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SURFOBJ (Compact 2013)

  • Article

3/28/2014

The SURFOBJ structure is the user object for a surface. A device driver usually calls methods on a surface object only when the surface object represents a GDI bitmap or a device-managed surface.

Syntax

typedef struct _SURFOBJ {
  DHSURF dhsurf;
  HSURF hsurf;
  DHPDEV dhpdev;
  HDEV hdev;
  SIZEL sizlBitmap;
  ULONG cjBits;
  PVOID pvBits;
  PVOID pvScan0;
  LONG lDelta;
  ULONG iUniq;
  ULONG iBitmapFormat;
  USHORT iType;
  USHORT fjBitmap;
} SURFOBJ;

Parameters

  • dhsurf
    Handle to a surface, provided that the surface is device-managed. Otherwise, this member is zero.
  • hsurf
    Handle to the surface.
  • dhpdev
    Identifies the device's PDEV that is associated with the specified surface.
  • hdev
    GDI's logical handle to the PDEV associated with this device.
  • sizlBitmap
    Specifies a SIZEL structure that contains the width and height, in pixels, of the surface. The SIZEL structure is identical to the SIZE structure.
  • cjBits
    Specifies the size of the buffer pointed to by pvBits.
  • pvBits
    If the surface is a standard format bitmap, this is a pointer to the surface's pixels. For BMF_JPEG or BMF_PNG images, this is a pointer to a buffer containing the image data in a JPEG or PNG format. Otherwise, this member is NULL.
  • pvScan0
    Pointer to the first scan line of the bitmap. If iBitmapFormat is BMF_JPEG or BMF_PNG, this member is NULL.
  • lDelta
    Specifies the count of bytes required to move down one scan line in the bitmap. If iBitmapFormat is BMF_JPEG or BMF_PNG, this member is NULL.

  • iUniq
    Specifies the current state of the specified surface. Every time the surface changes, this value is incremented. This enables drivers to cache source surfaces.

    For a surface that should not be cached, iUniq is set to zero. This value is used in conjunction with the BMF_DONTCACHE flag of fjBitmap.

  • iBitmapFormat
    Specifies the standard format most closely matching this surface. If the iType member specifies a bitmap (STYPE_BITMAP), this member specifies its format. NT-based operating systems support a set of predefined formats, although applications can also send device-specific formats by using SetDIBitsToDevice.

    Supported predefined formats include the following:

    Value

    Meaning

    BMF_1BPP

    1 bit per pixel.

    BMF_4BPP

    4 bits per pixel.

    BMF_8BPP

    8 bits per pixel.

    BMF_16BPP

    16 bits per pixel.

    BMF_24BPP

    24 bits per pixel.

    BMF_32BPP

    32 bits per pixel.

    BMF_4RLE

    4 bits per pixel, run length encoded.

    BMF_8RLE

    8 bits per pixel, run length encoded.

    BMF_JPEG

    JPEG compressed image.

    BMF_PNG

    PNG compressed image.

  • iType
    Surface type, which is one of the following:

    Type

    Definition

    STYPE_BITMAP

    The surface is a bitmap.

    STYPE_DEVBITMAP

    The surface is a device format bitmap.

    STYPE_DEVICE

    The surface is managed by the device.

  • fjBitmap
    If the surface is of type STYPE_BITMAP and is a standard uncompressed format bitmap, the following flags can be set. Otherwise, this member should be ignored.

    Value

    Meaning

    BMF_DONTCACHE

    The bitmap should not be cached by the driver because it is a transient bitmap, created by GDI, that the driver will never see again. If this flag is set, the iUniq member of this structure will be set to 0.

    BMF_KMSECTION

    Is used by GDI only and should be ignored by the driver.

    BMF_NOTSYSMEM

    The bitmap is not in system memory.

    BMF_NOZEROINIT

    The bitmap was not zero-initialized.

    BMF_TOPDOWN

    The first scan line represents the top of the bitmap.

    BMF_WINDOW_BLT

    GDI sets this flag to notify the driver of a window move from one screen location to another.

Remarks

When information about a particular surface is required by a driver, the driver must access the SURFOBJ. This structure allows quick access to the properties of the surface.

When a SURFOBJ structure represents a GDI bitmap, the driver must be able to determine the format of the bitmap and locate the bitmap bits.

When a SURFOBJ structure represents a device surface, the driver must be able to locate the device handle for the surface.

Requirements

Header

winddi.h

See Also

Reference

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