non-B&W GIF that has a color depth of 1 bit and a transparent background:

• 

[xnview]

We already have an option for that: Use transparent index (<=8bits).
This works for images with 16- and 256-color palettes, but not for monochrome images (2-color palettes):

B&W are not really a color palette picture!

I see. But why is transparency in “1-bit color graphics” or “binary images” ignored by XnView and handled differently than transparency in palette-based pictures?

Example of a non-B&W GIF that has a color depth of 1 bit and a transparent background:

• 

Yes, for me B&W picture are different than 1bit with color.
You have these different picture type B&W ( 1 ), Colour ( 1-8 ), Grey ( 8 ), 24/32 bits pictures

[XnTriq]

Thanks for explaining, Pierre.

So the difference between 1-bit monochrome and 1-bit with color is somewhat similar to the difference between 8-bit grayscale and an indexed color palette of black + white + 254 continuous shades of gray (“fake grayscale”)?

Grayscale images usually do not need palettes. The pixel values can be directly the gray level in a given range (0 to 15, 0 to 255), so image files that deal with grayscale images usually do not store a palette color map for this purpose.

[xnview]

So the difference between 1-bit monochrome and 1-bit with color is somewhat similar to the difference between 8-bit grayscale and an indexed color palette of black + white + 254 continuous shades of gray (“fake grayscale”)?

Yes