Displayed color doesn't match real values #117276

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Samuel · 2024-01-18T12:59:48+01:00

Samuel commented

2024-01-18 12:59:48 +01:00

Blender version 3.6+

The object (edit or object) colors displayed in the 3d viewport do not correspond to the real values saved in data.

Yes, there is some edit mode overlay (settings, themes), but even when that is set to pure white, the HEX values still do not match properly. And they also don't match in object mode, where pure colors should be displayed.

This has nothing to do with gamma adjustements, that makes much stronger value offsets, not just by a single digit.

Blender version 3.6+ The object (edit or object) colors displayed in the 3d viewport do not correspond to the real values saved in data. Yes, there is some edit mode overlay (settings, themes), but even when that is set to pure white, the HEX values still do not match properly. And they also don't match in object mode, where pure colors should be displayed. This has nothing to do with gamma adjustements, that makes much stronger value offsets, not just by a single digit.

2024-01-12_11.27.28.468.gif

3.7 MiB

Samuel added the

labels 2024-01-18 12:59:49 +01:00

Germano Cavalcante commented

2024-01-18 20:04:16 +01:00

Thank you for the report, @Mahrkeenerh.

Could you to provide steps on how to reproduce the issue?

Also you may want to check if any of the following related issues are similar to yours:

#87183: Unable to accurately sample colors in Vertex Paint mode
#107942: Hue correct node does not match other hsv nodes
#103953: Eyedropper values are slightly off from target color
#117023: Color RGB/HSV values are different in Image Editor compared to any other UI Color field
#87149: Color picker value not working as expected
#92444: Byte vertex colors are sometimes interpolated in sRGB, sometimes linear
#91759: The colors of the vertices do not correspond to the values in which I paint them with vertex paint.

Please let us know if any of these issues match your problem. If not, please provide the requested reproduction steps.

Thank you for the report, @Mahrkeenerh. Could you to provide steps on how to reproduce the issue? Also you may want to check if any of the following related issues are similar to yours: - #87183: Unable to accurately sample colors in Vertex Paint mode - #107942: Hue correct node does not match other hsv nodes - #103953: Eyedropper values are slightly off from target color - #117023: Color RGB/HSV values are different in Image Editor compared to any other UI Color field - #87149: Color picker value not working as expected - #92444: Byte vertex colors are sometimes interpolated in sRGB, sometimes linear - #91759: The colors of the vertices do not correspond to the values in which I paint them with vertex paint. Please let us know if any of these issues match your problem. If not, please provide the requested reproduction steps.

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labels 2024-01-18 20:04:46 +01:00

Samuel commented

2024-01-22 18:36:59 +01:00

@mano-wii Thank you very much for the links. The #87183 is the closest.

The gif I've attached in the main issue is an addon I'm developing, to make working with colors easier, but what it does will be kind of explained below.

version: 3.6 (but possibly earlier and also later)

Reproduction steps:

add a plane
go to vertex paint, select the face, and set color to hex 339022 (shift + k)
set shading to flat, attribute
go to object mode (deselect plane, so no overlays could be visible), and sample the color (for example using windows powertoys, or any other tool)
run the attached script to verify, that blender saved the value properly

sampled color displayed in object mode (or in edit mode, when you turn off the overlay: preferences -> themes -> 3d viewport -> face -> set to white, so it doesn't intervene) differs from the saved color.

339023 != 339022

How I sampled the color within blender (inside modal operator):

screen_buffer = fb.read_color(event.mouse_x, event.mouse_y, 1, 1, 3, 0, 'UBYTE')
color_rgb = screen_buffer.to_list()[0][0]
print('%02x%02x%02x'.upper() % (color_rgb[0], color_rgb[1], color_rgb[2]))

or using float:

screen_buffer = fb.read_color(event.mouse_x, event.mouse_y, 1, 1, 3, 0, 'FLOAT')
color_rgb = screen_buffer.to_list()[0][0]
color_hex = '%02x%02x%02x'.upper() % (round(color_rgb[0]*255), round(color_rgb[1]*255), round(color_rgb[2]*255))

scriptfile to verify saved values:

import bpy
import math

def gamma_correct(c: float):
    """Gamma correction."""

    c = max(0.0, c * 12.92) if c < 0.0031308 else 1.055 * math.pow(c, 1.0 / 2.4) - 0.055
    c = max(min(int(c * 255 + 0.5), 255), 0)

    return c / 255

def gamma_correct_color(rgb):
    """Gamma correction."""

    # return r / 255, g / 255, b / 255
    return gamma_correct(rgb[0]), gamma_correct(rgb[1]), gamma_correct(rgb[2])

for dat in bpy.context.object.data.color_attributes['Attribute'].data:
    col = list(dat.color)
    col = gamma_correct_color(col)
    print('%02x%02x%02x'.upper() % (round(col[0]*255), round(col[1]*255), round(col[2]*255)))

@mano-wii Thank you very much for the links. The #87183 is the closest. The gif I've attached in the main issue is an addon I'm developing, to make working with colors easier, but what it does will be kind of explained below. version: 3.6 (but possibly earlier and also later) Reproduction steps: - add a plane - go to vertex paint, select the face, and set color to hex 339022 (shift + k) - set shading to flat, attribute - go to object mode (deselect plane, so no overlays could be visible), and sample the color (for example using windows powertoys, or any other tool) - run the attached script to verify, that blender saved the value properly sampled color displayed in object mode (or in edit mode, when you turn off the overlay: preferences -> themes -> 3d viewport -> face -> set to white, so it doesn't intervene) differs from the saved color. 339023 != 339022 How I sampled the color within blender (inside modal operator): ``` screen_buffer = fb.read_color(event.mouse_x, event.mouse_y, 1, 1, 3, 0, 'UBYTE') color_rgb = screen_buffer.to_list()[0][0] print('%02x%02x%02x'.upper() % (color_rgb[0], color_rgb[1], color_rgb[2])) ``` or using float: ``` screen_buffer = fb.read_color(event.mouse_x, event.mouse_y, 1, 1, 3, 0, 'FLOAT') color_rgb = screen_buffer.to_list()[0][0] color_hex = '%02x%02x%02x'.upper() % (round(color_rgb[0]*255), round(color_rgb[1]*255), round(color_rgb[2]*255)) ``` scriptfile to verify saved values: ``` import bpy import math def gamma_correct(c: float): """Gamma correction.""" c = max(0.0, c * 12.92) if c < 0.0031308 else 1.055 * math.pow(c, 1.0 / 2.4) - 0.055 c = max(min(int(c * 255 + 0.5), 255), 0) return c / 255 def gamma_correct_color(rgb): """Gamma correction.""" # return r / 255, g / 255, b / 255 return gamma_correct(rgb[0]), gamma_correct(rgb[1]), gamma_correct(rgb[2]) for dat in bpy.context.object.data.color_attributes['Attribute'].data: col = list(dat.color) col = gamma_correct_color(col) print('%02x%02x%02x'.upper() % (round(col[0]*255), round(col[1]*255), round(col[2]*255))) ```

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Displayed color doesn't match real values #117276