C# IDeviceContext.ReleaseHdc方法代码示例

		public int UxThemeDrawThemeBackground (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, Rectangle bounds)
		{
			XplatUIWin32.RECT BoundsRect = XplatUIWin32.RECT.FromRectangle (bounds);

			int result = UXTheme.DrawThemeBackground(hTheme, dc.GetHdc (), iPartId, iStateId, ref BoundsRect, IntPtr.Zero);
			dc.ReleaseHdc ();
			return result;
		}

		public int UxThemeDrawThemeEdge (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, Rectangle bounds, Edges edges, EdgeStyle style, EdgeEffects effects, out Rectangle result)
		{
			XplatUIWin32.RECT BoundsRect = XplatUIWin32.RECT.FromRectangle (bounds);
			XplatUIWin32.RECT retval;

			int hresult = UXTheme.DrawThemeEdge (hTheme, dc.GetHdc (), iPartId, iStateId, ref BoundsRect, (uint)style, (uint)edges + (uint)effects, out retval);
			dc.ReleaseHdc ();
			result = retval.ToRectangle();
			return hresult;
		}

        Padding GetThemeMargins(IDeviceContext dc, MarginTypes marginType)
        {
            NativeMethods.Margins margins;
            try
            {
                IntPtr hDc = dc.GetHdc();

                if (NativeMethods.GetThemeMargins(Renderer.Handle, hDc, Renderer.Part, Renderer.State, (int)marginType, IntPtr.Zero, out margins) == 0)
                {
                    return new Padding(margins.cxLeftWidth, margins.cyTopHeight, margins.cxRightWidth, margins.cyBottomHeight);
                }

                return new Padding(0);
            }
            finally
            {
                dc.ReleaseHdc();
            }
        }

//.........这里部分代码省略.........
			GdkGCPointer gc = gdk_gc_new (drawable);
			GdkColor color = new GdkColor (background);
			gdk_gc_set_rgb_fg_color (gc, ref color);
			Paint (drawable, gc, bounds, widgetType, out pixbuf, out pixel_data, out rowstride, painted_area, painter, excludedArea);
			GdkPixbufPointer white_pixbuf = IntPtr.Zero;
			IntPtr white_pixel_data = IntPtr.Zero;
			int white_rowstride = 0;
			GdkColor white_color = new GdkColor();
			if (transparencyType == TransparencyType.Alpha) {
				white_color.red = guint16.MaxValue;
				white_color.green = guint16.MaxValue;
				white_color.blue = guint16.MaxValue;
				gdk_gc_set_rgb_fg_color (gc, ref white_color);
				Paint (drawable, gc, bounds, widgetType, out white_pixbuf, out white_pixel_data, out white_rowstride, painted_area, painter, excludedArea);
			}
			g_object_unref (gc);
			unsafe {
				byte* row = (byte*)pixel_data;
				byte* pixel;
				byte* white_row = (byte*)white_pixel_data;
				byte* white_pixel;

				for (int row_index = 0; row_index < painted_area.Height; row_index++) {
					pixel = row;
					white_pixel = white_row;
					for (int pixel_index = 0; pixel_index < painted_area.Width; pixel_index++) {
						const int GdkRedOffset = 0;
						const int GdkGreenOffset = 1;
						const int GdkBlueOffset = 2;
						const int BitmapAlphaOffset = 3;
						const int BitmapRedOffset = 2;
						const int BitmapBlueOffset = 0;
						switch (transparencyType) {
						case TransparencyType.Alpha:
							pixel [BitmapAlphaOffset] = (byte)(pixel [GdkRedOffset] - white_pixel [GdkRedOffset] + byte.MaxValue);
							break;
						case TransparencyType.Color:
							if (
								pixel [GdkRedOffset] == background.R &&
								pixel [GdkGreenOffset] == background.G &&
								pixel [GdkBlueOffset] == background.B) {
								const int AlphaFullyTransparent = 0;
								pixel [BitmapAlphaOffset] = AlphaFullyTransparent;
							}
							break;
						}

