gecko-dev/widget/gonk/nsWindow.cpp

872 lines
23 KiB
C++

/* Copyright 2012 Mozilla Foundation and Mozilla contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mozilla/DebugOnly.h"
#include <fcntl.h>
#include "android/log.h"
#include "mozilla/dom/TabParent.h"
#include "mozilla/Hal.h"
#include "mozilla/Preferences.h"
#include "mozilla/FileUtils.h"
#include "mozilla/ClearOnShutdown.h"
#include "Framebuffer.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "GLContextProvider.h"
#include "GLContext.h"
#include "nsAutoPtr.h"
#include "nsAppShell.h"
#include "nsIdleService.h"
#include "nsScreenManagerGonk.h"
#include "nsTArray.h"
#include "nsWindow.h"
#include "nsIWidgetListener.h"
#include "cutils/properties.h"
#include "ClientLayerManager.h"
#include "BasicLayers.h"
#include "libdisplay/GonkDisplay.h"
#include "pixelflinger/format.h"
#include "mozilla/BasicEvents.h"
#include "mozilla/layers/APZCTreeManager.h"
#include "mozilla/layers/CompositorParent.h"
#include "ParentProcessController.h"
#include "nsThreadUtils.h"
#include "HwcComposer2D.h"
#define LOG(args...) __android_log_print(ANDROID_LOG_INFO, "Gonk" , ## args)
#define LOGW(args...) __android_log_print(ANDROID_LOG_WARN, "Gonk", ## args)
#define LOGE(args...) __android_log_print(ANDROID_LOG_ERROR, "Gonk", ## args)
#define IS_TOPLEVEL() (mWindowType == eWindowType_toplevel || mWindowType == eWindowType_dialog)
using namespace mozilla;
using namespace mozilla::dom;
using namespace mozilla::hal;
using namespace mozilla::gl;
using namespace mozilla::layers;
using namespace mozilla::widget;
nsIntRect gScreenBounds;
static uint32_t sScreenRotation;
static uint32_t sPhysicalScreenRotation;
static nsIntRect sVirtualBounds;
static nsRefPtr<GLContext> sGLContext;
static nsTArray<nsWindow *> sTopWindows;
static nsWindow *gWindowToRedraw = nullptr;
static nsWindow *gFocusedWindow = nullptr;
static bool sFramebufferOpen;
static bool sUsingOMTC;
static bool sUsingHwc;
static bool sScreenInitialized;
static nsRefPtr<gfxASurface> sOMTCSurface;
namespace {
static uint32_t
EffectiveScreenRotation()
{
return (sScreenRotation + sPhysicalScreenRotation) % (360 / 90);
}
class ScreenOnOffEvent : public nsRunnable {
public:
ScreenOnOffEvent(bool on)
: mIsOn(on)
{}
NS_IMETHOD Run() {
for (uint32_t i = 0; i < sTopWindows.Length(); i++) {
nsWindow *win = sTopWindows[i];
if (nsIWidgetListener* listener = win->GetWidgetListener()) {
listener->SizeModeChanged(mIsOn ? nsSizeMode_Fullscreen : nsSizeMode_Minimized);
}
}
// Notify observers that the screen state has just changed.
nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
if (observerService) {
observerService->NotifyObservers(
nullptr, "screen-state-changed",
mIsOn ? MOZ_UTF16("on") : MOZ_UTF16("off")
);
}
return NS_OK;
}
private:
bool mIsOn;
};
static StaticRefPtr<ScreenOnOffEvent> sScreenOnEvent;
static StaticRefPtr<ScreenOnOffEvent> sScreenOffEvent;
static void
displayEnabledCallback(bool enabled)
{
NS_DispatchToMainThread(enabled ? sScreenOnEvent : sScreenOffEvent);
}
} // anonymous namespace
nsWindow::nsWindow()
{
if (!sScreenInitialized) {
sScreenOnEvent = new ScreenOnOffEvent(true);
ClearOnShutdown(&sScreenOnEvent);
sScreenOffEvent = new ScreenOnOffEvent(false);
ClearOnShutdown(&sScreenOffEvent);
GetGonkDisplay()->OnEnabled(displayEnabledCallback);
nsIntSize screenSize;
bool gotFB = Framebuffer::GetSize(&screenSize);
if (!gotFB) {
NS_RUNTIMEABORT("Failed to get size from framebuffer, aborting...");
}
gScreenBounds = nsIntRect(nsIntPoint(0, 0), screenSize);
char propValue[PROPERTY_VALUE_MAX];
property_get("ro.sf.hwrotation", propValue, "0");
sPhysicalScreenRotation = atoi(propValue) / 90;
sVirtualBounds = gScreenBounds;
sScreenInitialized = true;
nsAppShell::NotifyScreenInitialized();
// This is a hack to force initialization of the compositor
// resources, if we're going to use omtc.
