[Gwyddion-users] PNG Export-Issue

[Mathias Müller]

Hi Yeti,

the current stable version of Gwyddion (Linux, V2.39, R2014-11-14) seems to have problems to maintain the color scale when exporting
processed data to png. However, while writing this mail it seems this problem is persistent for other formats, too.
The displayed and the written color scale in the export dialog differs from that of the channel I am working on. It seems that the
export dialog sets the full data range for color specification per default.

Can you reproduce this issue on your machine?



Cheers,

/M

[David Nečas (Yeti)]

Post by Mathias Müller
the current stable version of Gwyddion (Linux, V2.39, R2014-11-14)
seems to have problems to maintain the color scale when exporting
processed data to png. However, while writing this mail it seems this
problem is persistent for other formats, too.

Exportes images are drawn using exactly the same code for all formats.
So apart from inherent differences (e.g. rastrer vs. vector formats),
they should look the same in all formats.

Post by Mathias Müller
The displayed and the written color scale in the export dialog differs
from that of the channel I am working on. It seems that the export
dialog sets the full data range for color specification per default.
Can you reproduce this issue on your machine?

No, I can't. I just tried to use autorange and manually selected fixed
range for a random data file. They are correctly reflected in both the
image data rendering and false colour map scale.

But one thing does not seem right: When I *invert* the gradient direction
using the colour range tool, then the false colour axis and image
rendering do not agree in the export. Is this what you observe?

Regards,

Yeti

[Mathias Müller]

Unfortunatelly not. But I can reproduce the issue

1) I open an image
2) set the adaptive color code
3) save as -> e.g. png

The dialog shows a full range color scale.

But, when setting the color code from adaptive to e.g. full range and again back
to adaptive (i.e. hooking and unhooking the color codes in the color range tool in
one turn) than the image export dialog shows the correct color code, i.e. adaptive
in my case.

This seems weird, but I can totally reproduce this issue. The issue seems to be "fixed"
for other freshly opened data as long there is an active channel left before. Closing
all channels and opening a new data file the issue occurs again.

/M

Post by David Nečas (Yeti)

Post by Mathias Müller
the current stable version of Gwyddion (Linux, V2.39, R2014-11-14)
seems to have problems to maintain the color scale when exporting
processed data to png. However, while writing this mail it seems this
problem is persistent for other formats, too.

Exportes images are drawn using exactly the same code for all formats.
So apart from inherent differences (e.g. rastrer vs. vector formats),
they should look the same in all formats.

Post by Mathias Müller
The displayed and the written color scale in the export dialog differs
from that of the channel I am working on. It seems that the export
dialog sets the full data range for color specification per default.
Can you reproduce this issue on your machine?

No, I can't. I just tried to use autorange and manually selected fixed
range for a random data file. They are correctly reflected in both the
image data rendering and false colour map scale.
But one thing does not seem right: When I *invert* the gradient direction
using the colour range tool, then the false colour axis and image
rendering do not agree in the export. Is this what you observe?
Regards,
Yeti

[Mathias Müller]

I should also mention, that the adaptive color code is default in my settings.
Maybe the default setting isn't read from the export dialog?

Post by David Nečas (Yeti)

Post by Mathias Müller
the current stable version of Gwyddion (Linux, V2.39, R2014-11-14)
seems to have problems to maintain the color scale when exporting
processed data to png. However, while writing this mail it seems this
problem is persistent for other formats, too.

Exportes images are drawn using exactly the same code for all formats.
So apart from inherent differences (e.g. rastrer vs. vector formats),
they should look the same in all formats.

Post by Mathias Müller
The displayed and the written color scale in the export dialog differs
from that of the channel I am working on. It seems that the export
dialog sets the full data range for color specification per default.
Can you reproduce this issue on your machine?

No, I can't. I just tried to use autorange and manually selected fixed
range for a random data file. They are correctly reflected in both the
image data rendering and false colour map scale.
But one thing does not seem right: When I *invert* the gradient direction
using the colour range tool, then the false colour axis and image
rendering do not agree in the export. Is this what you observe?
Regards,
Yeti

[David Nečas (Yeti)]

Post by Mathias Müller
I should also mention, that the adaptive color code is default in my settings.
Maybe the default setting isn't read from the export dialog?

Yes, that would be likely the reason. I will look into it.

Regards,

Yeti

[David Nečas (Yeti)]

Post by David Nečas (Yeti)

Post by Mathias Müller
I should also mention, that the adaptive color code is default in my settings.
Maybe the default setting isn't read from the export dialog?

Yes, that would be likely the reason. I will look into it.

It should work now. Where ‘now’ means tomorrow's development snapshot
unless you compile Gwyddion directly from svn.

Regards,

Yeti

[Mathias Müller]

Great, thanks Yeti.

/M

Post by David Nečas (Yeti)

Post by David Nečas (Yeti)

Post by Mathias Müller
I should also mention, that the adaptive color code is default in my settings.
Maybe the default setting isn't read from the export dialog?

Yes, that would be likely the reason. I will look into it.

It should work now. Where ‘now’ means tomorrow's development snapshot
unless you compile Gwyddion directly from svn.
Regards,
Yeti