						byte temporary = pixel [GdkRedOffset];
						pixel [BitmapBlueOffset] = pixel [GdkBlueOffset];
						pixel [BitmapRedOffset] = temporary;

						const int PixelSize = 4;
						pixel += PixelSize;
						white_pixel += PixelSize;
					}
					row += rowstride;
					white_row += white_rowstride;
				}
			}
			if (transparencyType == TransparencyType.Alpha)
				g_object_unref (white_pixbuf);
			g_object_unref (drawable);
			Bitmap bitmap = new Bitmap (painted_area.Width, painted_area.Height, rowstride, PixelFormat.Format32bppPArgb, pixel_data);
			Graphics g;
			bool graphics_is_from_hdc = false;
			switch (deviceContextType) {
			case DeviceContextType.Graphics:
				g = (Graphics)dc;
				break;
			case DeviceContextType.Native:
				g = Graphics.FromHdc (dc.GetHdc ());
				break;
			default:
				g = dc as Graphics;
				if (g == null) {
					graphics_is_from_hdc = true;
					g = Graphics.FromHdc (dc.GetHdc ());
				} else
					graphics_is_from_hdc = false;
				break;
			}
			painted_area.Offset (bounds.X, bounds.Y);
			g.DrawImage (bitmap, painted_area.Location);
			switch (deviceContextType) {
			case DeviceContextType.Graphics:
				break;
			case DeviceContextType.Native:
				g.Dispose ();
				dc.ReleaseHdc ();
				break;
			default:
				if (graphics_is_from_hdc) {
					g.Dispose ();
					dc.ReleaseHdc ();
				}
				break;
			}
			bitmap.Dispose ();
			g_object_unref (pixbuf);
		}

		public int UxThemeGetThemeBackgroundContentRect (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, Rectangle bounds, out Rectangle result)
		{
			XplatUIWin32.RECT BoundsRect = XplatUIWin32.RECT.FromRectangle (bounds);
			XplatUIWin32.RECT retval;

			int hresult = UXTheme.GetThemeBackgroundContentRect (hTheme, dc.GetHdc (), iPartId, iStateId, ref BoundsRect, out retval);
			dc.ReleaseHdc ();

			result = retval.ToRectangle ();
			return hresult;
		}

		public int UxThemeDrawThemeText (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, string text, TextFormatFlags textFlags, Rectangle bounds)
		{
			XplatUIWin32.RECT BoundsRect = XplatUIWin32.RECT.FromRectangle (bounds);

			int result = UXTheme.DrawThemeText (hTheme, dc.GetHdc (), iPartId, iStateId, text, text.Length, (uint)textFlags, 0, ref BoundsRect);
			dc.ReleaseHdc ();
			return result;
		}

		public void VisualStyleRendererDrawBackgroundExcludingArea (IntPtr theme, IDeviceContext dc, int part, int state, Rectangle bounds, Rectangle excludedArea)
		{
			XplatUIWin32.RECT bounds_rect = XplatUIWin32.RECT.FromRectangle (bounds);
			IntPtr hdc = dc.GetHdc ();
			XplatUIWin32.Win32ExcludeClipRect (hdc, excludedArea.Left, excludedArea.Top, excludedArea.Right, excludedArea.Bottom);
			UXTheme.DrawThemeBackground (theme, hdc, part, state, ref bounds_rect, IntPtr.Zero);
			IntPtr hrgn = XplatUIWin32.Win32CreateRectRgn (excludedArea.Left, excludedArea.Top, excludedArea.Right, excludedArea.Bottom);
			XplatUIWin32.Win32ExtSelectClipRgn (hdc, hrgn, (int)ClipCombineMode.RGN_OR);
			XplatUIWin32.Win32DeleteObject (hrgn);
			dc.ReleaseHdc ();
		}

