C# CGContext.ScaleCTM方法代码示例

        public void DrawLayer(CALayer layer, CGContext context)
        {
            // fill with white background
            context.SetFillColor (1f, 1f, 1f, 1f);
            context.FillRect (Bounds);
            context.SaveState ();

            // flip page so we render it as it's meant to be read
            context.TranslateCTM (0f, Bounds.Height);
            context.ScaleCTM (1f, -1f);

            // scale page at the view-zoom level
            context.ScaleCTM (MyScale, MyScale);
            context.DrawPDFPage (Page);
            context.RestoreState ();
        }

		public override void DrawLayer (CALayer layer, CGContext context)
		{
			// keep a copy since (a) it's a _virtual_ property and (b) it could change between filling and flipping
			RectangleF bounds = view.Bounds;
			
			// fill with white background
			context.SetFillColor (1.0f, 1.0f, 1.0f, 1.0f);
			context.FillRect (bounds);
			context.SaveState ();

			// flip page so we render it as it's meant to be read
			context.TranslateCTM (0.0f, bounds.Height);
			context.ScaleCTM (1.0f, -1.0f);
	
			// scale page at the view-zoom level
			context.ScaleCTM (view.Scale, view.Scale);
			context.DrawPDFPage (view.Page);
			context.RestoreState ();
		}

 public override void DrawLayer(CALayer layer, CGContext context)
 {
     context.SaveState ();
     context.SetFillColor (1.0f, 1.0f, 1.0f, 1.0f);
     context.FillRect (context.GetClipBoundingBox ());
     context.TranslateCTM (0.0f, layer.Bounds.Size.Height);
     context.ScaleCTM (1.0f, -1.0f);
     context.ConcatCTM (this.oParentController.currentPDFPage.GetDrawingTransform (CGPDFBox.Crop, layer.Bounds, 0, true));
     context.DrawPDFPage (this.oParentController.currentPDFPage);
     context.RestoreState ();
 }

        // TODO: Cannot use NSAttributedString in iOS5, only iOS6+
//        public static RectangleF MeasureString(SizeF sizeConstraint, string text, string fontName, float fontSize)
//        {
//            NSMutableDictionary dict = new NSMutableDictionary();
//            dict.Add(NSAttributedString.FontAttributeName, NSFont.FromFontName(fontName, fontSize));
//            NSString nsstr = new NSString(text);
//            RectangleF rect = nsstr.BoundingRectWithSize(sizeConstraint, NSStringDrawingOptions.UsesFontLeading | NSStringDrawingOptions.UsesLineFragmentOrigin, dict);
//            return rect;
//        }
        
        public static float MeasureStringWidth(CGContext context, string text, string fontName, float fontSize)
        {
			if (string.IsNullOrEmpty(text))
				return 0;

            context.SaveState();
            PointF pos = context.TextPosition;
            context.SelectFont(fontName, fontSize, CGTextEncoding.MacRoman);
            context.TextMatrix = CGAffineTransform.MakeScale(1.0f, -1.0f);
            //context.TranslateCTM(0, 20);
            context.ScaleCTM(1, -1);
            context.SetTextDrawingMode(CGTextDrawingMode.Invisible);
            context.ShowTextAtPoint(pos.X, pos.Y, text);
            PointF pos2 = context.TextPosition;
            context.RestoreState();
            
            return pos2.X - pos.X;
        }

	public override void DrawInContext (CGContext context)
	{
		// PDF page drawing expects a Lower-Left coordinate system, so we flip the coordinate system
		// before we start drawing.
		context.TranslateCTM (0, Bounds.Height);
		context.ScaleCTM (1, -1);
		
		// Grab the first PDF page
		using (CGPDFPage page = doc.GetPage (1)){
			// We're about to modify the context CTM to draw the PDF page where we want it, so save the graphics state in case we want to do more drawing
			context.SaveState ();
			
			// CGPDFPageGetDrawingTransform provides an easy way to get the transform for a PDF page. It will scale down to fit, including any
			// base rotations necessary to display the PDF page correctly.
			
