JXA Core AX Framework Bindings

core-ax.jxa.js

#!/usr/bin/env osascript -l JavaScript

function run() {
  const VSCode = axApp('com.microsoft.VSCode');
  const window = axGet(VSCode, 'AXWindows')[0];

  return axWindowSetBounds(window, 200, 200, 1200, 1400);
}

/**
 * -----------------------------------------------------------------------------
 * Objective-C Bindings
 * -----------------------------------------------------------------------------
 *
 * Import AX framework functions.
 */

// prettier-ignore
(() => {
ObjC.import('Cocoa');

ObjC.bindFunction('malloc', ['void*', ['int']]);
ObjC.bindFunction('memset', ['void*', ['void*', 'int', 'int']]);
ObjC.bindFunction('AXUIElementPerformAction', ['int', ['id', 'id']]);
ObjC.bindFunction('AXValueCreate', ['id', ['unsigned int', 'void*']]);
ObjC.bindFunction('AXValueGetValue', ['bool', ['id', 'int', 'void*']]);
ObjC.bindFunction('AXUIElementCreateApplication', ['id', ['unsigned int']]);
ObjC.bindFunction('AXUIElementSetAttributeValue', ['int', ['id', 'id', 'id']]);
ObjC.bindFunction('AXUIElementCopyAttributeValue',['int', ['id', 'id', 'id*']]);
})();

const kAXValueTypeCGPoint = 1;
const kAXValueTypeCGSize = 2;
const kAXValueTypeCGRect = 3;
const kAXValueTypeCFRange = 4;
const kAXValueTypeAXError = 5;
const kAXValueTypeIllegal = 0;

/**
 * -----------------------------------------------------------------------------
 * Helper Functions
 * -----------------------------------------------------------------------------
 *
 * Accessibility/UI-scripting logic, and process ID resolution.
 */

/**
 * Get an AXUIApplication using its bundle identifier.
 * @param bundleId The application's bundle identifier.
 * @returns {AXUIApplication}
 */
function axApp(bundleId) {
  const pid = ObjC.unwrap(
    $.NSArray.arrayWithArray(
      $.CFBridgingRelease($.NSWorkspace.sharedWorkspace.runningApplications),
    ),
  ).find(
    (runningApplication) =>
      (ObjC.unwrap(runningApplication.bundleIdentifier) ?? '').toLowerCase() ==
      bundleId.toLowerCase(),
  ).processIdentifier;

  return $.AXUIElementCreateApplication(pid);
}

/**
 * Get the value of an attribute of an AXUIElement.
 * @param $el The element from which to get an attribute value.
 * @param attribute The name of the attribute to retrieve.
 * @returns {Any}
 */
function axGet($el, attribute) {
  let $result = Ref();
  $.AXUIElementCopyAttributeValue($el, attribute, $result);

  return ObjC.deepUnwrap($result[0]);
}

/**
 * Set the value of an attribute on an AXUIElement.
 *
 * NOTE: Use the memory-coerced datatypes for special AXValue requirements.
 *
 * @param $el The element on which to set an attribute value.
 * @param attribute The name of the attribute to set.
 * @param value The value to assign to the named attribute.
 */
function axSet($el, attribute, value) {
  return $.AXUIElementSetAttributeValue($el, attribute, value);
}

/**
 * Set the position of an AXUIElement window.
 * @param $window The window whose position should set.
 * @param x The "x" coordinate of the position to set.
 * @param y The "y" coordinate of the position to set.
 * @returns {Number}
 */
function axWindowSetPosition($window, x, y) {
  return $.AXUIElementSetAttributeValue(
    $window,
    'AXPosition',
    $.AXValueCreate(kAXValueTypeCGPoint, CGPoint(x, y)),
  );
}

/**
 * Set the size of an AXUIElement window.
 * @param $window The window whose size should set.
 * @param w The width of the size to set.
 * @param h The height of the size to set.
 * @returns {Number}
 */
function axWindowSetSize($window, w, h) {
  return $.AXUIElementSetAttributeValue(
    $window,
    'AXSize',
    $.AXValueCreate(kAXValueTypeCGSize, CGSize(w, h)),
  );
}

/**
 * Set the bounds of an AXUIElement window.
 * @param $window The window whose bounds should set.
 * @param x The "x" coordinate of the position to set.
 * @param y The "y" coordinate of the position to set.
 * @param w The width of the size to set.
 * @param h The height of the size to set.
 * @returns {Number}
 */
function axWindowSetBounds($window, x, y, w, h) {
  return axWindowSetPosition($window, x, y) + axWindowSetSize($window, w, h);
}

/**
 * -----------------------------------------------------------------------------
 * Memory-coerced Datatypes
 * -----------------------------------------------------------------------------
 *
 * Functions which enforce datatype assignment via direct memory allocation.
 */

function Float(num) {
  const buffer = new ArrayBuffer(8);
  const floatArray = new Float64Array(buffer);
  floatArray[0] = num;
  const byteArray = new Uint8Array(buffer);
  return Array.from(byteArray);
}

function CGPoint(x, y) {
  let $cgPoint = $.malloc(16);
  $.memset($cgPoint, 0, 16);

  const bytes = [...Float(x), ...Float(y)];
  for (let i = 0; i < 16; i++) {
    $cgPoint[i] = bytes[i];
  }

  return $cgPoint;
}

function CGSize(w, h) {
  let $cgSize = $.malloc(16);
  $.memset($cgSize, 0, 16);

  const bytes = [...Float(w), ...Float(h)];
  for (let i = 0; i < 16; i++) {
    $cgSize[i] = bytes[i];
  }

  return $cgSize;
}

function CGRect(x, y, w, h) {
  let $cgRect = $.malloc(32);
  $.memset($cgRect, 0, 32);

  const bytes = [...Float(x), ...Float(y), ...Float(w), ...Float(h)];
  for (let i = 0; i < 32; i++) {
    $cgRect[i] = bytes[i];
  }

  return $cgRect;
}