gecko-dev/gfx/src/nsDeviceContext.cpp

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsDeviceContext.h"
#include <algorithm> // for max
#include "gfxASurface.h" // for gfxASurface, etc
#include "gfxFont.h" // for gfxFontGroup
#include "gfxImageSurface.h" // for gfxImageSurface
#include "gfxPoint.h" // for gfxSize
#include "mozilla/Attributes.h" // for MOZ_FINAL
#include "mozilla/Preferences.h" // for Preferences
#include "mozilla/Services.h" // for GetObserverService
#include "mozilla/mozalloc.h" // for operator new
#include "nsCRT.h" // for nsCRT
#include "nsDebug.h" // for NS_NOTREACHED, NS_ASSERTION, etc
#include "nsFont.h" // for nsFont
#include "nsFontMetrics.h" // for nsFontMetrics
#include "nsIAtom.h" // for nsIAtom, do_GetAtom
#include "nsID.h"
#include "nsIDeviceContextSpec.h" // for nsIDeviceContextSpec
#include "nsILanguageAtomService.h" // for nsILanguageAtomService, etc
#include "nsIObserver.h" // for nsIObserver, etc
#include "nsIObserverService.h" // for nsIObserverService
#include "nsIScreen.h" // for nsIScreen
#include "nsIScreenManager.h" // for nsIScreenManager
#include "nsISupportsUtils.h" // for NS_ADDREF, NS_RELEASE
#include "nsIWidget.h" // for nsIWidget, NS_NATIVE_WINDOW
#include "nsRect.h" // for nsRect
#include "nsRenderingContext.h" // for nsRenderingContext
#include "nsServiceManagerUtils.h" // for do_GetService
#include "nsString.h" // for nsDependentString
#include "nsTArray.h" // for nsTArray, nsTArray_Impl
#include "nsThreadUtils.h" // for NS_IsMainThread
#include "nsTraceRefcnt.h" // for MOZ_COUNT_CTOR, etc
#if !XP_MACOSX
#include "gfxPDFSurface.h"
#endif
#ifdef MOZ_WIDGET_GTK
#include "gfxPSSurface.h"
#elif XP_WIN
#include "gfxWindowsSurface.h"
#elif defined(XP_OS2)
#include "gfxOS2Surface.h"
#elif XP_MACOSX
#include "gfxQuartzSurface.h"
#endif
using namespace mozilla;
using mozilla::services::GetObserverService;
class nsFontCache MOZ_FINAL : public nsIObserver
{
public:
nsFontCache() { MOZ_COUNT_CTOR(nsFontCache); }
~nsFontCache() { MOZ_COUNT_DTOR(nsFontCache); }
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
void Init(nsDeviceContext* aContext);
void Destroy();
nsresult GetMetricsFor(const nsFont& aFont, nsIAtom* aLanguage,
gfxUserFontSet* aUserFontSet,
gfxTextPerfMetrics* aTextPerf,
nsFontMetrics*& aMetrics);
void FontMetricsDeleted(const nsFontMetrics* aFontMetrics);
void Compact();
void Flush();
protected:
nsDeviceContext* mContext; // owner
nsCOMPtr<nsIAtom> mLocaleLanguage;
nsTArray<nsFontMetrics*> mFontMetrics;
};
NS_IMPL_ISUPPORTS1(nsFontCache, nsIObserver)
// The Init and Destroy methods are necessary because it's not
// safe to call AddObserver from a constructor or RemoveObserver
// from a destructor. That should be fixed.
void
nsFontCache::Init(nsDeviceContext* aContext)
{
mContext = aContext;
// register as a memory-pressure observer to free font resources
// in low-memory situations.