			CGAffineTransform pdfTransform = page.GetDrawingTransform (CGPDFBox.Crop, Bounds, 0, true);

			// And apply the transform.
			context.ConcatCTM (pdfTransform);
			// Finally, we draw the page and restore the graphics state for further manipulations!
			context.DrawPDFPage (page);
			context.RestoreState();
		}
	}	

        /// <summary>
        /// Draws the document page
        /// </summary>		
        private void Draw(CGContext context)
        {
            if (!PDFDocument.DocumentHasLoaded) {
                return;
            }

            // Draw page
            context.SetFillColor(1.0f, 1.0f, 1.0f, 1.0f);
            using (CGPDFPage pdfPage = PDFDocument.GetPage(mPageNumber)) {
                context.TranslateCTM(0, Bounds.Height);
                context.ScaleCTM(1.0f, -1.0f);
                context.ConcatCTM(pdfPage.GetDrawingTransform(CGPDFBox.Crop, Bounds, 0, true));
                context.SetRenderingIntent(CGColorRenderingIntent.Default);
                context.InterpolationQuality = CGInterpolationQuality.Default;
                context.DrawPDFPage(pdfPage);
            }
        }

		public static void AddRoundedRectToPath(CGContext context, RectangleF rect, float ovalWidth, float ovalHeight)
		{
			float fw, fh;
			if (ovalWidth == 0 || ovalHeight == 0)
			{
				context.AddRect(rect);
				return;
			}
			context.SaveState();
			context.TranslateCTM(rect.GetMinX(), rect.GetMinY());
			context.ScaleCTM(ovalWidth, ovalHeight);
			fw = rect.Width / ovalWidth;
			fh = rect.Height / ovalHeight;
			context.MoveTo(fw, fh / 2);
			context.AddArcToPoint(fw, fh, fw / 2, fh, 1);
			context.AddArcToPoint(0, fh, 0, fh / 2, 1);
			context.AddArcToPoint(0, 0, fw / 2, 0, 1);
			context.AddArcToPoint(fw, 0, fw, fh / 2, 1);
			context.ClosePath();
			context.RestoreState();
		}

        void drawLabel(CGContext ctx, CGRect rect, nfloat yCoord, nfloat xCoord, CTTextAlignment alignment, UIColor color, string label, bool flipContext = true)
        {
            Console.WriteLine("Finish Draw code");

            var attrString = new NSMutableAttributedString (label);

            var range = new NSRange (0, attrString.Length);

            var uiFont = UIFont.FromName("HelveticaNeue-Medium", range.Length > 1 ? 15 : 22);

            var font = new CTFont (uiFont.Name, uiFont.PointSize);  //((uiFont.Name as NSString) as CFString, uiFont.pointSize, nil);

            var path = new CGPath ();

            var alignStyle = new CTParagraphStyle (new CTParagraphStyleSettings { Alignment = alignment });

            var attributes = new CTStringAttributes {
                Font = font,
                ForegroundColor = color.CGColor,
                ParagraphStyle = alignStyle
            };

            attrString.SetAttributes(attributes, new NSRange (0, attrString.Length));

            var target = new CGSize (nfloat.MaxValue, nfloat.MaxValue);

            var fit = new NSRange (0, 0);

            var framesetter = new CTFramesetter (attrString);

            var frameSize = framesetter.SuggestFrameSize(range, null, target, out fit);

            var textRect = new CGRect (xCoord - (frameSize.Width / 2), yCoord - (frameSize.Height / 2), frameSize.Width, frameSize.Height);

            path.AddRect(textRect);

            var frame = framesetter.GetFrame(range, path, null);

            if (flipContext) {

                ctx.SaveState();

                ctx.TranslateCTM(0, rect.Height);

                ctx.ScaleCTM(1, -1);

                frame.Draw(ctx);

                ctx.RestoreState();

