nsDeviceContext.cpp
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=4 expandtab: */
/* 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 "gfxContext.h"
#include "gfxImageSurface.h" // for gfxImageSurface
#include "gfxPoint.h" // for gfxSize
#include "gfxTextRun.h" // for gfxFontGroup
#include "mozilla/Attributes.h" // for final
#include "mozilla/gfx/PathHelpers.h"
#include "mozilla/gfx/PrintTarget.h"
#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_ASSERTION, etc
#include "nsFont.h" // for nsFont
#include "nsFontCache.h" // for nsFontCache
#include "nsFontMetrics.h" // for nsFontMetrics
#include "nsAtom.h" // for nsAtom, NS_Atomize
#include "nsID.h"
#include "nsIDeviceContextSpec.h" // for nsIDeviceContextSpec
#include "nsLanguageAtomService.h" // for nsLanguageAtomService
#include "nsIObserver.h" // for nsIObserver, etc
#include "nsIObserverService.h" // for nsIObserverService
#include "nsIScreen.h" // for nsIScreen
#include "nsISupportsImpl.h" // for MOZ_COUNT_CTOR, etc
#include "nsISupportsUtils.h" // for NS_ADDREF, NS_RELEASE
#include "nsIWidget.h" // for nsIWidget, NS_NATIVE_WINDOW
#include "nsRect.h" // for nsRect
#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 "mozilla/gfx/Logging.h"
#include "mozilla/widget/ScreenManager.h" // for ScreenManager
using namespace mozilla;
using namespace mozilla::gfx;
using mozilla::widget::ScreenManager;
nsDeviceContext::nsDeviceContext()
: mWidth(0),
mHeight(0),
mAppUnitsPerDevPixel(-1),
mAppUnitsPerDevPixelAtUnitFullZoom(-1),
mAppUnitsPerPhysicalInch(-1),
mFullZoom(1.0f),
mPrintingScale(1.0f),
mPrintingTranslate(gfxPoint(0, 0)),
mIsCurrentlyPrintingDoc(false)
#ifdef DEBUG
,
mIsInitialized(false)
#endif
{
MOZ_ASSERT(NS_IsMainThread(), "nsDeviceContext created off main thread");
}
nsDeviceContext::~nsDeviceContext() = default;
void nsDeviceContext::SetDPI(double* aScale) {
float dpi;
// Use the printing DC to determine DPI values, if we have one.
if (mDeviceContextSpec) {
dpi = mDeviceContextSpec->GetDPI();
mPrintingScale = mDeviceContextSpec->GetPrintingScale();
mPrintingTranslate = mDeviceContextSpec->GetPrintingTranslate();
mAppUnitsPerDevPixelAtUnitFullZoom =
NS_lround((AppUnitsPerCSSPixel() * 96) / dpi);
} else {
RefPtr<widget::Screen> primaryScreen =
ScreenManager::GetSingleton().GetPrimaryScreen();
MOZ_ASSERT(primaryScreen);
// 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 = StaticPrefs::layout_css_dpi();
if (prefDPI > 0) {
dpi = prefDPI;
} else if (mWidget) {
// PuppetWidget could return -1 if the value's not available yet.
dpi = mWidget->GetDPI();
// In case that the widget returns -1, use the primary screen's
// value as default.
if (dpi < 0) {
dpi = primaryScreen->GetDPI();
}
if (prefDPI < 0) {
dpi = std::max(96.0f, dpi);
}
} else {
dpi = 96.0f;
}
double devPixelsPerCSSPixel;
if (aScale && *aScale > 0.0) {
// if caller provided a scale, we just use it
devPixelsPerCSSPixel = *aScale;
} else {
// otherwise get from the widget, and return it in aScale for
// the caller to pass to child contexts if needed
CSSToLayoutDeviceScale scale =
mWidget ? mWidget->GetDefaultScale() : CSSToLayoutDeviceScale(1.0);
devPixelsPerCSSPixel = scale.scale;
// In case that the widget returns -1, use the primary screen's
// value as default.
if (devPixelsPerCSSPixel < 0) {
primaryScreen->GetDefaultCSSScaleFactor(&devPixelsPerCSSPixel);
}
if (aScale) {
*aScale = devPixelsPerCSSPixel;
}
}
mAppUnitsPerDevPixelAtUnitFullZoom =
std::max(1, NS_lround(AppUnitsPerCSSPixel() / devPixelsPerCSSPixel));
}
NS_ASSERTION(dpi != -1.0, "no dpi set");
mAppUnitsPerPhysicalInch =
NS_lround(dpi * mAppUnitsPerDevPixelAtUnitFullZoom);
UpdateAppUnitsForFullZoom();
}
nsresult nsDeviceContext::Init(nsIWidget* aWidget) {
#ifdef DEBUG
// We can't assert |!mIsInitialized| here since EndSwapDocShellsForDocument
// re-initializes nsDeviceContext objects. We can only assert in
// InitForPrinting (below).
