DeviceContext2.cs source code in C# .NET

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Code:

/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Misc / GDI / DeviceContext2.cs / 1305376 / DeviceContext2.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

 
#if [....]_NAMESPACE 
namespace System.Windows.Forms.Internal
#elif DRAWING_NAMESPACE 
namespace System.Drawing.Internal
#else
namespace System.Experimental.Gdi
#endif 
{
    using System; 
    using System.Internal; 
    using System.Security;
    using System.Runtime.InteropServices; 
    using System.Diagnostics;
    using System.ComponentModel;
    using System.Drawing;
    using System.Globalization; 
    using System.Runtime.Versioning;
 
    ///  
    /// 
    ///     Represents a Win32 device context.  Provides operations for setting some of the properties 
    ///     of a device context.  It's the managed wrapper for an HDC.
    ///
    ///     This class is divided into two files separating the code that needs to be compiled into
    ///     reatail builds and debugging code. 
    ///
    ///     WARNING: The properties of the dc are obtained on-demand, this object is light-weight because 
    ///     of that; if you need to put back the old value after changing a property you need to get it 
    ///     first and cache it.
    ///  
#if [....]_PUBLIC_GRAPHICS_LIBRARY
    public
#else
    internal 
#endif
    sealed partial class DeviceContext : MarshalByRefObject, IDeviceContext, IDisposable 
    { 
        WindowsFont selectedFont;
 
        /// 
        ///     See DeviceContext.cs for information about this class.  The class has been split to be able
        ///     to compile the right set of functionalities into different assemblies.
        ///  

 
        public WindowsFont ActiveFont { 
            get {
                return selectedFont; 
            }
        }

        ///  
        ///     DC background color.
        ///  
        public Color BackgroundColor 
        {
            get 
            {
                return ColorTranslator.FromWin32(IntUnsafeNativeMethods.GetBkColor( new HandleRef( this, this.Hdc )));
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY 
            set
            { 
                SetBackgroundColor( value ); 
            }
#endif 
        }

        /// 
        ///     Sets the DC background color and returns the old value. 
        /// 
        public Color SetBackgroundColor( Color newColor ) 
        { 
            return ColorTranslator.FromWin32(IntUnsafeNativeMethods.SetBkColor( new HandleRef( this, this.Hdc ), ColorTranslator.ToWin32(newColor)));
        } 

        /// 
        ///     DC background mode.
        ///  
        public DeviceContextBackgroundMode BackgroundMode
        { 
            get 
            {
                return (DeviceContextBackgroundMode) IntUnsafeNativeMethods.GetBkMode( new HandleRef( this, this.Hdc ) ); 
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY
            set
            { 
                SetBackgroundMode(value);
            } 
#endif 
        }
 
        /// 
        ///     Sets the DC background mode and returns the old value.
        /// 
        public DeviceContextBackgroundMode SetBackgroundMode( DeviceContextBackgroundMode newMode ) 
        {
            return (DeviceContextBackgroundMode) IntUnsafeNativeMethods.SetBkMode(new HandleRef(this, this.Hdc), (int) newMode); 
        } 

 
        /// 
        ///     ROP2 currently on the DC.
        /// 
        public DeviceContextBinaryRasterOperationFlags BinaryRasterOperation 
        {
            get 
            { 
                return (DeviceContextBinaryRasterOperationFlags) IntUnsafeNativeMethods.GetROP2( new HandleRef( this, this.Hdc ) );
            } 
            /*
             *

 

 
 

*/ 
        }

        /// 
        ///     Sets the DC ROP2 and returns the old value. 
        /// 
        public DeviceContextBinaryRasterOperationFlags SetRasterOperation(DeviceContextBinaryRasterOperationFlags rasterOperation ) 
        { 
            return (DeviceContextBinaryRasterOperationFlags) IntUnsafeNativeMethods.SetROP2(new HandleRef(this, this.Hdc), (int) rasterOperation);
        } 

