# ClearBitmap

Clears a screen or bitmap.

### Synopsis

`Err ClearBitmap (Item ioreq, Item scr_bm, Bitmap *bmPtr, int32 rgbValue)`

### Description

Sets all pixels in the screen or bitmap to the specified rgbValue. Uses `SetVRAMPages()` for fast operation.

The rgbValue is a pair of RGB555 values packed into a 32-bit word. If you don't want simple black (zero), use the `MakeRGB15Pair()` macro to create this value from separate red, green, and blue values.

For best performance, pass a non-zero IOreq parameter and a bitmap pointer instead of a screen or bitmap item. This will avoid `LookupItem()` and `CreateIOReq()` calls that would otherwise be made internally.

### Arguments

ioreq
  IOReq item obtained from`GetVRAMIOReq()`, or zero to have an IOReq created and deleted internally during the call.

scr_bm
  Screen or Bitmap item number. May be zero if a Bitmap pointer is provided.

bmPtr
  Bitmap pointer. May be NULL if a Screen or Bitmap item is provided.

rgbValue
  Color value to store into all screen or bitmap pixels.

### Return Value

Returns zero on success or a negative error code.

### Implementation

Library call implemented in lib3do.lib.

### Associated Files

lib3do.lib, displayutils.h