nsCOMPtr<nsIObserverService> obs = GetObserverService();
if (obs)
obs->AddObserver(this, "memory-pressure", false);
nsCOMPtr<nsILanguageAtomService> langService;
langService = do_GetService(NS_LANGUAGEATOMSERVICE_CONTRACTID);
if (langService) {
mLocaleLanguage = langService->GetLocaleLanguage();
}
if (!mLocaleLanguage) {
mLocaleLanguage = do_GetAtom("x-western");
}
}
void
nsFontCache::Destroy()
{
nsCOMPtr<nsIObserverService> obs = GetObserverService();
if (obs)
obs->RemoveObserver(this, "memory-pressure");
Flush();
}
NS_IMETHODIMP
nsFontCache::Observe(nsISupports*, const char* aTopic, const PRUnichar*)
{
if (!nsCRT::strcmp(aTopic, "memory-pressure"))
Compact();
return NS_OK;
}
nsresult
nsFontCache::GetMetricsFor(const nsFont& aFont, nsIAtom* aLanguage,
gfxUserFontSet* aUserFontSet,
gfxTextPerfMetrics* aTextPerf,
nsFontMetrics*& aMetrics)
{
if (!aLanguage)
aLanguage = mLocaleLanguage;
// First check our cache
// start from the end, which is where we put the most-recent-used element
nsFontMetrics* fm;
int32_t n = mFontMetrics.Length() - 1;
for (int32_t i = n; i >= 0; --i) {
fm = mFontMetrics[i];
if (fm->Font().Equals(aFont) && fm->GetUserFontSet() == aUserFontSet &&
fm->Language() == aLanguage) {
if (i != n) {
// promote it to the end of the cache
mFontMetrics.RemoveElementAt(i);
mFontMetrics.AppendElement(fm);
}
fm->GetThebesFontGroup()->UpdateFontList();
NS_ADDREF(aMetrics = fm);
return NS_OK;
}
}
// It's not in the cache. Get font metrics and then cache them.
fm = new nsFontMetrics();
NS_ADDREF(fm);
nsresult rv = fm->Init(aFont, aLanguage, mContext, aUserFontSet, aTextPerf);
if (NS_SUCCEEDED(rv)) {
// the mFontMetrics list has the "head" at the end, because append
// is cheaper than insert
mFontMetrics.AppendElement(fm);
aMetrics = fm;
NS_ADDREF(aMetrics);
return NS_OK;
}
fm->Destroy();
NS_RELEASE(fm);
// One reason why Init() fails is because the system is running out of
// resources. e.g., on Win95/98 only a very limited number of GDI
// objects are available. Compact the cache and try again.
Compact();
fm = new nsFontMetrics();
NS_ADDREF(fm);
rv = fm->Init(aFont, aLanguage, mContext, aUserFontSet, aTextPerf);
if (NS_SUCCEEDED(rv)) {
mFontMetrics.AppendElement(fm);
aMetrics = fm;
return NS_OK;
}
fm->Destroy();
NS_RELEASE(fm);
// could not setup a new one, send an old one (XXX search a "best
// match"?)
n = mFontMetrics.Length() - 1; // could have changed in Compact()
if (n >= 0) {
aMetrics = mFontMetrics[n];
NS_ADDREF(aMetrics);
return NS_OK;
}
NS_POSTCONDITION(NS_SUCCEEDED(rv),
"font metrics should not be null - bug 136248");
return rv;
}
void
nsFontCache::FontMetricsDeleted(const nsFontMetrics* aFontMetrics)
{
mFontMetrics.RemoveElement(aFontMetrics);
}
void
nsFontCache::Compact()
{
// Need to loop backward because the running element can be removed on
// the way
for (int32_t i = mFontMetrics.Length()-1; i >= 0; --i) {
nsFontMetrics* fm = mFontMetrics[i];
nsFontMetrics* oldfm = fm;
// Destroy() isn't here because we want our device context to be
// notified
NS_RELEASE(fm); // this will reset fm to nullptr
// if the font is really gone, it would have called back in
// FontMetricsDeleted() and would have removed itself
if (mFontMetrics.IndexOf(oldfm) != mFontMetrics.NoIndex) {
// nope, the font is still there, so let's hold onto it too
NS_ADDREF(oldfm);
}
}
}
void
nsFontCache::Flush()
{
for (int32_t i = mFontMetrics.Length()-1; i >= 0; --i) {
nsFontMetrics* fm = mFontMetrics[i];
// Destroy() will unhook our device context from the fm so that we
// won't waste time in triggering the notification of
// FontMetricsDeleted() in the subsequent release
fm->Destroy();
NS_RELEASE(fm);
}
mFontMetrics.Clear();
}
nsDeviceContext::nsDeviceContext()
: mWidth(0), mHeight(0), mDepth(0),
mAppUnitsPerDevPixel(-1), mAppUnitsPerDevNotScaledPixel(-1),
mAppUnitsPerPhysicalInch(-1),
mPixelScale(1.0f), mPrintingScale(1.0f),
mFontCache(nullptr)
{
MOZ_ASSERT(NS_IsMainThread(), "nsDeviceContext created off main thread");
}
// Note: we use a bare pointer for mFontCache so that nsFontCache
// can be an incomplete type in nsDeviceContext.h.