        ///
        ///     Get the number of pixels per logical inch along the device axes.
        ///     In a system with multiple display monitors, this value is the same for all monitors. 
        ///
        public Size Dpi 
        { 
            get
            { 
                return new Size(GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsX), GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsY));
            }
        }
 
        ///
        ///     Get the number of pixels per logical inch along the device width. 
        ///     In a system with multiple display monitors, this value is the same for all monitors. 
        ///
        public int DpiX 
        {
            get
            {
                return GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsX); 
            }
        } 
 
        ///
        ///     Get the number of pixels per logical inch along the device (screen) height. 
        ///     In a system with multiple display monitors, this value is the same for all monitors.
        ///
        public int DpiY
        { 
            get
            { 
                return GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsY); 
            }
        } 

        /// 
        ///     The font selected into the device context.
        ///     It's OK to call dispose on it, the HFONT won't be deleted since the WindowsFont did not create it, 
        ///     it got it from the HDC.
        ///  
 
        public WindowsFont Font
        { 
            [ResourceExposure(ResourceScope.Process)]
            [ResourceConsumption(ResourceScope.Process)]
            get
            { 
#if OPTIMIZED_MEASUREMENTDC
                if (MeasurementDCInfo.IsMeasurementDC(this)) 
                { 
                    WindowsFont font = MeasurementDCInfo.LastUsedFont;
                    if (font != null && (font.Hfont != IntPtr.Zero)) { 
#if DEBUG
                        WindowsFont currentDCFont = WindowsFont.FromHdc( this.Hdc );
                        if (!font.Equals(currentDCFont) ) {
                            // just use the face name, as ToString will call here re-entrantly. 
                            string lastUsedFontInfo = (font != null) ?  font.Name : "null";
                            string currentFontInfo = (currentDCFont != null) ?  currentDCFont.Name : "null"; 
                            Debug.Fail("Font does not match... Current: " + currentFontInfo + " Last known: " + lastUsedFontInfo); 
                        }
 
#endif
                        return font;

                    } 
                }
#endif 
                // Returns the currently selected object in the dc. 
                // Note: for common DCs, GetDC assigns default attributes to the DC each time it is retrieved,
                // the default font is System. 
                return WindowsFont.FromHdc( this.Hdc );
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY
            set 
            {
                Debug.Assert( value != null, "value == null." ); 
                IntPtr hOldFont = SelectFont( value ); 
                IntUnsafeNativeMethods.IntDeleteObject(new HandleRef(null, hOldFont));
            } 
#endif
        }

        ///  
        ///     Gets a DeviceContext object initialized to refer to the primary screen device.
        ///     Consider using WindowsGraphicsCacheManager.MeasurementGraphics instead. 
        ///  
        public static DeviceContext ScreenDC
        { 
            get
            {
                return DeviceContext.FromHwnd(IntPtr.Zero);
            } 
        }
 
        internal void DisposeFont(bool disposing) { 
            if (disposing) {
                DeviceContexts.RemoveDeviceContext(this); 
            }

            if (selectedFont != null && selectedFont.Hfont != IntPtr.Zero) {
                IntPtr hCurrentFont = IntUnsafeNativeMethods.GetCurrentObject(new HandleRef(this, hDC), IntNativeMethods.OBJ_FONT); 
                if (hCurrentFont == selectedFont.Hfont) {
                    // select initial font back in 
                    IntUnsafeNativeMethods.SelectObject(new HandleRef(this, this.Hdc), new HandleRef( null, hInitialFont)); 
                    hCurrentFont = hInitialFont;
                } 

                selectedFont.Dispose(disposing);
                selectedFont = null;
            } 
        }
 
        ///  
        ///     Selects the specified object into the dc.  If the specified object is the same as the one currently selected
        ///     in the dc, the object is not set and a null value is returned. 
        /// 
        public IntPtr SelectFont( WindowsFont font )
        {
 