mIsInitialized = true;
#endif
nsresult rv = NS_OK;
if (mScreenManager && mWidget == aWidget) return rv;
mWidget = aWidget;
SetDPI();
if (mScreenManager) return rv;
mScreenManager = do_GetService("@mozilla.org/gfx/screenmanager;1", &rv);
return rv;
}
// XXX This is only for printing. We should make that obvious in the name.
already_AddRefed<gfxContext> nsDeviceContext::CreateRenderingContext() {
return CreateRenderingContextCommon(/* not a reference context */ false);
}
already_AddRefed<gfxContext>
nsDeviceContext::CreateReferenceRenderingContext() {
return CreateRenderingContextCommon(/* a reference context */ true);
}
already_AddRefed<gfxContext> nsDeviceContext::CreateRenderingContextCommon(
bool aWantReferenceContext) {
MOZ_ASSERT(IsPrinterContext());
MOZ_ASSERT(mWidth > 0 && mHeight > 0);
if (NS_WARN_IF(!mPrintTarget)) {
// Printing canceled already.
return nullptr;
}
RefPtr<gfx::DrawTarget> dt;
if (aWantReferenceContext) {
dt = mPrintTarget->GetReferenceDrawTarget();
} else {
// This will be null if e10s is disabled or print.print_via_parent=false.
RefPtr<DrawEventRecorder> recorder;
mDeviceContextSpec->GetDrawEventRecorder(getter_AddRefs(recorder));
dt = mPrintTarget->MakeDrawTarget(gfx::IntSize(mWidth, mHeight), recorder);
}
if (!dt || !dt->IsValid()) {
gfxCriticalNote << "Failed to create draw target in device context sized "
<< mWidth << "x" << mHeight << " and pointer "
<< hexa(mPrintTarget);
return nullptr;
}
dt->AddUserData(&sDisablePixelSnapping, (void*)0x1, nullptr);
RefPtr<gfxContext> pContext = gfxContext::CreateOrNull(dt);
MOZ_ASSERT(pContext); // already checked draw target above
gfxMatrix transform;
transform.PreTranslate(mPrintingTranslate);
transform.PreScale(mPrintingScale, mPrintingScale);
pContext->SetMatrixDouble(transform);
return pContext.forget();
}
uint32_t nsDeviceContext::GetDepth() {
nsCOMPtr<nsIScreen> screen;
FindScreen(getter_AddRefs(screen));
if (!screen) {
ScreenManager& screenManager = ScreenManager::GetSingleton();
screenManager.GetPrimaryScreen(getter_AddRefs(screen));
MOZ_ASSERT(screen);
}
int32_t depth = 0;
screen->GetColorDepth(&depth);
return uint32_t(depth);
}
nsresult nsDeviceContext::GetDeviceSurfaceDimensions(nscoord& aWidth,
nscoord& aHeight) {
if (IsPrinterContext()) {
aWidth = mWidth;
aHeight = mHeight;
} else {
nsRect area;
ComputeFullAreaUsingScreen(&area);
aWidth = area.Width();
aHeight = area.Height();
}
return NS_OK;
}
nsresult nsDeviceContext::GetRect(nsRect& aRect) {
if (IsPrinterContext()) {
aRect.SetRect(0, 0, mWidth, mHeight);
} else
ComputeFullAreaUsingScreen(&aRect);
return NS_OK;
}
nsresult nsDeviceContext::GetClientRect(nsRect& aRect) {
if (IsPrinterContext()) {
aRect.SetRect(0, 0, mWidth, mHeight);
} else
ComputeClientRectUsingScreen(&aRect);
return NS_OK;
}
nsresult nsDeviceContext::InitForPrinting(nsIDeviceContextSpec* aDevice) {
NS_ENSURE_ARG_POINTER(aDevice);
MOZ_ASSERT(!mIsInitialized,
"Only initialize once, immediately after construction");
// We don't set mIsInitialized here. The Init() call below does that.
