Blended color in imported PDF

[mmm22]

Hello - I'm trying to open a pdf in Affinity Designer. The original file is a heat map with distinct patterns of color in rows and columns (first attachment). When Affinity opens the pdf, the colors are blended to obscure the rows and columns (second attachment). How do I import into Affinity without changing the color patterns? Thanks. 

[NotMyFault]

Any chance you can upload the actual PDF? If it is private / not to be seen publicly, you can request a private upload link from moderators.

[mmm22]

Here's the original pdf: 

Thanks!

original_pdf.pdf

[NotMyFault]

This file looks distorted right in Apple Safari / preview, unrelated to Affinity software. What SW are you using to get the „correct“ rendering?

[NotMyFault]

The ressource panel shows an image stretched extremely in x and y axis, with different factors.

if you reset the scaling to 100%, you get the pixels in original size.

 

[DWright]

I have logged this issue with our developers.

[NotMyFault]

I don't see any bug. The PDF contains an image layer which is stretched to the extremes. Depending on zoom level, you will see rendering artefacts caused by bilinear resampling. Works as designed for me. Apple Preview creates almost identical preview. 

 

Just change the zoom level to see all the to be expected rendering artefacts.

[thomaso]

On 9/21/2023 at 8:19 PM, mmm22 said:

How do I import into Affinity without changing the color patterns?

As mentioned by @NotMyFault this appearance is caused by a quality feature. To disable it you can switch to "Nearest Neighbour" in the app Preferences.

[mmm22]

Thank you, @thomaso and @NotMyFault! I zoomed in, and the heatmap ultimately resolved to its original color pattern. For zoomed out view, switching the quality to "Nearest Neighborhood" resolved the visual distortion. 

As an additional note, this problematic heat map was a vector graphic; rasterized version of the heat map did not have this issue. 

Edited September 29, 2023 by mmm22

[thomaso]

42 minutes ago, mmm22 said:

As an additional note, this problematic heat map was a vector graphic; rasterized version of the heat map did not have this issue. 

Are you referring to your uploaded PDF with "this problematic heat map" ? This was a raster image, not vector. The issue appears to be triggered by the extreme pixel distortion of stretching (horizontal) + compressing (vertical). Vector wouldn't get affected by scaling in such a way, – apart from possible moiré pattern on a monitors hardware pixels when rendering content in certain dimensions or angles.