            // Fonts are one of the most expensive objects to select in an hdc and in many cases we are passed a Font that is the
            // same as the one already selected in the dc so to avoid a perf hit we get the hdc font's log font and compare it 
            // with the one passed in before selecting it in the hdc. 
            // Also, we avoid performing GDI operations that if done on an enhanced metafile DC would add an entry to it, hence
            // reducing the size of the metafile. 
            if( font.Equals( this.Font ))
            {
                return IntPtr.Zero;
            } 
            IntPtr result = SelectObject( font.Hfont, GdiObjectType.Font);
 
            WindowsFont previousFont = selectedFont; 
            selectedFont = font;
            hCurrentFont = font.Hfont; 

            // the measurement DC always leaves fonts selected for pref reasons.
            // in this case, we need to diposse the font since the original
            // creator didn't fully dispose. 
            if (previousFont != null) {
#if DEBUG 
                //Disabling this assert until DevDiv Bugs 95968 gets fixed 
                //Debug.Assert(previousFont.Hfont != IntPtr.Zero, "A font has been disposed before it was unselected from the DC.  This will leak a GDI handle on Win9x! Call ResetFont()");
#endif 
                if (MeasurementDCInfo.IsMeasurementDC(this)) {
                    previousFont.Dispose();
                }
            } 

#if OPTIMIZED_MEASUREMENTDC 
            // once we've changed the font, update the last used font. 
            if (MeasurementDCInfo.IsMeasurementDC(this))
            { 
                if (result != IntPtr.Zero)
                {
                    MeasurementDCInfo.LastUsedFont = font;
                } 
                else
                { 
                   // there was an error selecting the Font into the DC, we dont know anything about it. 
                   MeasurementDCInfo.Reset();
                } 
            }
#endif
            return result;
        } 

        public void ResetFont() 
        { 

#if OPTIMIZED_MEASUREMENTDC 
            // in this case, GDI will copy back the previously saved font into the DC.
            // we dont actually know what the font is in our measurement DC so
            // we need to clear it off.
            MeasurementDCInfo.ResetIfIsMeasurementDC(this.Hdc); 
#endif
            IntUnsafeNativeMethods.SelectObject(new HandleRef(this, this.Hdc), new HandleRef( null, hInitialFont )); 
            selectedFont = null; 
            hCurrentFont = hInitialFont;
        } 

        /// 
        ///     Retrieves device-specific information for this device.
        ///  
        public int GetDeviceCapabilities( DeviceCapabilities capabilityIndex )
        { 
            return IntUnsafeNativeMethods.GetDeviceCaps( new HandleRef( this, this.Hdc ), (int) capabilityIndex ); 
        }
 
        /// 
        ///     DC map mode.
        /// 
        public DeviceContextMapMode MapMode 
        {
            get 
            { 
                return (DeviceContextMapMode) IntUnsafeNativeMethods.GetMapMode( new HandleRef( this, this.Hdc ) );
            } 
#if [....]_PUBLIC_GRAPHICS_LIBRARY
            set
            {
                SetMapMode(value); 
            }
#endif 
        } 

        public bool IsFontOnContextStack(WindowsFont wf) 
        {
            if (contextStack == null) {
                return false;
            } 

            foreach (GraphicsState g in contextStack) { 
                if (g.hFont == wf.Hfont) { 
                    return true;
                } 
            }

            return false;
        } 

        ///  
        ///     Sets the DC map mode and returns the old value. 
        /// 
        public DeviceContextMapMode SetMapMode( DeviceContextMapMode newMode ) 
        {
            return (DeviceContextMapMode) IntUnsafeNativeMethods.SetMapMode( new HandleRef(this, this.Hdc), (int) newMode );
        }
 
