MRP Posted November 19, 2016 Share Posted November 19, 2016 Hi! First of all, thank you for developing Affinity Photo. I've been testing it for a few days and it's working great! A much needed replacement for that well known "subscription" software. I've noticed that the quality of rescaled images is not as good as that produced by other graphics software. I've tried the different resampling algorithms but none of the reaches the quality of the other software, such as Krita, XNView or others. I'm including a couple of examples here, one rescaled with Affinity Photo, the other one with Krita. Please fix this, I take it implementing a better resampling algorithm must not be an overly difficult task and rescaling images is one of the most common processes used in image editing. Thank you for all your work. Affinity Photo rescaling Krita rescaling Link to comment Share on other sites More sharing options...
Staff Andy Somerfield Posted November 19, 2016 Staff Share Posted November 19, 2016 Hi, The Photo rescaling example you give is using Nearest Neighbour.. Try using the bilinear version - which in Photo is done from nearest mipmap - it is the best way to downsample documents. Hope this helps, Andy. Link to comment Share on other sites More sharing options...
MRP Posted November 19, 2016 Author Share Posted November 19, 2016 Thank you for the quick reply. I tried changing algorithms again and noticed they all give the same result, all the options (including Bilinear) seem to be using the same algorithm that gives the above result. Link to comment Share on other sites More sharing options...
Staff Andy Somerfield Posted November 19, 2016 Staff Share Posted November 19, 2016 Hi, Hmm - this looks like a Windows specific bug - I will look into it :) Thanks, Andy. Link to comment Share on other sites More sharing options...
MRP Posted November 19, 2016 Author Share Posted November 19, 2016 Great! Thanks for checking. Link to comment Share on other sites More sharing options...
MRP Posted November 24, 2016 Author Share Posted November 24, 2016 Hi! I noticed the release notes of the latest beta say the following bug was removed:Fixed wrong samplers being used when resizing documents I wanted to let you know that I tested it and the bug is still there. All the resampling algorithms in the Resize Document option give the same result in v1.5.0.39, which seems to be "nearest neighbour". Rescaled image using bilinear resampling - Affinity Photo 1.5.0.39 Link to comment Share on other sites More sharing options...
Mark Ingram Posted November 24, 2016 Share Posted November 24, 2016 I've just checked the 1.5.0.39 build, and the samplers are definitely different... Do you have a series of images with each sampler used on it? Link to comment Share on other sites More sharing options...
MRP Posted December 1, 2016 Author Share Posted December 1, 2016 Hi Mark, Thank you for your message an my apologies for the delay in replying, I was away from the net for a few days. Here's a new batch of images created with v1.5.0.42, with each one of the samplers. At the end you can find the original full-sized image, so you can test rescaling it to 750px like I did and see if you can get a result similar to Krita's rescaling. Thank you for your attention. Krita rescaling Affinity Photo rescaling - bilinear Affinity Photo rescaling - bicubic Affinity Photo rescaling - Lanczos Separable Affinity Photo rescaling - Lanczos Non Separable Affinity Photo rescaling - Nearest Neighbour Original image Link to comment Share on other sites More sharing options...
Opera Posted December 2, 2016 Share Posted December 2, 2016 Here's a new batch of images created with v1.5.0.42, with each one of the samplers. At the end you can find the original full-sized image, so you can test rescaling it to 750px like I did and see if you can get a result similar to Krita's rescaling. There is a huge difference between the scaling results. I hope Affinity will follow Krita's example. At the moment the poorly elaborated resizing dialog and scaling functions are the biggest barriers to use Affinity Photo for professional work. I own Affinity Designer but at the moment I am a little assailed by doubts wether the Photo Application will also replace Photoshop on Windows. I hope Affinity is aware of the importance of these essential functions. Link to comment Share on other sites More sharing options...
Mark Ingram Posted December 2, 2016 Share Posted December 2, 2016 Hi, thanks for the images, is there any chance you could upload a zip file of PNGs so I can compare? Either the JPGs have been saved with compression via Affinity, or the forum software has compressed them, as your original image looks terrible as well. Link to comment Share on other sites More sharing options...
jorismak Posted December 2, 2016 Share Posted December 2, 2016 https://1drv.ms/u/s!AgtoBEiLfbmcphLlSAZJcpyccCme I _thought_ I installed .42, but during launch it still shows .39. Maybe I made a mistake. Anyway, this is done with either .39 or .42 :). 'resample' box checked, all the options. I see no difference when flipping through the images, they seem pixel-for-pixel alike. Link to comment Share on other sites More sharing options...
MRP Posted December 2, 2016 Author Share Posted December 2, 2016 Hi Mark, It looks like I've stumbled upon something. I tried rescaling the images straight from the File->Export function, instead of using Resize Document. The resampling algorithms work as they should that way, and are similar to Krita's results. So there seems to be a bug in the Resize Document function and how it's (not) connecting to the resampling algorithms. Attached go some images and a zip file as you requested. Hope this helps catch the bug. Krita rescaling - bicubic AP rescaling using Resize Document - bicubic AP rescaling using Export - bicubic Zip file AP rescaling test.zip Link to comment Share on other sites More sharing options...
jorismak Posted December 2, 2016 Share Posted December 2, 2016 I tested again with .42, clearly a big difference compared to .39, it seemed to work now: https://1drv.ms/u/s!AgtoBEiLfbmcphNUbay_Tndtaqln Can I request something? Is it possible to offer an 'advanced' box for the Bicubic option to change the 'B' and 'C' parameters of the filter? Or in the lanczos case, change the number of taps? Or maybe add a preset box somewhere for the different kinds of Bicubic (Robidoux, Mitchell, CatmullRom, etc..). In it's current setting Bicubic seems (too) sharp compared to Lanczos. Link to comment Share on other sites More sharing options...
MRP Posted December 2, 2016 Author Share Posted December 2, 2016 Hi jorismak, that's rather strange. I'm using Windows 8.1 here, what version of Windows are you using? Link to comment Share on other sites More sharing options...
MRP Posted December 6, 2016 Author Share Posted December 6, 2016 I have found out some additional info on this one. The problem surfaces when I have both Affinity Photo and Krita open at the same time. Rescaling in Affinity Photo using Resize Document in those cases results in bad resampling. If I close both programs and open only Affinity Photo the rescaling function using Resize Document works fine. Thought you might like to know. Link to comment Share on other sites More sharing options...
jorismak Posted December 15, 2016 Share Posted December 15, 2016 Are you sure it's not a visible bug? The difference you see is still there when you save the files? So, having Krita open affects the calculations done to the buffer by Affinity Photo and not just how your videocard manages to draw it? That seems very weird, and a bit of a stretch. Then again, I've seen other weird stuff happening in Photo so who knows :P Link to comment Share on other sites More sharing options...
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