C# CGContext.ConcatCTM方法代码示例

 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 ();
 }

        /// <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 void EraseStart()
        {
            if (drawingBoard == null)
                return;

            UIGraphics.BeginImageContext (drawingBoard.Size);

            // erase lines
            ctx = UIGraphics.GetCurrentContext ();

            // Convert co-ordinate system to Cocoa's (origin in UL, not LL)
            ctx.TranslateCTM (0, drawingBoard.Size.Height);
            ctx.ConcatCTM (CGAffineTransform.MakeScale (1, -1));

            ctx.DrawImage (new RectangleF (0, 0, drawingBoard.Size.Width, drawingBoard.Size.Height),
                        drawingBoard.CGImage);
        }

	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();
		}
	}	

        // test draw pattern
        protected void DrawTexture(CGContext context)
        {
            var destRect = new CGRect (0,0,textureImage.Width,textureImage.Height);
            context.DrawImage(destRect, textureImage.NativeCGImage);

            if (wrapMode == WrapMode.TileFlipX)
            {
                context.ConcatCTM(CGAffineTransform.MakeScale(-1,1));
                context.DrawImage(destRect, textureImage.NativeCGImage);
            }

            if (wrapMode == WrapMode.TileFlipY)
            {
                var transformY = new CGAffineTransform(1, 0, 0, -1,
                                                       textureImage.Width,
                                                       textureImage.Height);
                context.ConcatCTM(transformY);
                context.DrawImage(destRect, textureImage.NativeCGImage);
            }

            if (wrapMode == WrapMode.TileFlipXY)
            {
                // draw the original
                var transform = new CGAffineTransform(1, 0, 0, 1,
                                                       0, textureImage.Height);
                context.ConcatCTM(transform);
                context.DrawImage(destRect, textureImage.NativeCGImage);

                // reset the transform
                context.ConcatCTM (context.GetCTM().Invert());

                // draw next to original one that is flipped by x axis
                transform = new CGAffineTransform(-1, 0, 0, 1,
                                                  textureImage.Width * 2, textureImage.Height);
                context.ConcatCTM(transform);
                context.DrawImage(destRect, textureImage.NativeCGImage);

                // reset the transform
                context.ConcatCTM (context.GetCTM().Invert());

                // draw one that is flipped by Y axis under the oricinal
                transform = new CGAffineTransform(1, 0, 0, -1,
                                                  0, textureImage.Height);
                context.ConcatCTM(transform);
                context.DrawImage(destRect, textureImage.NativeCGImage);

                // draw the last one of the quadrant which is flipped by both the y and x axis
                context.ConcatCTM (context.GetCTM().Invert());
                transform = new CGAffineTransform(-1, 0, 0, -1,
                                                  textureImage.Width * 2, textureImage.Height);
                context.ConcatCTM(transform);
                context.DrawImage(destRect, textureImage.NativeCGImage);
            }
        }