XnView Software

Hello Pierre,

XnViewMP version 1.00 has a tag "Origin" in: Info area --> tab properties --> images
My first thought was it is "Orientation" or similar, because for all my images "Top Left" is displayed.

Today I did a test with images that have different values for "Orientation".
BUT XnViewMP always shows "Top Left".

So my question is: what value is really displayed?

Thanks for your help in advance.
Best regards
herb

it's not always the orientation, but how the image is saved.

Is this the same bug as issue #915, herb?

• XnView Forum
  • EXIF orientation info is wrong
  • Question to various rotate
  • EXIF:orientation is always top-left(1)
  • "cmd_rotate" & "Change EXIF orientation ONLY"
• ImpulseAdventure: JPEG Rotation and EXIF Orientation
• JPEGclub.org: Exif Orientation Tag

Hello Pierre, hello XnTriq,

thanks for your replies.

@Pierre:

it's not always the orientation, but how the image is saved.

Sorry, but I miss a scenario where this tag/value changes. Can you please give a detailed one.
My 2nd question is where is this value stored / taken from for display.

@XnTriq:
Sorry, I cannot answer your question. There are so many scenarions with orientation and I do not have the overview how XnViewMP should behave.

Best regards
herb

for example:

TIFF: it's the field orientation
BMP and other formats: often images are encoded bottom to top

xnview wrote: Mon May 09, 2022 12:31 pmfor example:

TIFF: it's the field orientation
BMP and other formats: often images are encoded bottom to top

… like Truevision Targa:

• TGA image origin change
• Bottom-up checkbox option when saving in Targa (.tga) format
• Orientation of TGA generated by nconvert

Tools → Settings… → Formats → Write → TGA → Bottom-up orientation

https://en.wikipedia.org/wiki/Truevision_TGA#Header wrote:Bit 4 of the image descriptor byte indicates right-to-left pixel ordering if set. Bit 5 indicates an ordering of top-to-bottom. Otherwise, pixels are stored in bottom-to-top, left-to-right order.

Thanks for clarifying, Pierre!

Hello,

thanks for your quick replies.
But I am still confused:
Tag Exif:Orientation is used for the current orientation of the image.
As far as I know also in case of *.tiff or also *.bmp images.
Or do I miss somethings?

How can it be used for something like "but how the image is saved" (as Pierre wrote).
Thanks in advance for giving me more details.

I also did some experiments storing *.tiff images. But origin alsways was: Top left
Can you tell me the steps in order to get another value for "origin"

Best regards
herb

Does this answer (part of) your question, herb?

• Microsoft
  • Top-Down vs. Bottom-Up DIBs
  • Why are device-independent bitmaps upside down?
• Stack Overflow
  • Why do BITMAPS load "upwards"?
• Stack Exchange
  • Specific reasons why a top left origin is better/worse than a bottom left origin for computer graphics
  • Why is the origin in computer graphics coordinates at the top left?
  • Why do we use the top left corner as the origin in image processing?
  • Why is pixel 0,0 at the top left of some formats and bottom left of others?

Pixel grid origin = top/left: Pixel grid origin = bottom/left:

Hello XnTriq,

thanks for all the links. A very good private lession for me (although I have not read everything till now).
Things become clearer and clearer.

Best regards
herb