Noise Reduction & Color Reduction Settings
When an image is converted to pixel art, small color variations in the original appear as scattered single pixels ("noise") and an excessive number of colors. Since you will reproduce the design in the game one square at a time, pixel art with less noise and fewer colors is both easier to build and better looking. Noise reduction and color reduction are the two tools that clean this up.
1. Choosing a Noise Reduction Level
| Level | Effect | When to Use |
|---|---|---|
| Off | Faithful to the source image | Already-clean sources such as pixel art or icons |
| Low | Blends isolated single pixels into their surroundings | A safe first choice for most images |
| Medium | Also removes tiny 1–2 pixel islands | Photos and images with many gradients |
| High | Removes clusters up to 3 pixels for an illustration-like finish | Grainy photos, or when you want bold simplification |
The preview refreshes every time you switch levels, so balance "keeping the details" against "removing the specks".
2. Color Reduction (Two Steps)
Color reduction happens in two steps. Both are simple sliders with a live preview.
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Step 1: Remove rarely-used colors
Colors used in only a handful of squares are merged into their nearest neighbor. The look barely changes, but the number of colors you must place drops sharply. -
Step 2: Merge similar colors
Colors with small perceptual differences are combined to simplify the pattern further. The stronger you go, the more illustration-like the result.
3. Manual Color Reduction (Custom)
When you want to remove a specific color, open "Custom" on the color reduction screen. A list of all used colors appears; tapping a color merges it into its closest remaining neighbor. Removing subtle in-between shades while keeping the main colors makes in-game work far easier.
Rule of thumb: 15–25 colors is the sweet spot for comfortable work on a Heartopia canvas. Watch the color counter and reduce as much as you can without breaking the picture — fewer colors also means less noise and a cleaner finish.
4. Works on Inserted Images Too
The same settings appear when you insert an image in design edit mode: after placing the image and tapping apply, the conversion method, noise reduction and color reduction screens open in order. These only affect the inserted region — pixels you have already drawn are never touched.