mPrintTarget = aDevice->MakePrintTarget();
if (!mPrintTarget) {
return NS_ERROR_FAILURE;
}
mDeviceContextSpec = aDevice;
Init(nullptr);
if (!CalcPrintingSize()) {
return NS_ERROR_FAILURE;
}
return NS_OK;
}
nsresult nsDeviceContext::BeginDocument(const nsAString& aTitle,
const nsAString& aPrintToFileName,
int32_t aStartPage, int32_t aEndPage) {
MOZ_DIAGNOSTIC_ASSERT(!mIsCurrentlyPrintingDoc,
"Mismatched BeginDocument/EndDocument calls");
nsresult rv = mPrintTarget->BeginPrinting(aTitle, aPrintToFileName,
aStartPage, aEndPage);
if (NS_SUCCEEDED(rv)) {
if (mDeviceContextSpec) {
rv = mDeviceContextSpec->BeginDocument(aTitle, aPrintToFileName,
aStartPage, aEndPage);
}
mIsCurrentlyPrintingDoc = true;
}
// Warn about any failure (except user cancelling):
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv) || rv == NS_ERROR_ABORT,
"nsDeviceContext::BeginDocument failed");
return rv;
}
nsresult nsDeviceContext::EndDocument() {
MOZ_DIAGNOSTIC_ASSERT(mIsCurrentlyPrintingDoc,
"Mismatched BeginDocument/EndDocument calls");
MOZ_DIAGNOSTIC_ASSERT(mPrintTarget);
mIsCurrentlyPrintingDoc = false;
if (mPrintTarget) {
MOZ_TRY(mPrintTarget->EndPrinting());
mPrintTarget->Finish();
mPrintTarget = nullptr;
}
if (mDeviceContextSpec) {
MOZ_TRY(mDeviceContextSpec->EndDocument());
}
return NS_OK;
}
nsresult nsDeviceContext::AbortDocument() {
MOZ_DIAGNOSTIC_ASSERT(mIsCurrentlyPrintingDoc,
"Mismatched BeginDocument/EndDocument calls");
nsresult rv = mPrintTarget->AbortPrinting();
mIsCurrentlyPrintingDoc = false;
if (mDeviceContextSpec) {
mDeviceContextSpec->EndDocument();
}
mPrintTarget = nullptr;
return rv;
}
nsresult nsDeviceContext::BeginPage() {
MOZ_DIAGNOSTIC_ASSERT(!mIsCurrentlyPrintingDoc || mPrintTarget,
"What nulled out our print target while printing?");
if (mDeviceContextSpec) {
MOZ_TRY(mDeviceContextSpec->BeginPage());
}
if (mPrintTarget) {
MOZ_TRY(mPrintTarget->BeginPage());
}
return NS_OK;
}
nsresult nsDeviceContext::EndPage() {
MOZ_DIAGNOSTIC_ASSERT(!mIsCurrentlyPrintingDoc || mPrintTarget,
"What nulled out our print target while printing?");
if (mPrintTarget) {
MOZ_TRY(mPrintTarget->EndPage());
}
if (mDeviceContextSpec) {
MOZ_TRY(mDeviceContextSpec->EndPage());
}
return NS_OK;
}
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->SetRect(NSIntPixelsToAppUnits(x, AppUnitsPerDevPixel()),
NSIntPixelsToAppUnits(y, AppUnitsPerDevPixel()),
NSIntPixelsToAppUnits(width, AppUnitsPerDevPixel()),
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->SetRect(NSIntPixelsToAppUnits(x, AppUnitsPerDevPixel()),
NSIntPixelsToAppUnits(y, AppUnitsPerDevPixel()),
NSIntPixelsToAppUnits(width, AppUnitsPerDevPixel()),
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 || !mScreenManager) {
return;
}
CheckDPIChange();
nsCOMPtr<nsIScreen> screen = mWidget->GetWidgetScreen();
screen.forget(outScreen);
if (!(*outScreen)) {
mScreenManager->GetPrimaryScreen(outScreen);
}
}
bool nsDeviceContext::CalcPrintingSize() {
gfxSize size(mPrintTarget->GetSize());
// For printing, CSS inches and physical inches are identical
// so it doesn't matter which we use here
mWidth = NSToCoordRound(size.width * AppUnitsPerPhysicalInch() /
POINTS_PER_INCH_FLOAT);
mHeight = NSToCoordRound(size.height * AppUnitsPerPhysicalInch() /
POINTS_PER_INCH_FLOAT);
return (mWidth > 0 && mHeight > 0);
}
bool nsDeviceContext::CheckDPIChange(double* aScale) {
int32_t oldDevPixels = mAppUnitsPerDevPixelAtUnitFullZoom;
int32_t oldInches = mAppUnitsPerPhysicalInch;
SetDPI(aScale);
return oldDevPixels != mAppUnitsPerDevPixelAtUnitFullZoom ||
oldInches != mAppUnitsPerPhysicalInch;
}
bool nsDeviceContext::SetFullZoom(float aScale) {
if (aScale <= 0) {
MOZ_ASSERT_UNREACHABLE("Invalid full zoom value");
return false;
}
int32_t oldAppUnitsPerDevPixel = mAppUnitsPerDevPixel;
mFullZoom = aScale;
UpdateAppUnitsForFullZoom();
return oldAppUnitsPerDevPixel != mAppUnitsPerDevPixel;
}
void nsDeviceContext::UpdateAppUnitsForFullZoom() {
mAppUnitsPerDevPixel = std::max(
1, NSToIntRound(float(mAppUnitsPerDevPixelAtUnitFullZoom) / mFullZoom));
// adjust mFullZoom to reflect appunit rounding
mFullZoom = float(mAppUnitsPerDevPixelAtUnitFullZoom) / mAppUnitsPerDevPixel;
}
DesktopToLayoutDeviceScale nsDeviceContext::GetDesktopToDeviceScale() {
nsCOMPtr<nsIScreen> screen;
FindScreen(getter_AddRefs(screen));
if (screen) {
double scale;
screen->GetContentsScaleFactor(&scale);
return DesktopToLayoutDeviceScale(scale);
}
return DesktopToLayoutDeviceScale(1.0);
}