WNDOBJCHANGEPROC callback function (winddi.h)

  • Article

The WNDOBJCHANGEPROC function is a driver-defined callback function that GDI uses to notify the driver of changes to the window in question.

Syntax

WNDOBJCHANGEPROC Wndobjchangeproc;

void Wndobjchangeproc(
  WNDOBJ *pwo,
  FLONG fl
)
{...}

Parameters

pwo

Pointer to a WNDOBJ structure defining the window object that is currently changing. The window object contains the new size and position of the window. If fl is WOC_CHANGED, then this parameter is NULL.

fl

A flag that describes the change occurring to the window object. This parameter can be one of the following values:

  • WOC_RGN_CLIENT_DELTA
    The WNDOBJ contains a delta client region. The delta region is valid for this call only.

  • WOC_RGN_CLIENT
    The WNDOBJ contains a new client region.

  • WOC_RGN_SURFACE_DELTA
    The WNDOBJ contains a delta surface region. The pvConsumer member of the WNDOBJ structure is zero. The delta region is valid for this call only.

  • WOC_RGN_SURFACE
    The WNDOBJ refers to a surface region created by GDI. The pvConsumer member of the WNDOBJ structure is zero.

  • WOC_CHANGED
    All windows have been updated. GDI always notifies the driver at the end of a desktop update.

  • WOC_DELETE
    The WNDOBJ is being deleted as a result of the deletion of the window.

  • WOC_DRAWN
    The windows subsystem has completed the screen-to-screen blit calls (screen-to-screen DrvCopyBits necessary to update the screen contents to correspond with the window region changes.

  • WOC_SPRITE_OVERLAP
    A sprite overlaps with the WNDOBJ area. This parameter is used when a sprite is first moved on top of the WNDOBJ area or immediately after the WNDOBJ is created if it overlaps with a preexisting sprite.

  • WOC_SPRITE_NO_OVERLAP
    Sprites no longer overlap the WNDOBJ area. This parameter is used when all sprites have been moved off the WNDOBJ area, and will be used only if the callback was previously called with WOC_SPRITE_OVERLAP.

Return value

None

Remarks

The pfn parameter of the EngCreateWnd function points to this function.

Requirements

Requirement Value
Target Platform Desktop
Header winddi.h (include Winddi.h)

See also