//
// NB: GetPlatform() will create the gfxPlatform, which wants
// to know the color depth, which asks our native window.
// This has to happen after other init has finished.
gfxPlatform::GetPlatform();
sUsingOMTC = ShouldUseOffMainThreadCompositing();
property_get("ro.display.colorfill", propValue, "0");
//Update sUsingHwc whenever layers.composer2d.enabled changes
Preferences::AddBoolVarCache(&sUsingHwc, "layers.composer2d.enabled");
if (sUsingOMTC) {
sOMTCSurface = new gfxImageSurface(gfxIntSize(1, 1),
gfxImageFormat::RGB24);
}
}
}
nsWindow::~nsWindow()
{
}
void
nsWindow::DoDraw(void)
{
if (!hal::GetScreenEnabled()) {
gDrawRequest = true;
return;
}
if (!gWindowToRedraw) {
LOG(" no window to draw, bailing");
return;
}
nsIntRegion region = gWindowToRedraw->mDirtyRegion;
gWindowToRedraw->mDirtyRegion.SetEmpty();
nsIWidgetListener* listener = gWindowToRedraw->GetWidgetListener();
if (listener) {
listener->WillPaintWindow(gWindowToRedraw);
}
LayerManager* lm = gWindowToRedraw->GetLayerManager();
if (mozilla::layers::LayersBackend::LAYERS_CLIENT == lm->GetBackendType()) {
// No need to do anything, the compositor will handle drawing
} else if (mozilla::layers::LayersBackend::LAYERS_BASIC == lm->GetBackendType()) {
MOZ_ASSERT(sFramebufferOpen || sUsingOMTC);
nsRefPtr<gfxASurface> targetSurface;
if(sUsingOMTC)
targetSurface = sOMTCSurface;
else
targetSurface = Framebuffer::BackBuffer();
{
nsRefPtr<gfxContext> ctx = new gfxContext(targetSurface);
gfxUtils::PathFromRegion(ctx, region);
ctx->Clip();
// No double-buffering needed.
AutoLayerManagerSetup setupLayerManager(
gWindowToRedraw, ctx, mozilla::layers::BufferMode::BUFFER_NONE,
ScreenRotation(EffectiveScreenRotation()));
listener = gWindowToRedraw->GetWidgetListener();
if (listener) {
listener->PaintWindow(gWindowToRedraw, region);
}
}
if (!sUsingOMTC) {
targetSurface->Flush();
Framebuffer::Present(region);
}
} else {
NS_RUNTIMEABORT("Unexpected layer manager type");
}
listener = gWindowToRedraw->GetWidgetListener();
if (listener) {
listener->DidPaintWindow();
}
}
nsEventStatus
nsWindow::DispatchInputEvent(WidgetGUIEvent& aEvent, bool* aWasCaptured)
{
if (aWasCaptured) {
*aWasCaptured = false;
}
if (!gFocusedWindow) {
return nsEventStatus_eIgnore;
}
gFocusedWindow->UserActivity();
aEvent.widget = gFocusedWindow;
if (TabParent* capturer = TabParent::GetEventCapturer()) {
bool captured = capturer->TryCapture(aEvent);
if (aWasCaptured) {
*aWasCaptured = captured;
}
if (captured) {
return nsEventStatus_eConsumeNoDefault;
}
}
nsEventStatus status;
gFocusedWindow->DispatchEvent(&aEvent, status);
return status;
}
NS_IMETHODIMP
nsWindow::Create(nsIWidget *aParent,
void *aNativeParent,
const nsIntRect &aRect,
nsDeviceContext *aContext,
nsWidgetInitData *aInitData)
{
BaseCreate(aParent, IS_TOPLEVEL() ? sVirtualBounds : aRect,
aContext, aInitData);
mBounds = aRect;
nsWindow *parent = (nsWindow *)aNativeParent;
mParent = parent;
mVisible = false;
if (!aNativeParent) {
mBounds = sVirtualBounds;
}
if (!IS_TOPLEVEL())
return NS_OK;
sTopWindows.AppendElement(this);