// Therefore we have to do all the refcounting by hand.
nsDeviceContext::~nsDeviceContext()
{
if (mFontCache) {
mFontCache->Destroy();
NS_RELEASE(mFontCache);
}
}
nsresult
nsDeviceContext::GetMetricsFor(const nsFont& aFont,
nsIAtom* aLanguage,
gfxUserFontSet* aUserFontSet,
gfxTextPerfMetrics* aTextPerf,
nsFontMetrics*& aMetrics)
{
if (!mFontCache) {
mFontCache = new nsFontCache();
NS_ADDREF(mFontCache);
mFontCache->Init(this);
}
return mFontCache->GetMetricsFor(aFont, aLanguage, aUserFontSet,
aTextPerf, aMetrics);
}
nsresult
nsDeviceContext::FlushFontCache(void)
{
if (mFontCache)
mFontCache->Flush();
return NS_OK;
}
nsresult
nsDeviceContext::FontMetricsDeleted(const nsFontMetrics* aFontMetrics)
{
if (mFontCache) {
mFontCache->FontMetricsDeleted(aFontMetrics);
}
return NS_OK;
}
bool
nsDeviceContext::IsPrinterSurface()
{
return mPrintingSurface != nullptr;
}
void
nsDeviceContext::SetDPI()
{
float dpi = -1.0f;
// PostScript, PDF and Mac (when printing) all use 72 dpi
// Use a printing DC to determine the other dpi values
if (mPrintingSurface) {
switch (mPrintingSurface->GetType()) {
case gfxSurfaceTypePDF:
case gfxSurfaceTypePS:
case gfxSurfaceTypeQuartz:
dpi = 72.0f;
break;
#ifdef XP_WIN
case gfxSurfaceTypeWin32:
case gfxSurfaceTypeWin32Printing: {
HDC dc = reinterpret_cast<gfxWindowsSurface*>(mPrintingSurface.get())->GetDC();
int32_t OSVal = GetDeviceCaps(dc, LOGPIXELSY);
dpi = 144.0f;
mPrintingScale = float(OSVal) / dpi;
break;
}
#endif
#ifdef XP_OS2
case gfxSurfaceTypeOS2: {
LONG lDPI;
HDC dc = GpiQueryDevice(reinterpret_cast<gfxOS2Surface*>(mPrintingSurface.get())->GetPS());
if (DevQueryCaps(dc, CAPS_VERTICAL_FONT_RES, 1, &lDPI))
dpi = lDPI;
break;
}
#endif
default:
NS_NOTREACHED("Unexpected printing surface type");
break;
}
mAppUnitsPerDevNotScaledPixel =
NS_lround((AppUnitsPerCSSPixel() * 96) / dpi);
} else {
// A value of -1 means use the maximum of 96 and the system DPI.
// A value of 0 means use the system DPI. A positive value is used as the DPI.
// This sets the physical size of a device pixel and thus controls the
// interpretation of physical units.
int32_t prefDPI = Preferences::GetInt("layout.css.dpi", -1);
if (prefDPI > 0) {
dpi = prefDPI;
} else if (mWidget) {
dpi = mWidget->GetDPI();
if (prefDPI < 0) {
dpi = std::max(96.0f, dpi);
}
} else {
dpi = 96.0f;
}
CSSToLayoutDeviceScale scale = mWidget ? mWidget->GetDefaultScale()
: CSSToLayoutDeviceScale(1.0);
double devPixelsPerCSSPixel = scale.scale;
mAppUnitsPerDevNotScaledPixel =
std::max(1, NS_lround(AppUnitsPerCSSPixel() / devPixelsPerCSSPixel));
}
NS_ASSERTION(dpi != -1.0, "no dpi set");
mAppUnitsPerPhysicalInch = NS_lround(dpi * mAppUnitsPerDevNotScaledPixel);
UpdateScaledAppUnits();
}
nsresult
nsDeviceContext::Init(nsIWidget *aWidget)
{
if (mScreenManager && mWidget == aWidget)
return NS_OK;
mWidget = aWidget;
SetDPI();
if (mScreenManager)
return NS_OK;
mScreenManager = do_GetService("@mozilla.org/gfx/screenmanager;1");
return NS_OK;
}
nsresult
nsDeviceContext::CreateRenderingContext(nsRenderingContext *&aContext)
{
nsRefPtr<gfxASurface> printingSurface = mPrintingSurface;
#ifdef XP_MACOSX
// CreateRenderingContext() can be called (on reflow) after EndPage()
// but before BeginPage(). On OS X (and only there) mPrintingSurface
// will in this case be null, because OS X printing surfaces are
// per-page, and therefore only truly valid between calls to BeginPage()
// and EndPage(). But we can get away with fudging things here, if need
// be, by using a cached copy.