        /// 
        ///     Selects the specified object into the dc and returns the old object. 
        ///  
        public IntPtr SelectObject(IntPtr hObj, GdiObjectType type)
        { 
            switch (type) {
                case GdiObjectType.Pen:
                    hCurrentPen = hObj;
                    break; 
                case GdiObjectType.Brush:
                    hCurrentBrush = hObj; 
                    break; 

                case GdiObjectType.Bitmap: 
                    hCurrentBmp = hObj;
                    break;
            }
            return IntUnsafeNativeMethods.SelectObject(new HandleRef(this, this.Hdc), new HandleRef( null, hObj)); 
        }
 
        ///  
        ///     DC text alignment.
        ///  
        public DeviceContextTextAlignment TextAlignment
        {
            get
            { 
                return (DeviceContextTextAlignment) IntUnsafeNativeMethods.GetTextAlign( new HandleRef( this, this.Hdc ) );
            } 
#if [....]_PUBLIC_GRAPHICS_LIBRARY 
            set
            { 
                SetTextAlignment(value);
            }
#endif
        } 

        ///  
        ///     Sets the DC text alignment and returns the old value. 
        /// 
        public DeviceContextTextAlignment SetTextAlignment( DeviceContextTextAlignment newAligment ) 
        {
            return (DeviceContextTextAlignment) IntUnsafeNativeMethods.SetTextAlign(new HandleRef(this, this.Hdc), (int) newAligment );
        }
 

        ///  
        ///     DC current text color. 
        /// 
        public Color TextColor 
        {
            get
            {
                return ColorTranslator.FromWin32(IntUnsafeNativeMethods.GetTextColor( new HandleRef( this, this.Hdc ) )); 
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY 
            set 
            {
                SetTextColor(value); 
            }
#endif
        }
 
        /// 
        ///     Sets the DC text color and returns the old value. 
        ///  
        public Color SetTextColor( Color newColor )
        { 
            return ColorTranslator.FromWin32(IntUnsafeNativeMethods.SetTextColor(new HandleRef( this, this.Hdc), ColorTranslator.ToWin32(newColor)));
        }

        ///  
        ///     DC Viewport Extent in device units.
        ///  
        public Size ViewportExtent 
        {
            get 
            {
                IntNativeMethods.SIZE size = new IntNativeMethods.SIZE();
                IntUnsafeNativeMethods.GetViewportExtEx( new HandleRef( this, this.Hdc ), size );
 
                return size.ToSize();
            } 
             set 
             {
                SetViewportExtent( value ); 
             }
        }

        ///  
        ///     Sets the DC Viewport extent to the specified value and returns its previous value; extent values are in device units.
        ///  
        public Size SetViewportExtent( Size newExtent ) 
        {
            IntNativeMethods.SIZE oldExtent = new IntNativeMethods.SIZE(); 

            IntUnsafeNativeMethods.SetViewportExtEx( new HandleRef( this, this.Hdc ), newExtent.Width, newExtent.Height, oldExtent );

            return oldExtent.ToSize(); 
        }
 
        ///  
        ///     DC Viewport Origin in device units.
        ///  
        public Point ViewportOrigin
        {
            get
            { 
                IntNativeMethods.POINT point = new IntNativeMethods.POINT();
                IntUnsafeNativeMethods.GetViewportOrgEx( new HandleRef( this, this.Hdc ), point ); 
 
                return point.ToPoint();
            } 
             set
             {
                SetViewportOrigin( value );
             } 
        }
 
        ///  
        ///     Sets the DC Viewport origin to the specified value and returns its previous value; origin values are in device units.
        ///  
        public Point SetViewportOrigin( Point newOrigin )
        {
            IntNativeMethods.POINT oldOrigin = new IntNativeMethods.POINT();
            IntUnsafeNativeMethods.SetViewportOrgEx( new HandleRef( this, this.Hdc ), newOrigin.X, newOrigin.Y, oldOrigin ); 

            return oldOrigin.ToPoint(); 
        } 

    } 
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

 
#if [....]_NAMESPACE 
namespace System.Windows.Forms.Internal
#elif DRAWING_NAMESPACE 
namespace System.Drawing.Internal
#else
namespace System.Experimental.Gdi
#endif 
{
    using System; 
    using System.Internal; 
    using System.Security;
    using System.Runtime.InteropServices; 
    using System.Diagnostics;
    using System.ComponentModel;
    using System.Drawing;
    using System.Globalization; 
    using System.Runtime.Versioning;
 
