static private CreateGeometricTransform ( |
||
rect | Rectangle. | |
points | Point | Points. |
Résultat | CGAffineTransform |
/// <summary> /// Draws the specified Image at the specified location and with the specified shape and size. /// /// The destPoints parameter specifies three points of a parallelogram. The three PointF structures /// represent the upper-left, upper-right, and lower-left corners of the parallelogram. The fourth point /// is extrapolated from the first three to form a parallelogram. /// /// The image represented by the image object is scaled and sheared to fit the shape of the parallelogram /// specified by the destPoints parameter. /// </summary> /// <param name="image">Image.</param> /// <param name="destPoints">Destination points.</param> public void DrawImage(Image image, PointF [] destPoints) { if (image == null) { throw new ArgumentNullException("image"); } if (destPoints == null) { throw new ArgumentNullException("destPoints"); } if (destPoints.Length < 3) { throw new ArgumentException("Destination points must be an array with a length of 3 or 4. " + "A length of 3 defines a parallelogram with the upper-left, upper-right, " + "and lower-left corners. A length of 4 defines a quadrilateral with the " + "fourth element of the array specifying the lower-right coordinate."); } // Windows throws a Not Implemented error if the points are more than 3 if (destPoints.Length > 3) { throw new NotImplementedException(); } if (image.nativeMetafilePage != null) { throw new NotImplementedException(); } // create our rectangle. Offset is 0 because the CreateGeometricTransform bakes our x,y offset in there. var rect = new CGRect(0, 0, destPoints [1].X - destPoints [0].X, destPoints [2].Y - destPoints [0].Y); // We need to flip our Y axis so the image appears right side up var geoTransform = new CGAffineTransform(1, 0, 0, -1, 0, rect.Height); //var geott = GeomUtilities.CreateGeometricTransform (rect, destPoints); geoTransform.Multiply(GeomUtilities.CreateGeometricTransform(rect, destPoints)); // Apply our transform to the context context.ConcatCTM(geoTransform); // now we draw our image. context.DrawImage(rect, image.NativeCGImage); // Now we revert our image transform from the context var revert = CGAffineTransform.CGAffineTransformInvert(geoTransform); context.ConcatCTM(revert); }
/// <summary> /// Draws the specified portion of the specified Image at the specified location and with the specified size. /// /// The destPoints specifies a parallelogram with the first point specifying the upper left corner, /// second point specifying the upper right corner and the third point specifying the lower left corner. /// /// The srcRect parameter specifies a rectangular portion of the image object to draw. This portion is scaled /// up or down (in the case where source rectangle overruns the bounds of the image) to fit inside the rectangle /// specified by the destRect parameter. /// </summary> /// <param name="image">Image.</param> /// <param name="destPoints">Destination points.</param> /// <param name="srcRect">Source rect.</param> /// <param name="srcUnit">Source unit.</param> public void DrawImage(Image image, PointF [] destPoints, RectangleF srcRect, GraphicsUnit srcUnit) { if (image == null) { throw new ArgumentNullException("image"); } if (destPoints == null) { throw new ArgumentNullException("destPoints"); } if (destPoints.Length < 3) { throw new ArgumentException("Destination points must be an array with a length of 3 or 4. " + "A length of 3 defines a parallelogram with the upper-left, upper-right, " + "and lower-left corners. A length of 4 defines a quadrilateral with the " + "fourth element of the array specifying the lower-right coordinate."); } // Windows throws a Not Implemented error if the points are more than 3 if (destPoints.Length > 3) { throw new NotImplementedException(); } var srcRect1 = srcRect; // If the source units are not the same we need to convert them // The reason we check for Pixel here is that our graphics already has the Pixel's baked into the model view transform if (srcUnit != graphicsUnit && srcUnit != GraphicsUnit.Pixel) { ConversionHelpers.GraphicsUnitConversion(srcUnit, graphicsUnit, image.HorizontalResolution, image.VerticalResolution, ref srcRect1); } if (srcRect1.Location == Point.Empty && srcRect1.Size == image.Size) { DrawImage(image, destPoints); return; } if (image.NativeCGImage == null) { throw new NotImplementedException(); } // Obtain the subImage var subImage = image.NativeCGImage.WithImageInRect(srcRect1.ToCGRect()); // If we do not have anything to draw then we exit here if (subImage.Width == 0 || subImage.Height == 0) { return; } // create our rectangle. Offset is 0 because the CreateGeometricTransform bakes our x,y offset in there. var rect = new RectangleF(0, 0, destPoints [1].X - destPoints [0].X, destPoints [2].Y - destPoints [0].Y); // We need to flip our Y axis so the image appears right side up var geoTransform = new CGAffineTransform(1, 0, 0, -1, 0, rect.Height); // Make sure we scale the image in case the source rectangle // overruns our subimage bounds (width and/or height) float scaleX = subImage.Width / srcRect1.Width; float scaleY = subImage.Height / srcRect1.Height; geoTransform.Scale(scaleX, scaleY); //var geott = GeomUtilities.CreateGeometricTransform (rect, destPoints); geoTransform.Multiply(GeomUtilities.CreateGeometricTransform(rect, destPoints)); // Apply our transform to the context context.ConcatCTM(geoTransform); // now we draw our image. context.DrawImage(rect.ToCGRect(), subImage); // Now we revert our image transform from the context var revert = CGAffineTransform.CGAffineTransformInvert(geoTransform); context.ConcatCTM(revert); subImage.Dispose(); }