if (!printingSurface) {
printingSurface = mCachedPrintingSurface;
}
#endif
nsRefPtr<nsRenderingContext> pContext = new nsRenderingContext();
pContext->Init(this, printingSurface);
pContext->Scale(mPrintingScale, mPrintingScale);
aContext = pContext;
NS_ADDREF(aContext);
return NS_OK;
}
nsresult
nsDeviceContext::GetDepth(uint32_t& aDepth)
{
if (mDepth == 0) {
nsCOMPtr<nsIScreen> primaryScreen;
mScreenManager->GetPrimaryScreen(getter_AddRefs(primaryScreen));
primaryScreen->GetColorDepth(reinterpret_cast<int32_t *>(&mDepth));
}
aDepth = mDepth;
return NS_OK;
}
nsresult
nsDeviceContext::GetDeviceSurfaceDimensions(nscoord &aWidth, nscoord &aHeight)
{
if (mPrintingSurface) {
// we have a printer device
aWidth = mWidth;
aHeight = mHeight;
} else {
nsRect area;
ComputeFullAreaUsingScreen(&area);
aWidth = area.width;
aHeight = area.height;
}
return NS_OK;
}
nsresult
nsDeviceContext::GetRect(nsRect &aRect)
{
if (mPrintingSurface) {
// we have a printer device
aRect.x = 0;
aRect.y = 0;
aRect.width = mWidth;
aRect.height = mHeight;
} else
ComputeFullAreaUsingScreen ( &aRect );
return NS_OK;
}
nsresult
nsDeviceContext::GetClientRect(nsRect &aRect)
{
if (mPrintingSurface) {
// we have a printer device
aRect.x = 0;
aRect.y = 0;
aRect.width = mWidth;
aRect.height = mHeight;
}
else
ComputeClientRectUsingScreen(&aRect);
return NS_OK;
}
nsresult
nsDeviceContext::InitForPrinting(nsIDeviceContextSpec *aDevice)
{
NS_ENSURE_ARG_POINTER(aDevice);
mDeviceContextSpec = aDevice;
nsresult rv = aDevice->GetSurfaceForPrinter(getter_AddRefs(mPrintingSurface));
if (NS_FAILED(rv))
return NS_ERROR_FAILURE;
Init(nullptr);
CalcPrintingSize();
return NS_OK;
}
nsresult
nsDeviceContext::BeginDocument(const nsAString& aTitle,
PRUnichar* aPrintToFileName,
int32_t aStartPage,
int32_t aEndPage)
{
static const PRUnichar kEmpty[] = { '\0' };
nsresult rv;
rv = mPrintingSurface->BeginPrinting(aTitle,
nsDependentString(aPrintToFileName ? aPrintToFileName : kEmpty));
if (NS_SUCCEEDED(rv) && mDeviceContextSpec)
rv = mDeviceContextSpec->BeginDocument(aTitle, aPrintToFileName, aStartPage, aEndPage);
return rv;
}
nsresult
nsDeviceContext::EndDocument(void)
{
nsresult rv = NS_OK;
if (mPrintingSurface) {
rv = mPrintingSurface->EndPrinting();
if (NS_SUCCEEDED(rv))
mPrintingSurface->Finish();
}
if (mDeviceContextSpec)
mDeviceContextSpec->EndDocument();
return rv;
}
nsresult
nsDeviceContext::AbortDocument(void)
{
nsresult rv = mPrintingSurface->AbortPrinting();
if (mDeviceContextSpec)
mDeviceContextSpec->EndDocument();
return rv;
}
nsresult
nsDeviceContext::BeginPage(void)
{
nsresult rv = NS_OK;
if (mDeviceContextSpec)
rv = mDeviceContextSpec->BeginPage();
if (NS_FAILED(rv)) return rv;
#ifdef XP_MACOSX
// We need to get a new surface for each page on the Mac, as the
// CGContextRefs are only good for one page.
