rasSetAsyncPaint

BOOL32 __stdcall rasSetAsyncPaint(IPGC CachePtr, BOOL32 Enable);

function rasSetAsyncPaint(CachePtr: IPGC; Enable: LongBool): LongBool; stdcall;

Purpose. Turn background rasterisation on or off for a page cache, so a host application can paint flicker-free: the paint path never renders on the UI thread.

Description. With async paint enabled, a cache miss during painting draws a stand-in (the most recent rendering of the same page at another zoom, stretched, or a blank sheet), queues the page for the cache's worker thread, and returns immediately; when the worker finishes the bitmap it fires the cache's paint callback so the host invalidates and the next paint blits the real rendering. Enabling lazily starts the worker thread on first use. Disabling returns the paint path to synchronous rendering; an already-started worker simply idles and is joined when the cache is deleted. On SDK slices built without the viewer (mobile targets, where the library must not create threads) the request is refused rather than armed without a worker.

Parameters.

Return value. True on success; False for a NULL cache or on a slice where background rendering is unavailable.

See also. rasCreatePageCache, rasUpdateScrollBars.

C# (P/Invoke)

[return: MarshalAs(UnmanagedType.Bool)]