Borderless window defaults.

Limits borderless windows to the monitor usable area on non windows platforms to prevent the window from rendering behind taskbar/title bars.

Templates/BaseGame/game/core/gui/scripts/canvas.tscript

@@ -120,6 +120,13 @@ function configureCanvas()
 
    // Actually set the new video mode
    Canvas.setVideoMode(%resX, %resY, %fs, %bpp, %rate, %aa);
+
+   // For borderless on non-windows OS, move the window into position.
+   if (($pref::Video::deviceMode == $Video::ModeBorderless) && ($platform !$= "windows"))
+   {
+      %borderlessPos = getWords(Canvas.getMonitorUsableRect($pref::Video::deviceId), 0, 1);
+      Canvas.setWindowPosition(%borderlessPos);
+   }
    Canvas.setFocus();
 
    // Lock and unlock the mouse to force the position to sync with the platform window
@@ -244,5 +251,13 @@ function GuiCanvas::getBestCanvasRes(%this, %deviceId, %deviceMode)
          %bestRes = %testRes;
    }
 
+   // Borderless on non-windows OS should be the usable screen area.
+   if ((%deviceMode == $Video::ModeBorderless) && ($platform !$= "windows"))
+   {
+      %deviceRect = getWords(%this.getMonitorUsableRect(%deviceId), 2);
+      %bestRes = setWord(%bestRes, $WORD::RES_X, %deviceRect.x);
+      %bestRes = setWord(%bestRes, $WORD::RES_Y, %deviceRect.y);
+   }
+
    return %bestRes;
 }

Templates/BaseGame/game/core/rendering/scripts/graphicsOptions.tscript

@@ -845,6 +845,13 @@ function getScreenResolutionList(%deviceID, %deviceMode)
 {
    %returnsList = "";
 
+   // For borderless on non-windows OS only add the usable area.
+   if ((%deviceMode == $Video::ModeBorderless) && ($platform !$= "windows"))
+   {
+      %borderlessRes = getWords(Canvas.getMonitorUsableRect(%newDeviceID), 2);
+      return _makePrettyResString(%borderlessRes);
+   }
+
    %resCount = Canvas.getModeCount();
    for (%i = 0; %i < %resCount; %i++)
    {

Templates/BaseGame/game/data/ui/guis/optionsMenu.tscript

@@ -634,9 +634,14 @@ function onDisplayModeChange(%val)
    }
    %resolutionList = getScreenResolutionList(%newDeviceID, %newDeviceMode);
 
-   // If we're switching to borderless, default to monitor res
    if (%newDeviceMode == $Video::ModeBorderless)
-      %newRes = getWords(Canvas.getMonitorRect(%newDeviceID), 2);
+   {  // If we're switching to borderless, default to monitor res on Windows OS,
+      // monitor usable area for other platforms.
+      if ($platform $= "windows")
+         %newRes = getWords(Canvas.getMonitorRect(%newDeviceID), 2);
+      else
+         %newRes = getWords(Canvas.getMonitorUsableRect(%newDeviceID), 2);
+   }
    else
    {  // Otherwise, if our old resolution is still in the list, attempt to reset it.
       %oldRes = getWord(OptionsMenuSettingsList.getCurrentOption(3), 0) SPC getWord(OptionsMenuSettingsList.getCurrentOption(3), 2);