How to get a pixelcolor?

Question

Hello in VB I can read the Color of every Pixel under the Mouse-Cursor by using getPixelColor(xy). How can I do this in C# ? regards ralf

CScorner · Answer

Hello OK this is an example to use an old dll. I would try it. But is there an other methode to use? Thank you for help me Ralf

CScorner · Answer

Hello I had read anything about rectangles but I don't know about blit that.... What you're meaning? Cursor.Position is not a Problem. Can you give me an example? Thanks in advance Ralf

andrew · Answer

This seems awfully unefficient. It would be much better just to grab small rectangle under the current mouse position (Cursor.Position) and blit that instead.

jcity444 · Answer

Unfortunately I don't think there is any easy way to do this in .NET but below is the solution I came up with. You can wrap the code in a function and call it getPixelColor(int x int y) if you'd like and it will work. Best Regards -MIke G. 8) [System.Runtime.InteropServices.DllImportAttribute(gdi32.dll)] private static extern bool BitBlt( IntPtr hdcDest // handle to destination DC int nXDest // x-coord of destination upper-left corner int nYDest // y-coord of destination upper-left corner int nWidth // width of destination rectangle int nHeight // height of destination rectangle IntPtr hdcSrc // handle to source DC int nXSrc // x-coordinate of source upper-left corner int nYSrc // y-coordinate of source upper-left corner System.Int32 dwRop // raster operation code ); private void Form1_MouseDown(object sender System.Windows.Forms.MouseEventArgs e) { Graphics g1 = this.CreateGraphics(); Bitmap MyImage = new Bitmap(this.ClientRectangle.Width this.ClientRectangle.Height g1); // Bitmap MyImage = new Bitmap(ClientRectangle.Width ClientRectangle.Height this.CreateGraphics()); Graphics g2 = Graphics.FromImage(MyImage); IntPtr dc1 = g1.GetHdc(); IntPtr dc2 = g2.GetHdc(); BitBlt(dc2 0 0 this.ClientRectangle.Width this.ClientRectangle.Height dc1 0 0 13369376); g1.ReleaseHdc(dc1); g2.ReleaseHdc(dc2); Color x = MyImage.GetPixel(e.X e.Y); MessageBox.Show(Color =  + x.ToString()); }