AI Skill Report Card
Converting Images to Diamond Painting Patterns
Quick Start13 / 15
Pythonfrom PIL import Image import numpy as np def image_to_diamond_pattern(image_path, grid_width=100, palette=DMC_COLORS): img = Image.open(image_path).convert("RGB") aspect = img.height / img.width grid_height = round(grid_width * aspect) small = img.resize((grid_width, grid_height), Image.LANCZOS) pixels = np.array(small).reshape(-1, 3) mapped = [nearest_palette_color(p, palette) for p in pixels] return np.array(mapped).reshape(grid_height, grid_width, 3) def nearest_palette_color(pixel, palette): # palette: list of (r,g,b, dmc_code) dists = [sum((int(pixel[i]) - c[i])**2 for i in range(3)) for c in palette] return palette[dists.index(min(dists))][:3]
This is the core pipeline every diamond-painting generator repo implements: resize → quantize colors → map to palette → render grid with symbols/legend.
Recommendation▾
Add a concrete example showing the legend/shopping-list output format (e.g., actual text/table snippet) rather than just describing it in prose.
Workflow13 / 15
Progress:
- Step 1: Load image, determine target grid dimensions (drills wide × drills tall) preserving aspect ratio
- Step 2: Downsample image to grid resolution (one pixel = one drill/bead)
- Step 3: Reduce colors — either k-means clustering to N clusters, or nearest-match against a fixed palette (DMC threads, Hama beads, etc.)
- Step 4: Build a legend mapping each used color to a symbol + code (e.g., DMC 310 → "●" black)
- Step 5: Render canvas: grid lines every 10 cells (standard for diamond painting), colored cells, symbol overlay for colorblind/print accessibility
- Step 6: Export: PDF (multi-page for large canvases), PNG preview, and/or shopping list (color + drill count per color)
- Step 7: Provide UI controls for grid size, palette selection, and color count so users can trade off detail vs. cost
Recommendation▾
Include a 'bad output' example (e.g., RGB-space matching artifacts or unpaginated PDF) to illustrate pitfalls concretely, not just as bullet warnings.
Examples14 / 20
Example 1: Input: A 1200×900 photo, target width = 80 drills, palette = DMC 447-color set Output: 80×60 grid, each cell filled with nearest DMC color, legend listing ~35 distinct DMC codes used with drill counts (e.g., "DMC 310 — 412 drills"), downloadable as PDF with symbol overlays.
Example 2: Input: User wants Hama perler bead pattern instead of diamond painting Output: Same pipeline, swap palette to Hama's ~50 standard bead colors, adjust grid rendering to circular beads instead of diamond/gem shapes — demonstrates palette is a pluggable parameter, not hardcoded logic.
Recommendation▾
The code snippet references undefined DMC_COLORS and nearest_palette_color ordering inconsistently (function defined after use) — tighten the example so it's runnable as-is.
Best Practices
- Use Lab color space (not RGB) for nearest-color matching — perceptual distance gives far better visual results than raw RGB Euclidean distance.
- Limit total color count (typically 20–50) even if palette has hundreds of options; too many colors makes physical crafting impractical and increases cost.
- Cap grid dimensions to reasonable canvas sizes (e.g., max ~200×200) — extremely large grids are impractical to fill by hand and slow to render.
- Always generate a legend/shopping list — this is the most-requested feature across these repos; users need to know what to buy and how much.
- Support both symbol+color and color-only rendering — symbols aid accuracy during crafting and colorblind accessibility.
- Cache/downsample before color quantization, not after — quantizing a full-res image then downsampling introduces banding artifacts.
- Let users choose fixed grid width or physical size (cm/inches) + drill size — crafters think in physical canvas dimensions, not just pixel counts.
Common Pitfalls
- Don't do nearest-color matching in raw RGB when a perceptually uniform space (Lab) is available — colors will look mismatched.
- Don't forget aspect ratio preservation when resizing — stretched output is a common bug.
- Don't render every single pixel line — draw bold grid lines every 10 cells (diamond painting convention) so users can count during crafting.
- Don't allow unlimited color counts by default — dumping 300+ colors into a pattern defeats the purpose and inflates material cost.
- Don't skip PDF pagination for large canvases — a single unpaginated image is unusable for printing at craft-worthy resolution.
- Don't hardcode the palette — abstracting it (DMC vs. Hama vs. custom) is what separates reusable tools from one-off scripts.