Resize(0, 0, sVirtualBounds.width, sVirtualBounds.height, false);
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Destroy(void)
{
mOnDestroyCalled = true;
sTopWindows.RemoveElement(this);
if (this == gWindowToRedraw)
gWindowToRedraw = nullptr;
if (this == gFocusedWindow)
gFocusedWindow = nullptr;
nsBaseWidget::OnDestroy();
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Show(bool aState)
{
if (mWindowType == eWindowType_invisible)
return NS_OK;
if (mVisible == aState)
return NS_OK;
mVisible = aState;
if (!IS_TOPLEVEL())
return mParent ? mParent->Show(aState) : NS_OK;
if (aState) {
BringToTop();
} else {
for (unsigned int i = 0; i < sTopWindows.Length(); i++) {
nsWindow *win = sTopWindows[i];
if (!win->mVisible)
continue;
win->BringToTop();
break;
}
}
return NS_OK;
}
bool
nsWindow::IsVisible() const
{
return mVisible;
}
NS_IMETHODIMP
nsWindow::ConstrainPosition(bool aAllowSlop,
int32_t *aX,
int32_t *aY)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Move(double aX,
double aY)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Resize(double aWidth,
double aHeight,
bool aRepaint)
{
return Resize(0, 0, aWidth, aHeight, aRepaint);
}
NS_IMETHODIMP
nsWindow::Resize(double aX,
double aY,
double aWidth,
double aHeight,
bool aRepaint)
{
mBounds = nsIntRect(NSToIntRound(aX), NSToIntRound(aY),
NSToIntRound(aWidth), NSToIntRound(aHeight));
if (mWidgetListener)
mWidgetListener->WindowResized(this, mBounds.width, mBounds.height);
if (aRepaint && gWindowToRedraw)
gWindowToRedraw->Invalidate(sVirtualBounds);
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Enable(bool aState)
{
return NS_OK;
}
bool
nsWindow::IsEnabled() const
{
return true;
}
NS_IMETHODIMP
nsWindow::SetFocus(bool aRaise)
{
if (aRaise)
BringToTop();
gFocusedWindow = this;
return NS_OK;
}
NS_IMETHODIMP
nsWindow::ConfigureChildren(const nsTArray<nsIWidget::Configuration>&)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Invalidate(const nsIntRect &aRect)
{
nsWindow *parent = mParent;
while (parent && parent != sTopWindows[0])
parent = parent->mParent;
if (parent != sTopWindows[0])
return NS_OK;
mDirtyRegion.Or(mDirtyRegion, aRect);
gWindowToRedraw = this;
gDrawRequest = true;
mozilla::NotifyEvent();
return NS_OK;
}
nsIntPoint
nsWindow::WidgetToScreenOffset()
{
nsIntPoint p(0, 0);
nsWindow *w = this;
while (w && w->mParent) {
p.x += w->mBounds.x;
p.y += w->mBounds.y;
w = w->mParent;
}
return p;
}
void*
nsWindow::GetNativeData(uint32_t aDataType)
{
switch (aDataType) {
case NS_NATIVE_WINDOW:
return GetGonkDisplay()->GetNativeWindow();
case NS_NATIVE_WIDGET:
return this;
}
return nullptr;
}
NS_IMETHODIMP
nsWindow::DispatchEvent(WidgetGUIEvent* aEvent, nsEventStatus& aStatus)
{
if (mWidgetListener)
aStatus = mWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
return NS_OK;
}
NS_IMETHODIMP_(void)
nsWindow::SetInputContext(const InputContext& aContext,
const InputContextAction& aAction)
{
mInputContext = aContext;
}
NS_IMETHODIMP_(InputContext)
nsWindow::GetInputContext()
{
// There is only one IME context on Gonk.
