Using reflector, it turns out Image.Save() boils down to the GDI+ function GdipSaveImageToFile, with the encoderParams NULL. So I think the question is what the JPEG encoder does when it gets a null encoderParams. 75% has been suggested here, but I can’t find any solid reference. EDIT You could probably find out for yourself by … Read more
Yes, it is too slow. I ran into this problem several years ago while developing Paint.NET (right from the start, actually, and it was rather frustrating!). Rendering performance was abysmal, as it was always proportional to the size of the bitmap and not the size of the area that it was told to redraw. That … Read more
The window rect includes the non-client area, i.e. the window borders, caption bar etc. The client rect does not. GetWindowRect returns a rect in screen coordinates whereas GetClientRect returns a rect in client coordinates. InvalidateRect receives a rect in client coordinates. If you want to invalidate your entire client area, then pass NULL to InvalidateRect. … Read more
A Bitmap is an Image. It inherits from the Image class. From MSDN: [SerializableAttribute] [ComVisibleAttribute(true)] public sealed class Bitmap : Image
PNGs (and other formats) need to be saved to a seekable stream. Using an intermediate MemoryStream will do the trick: using (Bitmap image = new Bitmap(context.Server.MapPath(“images/stars_5.png”))) { using(MemoryStream ms = new MemoryStream()) { image.Save(ms, System.Drawing.Imaging.ImageFormat.Png); ms.WriteTo(context.Response.OutputStream); } }
You could try to save the image using this approach SaveFileDialog dialog=new SaveFileDialog(); if (dialog.ShowDialog()==DialogResult.OK) { int width = Convert.ToInt32(drawImage.Width); int height = Convert.ToInt32(drawImage.Height); using(Bitmap bmp = new Bitmap(width, height)) { drawImage.DrawToBitmap(bmp, new Rectangle(0, 0, width, height)); bmp.Save(dialog.FileName, ImageFormat.Jpeg); } }
If you have a reference to System.Windows.Forms, try using the TextRenderer class. There is a static method (MeasureText) which takes the string and font and returns the size. MSDN Link
While I still did not find out the reason what exactly caused the error when saving the image, I found a workaround to apply: const string i1Path = @”c:\my\i1.jpg”; const string i2Path = @”c:\my\i2.jpg”; var i = Image.FromFile(i1Path); var i2 = new Bitmap(i); i2.Save(i2Path, ImageFormat.Jpeg); I.e. by copying the image internally into a Bitmap instance … Read more
Here is a version with much less flickering, still not perfect though. public class GlassControlRenderer : NativeWindow { private Control Control; private Bitmap Bitmap; private Graphics ControlGraphics; private object Lock = new object(); protected override void WndProc(ref Message m) { switch (m.Msg) { case 0x14: // WM_ERASEBKGND this.CustomPaint(); break; case 0x0F: // WM_PAINT case 0x85: … Read more
Your question lacks a little clarity as to what the “best” rectangle is. I’m going to assume you mean the largest rectangle that will be 100% visible when printed. So lets start by making sure we understand what the print document graphics object “origins” are and how the OriginAtMargins property affects this origin. OriginAtMargins – … Read more