all files / displaySettingsHandler/src/ displaySettingsHandler.js

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76.67% Branches 23/30
100% Functions 13/13
94.44% Lines 85/90
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/*
 * Windows Display Settings Handler
 *
 * Copyright 2016 Raising the Floor - US
 *
 * Licensed under the New BSD license. You may not use this file except in
 * compliance with this License.
 *
 * You may obtain a copy of the License at
 * https://github.com/GPII/universal/blob/master/LICENSE.txt
 */
 
"use strict";
 
var ref = require("ref");
var Struct = require("ref-struct");
var arrayType = require("ref-array");
var ffi = require("ffi");
var fluid = require("universal");
 
var gpii = fluid.registerNamespace("gpii");
var windows = fluid.registerNamespace("gpii.windows");
 
fluid.registerNamespace("gpii.windows.display");
fluid.registerNamespace("gpii.windows.displaySettingsHandler");
 
var t = windows.types;
var c = windows.API_constants;
 
var CCHDEVICENAME = 32;
var CCHFORMNAME = 32;
 
// https://msdn.microsoft.com/en-us/library/windows/desktop/dd183565(v=vs.85).aspx
windows.DEVMODEW = new Struct([
    [arrayType(t.TCHAR, CCHDEVICENAME), "dmDeviceName"],
    [t.WORD, "dmSpecVersion"],
    [t.WORD, "dmDriverVersion"],
    [t.WORD, "dmSize"],
    [t.WORD, "dmDriverExtra"],
    [t.DWORD, "dmFields"],
    ["short", "dmOrientation"],
    ["short", "dmPaperSize"],
    ["short", "dmPaperLength"],
    ["short", "dmPaperWidth"],
    ["short", "dmScale"],
    ["short", "dmCopies"],
    ["short", "dmDefaultSource"],
    ["short", "dmPrintQuality"],
    ["short", "dmColor"],
    ["short", "dmDuplex"],
    ["short", "dmYResolution"],
    ["short", "dmTTOption"],
    ["short", "dmCollate"],
    [arrayType(t.TCHAR, CCHFORMNAME), "dmFormName"],
    [t.WORD, "dmLogPixels"],
    [t.DWORD, "dmBitsPerPel"],
    [t.DWORD, "dmPelsWidth"],
    [t.DWORD, "dmPelsHeight"],
    [t.DWORD, "dmDisplayFlags"],
    [t.DWORD, "dmDisplayFrequency"],
    [t.DWORD, "dmICMMethod"],
    [t.DWORD, "dmICMIntent"],
    [t.DWORD, "dmMediaType"],
    [t.DWORD, "dmDitherType"],
    [t.DWORD, "dmReserved1"],
    [t.DWORD, "dmReserved2"],
    [t.DWORD, "dmPanningWidth"],
    [t.DWORD, "dmPanningHeight"]
]);
 
windows.display.user32 = ffi.Library("user32", {
    // https://msdn.microsoft.com/en-us/library/windows/desktop/dd162611(v=vs.85).aspx
    // LPCWSTR, DWORD, DEVMODE*
    "EnumDisplaySettingsW": [
        t.BOOL, ["pointer", t.DWORD, "pointer"]
    ],
    // https://msdn.microsoft.com/en-us/library/windows/desktop/dd183411(v=vs.85).aspx
    // DEVMODE*, DWORD
    "ChangeDisplaySettingsW": [
        t.LONG, ["pointer", t.DWORD]
    ]
});
 
/*
 * Creates and initializes a new DEVMODEW structure
 */
windows.display.createDevModeStruct = function () {
    var dm = new windows.DEVMODEW();
    dm.ref().fill(0);
    dm.dmSize = windows.DEVMODEW.size;
    return dm;
};
 
/*
 * Returns if a screen resolution is invalid
 *
 * @param (Object)
 * @returns {boolean} true if invalid
 */
windows.display.isInvalid = function (screenRes) {
    var isInvalid = true;
    if (typeof(screenRes.width) === "number" && typeof(screenRes.height) === "number" && screenRes.width > 0 && screenRes.height > 0) {
        fluid.each(windows.display.getAvailableResolutions(), function (validScreenRes) {
            if (validScreenRes.dmPelsWidth === screenRes.width && validScreenRes.dmPelsHeight === screenRes.height) {
                isInvalid = false;
            };
        });
    }
    return isInvalid;
};
 