            } else {
                frame.Draw(ctx);
            }
        }

		void drawLabel (CGContext ctx, CGRect rect, nfloat yCoord, nfloat xCoord, UITextAlignment alignment, string label, bool flipContext = true, bool centerVertical = false)
		{
			// Draw light the sunrise and Sunset labels at the ends of the light box
			using (UIColor fontColor = UIColor.White, shadowColor = UIColor.Black.ColorWithAlpha (0.1f)) {

				var fontAttributes = new UIFontAttributes (new UIFontFeature (CTFontFeatureNumberSpacing.Selector.ProportionalNumbers));

				using (var desc = UIFont.SystemFontOfSize (fontSize).FontDescriptor.CreateWithAttributes (fontAttributes)) {

					using (UIFont font = UIFont.FromDescriptor (desc, fontSize)) {

						// calculating the range of our attributed string
						var range = new NSRange (0, label.Length);

						// set justification for text block
						using (var alignStyle = new NSMutableParagraphStyle { Alignment = alignment }) {

							// add stylistic attributes to out attributed string
							var stringAttributes = new UIStringAttributes {
								ForegroundColor = fontColor,
								Font = font,
								ParagraphStyle = alignStyle
							};

							var target = new CGSize (float.MaxValue, float.MaxValue);

							NSRange fit;

							using (NSMutableAttributedString attrString = new NSMutableAttributedString (label, stringAttributes)) {

								//creating a container for out attributed string 
								using (CTFramesetter framesetter = new CTFramesetter (attrString)) {


									CGSize frameSize = framesetter.SuggestFrameSize (range, null, target, out fit);


									if (alignment == UITextAlignment.Center) xCoord -= (frameSize.Width / 2);

									if (alignment == UITextAlignment.Right) xCoord -= frameSize.Width;


									// subtract the frameSize so the flipped context behaves as expected
									yCoord -= frameSize.Height;

									if (centerVertical) yCoord += (frameSize.Height / 2);


									var textRect = new CGRect (xCoord, yCoord, frameSize.Width, frameSize.Height);

									using (CGPath path = new CGPath ()) {

										path.AddRect (textRect);

										ctx.SetShadow (new CGSize (0.0f, 1.0f), 0.0f, shadowColor.CGColor);

										using (CTFrame frame = framesetter.GetFrame (range, path, null)) {

											if (flipContext) {

												ctx.SaveState ();
												ctx.TranslateCTM (0, rect.Height);
												ctx.ScaleCTM (1, -1);

												frame.Draw (ctx);

												ctx.RestoreState ();

											} else {

												frame.Draw (ctx);
											}
										}
									}
								}
							}
						}
					}
				}
			}
		}

        private void DrawText(string text, CGContext context, RectangleF bounds, bool withShadow)
        {
            // save state and transform
            context.SaveState ();
            context.TranslateCTM (0, bounds.Height);
            context.ScaleCTM (1.0f, -1.0f);

            // calculate location
            context.SelectFont("Helvetica", UIFont.LabelFontSize,CGTextEncoding.MacRoman);
            NSString t = new NSString(text);
            var font = UIFont.FromName("Helvetica", UIFont.LabelFontSize);
            var size = t.StringSize(font);
            var x = bounds.Left;
            var y = bounds.Height/2 - size.Height/2;

            // draw the shadow at an offset
            if (withShadow) {
                UIColor.FromRGB(193,193,193).SetFill();
                context.ShowTextAtPoint(x+1, y+4, text);
            }

            // draw the text
            if (_parentCell.Highlighted && !_menuItem.IsHeader)
                _headerForegroundColor.SetFill ();
            else if (_menuItem.IsHeader)
                _headerForegroundColor.SetFill ();
            else
                _foregroundColor.SetFill();
            context.ShowTextAtPoint(x, y+5, text);

            // restore context
            context.RestoreState();
        }

 private void DrawImage(UIImage image, CGContext context, RectangleF bounds)
 {
     // required hack to get the images to draw rightside up
     context.SaveState();
     context.TranslateCTM(0, bounds.Height);
     context.ScaleCTM(1.0f, -1.0f);
     bounds.Y = -bounds.Y;
     context.DrawImage(bounds, image.CGImage);
     context.RestoreState();
 }