mDeviceContextSpec->GetSurfaceForPrinter(getter_AddRefs(mPrintingSurface));
#endif
rv = mPrintingSurface->BeginPage();
return rv;
}
nsresult
nsDeviceContext::EndPage(void)
{
nsresult rv = mPrintingSurface->EndPage();
#ifdef XP_MACOSX
// We need to release the CGContextRef in the surface here, plus it's
// not something you would want anyway, as these CGContextRefs are only
// good for one page. But we need to keep a cached reference to it, since
// CreateRenderingContext() may try to access it when mPrintingSurface
// would normally be null. See bug 665218. If we just stop nulling out
// mPrintingSurface here (and thereby make that our cached copy), we'll
// break all our null checks on mPrintingSurface. See bug 684622.
mCachedPrintingSurface = mPrintingSurface;
mPrintingSurface = nullptr;
#endif
if (mDeviceContextSpec)
mDeviceContextSpec->EndPage();
return rv;
}
void
nsDeviceContext::ComputeClientRectUsingScreen(nsRect* outRect)
{
// we always need to recompute the clientRect
// because the window may have moved onto a different screen. In the single
// monitor case, we only need to do the computation if we haven't done it
// once already, and remember that we have because we're assured it won't change.
nsCOMPtr<nsIScreen> screen;
FindScreen (getter_AddRefs(screen));
if (screen) {
int32_t x, y, width, height;
screen->GetAvailRect(&x, &y, &width, &height);
// convert to device units
outRect->y = NSIntPixelsToAppUnits(y, AppUnitsPerDevPixel());
outRect->x = NSIntPixelsToAppUnits(x, AppUnitsPerDevPixel());
outRect->width = NSIntPixelsToAppUnits(width, AppUnitsPerDevPixel());
outRect->height = NSIntPixelsToAppUnits(height, AppUnitsPerDevPixel());
}
}
void
nsDeviceContext::ComputeFullAreaUsingScreen(nsRect* outRect)
{
// if we have more than one screen, we always need to recompute the clientRect
// because the window may have moved onto a different screen. In the single
// monitor case, we only need to do the computation if we haven't done it
// once already, and remember that we have because we're assured it won't change.
nsCOMPtr<nsIScreen> screen;
FindScreen ( getter_AddRefs(screen) );
if ( screen ) {
int32_t x, y, width, height;
screen->GetRect ( &x, &y, &width, &height );
// convert to device units
outRect->y = NSIntPixelsToAppUnits(y, AppUnitsPerDevPixel());
outRect->x = NSIntPixelsToAppUnits(x, AppUnitsPerDevPixel());
outRect->width = NSIntPixelsToAppUnits(width, AppUnitsPerDevPixel());
outRect->height = NSIntPixelsToAppUnits(height, AppUnitsPerDevPixel());
mWidth = outRect->width;
mHeight = outRect->height;
}
}
//
// FindScreen
//
// Determines which screen intersects the largest area of the given surface.
