Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Misc / GDI / MeasurementDCInfo.cs / 1 / MeasurementDCInfo.cs
#if OPTIMIZED_MEASUREMENTDC #if WGCM_TEST_SUITE // Enable tracking when built for the test suites. #define TRACK_HDC #define GDI_FONT_CACHE_TRACK #endif #if WINFORMS_NAMESPACE namespace System.Windows.Forms.Internal { #elif DRAWING_NAMESPACE namespace System.Drawing.Internal { #else namespace System.Experimental.Gdi { #endif #if WINFORMS_PUBLIC_GRAPHICS_LIBRARY public #else internal #endif static class MeasurementDCInfo { /// MeasurementDCInfo /// This class optimizes the MeasurmentGraphics as it caches in the last used font and TextMargins used. /// This prevents unnecessary p/invoke calls to GetCurrentObject, etc /// It has been found to give close to 2x performance when drawing lots of text in rapid succession /// DataGridView with lots of text, etc. /// To turn it on for your DLL, use the OPTIMIZED_MEASUREMENTDC compiler switch and add this class to the sources. [ThreadStatic] private static CachedInfo cachedMeasurementDCInfo; /// IsMeasurementDC /// Returns whether the IDeviceContext passed in is our static MeasurementDC. /// If it is, we know a bit more information about it. internal static bool IsMeasurementDC(DeviceContext dc) { WindowsGraphics sharedGraphics = WindowsGraphicsCacheManager.GetCurrentMeasurementGraphics(); return sharedGraphics != null && sharedGraphics.DeviceContext != null && sharedGraphics.DeviceContext.Hdc == dc.Hdc; } /// LastUsedFont - /// Returns the font we think was last selected into the MeasurementGraphics. /// internal static WindowsFont LastUsedFont { get { return (cachedMeasurementDCInfo == null) ? null : cachedMeasurementDCInfo.LastUsedFont; } set { if (cachedMeasurementDCInfo == null) { cachedMeasurementDCInfo = new CachedInfo(); } cachedMeasurementDCInfo.UpdateFont(value); } } /// GetTextMargins - checks to see if we have cached information about the current font, /// returns info about it. /// An MRU of Font margins was considered, but seems like overhead. internal static IntNativeMethods.DRAWTEXTPARAMS GetTextMargins(WindowsGraphics wg, WindowsFont font) { // PERF: operate on a local reference rather than party directly on the thread static one. CachedInfo currentCachedInfo = cachedMeasurementDCInfo; if (currentCachedInfo != null && currentCachedInfo.LeftTextMargin >0 && currentCachedInfo.RightTextMargin >0 && font == currentCachedInfo.LastUsedFont) { // we have to return clones as DrawTextEx will modify this struct return new IntNativeMethods.DRAWTEXTPARAMS(currentCachedInfo.LeftTextMargin,currentCachedInfo.RightTextMargin); } else if (currentCachedInfo == null) { currentCachedInfo = new CachedInfo(); cachedMeasurementDCInfo = currentCachedInfo; } IntNativeMethods.DRAWTEXTPARAMS drawTextParams = wg.GetTextMargins(font); currentCachedInfo.LeftTextMargin = drawTextParams.iLeftMargin; currentCachedInfo.RightTextMargin = drawTextParams.iRightMargin; // returning a copy here to be consistent with the return value from the cache. return new IntNativeMethods.DRAWTEXTPARAMS(currentCachedInfo.LeftTextMargin,currentCachedInfo.RightTextMargin); } internal static void ResetIfIsMeasurementDC(IntPtr hdc) { WindowsGraphics sharedGraphics = WindowsGraphicsCacheManager.GetCurrentMeasurementGraphics(); if (sharedGraphics != null && sharedGraphics.DeviceContext != null && sharedGraphics.DeviceContext.Hdc == hdc) { CachedInfo currentCachedInfo = cachedMeasurementDCInfo; if (currentCachedInfo != null) { currentCachedInfo.UpdateFont(null); } } } /// Reset /// clear the current cached information about the measurement dc. internal static void Reset() { CachedInfo currentCachedInfo = cachedMeasurementDCInfo; if (currentCachedInfo != null) { currentCachedInfo.UpdateFont(null); } } /// CachedInfo /// store all the thread statics together so we dont have to fetch individual fields out of TLS private sealed class CachedInfo { public WindowsFont LastUsedFont; public int LeftTextMargin; public int RightTextMargin; internal void UpdateFont(WindowsFont font) { if (LastUsedFont != font) { LastUsedFont = font; LeftTextMargin = -1; RightTextMargin = -1; } } } } } #endif // OPTIMIZED_MEASUREMENTDC // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- RpcResponse.cs
- DeferredTextReference.cs
- GuidelineSet.cs
- DependencySource.cs
- SmiEventSink_Default.cs
- Model3DGroup.cs
- SystemIPGlobalProperties.cs
- DocumentPaginator.cs
- EFColumnProvider.cs
- FrameworkContentElement.cs
- EventWaitHandleSecurity.cs
- CompoundFileStreamReference.cs
- PageThemeBuildProvider.cs
- MainMenu.cs
- BevelBitmapEffect.cs
- AddInIpcChannel.cs
- PropertyTabChangedEvent.cs
- WebPartHeaderCloseVerb.cs
- Oid.cs
- PeerToPeerException.cs
- NamespaceTable.cs
- PartialCachingControl.cs
- BezierSegment.cs
- InstanceData.cs
- ExecutorLocksHeldException.cs
- DataGridViewComboBoxCell.cs
- MdiWindowListItemConverter.cs
- PhysicalAddress.cs
- ResourceSet.cs
- Faults.cs
- LockingPersistenceProvider.cs
- RelationshipNavigation.cs
- TraceFilter.cs
- FileVersion.cs
- DisplayNameAttribute.cs
- WebPartCollection.cs
- CopyNodeSetAction.cs
- basevalidator.cs
- EncodingDataItem.cs
- Helper.cs
- EntityDataSourceState.cs
- xdrvalidator.cs
- FlowDocumentView.cs
- SelectionProviderWrapper.cs
- webbrowsersite.cs
- RegistrySecurity.cs
- ApplicationDirectoryMembershipCondition.cs
- EDesignUtil.cs
- WindowsRebar.cs
- ISFClipboardData.cs
- NonClientArea.cs
- InputScopeManager.cs
- BaseTreeIterator.cs
- ValueUtilsSmi.cs
- LinqDataSourceSelectEventArgs.cs
- PersianCalendar.cs
- Bold.cs
- ObjectDataSourceStatusEventArgs.cs
- MailAddressCollection.cs
- ValueSerializerAttribute.cs
- IpcPort.cs
- JsonEncodingStreamWrapper.cs
- TransactionalPackage.cs
- HtmlPageAdapter.cs
- Context.cs
- ILGenerator.cs
- ArcSegment.cs
- HitTestParameters3D.cs
- WsatRegistrationHeader.cs
- TranslateTransform.cs
- mansign.cs
- SrgsGrammarCompiler.cs
- ConfigDefinitionUpdates.cs
- ToolboxItem.cs
- WebHttpSecurity.cs
- DependencyStoreSurrogate.cs
- TabPage.cs
- WorkerRequest.cs
- IdentityNotMappedException.cs
- WebServiceEndpoint.cs
- BindingValueChangedEventArgs.cs
- SqlClientMetaDataCollectionNames.cs
- ChoiceConverter.cs
- TextCollapsingProperties.cs
- ProjectedWrapper.cs
- MimeTypePropertyAttribute.cs
- FlowDocumentScrollViewer.cs
- OletxEnlistment.cs
- Currency.cs
- PeerMessageDispatcher.cs
- DtdParser.cs
- OutputCacheSettingsSection.cs
- Config.cs
- RootProfilePropertySettingsCollection.cs
- BitmapCodecInfo.cs
- EntityDataSourceView.cs
- VideoDrawing.cs
- StreamInfo.cs
- CaretElement.cs
- EnumValAlphaComparer.cs