Orchface

The reason it looks weird is because I am using a Robinson projection. Trust me, the original image is exactly how it should be. I am making a topographic relief map that will be processed by a program; that's why I need the colors and scaling to be precise.

Good point. By this point, I think it is safe to say that there is no pre-existing algorithm which can accomplish this. The colors would be determined by a simple difference comparator. I'm not altering the brightness or adding any filters to this image, so Euclidian color distance should work fine for finding a numerical representation of similarity between two colors. The algorithm would go as follows: 1. get a set of all colors on the original image palette 2. resize the image using bicubic 3. get a set of all pixels whose colors do not match one of those on the original palette 4. for each pixel, go through the set of colors from the original palette, find the color with the least difference from this pixel's color, and set this pixel's color to that color. Obviously the TC on this algorithm is horrible, but you get the idea. Here's a portion of the half-circle from earlier with two arbitrary colors, resized with bicubic. Now here is what is might look like afterward: The blended pixels whose color was closer to #FFD800 were turned to #FFD800 and the pixels whose color was closer to #0094FF were changed to #0094FF. This could be done for three or more colors as well.

Here is a photo that I manually edited after resizing to produce the intended effect (there was no way to do this in a single step during resize): Original (two colors only): Resized 200% with bicubic, and then manually recolored to remove blended pixels (still two colors only): Notice that in the second image, the smooth rasterization is present, yet all pixels are 100% black or white. No gray/blended pixels to be found. And the diagonal edges from the first image were transformed into single-pixel lines in the resized image, rather than just turning each pixel into a 2x2 square like Nearest Neighbor. Here is an illustration of a 200% resize using smooth rasterization without any blended pixels: This is what I mean by preserving quality but doing away with blended colors. Sorry if I was unclear.

Hello, I am working on a geographical map image that will ultimately be interpreted by a computer program. Thus, it is crucial that the final resized image has exactly the same colors as the original. I cannot have any blended/antialiased pixels anywhere on the resized image. I read up on a similar thread from many years ago, and it pointed to TR's color reducer plugin: https://forums.getpaint.net/topic/29424-trs-color-reducer-and-palette-maker-2014-08-01/ However, I couldn't figure out how to use this plugin to accomplish what I need. The only resizing algorithm that seems to avoid blending pixels is the Nearest Neighbor, but if I resize the image 200% for example, each 1 pixel on the original image turns into a 2x2 homogenous square on the resized image. Although it retains the exact colors of the original, I need the quality to be comparable to the Best Quality or Bicubic algorithms. Here is a sample of part of my map image. Original: Resized using Bicubic: The issue here is that the algorithm blends pixels at the borders of different colors, so this image has a much larger palette than my original. I can't have this, since the computer can only process the colors in the original. Resized with Nearest Neighbor: This preserved the color palette of the original, but it turned each pixel from the original into a 2x2 square of homogenous pixels. This greatly reduces the sharpness and quality of the resized image. In summary, I need to be able to resize the image with the quality of the Bicubic algorithm, but avoid blending pixels like the nearest neighbor algorithm. I can't do anything manually, since my map is over 40000x20000 pixels, and it would take years to go over every blended edge with a tool. If someone knows how to do this using a plugin without any kind of manual input, that would be great. Thank you for your help!

I need to produce an image in which every pixel has an opacity of 255, such that there is absolutely no transparency. Is there a method to change the opacity of every alpha pixel in a selection to 255 (preferably without having to download external plugins like UnAlpha)?