mInputContext.mNativeIMEContext = nullptr;
return mInputContext;
}
NS_IMETHODIMP
nsWindow::ReparentNativeWidget(nsIWidget* aNewParent)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::MakeFullScreen(bool aFullScreen)
{
if (mWindowType != eWindowType_toplevel) {
// Ignore fullscreen request for non-toplevel windows.
NS_WARNING("MakeFullScreen() on a dialog or child widget?");
return nsBaseWidget::MakeFullScreen(aFullScreen);
}
if (aFullScreen) {
// Fullscreen is "sticky" for toplevel widgets on gonk: we
// must paint the entire screen, and should only have one
// toplevel widget, so it doesn't make sense to ever "exit"
// fullscreen. If we do, we can leave parts of the screen
// unpainted.
Resize(sVirtualBounds.x, sVirtualBounds.y,
sVirtualBounds.width, sVirtualBounds.height,
/*repaint*/true);
}
return NS_OK;
}
float
nsWindow::GetDPI()
{
return GetGonkDisplay()->xdpi;
}
double
nsWindow::GetDefaultScaleInternal()
{
float dpi = GetDPI();
// The mean pixel density for mdpi devices is 160dpi, 240dpi for hdpi,
// and 320dpi for xhdpi, respectively.
// We'll take the mid-value between these three numbers as the boundary.
if (dpi < 200.0) {
return 1.0; // mdpi devices.
}
if (dpi < 300.0) {
return 1.5; // hdpi devices.
}
// xhdpi devices and beyond.
return floor(dpi / 150.0 + 0.5);
}
LayerManager *
nsWindow::GetLayerManager(PLayerTransactionChild* aShadowManager,
LayersBackend aBackendHint,
LayerManagerPersistence aPersistence,
bool* aAllowRetaining)
{
if (aAllowRetaining)
*aAllowRetaining = true;
if (mLayerManager) {
// This layer manager might be used for painting outside of DoDraw(), so we need
// to set the correct rotation on it.
if (mLayerManager->GetBackendType() == LayersBackend::LAYERS_BASIC) {
BasicLayerManager* manager =
static_cast<BasicLayerManager*>(mLayerManager.get());
manager->SetDefaultTargetConfiguration(mozilla::layers::BufferMode::BUFFER_NONE,
ScreenRotation(EffectiveScreenRotation()));
} else if (mLayerManager->GetBackendType() == LayersBackend::LAYERS_CLIENT) {
ClientLayerManager* manager =
static_cast<ClientLayerManager*>(mLayerManager.get());
manager->SetDefaultTargetConfiguration(mozilla::layers::BufferMode::BUFFER_NONE,
ScreenRotation(EffectiveScreenRotation()));
}
return mLayerManager;
}
// Set mUseLayersAcceleration here to make it consistent with
// nsBaseWidget::GetLayerManager
mUseLayersAcceleration = ComputeShouldAccelerate(mUseLayersAcceleration);
nsWindow *topWindow = sTopWindows[0];
if (!topWindow) {
LOGW(" -- no topwindow\n");
return nullptr;
}
if (sUsingOMTC) {
CreateCompositor();
if (mCompositorParent) {
uint64_t rootLayerTreeId = mCompositorParent->RootLayerTreeId();
CompositorParent::SetControllerForLayerTree(rootLayerTreeId, new ParentProcessController());
CompositorParent::GetAPZCTreeManager(rootLayerTreeId)->SetDPI(GetDPI());
}
if (mLayerManager)
return mLayerManager;
}
if (mUseLayersAcceleration) {
DebugOnly<nsIntRect> fbBounds = gScreenBounds;
if (!sGLContext) {
sGLContext = GLContextProvider::CreateForWindow(this);
}
MOZ_ASSERT(fbBounds.value == gScreenBounds);
}
// Fall back to software rendering.
