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
There are some problem to fix here: → fadeTimer.Interval = 10;: You’re (possibly) using the wrong Timer: the System.Timers.Timer’s Elapsed is raised in a ThreadPool Thread. Unless you have set the SynchronizingObject to a Control object, which is then used to marshal the handler calls, referencing a Control in the handler will cause trouble (cross-thread … Read more
I propose you a slightly different method, using the GraphicsPath class to both measure and draw the text on a Bitmap object. The advantage is that the GraphicsPath class reports the actual coordinates where the object(s) that it contains will be drawn and also the size of the text, in relation to a specific Font. … Read more
I would use a function similar to this: public void RotateRectangle(Graphics g, Rectangle r, float angle) { using (Matrix m = new Matrix()) { m.RotateAt(angle, new PointF(r.Left + (r.Width / 2), r.Top + (r.Height / 2))); g.Transform = m; g.DrawRectangle(Pens.Black, r); g.ResetTransform(); } } It uses a matrix to perform the rotation at a certain … Read more
Image is an abstract class: what you want to do depends on whether you are dealing with a Metafile or a Bitmap. Creating an image with GDI+ and saving it as an EMF is simple with Metafile. Per Mike’s post: var path = @”c:\foo.emf” var g = CreateGraphics(); // get a graphics object from your … Read more
WinForms (and underlying User32) does not support transparency at all. WinForms however can simulate transparency by using control style you provide – SupportsTransparentBackColor, but in this case all that “transparent” control does, it to allow drawing parent its background. ButtonBase uses some windows styles that prevent working this mechanism. I see two solutions: one is … Read more
The problem is int center = radius which you are setting int radius = 576. This doesn’t make sense as surely you are rotating about a point that should have an x and y location. Given you are rotating around the origin the center x and y should both be 0 not 576. So, given … Read more
Seems like we can do it using FreeImage (which is free) FIBITMAP dib = FreeImage.LoadEx(“test.jp2”); //save the image out to disk FreeImage.Save(FREE_IMAGE_FORMAT.FIF_JPEG, dib, “test.jpg”, FREE_IMAGE_SAVE_FLAGS.JPEG_QUALITYNORMAL); //or even turn it into a normal Bitmap for later use Bitmap bitmap = FreeImage.GetBitmap(dib);
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
When drawing a string of characters (ASCII or a form of Unicode encoded symbols) using Graphics.DrawString() with a fixed sized Font, the resulting graphics appear to generate a sort of grid, degrading the visual quality of the rendering. A solution is to substitute the GDI+ Graphics methods with the GDI methods, using TextRenderer.MeasureText() and TextRenderer.DrawText(). … Read more