Opened 3 years ago

Last modified 3 years ago

#17157 assigned bug

Bilinear image scaling error — at Version 4

Reported by: jscipione Owned by: jua
Priority: normal Milestone: Unscheduled
Component: Servers/app_server Version: R1/beta3
Keywords: Cc:
Blocked By: Blocking:
Platform: All

Description (last modified by pulkomandy)

Scaling images using bilinear scaling algorithm produces slightly incorrect colors.

Steps to reproduce:

  1. Open an image with a pure white background in ShowImage.
  2. Make sure the image is not scaled by pushing the Original size button (the magnifying glass with a 1 inside).
  3. Open Magnify and hover your mouse over the background to verify that it is #ffffff.
  4. Scale the image by pushing Magnify + or Magnify - button or scrolling your mouse wheel, it doesn't seem to matter if you up or downscale the image.
  5. Observe with Magnify by hovering your mouse over the background of the image that the background has changed to #fefefe.

Change History (6)

by jscipione, 3 years ago

Attachment: apple26.jpeg​ added

sample image apple26.jpeg

comment:1 by jscipione, 3 years ago

Owner: changed from axeld to jua
Status: new → assigned

comment:2 by jscipione, 3 years ago

Assigning to jua because he committed the code responsible for this in src/servers/app/drawing/Painter/bitmap_painter/DrawBitmapBilinear.h back in 2015.

comment:3 by X512, 3 years ago

JPEG is a bad example for investigating pixel-precise problems.

Last edited 3 years ago by X512 (previous) (diff)

by jscipione, 3 years ago

Attachment: bartlett-pear-1269879.height-400.width-750.png​ added

sample png image bartlett-pear.png

comment:4 by pulkomandy, 3 years ago

Description: modified (diff)
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