For built- in GUI elements, like if you create a game built out of Image. Buttons and Labels, the built- in double- buffered mode is great at hiding the redrawing of the control tree. However, there are a couple major problems with using it for a custom drawing area: The draw buffer created when you just set up the application to draw double- buffered is used to draw the whole window and all child controls, not just your custom drawing area, so you add the overhead of redrawing every GUI element on the back buffer before page- flipping. If anything invalidates the control, the Paint method is called. You may not be finished drawing when that happens and so you'll get an incomplete image shown to the user (not good in real- time graphics). By keeping the basic window GUI single- buffered, but creating an area on which you control the buffering, both of these problems are minimized. Double- buffering methods can be as simple as creating a Bitmap object as a back- buffer and drawing it to the draw area when you're good and ready, or setting up a seperate Buffered.
How can I use double buffering? How can I use doublebuffering in C#. Manuales.NET : Manual C#. Custom Drawing Controls in C# – Manual Double Buffering. One of the first times I started double buffering on a custom control was for a custom chart and. C# / C Sharp Forums on Bytes. Graphics. Context to manage buffering of your custom draw area. All or Nothing at all : : . As much as we would like it not to be the case, graphics can be slow enough to watch as the screen is refreshed. Our eyes, sensitive to movement and particularly to edge detection so that we don't walk off of cliffs or run into trees, often pick up the redraw cycle of computer graphics which, at best is mildly annoying or at worst can cause headaches, eyestrain and in susceptible people, even fits. Much of this effect is caused by the sequential re- drawing of many graphical elements such as a chart with many lines or a game with many moving items. In a perfect world, the sequential redraw would be completely hidden from the user and the completed graphic presented in its entirety. This is essentially the technique used in double buffering. Windows Forms provides an automatic method of double buffering that can be used by simply setting a few styles in your form or control. For most applications, this is enough but in certain cases, more control over the process is desirable so manually double buffering a control is also possible. First, take a look at the standard and built in method of double buffering. This is accomplished by setting the styles: Control. Styles. All. Painting. In. Wm. Paint. Control. Styles. User. Paint. Control. Styles. Double. Buffer. When these are all set true, the draw process is modified so that instead of your Paint handler being passed a Graphics for the screen, it is passed a Graphics for an in- memory bitmap. When you draw to this Graphics object, you are drawing on an invisible image. At the end of the draw cycle, this bitmap is copied to the main window automatically and the actual pixels you see are all changed in a fraction of a second instead of one at a time as the draw cycle progresses. To set up automatic double buffering for a Form, you would use the following line of code in the constructor, after the Initialize. Component method call. C#this. Set. Style( Control. Styles. All. Painting. In. Wm. Paint . There are a few simple rules that you need to follow to get manual double buffering right. First, don't create a new back- buffer every draw cycle. Only create or destroy the bitmap when the window's client size changes. Second, only create a bitmap of the size you need. Clearing pixels takes time and so if there are more pixels than you need, you're just wasting processor cycles. Lastly, use the simplest draw method to copy the bitmap to the screen. Draw. Image. Unscaled is the way to go here. Before the big demo, listing 1 shows all the salient points of a manual double buffered application. C# private Bitmap . A checkbox enables you to choose whether double buffering is used or if the graphics are drawn directly to the screen for the sake of comparison. C#using System; using System. Drawing; using System. Drawing. Drawing. D; using System. Collections; using System. Component. Model; using System. Windows. Forms; using System. Data; namespace Double.
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December 2016
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