{ "openapi": "3.1.1", "info": { "title": "Pixel Art Image Converter API", "version": "1.0.0", "summary": "Convert images into pixel art with palettes, dithering and retro effects.", "description": "Every endpoint performs the same calculation as the human page and returns inputs, result, units, assumptions, sources, warnings and computedAt. MCP endpoint: /mcp." }, "servers": [ { "url": "https://fliplinepixelquantizer.usefulweb.app" } ], "paths": { "/api/v1/calculate": { "post": { "operationId": "calculate", "summary": "Convert images into pixel art with palettes, dithering and retro effects.", "description": "Resize a photo or drawing, adjust its colors, and apply an automatic or imported palette with ordered or error-diffusion dithering. Download a transparent PNG, editable pixel sprite and reusable recipe.\n\nMethodology:\n- Auto-orient and convert the source to sRGB, then sample native output pixels using nearest-neighbor fit, centered fill or stretch. Images are limited to 4 MB and 2 MP.\n- Apply RGB offsets, brightness and contrast, gamma, then saturation. Palette matching uses squared sRGB distance with first-entry tie-breaking. Automatic palettes select frequent adjusted colors.\n- Ordered dithering uses a 4 × 4 Bayer bias. Serpentine Floyd–Steinberg distributes errors with 7/16, 3/16, 5/16 and 1/16 weights; transparent pixels neither receive nor spread errors. Strength zero equals no dithering.\n- Alpha below the threshold becomes transparent. PNG integer scaling repeats pixels exactly. Dithering runs on native pixels and does not change with preview zoom or export scale.", "tags": [ "apps" ], "x-mcp-tool": "flipline_pixel_quantizer", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/FliplinePixelQuantizerInput" }, "examples": { "example1": { "summary": "A small red pixel sprite", "value": { "image": { "filename": "red.png", "contentType": "image/png", "contentBase64": "iVBORw0KGgoAAAANSUhEUgAAACAAAAAgAQMAAABJtOi3AAAABlBMVEX/////AADrWueTAAAAEklEQVQI12NgIBb8/09dgjgAAPcnH+GApkH4AAAAAElFTkSuQmCC" }, "width": 8, "height": 8, "colors": 4, "scale": 4 } }, "example2": { "summary": "Moss ordered dither", "value": { "image": { "filename": "red.png", "contentType": "image/png", "contentBase64": "iVBORw0KGgoAAAANSUhEUgAAACAAAAAgAQMAAABJtOi3AAAABlBMVEX/////AADrWueTAAAAEklEQVQI12NgIBb8/09dgjgAAPcnH+GApkH4AAAAAElFTkSuQmCC" }, "width": 16, "height": 16, "scale": 4, "palette": "#172c2f,#416350,#93ab69,#e3e6b1", "dither": "bayer", "contrast": 12 } } } } } }, "responses": { "200": { "description": "Calculation result envelope.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/FliplinePixelQuantizerResult" } } } }, "400": { "description": "Malformed JSON body.", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "422": { "description": "Invalid input (see errors[]).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "429": { "description": "Rate limit exceeded (see Retry-After).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } } } } }, "/api/v1/tool": { "get": { "operationId": "getToolDefinition", "summary": "Inputs, output schema and examples for this tool", "responses": { "200": { "description": "Tool definition.", "content": { "application/json": { "schema": { "type": "object" } } } } } } } }, "components": { "schemas": { "Problem": { "type": "object", "description": "RFC 9457 problem details. 422 responses include per-field `errors`.", "required": [ "type", "title", "status", "detail" ], "properties": { "type": { "type": "string" }, "title": { "type": "string" }, "status": { "type": "integer" }, "detail": { "type": "string" }, "code": { "type": "string" }, "errors": { "type": "array", "items": { "type": "object", "required": [ "field", "message" ], "properties": { "field": { "type": "string" }, "message": { "type": "string" } } } } } }, "FliplinePixelQuantizerInput": { "type": "object", "additionalProperties": false, "properties": { "image": { "title": "Image (PNG, JPEG or WebP)", "type": "object", "description": "Upload as {filename, contentType?, contentBase64}. Max 