    ///  
    /// 
    ///     Represents a Win32 device context.  Provides operations for setting some of the properties 
    ///     of a device context.  It's the managed wrapper for an HDC.
    ///
    ///     This class is divided into two files separating the code that needs to be compiled into
    ///     reatail builds and debugging code. 
    ///
    ///     WARNING: The properties of the dc are obtained on-demand, this object is light-weight because 
    ///     of that; if you need to put back the old value after changing a property you need to get it 
    ///     first and cache it.
    ///  
#if [....]_PUBLIC_GRAPHICS_LIBRARY
    public
#else
    internal 
#endif
    sealed partial class DeviceContext : MarshalByRefObject, IDeviceContext, IDisposable 
    { 
        WindowsFont selectedFont;
 
        /// 
        ///     See DeviceContext.cs for information about this class.  The class has been split to be able
        ///     to compile the right set of functionalities into different assemblies.
        ///  

 
        public WindowsFont ActiveFont { 
            get {
                return selectedFont; 
            }
        }

        ///  
        ///     DC background color.
        ///  
        public Color BackgroundColor 
        {
            get 
            {
                return ColorTranslator.FromWin32(IntUnsafeNativeMethods.GetBkColor( new HandleRef( this, this.Hdc )));
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY 
            set
            { 
                SetBackgroundColor( value ); 
            }
#endif 
        }

        /// 
        ///     Sets the DC background color and returns the old value. 
        /// 
        public Color SetBackgroundColor( Color newColor ) 
        { 
            return ColorTranslator.FromWin32(IntUnsafeNativeMethods.SetBkColor( new HandleRef( this, this.Hdc ), ColorTranslator.ToWin32(newColor)));
        } 

        /// 
        ///     DC background mode.
        ///  
        public DeviceContextBackgroundMode BackgroundMode
        { 
            get 
            {
                return (DeviceContextBackgroundMode) IntUnsafeNativeMethods.GetBkMode( new HandleRef( this, this.Hdc ) ); 
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY
            set
            { 
                SetBackgroundMode(value);
            } 
#endif 
        }
 
        /// 
        ///     Sets the DC background mode and returns the old value.
        /// 
        public DeviceContextBackgroundMode SetBackgroundMode( DeviceContextBackgroundMode newMode ) 
        {
            return (DeviceContextBackgroundMode) IntUnsafeNativeMethods.SetBkMode(new HandleRef(this, this.Hdc), (int) newMode); 
        } 

 
        /// 
        ///     ROP2 currently on the DC.
        /// 
        public DeviceContextBinaryRasterOperationFlags BinaryRasterOperation 
        {
            get 
            { 
                return (DeviceContextBinaryRasterOperationFlags) IntUnsafeNativeMethods.GetROP2( new HandleRef( this, this.Hdc ) );
            } 
            /*
             *

 

 
 

*/ 
        }

        /// 
        ///     Sets the DC ROP2 and returns the old value. 
        /// 
        public DeviceContextBinaryRasterOperationFlags SetRasterOperation(DeviceContextBinaryRasterOperationFlags rasterOperation ) 
        { 
            return (DeviceContextBinaryRasterOperationFlags) IntUnsafeNativeMethods.SetROP2(new HandleRef(this, this.Hdc), (int) rasterOperation);
        } 