/*
 * Gets the current display's screen resolution
 *
 * @return {Object) The width and height of the screen.
 */
windows.display.getScreenResolution = function () {
    var dm = windows.display.createDevModeStruct();
    Eif (windows.display.user32.EnumDisplaySettingsW(ref.NULL, c.ENUM_CURRENT_SETTINGS, dm.ref()) !== c.FALSE) {
        // note for unknown reason on win 10 the returned dmSize is 188 not expected 220
        var closestScreenRes = windows.display.findClosestResolution({width: dm.dmPelsWidth, height: dm.dmPelsHeight});
        return { width: closestScreenRes.dmPelsWidth, height: closestScreenRes.dmPelsHeight };
    } else {
        fluid.fail("Couldn't retrieve the current screen resolution");
    }
};
 
/*
 * Gets available resolutions
 *
 * @return {list} of resolutions
 */
windows.display.getAvailableResolutions = function () {
    var index = 0;
    var dm = windows.display.createDevModeStruct();
    var availableResolutions = [];
 
    while (windows.display.user32.EnumDisplaySettingsW(ref.NULL, index++, dm.ref()) !== c.FALSE) {
        var curr = {
            dmPelsWidth: dm.dmPelsWidth,
            dmPelsHeight: dm.dmPelsHeight
        };
        availableResolutions.push(curr);
    };
 
    fluid.log("windows.display.getAvailableResolutions got available screen resolutions ", availableResolutions);
 
    return availableResolutions;
};
 
/*
 * Sets the current display's screen resolution if possible
 *
 * @param {Object} The new screen resolution width and height
 * @return {boolean} true if successfu
 */
windows.display.setScreenResolution = function (newRes) {
    if (windows.display.isInvalid(newRes)) {
        fluid.fail("Received an invalid screen resolution: ", newRes);
    } else {
        var dmCurrent = windows.display.createDevModeStruct();
        Eif (windows.display.user32.EnumDisplaySettingsW(ref.NULL, c.ENUM_CURRENT_SETTINGS, dmCurrent.ref()) !== c.FALSE) {
            fluid.log("windows.display.setScreenResolution about to set resolution ", newRes);
            // Note: ChangeDisplaySettings has no effect if new is same as current
            dmCurrent.dmPelsWidth = newRes.width;
            dmCurrent.dmPelsHeight = newRes.height;
            var lRet = windows.display.user32.ChangeDisplaySettingsW(dmCurrent.ref(), 0);
            Eif (lRet === c.DISP_CHANGE_SUCCESSFUL) {
                return true;
            } else if (lRet === c.DISP_CHANGE_RESTART) {
                // TODO: According to the returned code, the computer must be restarted for
                // the graphics mode to work. For now we return 'true', but this special case
                // is related to https://issues.gpii.net/browse/GPII-1982, and we must consider
                // this as something that needs to be taken into account and even notified to
                // the user.
                //
                return true;
            } else {
                // Return codes explained at https://msdn.microsoft.com/en-us/library/dd183411.aspx
                fluid.fail("Couldn't set screen resolution, return code was " + lRet);
            }
        }
    }
};
 
windows.display.setImpl = function (payload) {
    var oldRes = windows.display.getScreenResolution();
    var newRes = oldRes;
 
    var targetRes = payload.settings["screen-resolution"];
    Iif (typeof(targetRes.width) !== "number" || typeof(targetRes.height) !== "number") {
        fluid.fail("Incorrect payload for screen resolution: " +
                    JSON.stringify(payload, null, 4));
    }
    else Eif (windows.display.setScreenResolution(targetRes)) {
        newRes = targetRes;
    }
 
    var results = {};
    results["screen-resolution"] = { oldValue: oldRes, newValue: newRes };
 
    fluid.log("display settings handler SET returning results ", results);
    return results;
};
 
windows.display.getImpl = function () {
    var curRes = windows.display.getScreenResolution();
    var results = { "screen-resolution": curRes };
 
    return results;
};
 
windows.displaySettingsHandler.get = function (payload) {
    return gpii.settingsHandlers.invokeSettingsHandler(windows.display.getImpl, payload);
};
 
windows.displaySettingsHandler.set = function (payload) {
    return gpii.settingsHandlers.invokeSettingsHandler(windows.display.setImpl, payload);
};
 
// Internal utilities
// TODO: Move this into gpii.settingsHandlerUtilities and add tests
 
windows.display.calculateDistance = function (x, y) {
    var a = x[0] - y[0];
    var b = x[1] - y[1];
    return Math.sqrt(a * a + b * b);
};
 
windows.display.findClosestResolution = function (res) {
    var distance = null;
    var closest = null;
 
    var availableResolutions = windows.display.getAvailableResolutions();
 
    fluid.each(availableResolutions, function (currRes) {
        var currDist = windows.display.calculateDistance([res.width, res.height], [currRes.dmPelsWidth, currRes.dmPelsHeight]);
        if (distance === null || currDist < distance) {
            distance = currDist;
            closest = currRes;
        }
    });
    return closest;
};