It looks like we have some support in Windows for vector images using the EMF file format. EMFs (Enhanced Metafiles) let you save both vectors and bitmaps within them. However, if you use the Metafile constructor properly, you can save to disk and load from disk the entire sequence of operations that are a part of this vector format. Here is an example of how you can get started with Metafiles:
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;
using System.Drawing.Text;
namespace ExtendedMetafileApplication
{
class Program
{
[DllImport("gdiplus.dll")]
private static extern uint GdipEmfToWmfBits(IntPtr hemf, uint cbData16, byte[] pData16, int iMapMode, int eFlags);
static void Main(string[] args)
{
// Create an EMF vector image stream in memory.
using (var metaStream = CreateMemoryEMF())
{
// Saving the vector image as an EMF file to disk.
CreateDiskEMF("Image.emf", metaStream);
// Save the vector image as its rasterized PNG counterparts at different scales.
CreateDiskPNG("Image.png", metaStream);
CreateDiskPNG("Image5X.png", metaStream, 5);
CreateDiskPNG("Image10X.png", metaStream, 10);
// Save the vector image to disk as a WMF (also a vector format for images).
CreateDiskWMF("Image.wmf", metaStream);
}
}
static void CreateDiskWMF(string path, Stream metaStream)
{
using (var metafile = new Metafile(metaStream))
{
var iMapMode = 3; // MM_HIMETRIC
var eFlags = 2; // EmfToWmfBitsFlagsIncludePlaceable
var hemf = metafile.GetHenhmetafile();
// The stream of our EMF image must be created using EmfPlusDual in order for the following function to work.
var size = GdipEmfToWmfBits(hemf, 0, null, iMapMode, eFlags);
var buffer = new byte[size];
GdipEmfToWmfBits(hemf, size, buffer, iMapMode, eFlags);
File.WriteAllBytes(path, buffer);
}
metaStream.Seek(0, SeekOrigin.Begin);
}
static void SetGraphicsQuality(Graphics graphics)
{
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.CompositingMode = CompositingMode.SourceOver;
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
}
static void CreateDiskPNG(string path, Stream metaStream, float scale = 1)
{
var image = Image.FromStream(metaStream);
metaStream.Seek(0, SeekOrigin.Begin);
var bitmap = new Bitmap(image, (int)(image.Size.Width * scale), (int)(image.Size.Height * scale));
using (var graphics = Graphics.FromImage(bitmap))
{
SetGraphicsQuality(graphics);
graphics.DrawImage(image, 0, 0, bitmap.Width, bitmap.Height);
bitmap.Save(path, ImageFormat.Png);
}
}
static void DrawGraphics(Metafile metafile)
{
var brush = Brushes.BlueViolet;
var pen = new Pen(brush, 3);
using (var graphics = Graphics.FromImage(metafile))
{
graphics.Clear(Color.White);
SetGraphicsQuality(graphics);
graphics.DrawEllipse(pen, 2.5f, 2.5f, 45, 45);
graphics.DrawEllipse(pen, 52.5f, 2.5f, 45, 45);
graphics.FillEllipse(brush, 4f, 15f, 25, 25);
graphics.FillEllipse(brush, 54f, 15f, 25, 25);
graphics.DrawArc(pen, 30, 55, 50, 35, 90, 180);
graphics.DrawArc(pen, 5, 45, 90, 70, 0, 180);
graphics.DrawString("Hello, world.", new Font(FontFamily.GenericSerif, 14), brush, new Rectangle(0, 120, 150, 30));
}
}
static Stream CreateMemoryEMF()
{
var result = new MemoryStream();
Metafile metafile;
using (var graphics = Graphics.FromHwnd(IntPtr.Zero))
{
SetGraphicsQuality(graphics);
var context = graphics.GetHdc();
metafile = new Metafile(result, context, EmfType.EmfPlusDual);
graphics.ReleaseHdc(context);
}
DrawGraphics(metafile);
result.Flush();
result.Seek(0, SeekOrigin.Begin);
return result;
}
static void CreateDiskEMF(string path, Stream metaStream)
{
using (var fileStream = File.Create(path))
metaStream.CopyTo(fileStream);
metaStream.Seek(0, SeekOrigin.Begin);
}
}
}
The code above outputs the following set of images:
If you’re looking for a nice way to do some simple graphics in Windows applications for business or otherwise, this is probably one of the best formats to use if you want to be able to scale.