        ///
        ///     Get the number of pixels per logical inch along the device axes.
        ///     In a system with multiple display monitors, this value is the same for all monitors. 
        ///
        public Size Dpi 
        { 
            get
            { 
                return new Size(GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsX), GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsY));
            }
        }
 
        ///
        ///     Get the number of pixels per logical inch along the device width. 
        ///     In a system with multiple display monitors, this value is the same for all monitors. 
        ///
        public int DpiX 
        {
            get
            {
                return GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsX); 
            }
        } 
 
        ///
        ///     Get the number of pixels per logical inch along the device (screen) height. 
        ///     In a system with multiple display monitors, this value is the same for all monitors.
        ///
        public int DpiY
        { 
            get
            { 
                return GetDeviceCapabilities(DeviceCapabilities.LogicalPixelsY); 
            }
        } 

        /// 
        ///     The font selected into the device context.
        ///     It's OK to call dispose on it, the HFONT won't be deleted since the WindowsFont did not create it, 
        ///     it got it from the HDC.
        ///  
 
        public WindowsFont Font
        { 
            [ResourceExposure(ResourceScope.Process)]
            [ResourceConsumption(ResourceScope.Process)]
            get
            { 
#if OPTIMIZED_MEASUREMENTDC
                if (MeasurementDCInfo.IsMeasurementDC(this)) 
                { 
                    WindowsFont font = MeasurementDCInfo.LastUsedFont;
                    if (font != null && (font.Hfont != IntPtr.Zero)) { 
#if DEBUG
                        WindowsFont currentDCFont = WindowsFont.FromHdc( this.Hdc );
                        if (!font.Equals(currentDCFont) ) {
                            // just use the face name, as ToString will call here re-entrantly. 
                            string lastUsedFontInfo = (font != null) ?  font.Name : "null";
                            string currentFontInfo = (currentDCFont != null) ?  currentDCFont.Name : "null"; 
                            Debug.Fail("Font does not match... Current: " + currentFontInfo + " Last known: " + lastUsedFontInfo); 
                        }
 
#endif
                        return font;

                    } 
                }
#endif 
                // Returns the currently selected object in the dc. 
                // Note: for common DCs, GetDC assigns default attributes to the DC each time it is retrieved,
                // the default font is System. 
                return WindowsFont.FromHdc( this.Hdc );
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY
            set 
            {
                Debug.Assert( value != null, "value == null." ); 
                IntPtr hOldFont = SelectFont( value ); 
                IntUnsafeNativeMethods.IntDeleteObject(new HandleRef(null, hOldFont));
            } 
#endif
        }

        ///  
        ///     Gets a DeviceContext object initialized to refer to the primary screen device.
        ///     Consider using WindowsGraphicsCacheManager.MeasurementGraphics instead. 
        ///  
        public static DeviceContext ScreenDC
        { 
            get
            {
                return DeviceContext.FromHwnd(IntPtr.Zero);
            } 
        }
 
        internal void DisposeFont(bool disposing) { 
            if (disposing) {
                DeviceContexts.RemoveDeviceContext(this); 
            }

            if (selectedFont != null && selectedFont.Hfont != IntPtr.Zero) {
                IntPtr hCurrentFont = IntUnsafeNativeMethods.GetCurrentObject(new HandleRef(this, hDC), IntNativeMethods.OBJ_FONT); 
                if (hCurrentFont == selectedFont.Hfont) {
                    // select initial font back in 
                    IntUnsafeNativeMethods.SelectObject(new HandleRef(this, this.Hdc), new HandleRef( null, hInitialFont)); 
                    hCurrentFont = hInitialFont;
                } 

                selectedFont.Dispose(disposing);
                selectedFont = null;
            } 
        }
 
        ///  
        ///     Selects the specified object into the dc.  If the specified object is the same as the one currently selected
        ///     in the dc, the object is not set and a null value is returned. 
        /// 
        public IntPtr SelectFont( WindowsFont font )
        {
 