sFramebufferOpen = Framebuffer::Open();
if (sFramebufferOpen) {
LOG("Falling back to framebuffer software rendering");
} else {
LOGE("Failed to mmap fb(?!?), aborting ...");
NS_RUNTIMEABORT("Can't open GL context and can't fall back on /dev/graphics/fb0 ...");
}
mLayerManager = new ClientLayerManager(this);
mUseLayersAcceleration = false;
return mLayerManager;
}
gfxASurface *
nsWindow::GetThebesSurface()
{
/* This is really a dummy surface; this is only used when doing reflow, because
* we need a RenderingContext to measure text against.
*/
// XXX this really wants to return already_AddRefed, but this only really gets used
// on direct assignment to a gfxASurface
return new gfxImageSurface(gfxIntSize(5,5), gfxImageFormat::RGB24);
}
void
nsWindow::BringToTop()
{
if (!sTopWindows.IsEmpty()) {
if (nsIWidgetListener* listener = sTopWindows[0]->GetWidgetListener())
listener->WindowDeactivated();
}
sTopWindows.RemoveElement(this);
sTopWindows.InsertElementAt(0, this);
if (mWidgetListener)
mWidgetListener->WindowActivated();
Invalidate(sVirtualBounds);
}
void
nsWindow::UserActivity()
{
if (!mIdleService) {
mIdleService = do_GetService("@mozilla.org/widget/idleservice;1");
}
if (mIdleService) {
mIdleService->ResetIdleTimeOut(0);
}
}
uint32_t
nsWindow::GetGLFrameBufferFormat()
{
if (mLayerManager &&
mLayerManager->GetBackendType() == mozilla::layers::LayersBackend::LAYERS_OPENGL) {
// We directly map the hardware fb on Gonk. The hardware fb
// has RGB format.
return LOCAL_GL_RGB;
}
return LOCAL_GL_NONE;
}
nsIntRect
nsWindow::GetNaturalBounds()
{
return gScreenBounds;
}
bool
nsWindow::NeedsPaint()
{
if (!mLayerManager) {
return false;
}
return nsIWidget::NeedsPaint();
}
Composer2D*
nsWindow::GetComposer2D()
{
if (!sUsingHwc) {
return nullptr;
}
if (HwcComposer2D* hwc = HwcComposer2D::GetInstance()) {
return hwc->Initialized() ? hwc : nullptr;
}
return nullptr;
}
// nsScreenGonk.cpp
nsScreenGonk::nsScreenGonk(void *nativeScreen)
{
}
nsScreenGonk::~nsScreenGonk()
{
}
NS_IMETHODIMP
nsScreenGonk::GetRect(int32_t *outLeft, int32_t *outTop,
int32_t *outWidth, int32_t *outHeight)
{
*outLeft = sVirtualBounds.x;
*outTop = sVirtualBounds.y;
*outWidth = sVirtualBounds.width;
*outHeight = sVirtualBounds.height;
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::GetAvailRect(int32_t *outLeft, int32_t *outTop,
int32_t *outWidth, int32_t *outHeight)
{
return GetRect(outLeft, outTop, outWidth, outHeight);
}
static uint32_t
ColorDepth()
{
switch (GetGonkDisplay()->surfaceformat) {
case GGL_PIXEL_FORMAT_RGB_565:
return 16;
case GGL_PIXEL_FORMAT_RGBA_8888:
return 32;
}
return 24; // GGL_PIXEL_FORMAT_RGBX_8888
}
NS_IMETHODIMP
nsScreenGonk::GetPixelDepth(int32_t *aPixelDepth)
{
// XXX: this should actually return 32 when we're using 24-bit
// color, because we use RGBX.
