screenshot
Capture the current VICE C64 emulator display as image data with pixel information, dimensions, and palette values for visual debugging and analysis.
Instructions
Capture the current VICE display as image data.
Returns the raw display buffer with:
Pixel data (indexed 8-bit palette colors)
Display dimensions and visible area
Current palette RGB values
The data can be used to understand what's currently on screen visually. For text mode screens, readScreen provides a simpler text representation.
Options:
includePalette: Also return the color palette (default: true)
Related tools: readScreen, readVicState
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| includePalette | No | Include palette RGB values (default: true) |
Implementation Reference
- src/index.ts:1530-1583 (registration)Registration of the 'screenshot' MCP tool including description, input schema, and handler function.server.registerTool( "screenshot", { description: `Capture the current VICE display as image data. Returns the raw display buffer with: - Pixel data (indexed 8-bit palette colors) - Display dimensions and visible area - Current palette RGB values The data can be used to understand what's currently on screen visually. For text mode screens, readScreen provides a simpler text representation. Options: - includePalette: Also return the color palette (default: true) Related tools: readScreen, readVicState`, inputSchema: z.object({ includePalette: z.boolean().optional().describe("Include palette RGB values (default: true)"), }), }, async (args) => { try { const display = await client.getDisplay(); const response: Record<string, unknown> = { width: display.width, height: display.height, bitsPerPixel: display.bitsPerPixel, visibleArea: { offsetX: display.offsetX, offsetY: display.offsetY, innerWidth: display.innerWidth, innerHeight: display.innerHeight, }, pixelCount: display.pixels.length, // Return pixels as base64 for efficient transfer pixelsBase64: display.pixels.toString("base64"), }; if (args.includePalette !== false) { const palette = await client.getPalette(); response.palette = palette; response.paletteCount = palette.length; } response.hint = `Display is ${display.width}x${display.height} (visible: ${display.innerWidth}x${display.innerHeight}). Use readScreen() for text mode content.`; return formatResponse(response); } catch (error) { return formatError(error as ViceError); } } );
- src/index.ts:1551-1582 (handler)The main handler for the 'screenshot' tool. Captures display data via ViceClient.getDisplay(), optionally fetches palette, encodes pixels to base64, and returns formatted response.async (args) => { try { const display = await client.getDisplay(); const response: Record<string, unknown> = { width: display.width, height: display.height, bitsPerPixel: display.bitsPerPixel, visibleArea: { offsetX: display.offsetX, offsetY: display.offsetY, innerWidth: display.innerWidth, innerHeight: display.innerHeight, }, pixelCount: display.pixels.length, // Return pixels as base64 for efficient transfer pixelsBase64: display.pixels.toString("base64"), }; if (args.includePalette !== false) { const palette = await client.getPalette(); response.palette = palette; response.paletteCount = palette.length; } response.hint = `Display is ${display.width}x${display.height} (visible: ${display.innerWidth}x${display.innerHeight}). Use readScreen() for text mode content.`; return formatResponse(response); } catch (error) { return formatError(error as ViceError); } }
- src/index.ts:1547-1549 (schema)Input schema for the 'screenshot' tool using Zod, defining optional 'includePalette' boolean parameter.inputSchema: z.object({ includePalette: z.boolean().optional().describe("Include palette RGB values (default: true)"), }),
- src/protocol/client.ts:723-769 (helper)ViceClient.getDisplay() method: sends DisplayGet command to VICE binary monitor, parses response to extract display buffer (screenshot pixels), dimensions, and metadata.async getDisplay(useVicii = true): Promise<{ width: number; height: number; bitsPerPixel: number; offsetX: number; offsetY: number; innerWidth: number; innerHeight: number; pixels: Buffer; }> { // Ensure VICE is stopped before display capture await this.ensureStopped(); // Body: useVicii(1) + format(1) // Format: 0 = indexed 8-bit const body = Buffer.alloc(2); body[0] = useVicii ? 1 : 0; body[1] = 0; // 8-bit indexed // Response type is 0x84 (same as command) const response = await this.sendCommand(Command.DisplayGet, body, ResponseType.DisplayGet); // Parse response per VICE docs: // FL(4) + DW(2) + DH(2) + XO(2) + YO(2) + IW(2) + IH(2) + BP(1) + BL(4) + BD(BL) // FL = length of fields before display buffer (should be 17) // const fieldsLength = response.body.readUInt32LE(0); // Not used but documented const width = response.body.readUInt16LE(4); // DW - debug width const height = response.body.readUInt16LE(6); // DH - debug height const offsetX = response.body.readUInt16LE(8); // XO - x offset const offsetY = response.body.readUInt16LE(10); // YO - y offset const innerWidth = response.body.readUInt16LE(12); // IW - inner width const innerHeight = response.body.readUInt16LE(14); // IH - inner height const bitsPerPixel = response.body[16]; // BP - bits per pixel const bufferLength = response.body.readUInt32LE(17); // BL - buffer length const pixels = response.body.subarray(21, 21 + bufferLength); // BD - display buffer return { width, height, bitsPerPixel, offsetX, offsetY, innerWidth, innerHeight, pixels, }; }