C# ImageData.ToImage方法代码示例

        /// <summary>
        /// Resamples one VML or DrawingML image
        /// </summary>
        private static bool ResampleCore(ImageData imageData, SizeF shapeSizeInPoints, int ppi, int jpegQuality)
        {
            // The are actually several shape types that can have an image (picture, ole object, ole control), let's skip other shapes.
            if (imageData == null)
                return false;

            // An image can be stored in the shape or linked from somewhere else. Let's skip images that do not store bytes in the shape.
            byte[] originalBytes = imageData.ImageBytes;
            if (originalBytes == null)
                return false;

            // Ignore metafiles, they are vector drawings and we don't want to resample them.
            ImageType imageType = imageData.ImageType;
            if (imageType.Equals(ImageType.Wmf) || imageType.Equals(ImageType.Emf))
                return false;

            try
            {
                double shapeWidthInches = ConvertUtil.PointToInch(shapeSizeInPoints.Width);
                double shapeHeightInches = ConvertUtil.PointToInch(shapeSizeInPoints.Height);

                // Calculate the current PPI of the image.
                ImageSize imageSize = imageData.ImageSize;
                double currentPpiX = imageSize.WidthPixels / shapeWidthInches;
                double currentPpiY = imageSize.HeightPixels / shapeHeightInches;

                Console.Write("Image PpiX:{0}, PpiY:{1}. ", (int)currentPpiX, (int)currentPpiY);

                // Let's resample only if the current PPI is higher than the requested PPI (e.g. we have extra data we can get rid of).
                if ((currentPpiX <= ppi) || (currentPpiY <= ppi))
                {
                    Console.WriteLine("Skipping.");
                    return false;
                }

                using (Image srcImage = imageData.ToImage())
                {
                    // Create a new image of such size that it will hold only the pixels required by the desired ppi.
                    int dstWidthPixels = (int)(shapeWidthInches * ppi);
                    int dstHeightPixels = (int)(shapeHeightInches * ppi);
                    using (Bitmap dstImage = new Bitmap(dstWidthPixels, dstHeightPixels))
                    {
                        // Drawing the source image to the new image scales it to the new size.
                        using (Graphics gr = Graphics.FromImage(dstImage))
                        {
                            gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
                            gr.DrawImage(srcImage, 0, 0, dstWidthPixels, dstHeightPixels);
                        }

                        // Create JPEG encoder parameters with the quality setting.
                        ImageCodecInfo encoderInfo = GetEncoderInfo(ImageFormat.Jpeg);
                        EncoderParameters encoderParams = new EncoderParameters();
                        encoderParams.Param[0] = new EncoderParameter(Encoder.Quality, jpegQuality);

                        // Save the image as JPEG to a memory stream.
                        MemoryStream dstStream = new MemoryStream();
                        dstImage.Save(dstStream, encoderInfo, encoderParams);

                        // If the image saved as JPEG is smaller than the original, store it in the shape.
                        Console.WriteLine("Original size {0}, new size {1}.", originalBytes.Length, dstStream.Length);
                        if (dstStream.Length < originalBytes.Length)
                        {
                            dstStream.Position = 0;
                            imageData.SetImage(dstStream);
                            return true;
                        }
                    }
                }
            }
            catch (Exception e)
            {
                // Catch an exception, log an error and continue if cannot process one of the images for whatever reason.
                Console.WriteLine("Error processing an image, ignoring. " + e.Message);
            }

            return false;
        }