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contrast manipulation code in gimp

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contrast manipulation code in gimp Carlos Eduardo Rodrigues Diogenes 01 Sep 03:02
  contrast manipulation code in gimp Sven Neumann 01 Sep 07:57
   contrast manipulation code in gimp Carlos Eduardo Rodrigues Diogenes 02 Sep 01:28
    contrast manipulation code in gimp Sven Neumann 02 Sep 14:15
contrast manipulation code in gimp William Skaggs 01 Sep 18:17
contrast manipulation code in gimp William Skaggs 03 Sep 18:37
Carlos Eduardo Rodrigues Diogenes
2006-09-01 03:02:09 UTC (over 17 years ago)

contrast manipulation code in gimp

Hi,

Where is the real contrast manipulation code in gimp?

I look at the gimp_brightness_contrast, but I'm too lazy to see where that wire code goes.

I also search for contrast with cscope but doesn't find anything useful.

Thanks, Carlos.



_______________________________________________________ Voc

Sven Neumann
2006-09-01 07:57:30 UTC (over 17 years ago)

contrast manipulation code in gimp

Hi,

On Thu, 2006-08-31 at 22:02 -0300, Carlos Eduardo Rodrigues Diogenes wrote:

Where is the real contrast manipulation code in gimp?

I look at the gimp_brightness_contrast, but I'm too lazy to see where that wire code goes.

Well, we are lazy as well and you didn't even tell us why you are looking for this code.

Sven

William Skaggs
2006-09-01 18:17:16 UTC (over 17 years ago)

contrast manipulation code in gimp

From: Carlos Eduardo Rodrigues Diogenes Date: Thu, 31 Aug 2006 22:02:09 -0300

Hi,

Where is the real contrast manipulation code in gimp?

I look at the gimp_brightness_contrast, but I'm too lazy to see where that wire code goes.

This is definitely a reasonable question, because the structure of the code is not very easy to figure out, but you should avoid using the word "lazy", because people will feel like fools if they do your work for you while you are being lazy.

The Brightness-Contrast tool is one of the "Image Map" tools, along with Hue-Saturation, Levels, Curves, etc. For all of these tools, much of the relevant code is in app/tools/gimpimagemaptool.c, and only the things that distinguish the individual tools from each other are in different files.

You should also know that GIMP keeps a hard distinction between gui code, and code that acts directly on images. For the image map tools, the gui code is in the app/tools directory, and the code that actually performs the actions for the tools is in app/base.

Several of the image map tools work by using a "look up table", or lut. When you alter settings for the tool, the "map" method for the tool is executed, in this case gimp_brightness_contrast_tool_map() in app/tools/gimpbrightnesscontrasttool.c. This function, as you can see by looking at it, calls brightness_contrast_lut_setup(), which is located in the file app/base/lut-funcs.c, and then gimp_image_map_apply(), which applies the altered lut to the image.

-- Bill


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Carlos Eduardo Rodrigues Diogenes
2006-09-02 01:28:54 UTC (over 17 years ago)

contrast manipulation code in gimp

Hi,

Em Sex, 2006-09-01 às 07:57 +0200, Sven Neumann escreveu:

Hi,

On Thu, 2006-08-31 at 22:02 -0300, Carlos Eduardo Rodrigues Diogenes wrote:

Where is the real contrast manipulation code in gimp?

I look at the gimp_brightness_contrast, but I'm too lazy to see where that wire code goes.

Well, we are lazy as well and you didn't even tell us why you are looking for this code.

Ow, sorry. I'm the co-maintainer of gnome-mag and I'm implementing contrast manipulation in it, but I did it in a way that the maintainer think that is incorrect. I search a little in google and read some books (Digital Image Processing by Gonzalez & Woodz and The Image Processing Handbook by Jonh C. Russ) to try to define better contrast manipulation in my head, but doesn't find any reasonable answear.

So I decided to look how it is done in gimp and here start the old mail.

Thanks, Carlos.


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Sven Neumann
2006-09-02 14:15:01 UTC (over 17 years ago)

contrast manipulation code in gimp

Hi,

On Fri, 2006-09-01 at 20:28 -0300, Carlos Eduardo Rodrigues Diogenes wrote:

So I decided to look how it is done in gimp and here start the old mail.

Have a look in app/base. Here's where the (ugly) code resides that does the actual color correction.

Sven

William Skaggs
2006-09-03 18:37:55 UTC (over 17 years ago)

contrast manipulation code in gimp

From: Carlos Eduardo Rodrigues Diogenes

Ow, sorry. I'm the co-maintainer of gnome-mag and I'm implementing contrast manipulation in it, but I did it in a way that the maintainer think that is incorrect. I search a little in google and read some books (Digital Image Processing by Gonzalez & Woodz and The Image Processing Handbook by Jonh C. Russ) to try to define better contrast manipulation in my head, but doesn't find any reasonable answear.

So I decided to look how it is done in gimp and here start the old mail.

We have had some difficulties with the implementation of this ourselves. You might be interested in looking at these bug reports:

Bug 89022 ? Brightness & contrast could be improved: http://bugzilla.gnome.org/show_bug.cgi?id=89022

Bug 332068 ? Contrast tool gives unexpected results: http://bugzilla.gnome.org/show_bug.cgi?id=332068

Bug 337055 ? Brighten/darken should be more realistic: http://bugzilla.gnome.org/show_bug.cgi?id=337055

-- Bill


______________ ______________ ______________ ______________ Sent via the CNPRC Email system at primate.ucdavis.edu