Using the same inage in Image Editor and Compositor makes image dark #27997

New Issue

Sergey Sharybin · 2011-07-17T10:26:37+02:00

Sergey Sharybin commented

2011-07-17 10:26:37 +02:00

%%%Hi,

First of all you'll need to display both of Nodes Editor and Image editor in the same layout. Then you should open image in image editor and add Image node to compositor and attach Viewer to this Image Node. Enable Backdrop.

Everything is fine.

But if you'll make brush stroke in image editor, the whole image would become darker in image editor.

Briefly, this happens due to sequent usage of float_from_rect and rect_from_float called for the same image. Compositor works with float images, so it uses float_from_rect to produce float data. Then, when you make stroke, image editor makes changes to float image. But this image editor doesn't use float buffer for display -- it creates rect from float.

Some ideas: color profile is incorrect in ImBuf, or color correction happens twice for such sequent calculation rect from float and float from rect.

Attaching sample .blend file and original image.%%%

%%%Hi, First of all you'll need to display both of Nodes Editor and Image editor in the same layout. Then you should open image in image editor and add Image node to compositor and attach Viewer to this Image Node. Enable Backdrop. Everything is fine. But if you'll make brush stroke in image editor, the whole image would become darker in image editor. Briefly, this happens due to sequent usage of float_from_rect and rect_from_float called for the same image. Compositor works with float images, so it uses float_from_rect to produce float data. Then, when you make stroke, image editor makes changes to float image. But this image editor doesn't use float buffer for display -- it creates rect from float. Some ideas: color profile is incorrect in ImBuf, or color correction happens twice for such sequent calculation rect from float and float from rect. Attaching sample .blend file and original image.%%%

Sergey Sharybin commented

2011-07-17 10:26:37 +02:00

Changed status to: 'Open'

Troy Sobotka commented

2011-07-18 01:47:07 +02:00

%%%Hmm. I noticed that the image suddenly flips to darkness on some motion picture files and filed a bug report. I wonder if it is strictly to do with painting then?

I can't find the damn bug report. Grr.%%%

%%%Hmm. I noticed that the image suddenly flips to darkness on some motion picture files and filed a bug report. I wonder if it is strictly to do with painting then? I can't find the damn bug report. Grr.%%%

Campbell Barton commented

2011-07-18 12:04:15 +02:00

%%%attached possible fix.
this changes it so 'IB_PROFILE_SRGB' are not assumed to be 'IB_PROFILE_LINEAR_RGB'%%%

%%%attached possible fix. this changes it so 'IB_PROFILE_SRGB' are not assumed to be 'IB_PROFILE_LINEAR_RGB'%%%

Campbell Barton commented

2011-07-18 12:07:46 +02:00

%%%I should have said that I think the fix is correct, but since this changes the logic in IMB_float_from_rect(). perhaps it should be done differently.

Another way to fix would be to have the JPEG image initialize its profile as IB_PROFILE_NONE rather then IB_PROFILE_SRGB,
but JPEG/PNG/BMP/TARGA/IRIS all do this so think its best not to change that.%%%

%%%I should have said that I think the fix is correct, but since this changes the logic in IMB_float_from_rect(). perhaps it should be done differently. Another way to fix would be to have the JPEG image initialize its profile as IB_PROFILE_NONE rather then IB_PROFILE_SRGB, but JPEG/PNG/BMP/TARGA/IRIS all do this so think its best not to change that.%%%

Campbell Barton commented

2011-07-18 12:30:58 +02:00

%%%To explain whats going wrong:
byte buffer is always non linear, so initializing as IB_PROFILE_SRGB is fine.

But IMB_float_from_rect checks (ibuf->profile != IB_PROFILE_NONE) and adds a linear float buffer.

Now the image is left with a linear buffer but IB_PROFILE_SRGB which is incorrect, it should probably set the profile to linear.%%%

%%%To explain whats going wrong: byte buffer is _always_ non linear, so initializing as IB_PROFILE_SRGB is fine. But IMB_float_from_rect checks (ibuf->profile != IB_PROFILE_NONE) and adds a linear float buffer. Now the image is left with a linear buffer but IB_PROFILE_SRGB which is incorrect, it should probably set the profile to linear.%%%

Campbell Barton commented

2011-07-18 12:35:16 +02:00

%%%attached a patch which only sets the buffer to linear. this also fixes the reported bug.%%%

Ton Roosendaal commented

2011-07-20 18:26:05 +02:00

%%%Campbell: the profile flag is only to denote the format of the byte buffer. By definition the float buffer is "work space" or actually linear for us.

It should never be needed to correct float buffers either, not flag float buffers into a type.

More over; I'm unsure if when "color management" is set, the profiles should be used even... asked matt about it in another report.%%%

%%%Campbell: the profile flag is only to denote the format of the byte buffer. By definition the float buffer is "work space" or actually linear for us. It should never be needed to correct float buffers either, not flag float buffers into a type. More over; I'm unsure if when "color management" is set, the profiles should be used even... asked matt about it in another report.%%%

Troy Sobotka commented

2011-11-04 11:41:46 +01:00

%%%I'll chime in here thanks to Sergey's notification in IRC.

It would seem that according to Matt's code that he opened up the potential for various color spaces to be indicated in the ImBuf.

This should be irrespective of the byte or float buffer, and this appears to be Matt's intention. A good example of this would be the VSE using a float buffer with sRGB.

While the profile connection space within Blender is assumed to be the linear space (which is a rather arbitrary one currently and should probably be more well defined), it doesn't appear that Matt's original intention is as Ton states above.%%%

%%%I'll chime in here thanks to Sergey's notification in IRC. It would seem that according to Matt's code that he opened up the potential for various color spaces to be indicated in the ImBuf. This should be irrespective of the byte or float buffer, and this appears to be Matt's intention. A good example of this would be the VSE using a float buffer with sRGB. While the profile connection space within Blender is assumed to be the linear space (which is a rather arbitrary one currently and should probably be more well defined), it doesn't appear that Matt's original intention is as Ton states above.%%%

Sergey Sharybin commented

2012-09-13 12:55:21 +02:00

%%%This issue was resolved in tomato branch which is currently being preparing for merge into trunk. Marking the issue as resolved now. %%%

Sergey Sharybin commented

2012-09-13 12:55:21 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2012-09-13 12:55:21 +02:00

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Using the same inage in Image Editor and Compositor makes image dark #27997