            // Fonts are one of the most expensive objects to select in an hdc and in many cases we are passed a Font that is the
            // same as the one already selected in the dc so to avoid a perf hit we get the hdc font's log font and compare it 
            // with the one passed in before selecting it in the hdc. 
            // Also, we avoid performing GDI operations that if done on an enhanced metafile DC would add an entry to it, hence
            // reducing the size of the metafile. 
            if( font.Equals( this.Font ))
            {
                return IntPtr.Zero;
            } 
            IntPtr result = SelectObject( font.Hfont, GdiObjectType.Font);
 
            WindowsFont previousFont = selectedFont; 
            selectedFont = font;
            hCurrentFont = font.Hfont; 

            // the measurement DC always leaves fonts selected for pref reasons.
            // in this case, we need to diposse the font since the original
            // creator didn't fully dispose. 
            if (previousFont != null) {
#if DEBUG 
                //Disabling this assert until DevDiv Bugs 95968 gets fixed 
                //Debug.Assert(previousFont.Hfont != IntPtr.Zero, "A font has been disposed before it was unselected from the DC.  This will leak a GDI handle on Win9x! Call ResetFont()");
#endif 
                if (MeasurementDCInfo.IsMeasurementDC(this)) {
                    previousFont.Dispose();
                }
            } 

#if OPTIMIZED_MEASUREMENTDC 
            // once we've changed the font, update the last used font. 
            if (MeasurementDCInfo.IsMeasurementDC(this))
            { 
                if (result != IntPtr.Zero)
                {
                    MeasurementDCInfo.LastUsedFont = font;
                } 
                else
                { 
                   // there was an error selecting the Font into the DC, we dont know anything about it. 
                   MeasurementDCInfo.Reset();
                } 
            }
#endif
            return result;
        } 

        public void ResetFont() 
        { 

#if OPTIMIZED_MEASUREMENTDC 
            // in this case, GDI will copy back the previously saved font into the DC.
            // we dont actually know what the font is in our measurement DC so
            // we need to clear it off.
            MeasurementDCInfo.ResetIfIsMeasurementDC(this.Hdc); 
#endif
            IntUnsafeNativeMethods.SelectObject(new HandleRef(this, this.Hdc), new HandleRef( null, hInitialFont )); 
            selectedFont = null; 
            hCurrentFont = hInitialFont;
        } 

        /// 
        ///     Retrieves device-specific information for this device.
        ///  
        public int GetDeviceCapabilities( DeviceCapabilities capabilityIndex )
        { 
            return IntUnsafeNativeMethods.GetDeviceCaps( new HandleRef( this, this.Hdc ), (int) capabilityIndex ); 
        }
 
        /// 
        ///     DC map mode.
        /// 
        public DeviceContextMapMode MapMode 
        {
            get 
            { 
                return (DeviceContextMapMode) IntUnsafeNativeMethods.GetMapMode( new HandleRef( this, this.Hdc ) );
            } 
#if [....]_PUBLIC_GRAPHICS_LIBRARY
            set
            {
                SetMapMode(value); 
            }
#endif 
        } 

        public bool IsFontOnContextStack(WindowsFont wf) 
        {
            if (contextStack == null) {
                return false;
            } 

            foreach (GraphicsState g in contextStack) { 
                if (g.hFont == wf.Hfont) { 
                    return true;
                } 
            }

            return false;
        } 

        ///  
        ///     Sets the DC map mode and returns the old value. 
        /// 
        public DeviceContextMapMode SetMapMode( DeviceContextMapMode newMode ) 
        {
            return (DeviceContextMapMode) IntUnsafeNativeMethods.SetMapMode( new HandleRef(this, this.Hdc), (int) newMode );
        }
 