3906 KiB. Accepts .png,.jpg,.jpeg,.webp.", "additionalProperties": false, "required": [ "filename", "contentBase64" ], "properties": { "filename": { "type": "string" }, "contentType": { "type": "string" }, "contentBase64": { "type": "string" } } }, "width": { "title": "Pixel canvas width", "type": "integer", "minimum": 1, "maximum": 128, "default": 32 }, "height": { "title": "Pixel canvas height", "type": "integer", "minimum": 1, "maximum": 128, "default": 32 }, "colors": { "title": "Automatic palette colors", "type": "integer", "minimum": 1, "maximum": 32, "default": 16 }, "palette": { "title": "Custom HEX, GPL or JASC-PAL palette (optional)", "type": "string", "maxLength": 16384, "default": "" }, "alpha": { "title": "Alpha threshold", "type": "integer", "minimum": 1, "maximum": 255, "default": 128 }, "scale": { "title": "PNG integer scale", "type": "integer", "minimum": 1, "maximum": 8, "default": 8 }, "fit": { "title": "Image fit", "type": "string", "enum": [ "stretch", "contain", "cover" ], "default": "stretch" }, "dither": { "title": "Dithering", "type": "string", "enum": [ "none", "bayer", "floyd" ], "default": "none" }, "strength": { "title": "Dither strength (%)", "type": "number", "minimum": 0, "maximum": 100, "default": 75 }, "brightness": { "title": "Brightness", "type": "number", "minimum": -100, "maximum": 100, "default": 0 }, "contrast": { "title": "Contrast", "type": "number", "minimum": -100, "maximum": 100, "default": 0 }, "gamma": { "title": "Gamma", "type": "number", "minimum": 0.2, "maximum": 3, "default": 1 }, "saturation": { "title": "Saturation (%)", "type": "number", "minimum": 0, "maximum": 200, "default": 100 }, "red": { "title": "Red shift (RGB units)", "type": "number", "minimum": -64, "maximum": 64, "default": 0 }, "green": { "title": "Green shift (RGB units)", "type": "number", "minimum": -64, "maximum": 64, "default": 0 }, "blue": { "title": "Blue shift (RGB units)", "type": "number", "minimum": -64, "maximum": 64, "default": 0 } }, "required": [ "image" ] }, "FliplinePixelQuantizerResult": { "type": "object", "additionalProperties": false, "required": [ "schemaVersion", "tool", "computedAt", "inputs", "summary", "result", "units", "assumptions", "sources", "warnings", "presentation", "links" ], "properties": { "schemaVersion": { "type": "string", "const": "1.0" }, "tool": { "type": "object", "additionalProperties": false, "required": [ "id", "name", "version" ], "properties": { "id": { "type": "string" }, "name": { "type": "string" }, "version": { "type": "string" } } }, "computedAt": { "type": "string", "format": "date-time" }, "inputs": { "type": "object", "description": "Normalised inputs actually used, including applied defaults." }, "summary": { "type": "string" }, "result": { "type": "object", "additionalProperties": false, "required": [ "width", "height", "palette", "artifact", "project", "recipe" ], "properties": { "width": { "type": "integer" }, "height": { "type": "integer" }, "palette": { "type": "array", "items": { "type": "string" } }, "artifact": { "type": "object", "additionalProperties": false, "required": [ "artifactId", "filename", "mime", "bytes", "sha256", "path" ], "properties": { "artifactId": { "type": "string" }, "filename": { "type": "string" }, "mime": { "type": "string" }, "bytes": { "type": "integer" }, "sha256": { "type": "string" }, "path": { "type": "string", "description": "Download path on the same site (valid for about 2 hours)." } } }, "project": { "type": "object", "additionalProperties": false, "required": [ "format", "version", "name", "width", "height", "fps", "background", "palette", "frames", "layers" ], "properties": { "format": { "const": "flipline-pixels" }, "version": { "const": 1 }, "name": { "type": "string", "maxLength": 120 }, "width": { "type": "integer", "minimum": 1, "maximum": 128 }, "height": { "type": "integer", "minimum": 1, "maximum": 128 }, "fps": { "type": "integer", "minimum": 1, "maximum": 30 }, "background": { "type": "string", "pattern": "^#[a-fA-F0-9]{6}$" }, "palette": { "type": "array", "minItems": 