		public int UxThemeHitTestThemeBackground (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, HitTestOptions options, Rectangle backgroundRectangle, IntPtr hrgn, Point pt, out HitTestCode result)
		{
			XplatUIWin32.RECT BoundsRect = XplatUIWin32.RECT.FromRectangle (backgroundRectangle);
			int retval;

			int hresult = UXTheme.HitTestThemeBackground (hTheme, dc.GetHdc (), iPartId, iStateId, (uint)options, ref BoundsRect, hrgn, new POINT(pt.X, pt.Y), out retval);
			dc.ReleaseHdc ();

			result = (HitTestCode)retval;
			return hresult;
		}

		public int UxThemeGetThemeTextMetrics (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, out TextMetrics result)
		{
			XplatUIWin32.TEXTMETRIC metrics;
			
			int hresult = UXTheme.GetThemeTextMetrics (hTheme, dc.GetHdc (), iPartId, iStateId, out metrics);
			dc.ReleaseHdc ();

			TextMetrics retval = new TextMetrics ();
			retval.Ascent = metrics.tmAscent;
			retval.AverageCharWidth = metrics.tmAveCharWidth;
			retval.BreakChar =(char)metrics.tmBreakChar;
			retval.CharSet = (TextMetricsCharacterSet)metrics.tmCharSet;
			retval.DefaultChar = (char)metrics.tmDefaultChar;
			retval.Descent = metrics.tmDescent;
			retval.DigitizedAspectX = metrics.tmDigitizedAspectX;
			retval.DigitizedAspectY = metrics.tmDigitizedAspectY;
			retval.ExternalLeading = metrics.tmExternalLeading;
			retval.FirstChar = (char)metrics.tmFirstChar;
			retval.Height = metrics.tmHeight;
			retval.InternalLeading = metrics.tmInternalLeading;
			retval.Italic = metrics.tmItalic == 0 ? false : true;
			retval.LastChar = (char)metrics.tmLastChar;
			retval.MaxCharWidth = metrics.tmMaxCharWidth;
			retval.Overhang = metrics.tmOverhang;
			retval.PitchAndFamily = (TextMetricsPitchAndFamilyValues)metrics.tmPitchAndFamily;
			retval.StruckOut = metrics.tmStruckOut == 0 ? false : true;
			retval.Underlined = metrics.tmUnderlined == 0 ? false : true;
			retval.Weight = metrics.tmWeight;

			result = retval;
			return hresult;
		}

		public int UxThemeGetThemeTextExtent (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, string textToDraw, TextFormatFlags flags, out Rectangle result)
		{
			XplatUIWin32.RECT retval;
			
			int hresult = UXTheme.GetThemeTextExtent (hTheme, dc.GetHdc (), iPartId, iStateId, textToDraw, textToDraw.Length, (int)flags, 0, out retval);
			dc.ReleaseHdc ();

			result = retval.ToRectangle ();
			return hresult;
		}

		public int UxThemeGetThemePartSize (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, ThemeSizeType type, out Size result)
		{
			UXTheme.SIZE retval;

			int hresult = UXTheme.GetThemePartSize (hTheme, dc.GetHdc (), iPartId, iStateId, IntPtr.Zero, (int)type, out retval);
			dc.ReleaseHdc ();

			result = retval.ToSize ();
			return hresult;
		}

		public int UxThemeGetThemeMargins (IntPtr hTheme, IDeviceContext dc, int iPartId, int iStateId, MarginProperty prop, out Padding result)
		{
			UXTheme.MARGINS retval = new UXTheme.MARGINS ();
			XplatUIWin32.RECT BoundsRect;

			int hresult = UXTheme.GetThemeMargins (hTheme, dc.GetHdc (), iPartId, iStateId, (int)prop, out BoundsRect, out retval);
			dc.ReleaseHdc ();

			result = retval.ToPadding();
			return hresult;
		}