The Tor Browser: widget/windows/nsScreenManagerWin.cpp@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "nsScreenManagerWin.h"

     7 #include "nsScreenWin.h"

     8 #include "gfxWindowsPlatform.h"

     9 #include "nsIWidget.h"

    12 BOOL CALLBACK CountMonitors ( HMONITOR, HDC, LPRECT, LPARAM ioCount ) ;

    14 nsScreenManagerWin :: nsScreenManagerWin ( )

    15   : mNumberOfScreens(0)

    16 {

    17   // nothing to do. I guess we could cache a bunch of information

    18   // here, but we want to ask the device at runtime in case anything

    19   // has changed.

    20 }

    23 nsScreenManagerWin :: ~nsScreenManagerWin()

    24 {

    25 }

    28 // addref, release, QI

    29 NS_IMPL_ISUPPORTS(nsScreenManagerWin, nsIScreenManager)

    32 //

    33 // CreateNewScreenObject

    34 //

    35 // Utility routine. Creates a new screen object from the given device handle

    36 //

    37 // NOTE: For this "single-monitor" impl, we just always return the cached primary

    38 //        screen. This should change when a multi-monitor impl is done.

    39 //

    40 nsIScreen*

    41 nsScreenManagerWin :: CreateNewScreenObject ( HMONITOR inScreen )

    42 {

    43   nsIScreen* retScreen = nullptr;

    45   // look through our screen list, hoping to find it. If it's not there,

    46   // add it and return the new one.

    47   for ( unsigned i = 0; i < mScreenList.Length(); ++i ) {

    48     ScreenListItem& curr = mScreenList[i];

    49     if ( inScreen == curr.mMon ) {

    50       NS_IF_ADDREF(retScreen = curr.mScreen.get());

    51       return retScreen;

    52     }

    53   } // for each screen.

    55   retScreen = new nsScreenWin(inScreen);

    56   mScreenList.AppendElement ( ScreenListItem ( inScreen, retScreen ) );

    58   NS_IF_ADDREF(retScreen);

    59   return retScreen;

    60 }

    63 //

    64 // ScreenForRect

    65 //

    66 // Returns the screen that contains the rectangle. If the rect overlaps

    67 // multiple screens, it picks the screen with the greatest area of intersection.

    68 //

    69 // The coordinates are in pixels (not twips) and in logical screen coordinates.

    70 //

    71 NS_IMETHODIMP

    72 nsScreenManagerWin :: ScreenForRect ( int32_t inLeft, int32_t inTop, int32_t inWidth, int32_t inHeight,

    73                                         nsIScreen **outScreen )

    74 {

    75   if ( !(inWidth || inHeight) ) {

    76     NS_WARNING ( "trying to find screen for sizeless window, using primary monitor" );

    77     *outScreen = CreateNewScreenObject ( nullptr );    // addrefs

    78     return NS_OK;

    79   }

    81   // convert coordinates from logical to device pixels for MonitorFromRect

    82   double dpiScale = nsIWidget::DefaultScaleOverride();

    83   if (dpiScale <= 0.0) {

    84     dpiScale = gfxWindowsPlatform::GetPlatform()->GetDPIScale();

    85   }

    86   RECT globalWindowBounds = {

    87     NSToIntRound(dpiScale * inLeft),

    88     NSToIntRound(dpiScale * inTop),

    89     NSToIntRound(dpiScale * (inLeft + inWidth)),

    90     NSToIntRound(dpiScale * (inTop + inHeight))

    91   };

    93   HMONITOR genScreen = ::MonitorFromRect( &globalWindowBounds, MONITOR_DEFAULTTOPRIMARY );

    95   *outScreen = CreateNewScreenObject ( genScreen );    // addrefs

    97   return NS_OK;

    99 } // ScreenForRect

   102 //

   103 // GetPrimaryScreen

   104 //

   105 // The screen with the menubar/taskbar. This shouldn't be needed very

   106 // often.

   107 //

   108 NS_IMETHODIMP

   109 nsScreenManagerWin :: GetPrimaryScreen(nsIScreen** aPrimaryScreen)

   110 {

   111   *aPrimaryScreen = CreateNewScreenObject ( nullptr );    // addrefs

   112   return NS_OK;

   114 } // GetPrimaryScreen

   117 //

   118 // CountMonitors

   119 //

   120 // Will be called once for every monitor in the system. Just

   121 // increments the parameter, which holds a ptr to a PRUin32 holding the

   122 // count up to this point.

   123 //

   124 BOOL CALLBACK

   125 CountMonitors ( HMONITOR, HDC, LPRECT, LPARAM ioParam )

   126 {

   127   uint32_t* countPtr = reinterpret_cast<uint32_t*>(ioParam);

   128   ++(*countPtr);

   130   return TRUE; // continue the enumeration

   132 } // CountMonitors

   135 //

   136 // GetNumberOfScreens

   137 //

   138 // Returns how many physical screens are available.

   139 //

   140 NS_IMETHODIMP

   141 nsScreenManagerWin :: GetNumberOfScreens(uint32_t *aNumberOfScreens)

   142 {

   143   if ( mNumberOfScreens )

   144     *aNumberOfScreens = mNumberOfScreens;

   145   else {

   146     uint32_t count = 0;

   147     BOOL result = ::EnumDisplayMonitors(nullptr, nullptr, (MONITORENUMPROC)CountMonitors, (LPARAM)&count);

   148     if (!result)

   149       return NS_ERROR_FAILURE;

   150     *aNumberOfScreens = mNumberOfScreens = count;

   151   }

   153   return NS_OK;

   155 } // GetNumberOfScreens

   157 NS_IMETHODIMP

   158 nsScreenManagerWin::GetSystemDefaultScale(float *aDefaultScale)

   159 {

   160   *aDefaultScale = float(gfxWindowsPlatform::GetPlatform()->GetDPIScale());

   161   return NS_OK;

   162 }

   164 NS_IMETHODIMP

   165 nsScreenManagerWin :: ScreenForNativeWidget(void *aWidget, nsIScreen **outScreen)

   166 {

   167   HMONITOR mon = MonitorFromWindow ((HWND) aWidget, MONITOR_DEFAULTTOPRIMARY);

   168   *outScreen = CreateNewScreenObject (mon);

   169   return NS_OK;

   170 }

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