*aPixelDepth = ColorDepth();
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::GetColorDepth(int32_t *aColorDepth)
{
return GetPixelDepth(aColorDepth);
}
NS_IMETHODIMP
nsScreenGonk::GetRotation(uint32_t* aRotation)
{
*aRotation = sScreenRotation;
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::SetRotation(uint32_t aRotation)
{
if (!(aRotation <= ROTATION_270_DEG))
return NS_ERROR_ILLEGAL_VALUE;
if (sScreenRotation == aRotation)
return NS_OK;
sScreenRotation = aRotation;
uint32_t rotation = EffectiveScreenRotation();
if (rotation == nsIScreen::ROTATION_90_DEG ||
rotation == nsIScreen::ROTATION_270_DEG) {
sVirtualBounds = nsIntRect(0, 0, gScreenBounds.height,
gScreenBounds.width);
} else {
sVirtualBounds = gScreenBounds;
}
for (unsigned int i = 0; i < sTopWindows.Length(); i++)
sTopWindows[i]->Resize(sVirtualBounds.width,
sVirtualBounds.height,
!i);
nsAppShell::NotifyScreenRotation();
return NS_OK;
}
// NB: This isn't gonk-specific, but gonk is the only widget backend
// that does this calculation itself, currently.
static ScreenOrientation
ComputeOrientation(uint32_t aRotation, const nsIntSize& aScreenSize)
{
bool naturallyPortrait = (aScreenSize.height > aScreenSize.width);
switch (aRotation) {
case nsIScreen::ROTATION_0_DEG:
return (naturallyPortrait ? eScreenOrientation_PortraitPrimary :
eScreenOrientation_LandscapePrimary);
case nsIScreen::ROTATION_90_DEG:
// Arbitrarily choosing 90deg to be primary "unnatural"
// rotation.
return (naturallyPortrait ? eScreenOrientation_LandscapePrimary :
eScreenOrientation_PortraitPrimary);
case nsIScreen::ROTATION_180_DEG:
return (naturallyPortrait ? eScreenOrientation_PortraitSecondary :
eScreenOrientation_LandscapeSecondary);
case nsIScreen::ROTATION_270_DEG:
return (naturallyPortrait ? eScreenOrientation_LandscapeSecondary :
eScreenOrientation_PortraitSecondary);
default:
MOZ_CRASH("Gonk screen must always have a known rotation");
}
}
/*static*/ uint32_t
nsScreenGonk::GetRotation()
{
return sScreenRotation;
}
/*static*/ ScreenConfiguration
nsScreenGonk::GetConfiguration()
{
ScreenOrientation orientation = ComputeOrientation(sScreenRotation,
gScreenBounds.Size());
uint32_t colorDepth = ColorDepth();
// NB: perpetuating colorDepth == pixelDepth illusion here, for
// consistency.
return ScreenConfiguration(sVirtualBounds, orientation,
colorDepth, colorDepth);
}
NS_IMPL_ISUPPORTS1(nsScreenManagerGonk, nsIScreenManager)
nsScreenManagerGonk::nsScreenManagerGonk()
{
mOneScreen = new nsScreenGonk(nullptr);
}
nsScreenManagerGonk::~nsScreenManagerGonk()
{
}
NS_IMETHODIMP
nsScreenManagerGonk::GetPrimaryScreen(nsIScreen **outScreen)
{
NS_IF_ADDREF(*outScreen = mOneScreen.get());
return NS_OK;
}
NS_IMETHODIMP
nsScreenManagerGonk::ScreenForRect(int32_t inLeft,
int32_t inTop,
int32_t inWidth,
int32_t inHeight,
nsIScreen **outScreen)
{
return GetPrimaryScreen(outScreen);
}
NS_IMETHODIMP
nsScreenManagerGonk::ScreenForNativeWidget(void *aWidget, nsIScreen **outScreen)
{
return GetPrimaryScreen(outScreen);
}
NS_IMETHODIMP
nsScreenManagerGonk::GetNumberOfScreens(uint32_t *aNumberOfScreens)
{
*aNumberOfScreens = 1;
return NS_OK;
}
NS_IMETHODIMP
nsScreenManagerGonk::GetSystemDefaultScale(float *aDefaultScale)
{
*aDefaultScale = 1.0f;
return NS_OK;
}