Skip to main content

SetViewOffscreenBackground

Since: IVPrismaUI9

virtual void SetViewOffscreenBackground(PrismaView view, uint32_t argb) noexcept = 0;

Sets the clear/background color associated with a view's offscreen rendering path.

Parameters​

  • view - target view handle.
  • argb - ARGB clear color. 0 requests transparent clear color.

PrismaUI_F4 2.1.0 behavior​

The Ultralight backend stores the requested clear color and applies it to the view's live BitmapSurface when available.

Unlike the retired legacy-runtime implementation, 2.1.0 does not require this call to happen before SetViewOffscreen(view, true) solely because of browser-creation timing. The current backend can apply the color to an existing live surface.

g_api->SetViewOffscreenBackground(view, 0x00000000);
g_api->SetViewOffscreen(view, true);

It is still reasonable to set the desired background before enabling offscreen mode so the intended state is established before presentation begins, but that is an application-order preference, not the old legacy-runtime creation-time limitation.

Transparency​

A transparent clear color is useful when an offscreen page is meant to composite over another surface instead of presenting an opaque black backing.

The page's own CSS still matters:

html, body {
  background: transparent;
}

Compatibility​

This method was appended to V9 before V10 was introduced. Consumers using it should require a current PrismaUI_F4 release rather than assuming every historical V9 binary exposed the late-added slot.

See also​

SetViewOffscreen, SetViewOffscreenSize, BindViewToGeometry, BindViewToScreenTexture.