        /// 
        ///     Selects the specified object into the dc and returns the old object. 
        ///  
        public IntPtr SelectObject(IntPtr hObj, GdiObjectType type)
        { 
            switch (type) {
                case GdiObjectType.Pen:
                    hCurrentPen = hObj;
                    break; 
                case GdiObjectType.Brush:
                    hCurrentBrush = hObj; 
                    break; 

                case GdiObjectType.Bitmap: 
                    hCurrentBmp = hObj;
                    break;
            }
            return IntUnsafeNativeMethods.SelectObject(new HandleRef(this, this.Hdc), new HandleRef( null, hObj)); 
        }
 
        ///  
        ///     DC text alignment.
        ///  
        public DeviceContextTextAlignment TextAlignment
        {
            get
            { 
                return (DeviceContextTextAlignment) IntUnsafeNativeMethods.GetTextAlign( new HandleRef( this, this.Hdc ) );
            } 
#if [....]_PUBLIC_GRAPHICS_LIBRARY 
            set
            { 
                SetTextAlignment(value);
            }
#endif
        } 

        ///  
        ///     Sets the DC text alignment and returns the old value. 
        /// 
        public DeviceContextTextAlignment SetTextAlignment( DeviceContextTextAlignment newAligment ) 
        {
            return (DeviceContextTextAlignment) IntUnsafeNativeMethods.SetTextAlign(new HandleRef(this, this.Hdc), (int) newAligment );
        }
 

        ///  
        ///     DC current text color. 
        /// 
        public Color TextColor 
        {
            get
            {
                return ColorTranslator.FromWin32(IntUnsafeNativeMethods.GetTextColor( new HandleRef( this, this.Hdc ) )); 
            }
#if [....]_PUBLIC_GRAPHICS_LIBRARY 
            set 
            {
                SetTextColor(value); 
            }
#endif
        }
 
        /// 
        ///     Sets the DC text color and returns the old value. 
        ///  
        public Color SetTextColor( Color newColor )
        { 
            return ColorTranslator.FromWin32(IntUnsafeNativeMethods.SetTextColor(new HandleRef( this, this.Hdc), ColorTranslator.ToWin32(newColor)));
        }

        ///  
        ///     DC Viewport Extent in device units.
        ///  
        public Size ViewportExtent 
        {
            get 
            {
                IntNativeMethods.SIZE size = new IntNativeMethods.SIZE();
                IntUnsafeNativeMethods.GetViewportExtEx( new HandleRef( this, this.Hdc ), size );
 
                return size.ToSize();
            } 
             set 
             {
                SetViewportExtent( value ); 
             }
        }

        ///  
        ///     Sets the DC Viewport extent to the specified value and returns its previous value; extent values are in device units.
        ///  
        public Size SetViewportExtent( Size newExtent ) 
        {
            IntNativeMethods.SIZE oldExtent = new IntNativeMethods.SIZE(); 

            IntUnsafeNativeMethods.SetViewportExtEx( new HandleRef( this, this.Hdc ), newExtent.Width, newExtent.Height, oldExtent );

            return oldExtent.ToSize(); 
        }
 
        ///  
        ///     DC Viewport Origin in device units.
        ///  
        public Point ViewportOrigin
        {
            get
            { 
                IntNativeMethods.POINT point = new IntNativeMethods.POINT();
                IntUnsafeNativeMethods.GetViewportOrgEx( new HandleRef( this, this.Hdc ), point ); 
 
                return point.ToPoint();
            } 
             set
             {
                SetViewportOrigin( value );
             } 
        }
 
        ///  
        ///     Sets the DC Viewport origin to the specified value and returns its previous value; origin values are in device units.
        ///  
        public Point SetViewportOrigin( Point newOrigin )
        {
            IntNativeMethods.POINT oldOrigin = new IntNativeMethods.POINT();
            IntUnsafeNativeMethods.SetViewportOrgEx( new HandleRef( this, this.Hdc ), newOrigin.X, newOrigin.Y, oldOrigin ); 

            return oldOrigin.ToPoint(); 
        } 

    } 
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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