1, "maxItems": 32, "items": { "type": "string", "pattern": "^#[a-fA-F0-9]{6}$" } }, "frames": { "type": "array", "minItems": 1, "maxItems": 24, "items": { "type": "object", "additionalProperties": false, "required": [ "hold", "label" ], "properties": { "hold": { "type": "integer", "minimum": 1, "maximum": 10 }, "label": { "type": "string", "maxLength": 80 } } } }, "layers": { "type": "array", "minItems": 1, "maxItems": 4, "items": { "type": "object", "additionalProperties": false, "required": [ "name", "visible", "locked", "opacity", "cels" ], "properties": { "name": { "type": "string", "maxLength": 80 }, "visible": { "type": "boolean" }, "locked": { "type": "boolean" }, "opacity": { "type": "number", "minimum": 0, "maximum": 1 }, "cels": { "type": "array", "minItems": 1, "maxItems": 24, "items": { "type": "array", "minItems": 1, "maxItems": 16384, "items": { "type": "integer", "minimum": 0, "maximum": 32 } } } } } } }, "description": "Palette indices: 0 is transparent; 1–32 refer to palette entries. Every cel has width × height pixels and every layer has one cel per frame. Indices cannot exceed palette length. Maximum 524288 total stored cel pixels. Layers are front to back. Files: .flipline-pixels.json." }, "recipe": { "type": "object", "additionalProperties": false, "required": [ "format", "version", "settings" ], "properties": { "format": { "const": "flipline-retro" }, "version": { "const": 1 }, "settings": { "type": "object", "additionalProperties": false, "required": [ "width", "height", "scale", "fit", "colors", "palette", "dither", "strength", "brightness", "contrast", "gamma", "saturation", "red", "green", "blue", "alpha" ], "properties": { "width": { "type": "integer", "minimum": 1, "maximum": 128 }, "height": { "type": "integer", "minimum": 1, "maximum": 128 }, "scale": { "type": "integer", "minimum": 1, "maximum": 8 }, "fit": { "enum": [ "contain", "cover", "stretch" ] }, "colors": { "type": "integer", "minimum": 1, "maximum": 32 }, "palette": { "type": "array", "maxItems": 32, "items": { "type": "string", "pattern": "^#[a-fA-F0-9]{6}$" } }, "dither": { "enum": [ "none", "bayer", "floyd" ] }, "strength": { "type": "number", "minimum": 0, "maximum": 100 }, "brightness": { "type": "number", "minimum": -100, "maximum": 100 }, "contrast": { "type": "number", "minimum": -100, "maximum": 100 }, "gamma": { "type": "number", "minimum": 0.2, "maximum": 3 }, "saturation": { "type": "number", "minimum": 0, "maximum": 200 }, "red": { "type": "number", "minimum": -64, "maximum": 64 }, "green": { "type": "number", "minimum": -64, "maximum": 64 }, "blue": { "type": "number", "minimum": -64, "maximum": 64 }, "alpha": { "type": "integer", "minimum": 1, "maximum": 255 } } } }, "description": "A settings-only retro conversion recipe. No images are embedded. Empty palette selects frequent adjusted image colors; batch exports resolve it from the first image and share that palette. Dithering runs in native output pixel coordinates, independent of display zoom and export scale." } } }, "units": { "type": "object", "additionalProperties": { "type": "string" } }, "assumptions": { "type": "array", "items": { "type": "string" } }, "sources": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "title" ], "properties": { "title": { "type": "string" }, "url": { "type": "string" }, "publisher": { "type": "string" }, "retrievedAt": { "type": "string" }, "note": { "type": "string" } } } }, "warnings": { "type": "array", "items": { "type": "string" } }, "presentation": { "type": "array", "items": { "type": "object" }, "description": "Display blocks used by the human page (same data)." }, "links": { "type": "object", "additionalProperties": false, "required": [ "human", "api", "openapi", "methodology" ], "properties": { "human": { "type": "string", "format": "uri" }, "api": { "type": "string", "format": "uri" }, "openapi": { "type": "string", "format": "uri" }, "methodology": { "type": "string", "format": "uri" } } } } } } } }