//
void
nsDeviceContext::FindScreen(nsIScreen** outScreen)
{
if (mWidget && mWidget->GetNativeData(NS_NATIVE_WINDOW))
mScreenManager->ScreenForNativeWidget(mWidget->GetNativeData(NS_NATIVE_WINDOW),
outScreen);
else
mScreenManager->GetPrimaryScreen(outScreen);
}
void
nsDeviceContext::CalcPrintingSize()
{
if (!mPrintingSurface)
return;
bool inPoints = true;
gfxSize size(0, 0);
switch (mPrintingSurface->GetType()) {
case gfxSurfaceTypeImage:
inPoints = false;
size = reinterpret_cast<gfxImageSurface*>(mPrintingSurface.get())->GetSize();
break;
#if defined(MOZ_PDF_PRINTING)
case gfxSurfaceTypePDF:
inPoints = true;
size = reinterpret_cast<gfxPDFSurface*>(mPrintingSurface.get())->GetSize();
break;
#endif
#ifdef MOZ_WIDGET_GTK
case gfxSurfaceTypePS:
inPoints = true;
size = reinterpret_cast<gfxPSSurface*>(mPrintingSurface.get())->GetSize();
break;
#endif
#ifdef XP_MACOSX
case gfxSurfaceTypeQuartz:
inPoints = true; // this is really only true when we're printing
size = reinterpret_cast<gfxQuartzSurface*>(mPrintingSurface.get())->GetSize();
break;
#endif
#ifdef XP_WIN
case gfxSurfaceTypeWin32:
case gfxSurfaceTypeWin32Printing:
{
inPoints = false;
HDC dc = reinterpret_cast<gfxWindowsSurface*>(mPrintingSurface.get())->GetDC();
if (!dc)
dc = GetDC((HWND)mWidget->GetNativeData(NS_NATIVE_WIDGET));
size.width = NSFloatPixelsToAppUnits(::GetDeviceCaps(dc, HORZRES)/mPrintingScale, AppUnitsPerDevPixel());
size.height = NSFloatPixelsToAppUnits(::GetDeviceCaps(dc, VERTRES)/mPrintingScale, AppUnitsPerDevPixel());
mDepth = (uint32_t)::GetDeviceCaps(dc, BITSPIXEL);
if (dc != reinterpret_cast<gfxWindowsSurface*>(mPrintingSurface.get())->GetDC())
ReleaseDC((HWND)mWidget->GetNativeData(NS_NATIVE_WIDGET), dc);
break;
}
#endif
#ifdef XP_OS2
case gfxSurfaceTypeOS2:
{
inPoints = false;
// we already set the size in the surface constructor we set for
// printing, so just get those values here
size = reinterpret_cast<gfxOS2Surface*>(mPrintingSurface.get())->GetSize();
// as they are in pixels we need to scale them to app units
size.width = NSFloatPixelsToAppUnits(size.width, AppUnitsPerDevPixel());
size.height = NSFloatPixelsToAppUnits(size.height, AppUnitsPerDevPixel());
// still need to get the depth from the device context
HDC dc = GpiQueryDevice(reinterpret_cast<gfxOS2Surface*>(mPrintingSurface.get())->GetPS());
LONG value;
if (DevQueryCaps(dc, CAPS_COLOR_BITCOUNT, 1, &value))
mDepth = value;
else
mDepth = 8; // default to 8bpp, should be enough for printers
break;
}
#endif
default:
NS_ERROR("trying to print to unknown surface type");
}
if (inPoints) {
// For printing, CSS inches and physical inches are identical
// so it doesn't matter which we use here
mWidth = NSToCoordRound(float(size.width) * AppUnitsPerPhysicalInch() / 72);
mHeight = NSToCoordRound(float(size.height) * AppUnitsPerPhysicalInch() / 72);
} else {
mWidth = NSToIntRound(size.width);
mHeight = NSToIntRound(size.height);
}
}
bool nsDeviceContext::CheckDPIChange() {
int32_t oldDevPixels = mAppUnitsPerDevNotScaledPixel;
int32_t oldInches = mAppUnitsPerPhysicalInch;
SetDPI();
return oldDevPixels != mAppUnitsPerDevNotScaledPixel ||
oldInches != mAppUnitsPerPhysicalInch;
}
bool
nsDeviceContext::SetPixelScale(float aScale)
{
if (aScale <= 0) {
NS_NOTREACHED("Invalid pixel scale value");
return false;
}
int32_t oldAppUnitsPerDevPixel = mAppUnitsPerDevPixel;
mPixelScale = aScale;
UpdateScaledAppUnits();
return oldAppUnitsPerDevPixel != mAppUnitsPerDevPixel;
}
void
nsDeviceContext::UpdateScaledAppUnits()
{
mAppUnitsPerDevPixel =
std::max(1, NSToIntRound(float(mAppUnitsPerDevNotScaledPixel) / mPixelScale));
// adjust mPixelScale to reflect appunit rounding
mPixelScale = float(mAppUnitsPerDevNotScaledPixel) / mAppUnitsPerDevPixel;
}