Modify Selection

Instructions

Implementation Reference

• src/tools/image.ts:197-211 (registration)

  Registration of the 'photopea_modify_selection' tool with input schema (action enum + optional amount) and handler that delegates to buildModifySelection.

  server.registerTool("photopea_modify_selection", {
    title: "Modify Selection",
    description: "Modify the current active selection. Requires an existing selection created by make_selection. For expand, contract, and feather, the amount parameter specifies pixels. Invert swaps selected and unselected areas.",
    inputSchema: {
      action: z.enum(["expand", "contract", "feather", "invert"]).describe("How to modify the selection: 'expand' grows it, 'contract' shrinks it, 'feather' softens edges, 'invert' swaps selected/unselected"),
      amount: z.number().min(0).optional().describe("Modification amount in pixels (required for expand, contract, feather; ignored for invert)"),
    },
    annotations: { readOnlyHint: false, destructiveHint: false, idempotentHint: false, openWorldHint: false },
  }, async (params) => {
    const script = buildModifySelection(params);
    bridge.sendActivity({ type: "activity", id: "", tool: "modify_selection", summary: `Modify selection: ${params.action}` });
    const result = await bridge.executeScript(script);
    if (!result.success) return { isError: true, content: [{ type: "text" as const, text: result.error || "Failed to modify selection" }] };
    return { content: [{ type: "text" as const, text: `Selection modified: ${params.action}` }] };
  });

• src/tools/image.ts:205-211 (handler)

  Handler function for photopea_modify_selection: builds script, sends activity, executes script, returns result or error.

  }, async (params) => {
    const script = buildModifySelection(params);
    bridge.sendActivity({ type: "activity", id: "", tool: "modify_selection", summary: `Modify selection: ${params.action}` });
    const result = await bridge.executeScript(script);
    if (!result.success) return { isError: true, content: [{ type: "text" as const, text: result.error || "Failed to modify selection" }] };
    return { content: [{ type: "text" as const, text: `Selection modified: ${params.action}` }] };
  });

• src/tools/image.ts:200-203 (schema)

  Input schema for photopea_modify_selection: 'action' (enum: expand/contract/feather/invert) and optional 'amount' (number, min 0).

  inputSchema: {
    action: z.enum(["expand", "contract", "feather", "invert"]).describe("How to modify the selection: 'expand' grows it, 'contract' shrinks it, 'feather' softens edges, 'invert' swaps selected/unselected"),
    amount: z.number().min(0).optional().describe("Modification amount in pixels (required for expand, contract, feather; ignored for invert)"),
  },

• src/bridge/script-builder.ts:753-775 (helper)

  buildModifySelection function: generates Photopea JavaScript string for selection modification (expand, contract, feather, or invert).

  export function buildModifySelection(params: ModifySelectionParams): string {
    const { action, amount = 0 } = params;
    const lines: string[] = [];
    const sel = `app.activeDocument.selection`;
  
    switch (action) {
      case "expand":
        lines.push(`${sel}.expand(${amount});`);
        break;
      case "contract":
        lines.push(`${sel}.contract(${amount});`);
        break;
      case "feather":
        lines.push(`${sel}.feather(${amount});`);
        break;
      case "invert":
        lines.push(`${sel}.invert();`);
        break;
    }
  
    lines.push(`app.echoToOE('ok');`);
    return lines.join("\n");
  }

• src/bridge/types.ts:227-230 (helper)

  Type definition for ModifySelectionParams: action (expand/contract/feather/invert) and optional amount.

  export interface ModifySelectionParams {
    action: "expand" | "contract" | "feather" | "invert";
    amount?: number;
  }