BeginRefresh -- prepare display for optimized refresh (V5.3)
This command prepares the active display for optimized refreshing. On platforms supporting optimized refreshing, this means that all drawing commands that follow BeginRefresh() will be queued until you call EndRefresh(). By caching all drawing commands that are called between BeginRefresh() and EndRefresh(), the latter will be able to refresh your whole display in a single frame which on many platforms is the most efficient way of drawing besides using a double buffer. On platforms that don't support optimized refreshing, calling BeginRefresh() and EndRefresh() won't have any effect at all so it is safe to always use it in your scripts and Hollywood will enable it automatically when needed.

Optimized refreshing is always supported on Windows (except when the software renderer is active), macOS (except on PowerPC), iOS and Android. On all other platforms optimized refreshing is only supported when the auto scaling engine is active. See Scaling engines for details.

To better understand the concept behind optimized refreshing, you need to understand that on some systems all drawing operations will always result in a complete redraw of the whole display, even if just a single pixel is changed. Now imagine the following situation: For every new frame your game has to draw 48 sprites to the screen. On systems that always refresh the whole display even if just a single pixel has changed this means that Hollywood has to redraw the whole screen 48 times and this 50 times a second if your game runs at 50fps. Thus, 2400 complete screen refreshes (48 * 50) would be necessary per second (!). This of course will significantly kill your game's performance. If you encapsulate the drawing of the 48 sprites inside a BeginRefresh() and EndRefresh() section instead, Hollywood will only have to refresh the screen once per frame (50 times per second), which leads to a much smoother appearance. Thus, using BeginRefresh() in this case is absolutely mandatory to ensure a good performance of your game.

Optimized refresh can also greatly enhance the performance of your script when autoscaling is active. If you use normal drawing with autoscaling, Hollywood will have to scale its refresh buffer to the desired dimensions on every single command that draws something. If you use a BeginRefresh() section here instead, Hollywood will just have to scale its refresh buffer once EndRefresh() is called. This of course can also enhance the performance significantly.

By default, BeginRefresh() will only use optimized refresh if its use is either encouraged on the host platform or if autoscaling is enabled. You can change this behaviour by passing True in the optional force argument. If force is set to True, BeginRefresh() will always use optimized refresh but this is not recommended because optimized refresh can also be slower than normal refresh in some cases. That is why you should leave the decision whether to use optimized refresh or not to Hollywood.

Please note that you only need to use BeginRefresh() sections if your script does its drawing without a double buffer. If your script uses a double-buffer, drawing is already pipelined to one refresh per frame and thus using BeginRefresh() is not needed in this case.

optional: force the use of optimized refresh or leave the decision to Hollywood. See above for more information (defaults to False which means leave the decision to Hollywood)
For Local k = 1 To 48
   DisplaySprite(k, sprites[k].x, sprites[k].y)
The code above updates the positions of 48 sprites using a BeginRefresh() section. This means that on systems that always refresh the whole display (e.g. Android) Hollywood just has to update the screen once to reposition all 48 sprites. Without BeginRefresh() Hollywood would have to update the screen 48 times which is of course much slower.

Show TOC