RRUZとJiffyWhipからの回答をマージし、コードをクリーンアップしました。
これで、画像をPNGまたはWMFとして挿入できます。
また、WMFは不透明度をサポートしていないため、透明度を白色に置き換えました。
private static string GetWidthAndHeight(Image image, float dpiX, float dpiY)
{
float width = (float)image.Width / dpiX;
float height = (float)image.Height / dpiY;
int picw = (int)(width * 2540);
int pich = (int)(height * 2540);
int picwgoal = (int)(width * 1440);
int pichgoal = (int)(height * 1440);
return "\\picw" + picw + "\\pich" + pich + "\\picwgoal" + picwgoal + "\\pichgoal" + pichgoal;
}
public static string InsertPngImage(Image image)
{
byte[] buffer;
using (var stream = new MemoryStream())
{
image.Save(stream, ImageFormat.Png);
buffer = stream.ToArray();
}
string hex = BitConverter.ToString(buffer, 0).Replace("-", string.Empty);
string widthAndHeight = GetWidthAndHeight(image, image.HorizontalResolution, image.VerticalResolution);
return "{\\pict\\pngblip" + widthAndHeight + " " + hex + "}";
}
[Flags]
enum EmfToWmfBitsFlags
{
EmfToWmfBitsFlagsDefault = 0x00000000,
EmfToWmfBitsFlagsEmbedEmf = 0x00000001,
EmfToWmfBitsFlagsIncludePlaceable = 0x00000002,
EmfToWmfBitsFlagsNoXORClip = 0x00000004
}
private static int MM_ANISOTROPIC = 8;
[DllImportAttribute("gdiplus.dll")]
private static extern uint GdipEmfToWmfBits(IntPtr hEmf, uint bufferSize, byte[] buffer, int mappingMode, EmfToWmfBitsFlags flags);
public static string InsertWmfImage(Image image)
{
image = ReplaceTransparency(image, Color.White);
Metafile metaFile;
float dpiX;
float dpiY;
using (Graphics graphics = Graphics.FromImage(image))
{
IntPtr hdc = graphics.GetHdc();
metaFile = new Metafile(hdc, EmfType.EmfOnly);
graphics.ReleaseHdc(hdc);
}
using (Graphics graphics = Graphics.FromImage(metaFile))
{
graphics.DrawImage(image, 0, 0, image.Width, image.Height);
dpiX = graphics.DpiX;
dpiY = graphics.DpiY;
}
IntPtr hEmf = metaFile.GetHenhmetafile();
uint bufferSize = GdipEmfToWmfBits(hEmf, 0, null, MM_ANISOTROPIC, EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);
byte[] buffer = new byte[bufferSize];
uint convertedSize = GdipEmfToWmfBits(hEmf, bufferSize, buffer, MM_ANISOTROPIC, EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);
string hex = BitConverter.ToString(buffer, 0).Replace("-", string.Empty);
string widthAndHeight = GetWidthAndHeight(image, dpiX, dpiY);
return "{\\pict\\wmetafile8" + widthAndHeight + " " + hex + "}";
}
private static Image ReplaceTransparency(Image image, Color background)
{
Bitmap bitmap = new Bitmap(image.Width, image.Height, PixelFormat.Format24bppRgb);
using (Graphics graphics = Graphics.FromImage(bitmap))
{
graphics.Clear(background);
graphics.CompositingMode = CompositingMode.SourceOver;
graphics.DrawImage(image, 0, 0, image.Width, image.Height);
}
return bitmap;
}