invalidation

I'm using f.Invalidate() to repaint graphics in my C# program but the graphic blinks as it refreshes. I'm also using e.Graphics.DrawImage() inside the f_Paint() method. You need to set DoubleBuffered to true. Since it's a protected property, you'll need to make your own control: class Canvas : Control { public Canvas() { DoubleBufferred = true; } } You may need to do all of your drawing to an in memory bitmap first, then paint that bitmap to the form so that it is all drawn on screen at once. Image buffer = new Bitmap(width, height, colorDepth); //I usually use 32BppARGB as my color depth

The STL standard defines that when an erase occurs on containers such as std::deque, std::list etc iterators are invalidated. My question is as follows, assuming the list of integers contained in a std::deque, and a pair of indicies indicating a range of elements in the std::deque, what is the correct way to delete all even elements? So far I have the following, however the problem here is that the assumed end is invalidated after an erase: #include <cstddef> #include <deque> int main() { std::deque<int> deq; for (int i = 0; i < 100; deq.push_back(i++)); // range, 11th to 51st element std:

This question already has an answer here: how to add blank page in digitally signed pdf using java? 2 answers I am having trouble with stamping PDF documents without invalidating digital signatures. Current, I succeeded stamping a PDF. However, if the document is previously signed the signature is no longer valid. I understand why that happens, but if I use Acrobat to add text or stamp it using annotation, the signature is valid. I tried adding annotations or comments but it still invalidates the signature. Is there a way to add stamp to a PDF using iText without invalidating digital

changing the text of a label (or sophisticatedly we can say a text-based progress bar). in winforms you just Invalidate / Update. But how to do this in WPF without using Background Threads. ??? public static class ExtensionMethods { private static Action EmptyDelegate = delegate() { }; public static void Refresh(this UIElement uiElement) { uiElement.Dispatcher.Invoke(DispatcherPriority.Render, EmptyDelegate); } } private void LoopingMethod() { for (int i = 0; i < 10; i++) { label1.Content = i.ToString(); label1.Refresh(); Thread.Sleep(500); } } Reference: http://geekswithblogs.net

It seems like Android really doesn't like invalidate (Rect dirty) , which is used to invalidate only part of a canvas. When I invalidate part of a canvas (shown in green below) and a ToggleButton outside of the canvas needs to be redrawn at the same time, the entire region shown in red is erased! It seems as though Android is just invalidating everything within the smallest rectangle encompassing the union of the two regions that need to be redrawn, even if one of the regions is outside of the View whose canvas I'm invalidating. Is this standard behaviour, and if so, why would anyone use