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IOFramebufferShared.h Reference

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IOFramebufferShared.h Reference

The IOFramebufferShared.h header contains definitions of objects and types shared between a kernel level IOFrameBuffer service and a non-kernel window server. In Mac OS X this structure is used by the CoreGraphics server and IOGraphics Family, and is not available to other clients. IOFramebuffer subclasses and IOFramebuffer clients within the kernel should also not rely on this structure definition and constants. It is public only for use on Darwin based window servers. Cursor and window server state data is exchanged by kernel and non-kernel tasks through a slice of shared memory containing a StdFBShmem_t structure.

For a non-kernel task to get access to this slice of shared memory, a connection to an IOFramebuffer service must be made. A connection is made with the IOServiceOpen() function described in IOKitLib.h. A connection type of kIOFBServerConnectType or kIOFBSharedConnectType (for read-only access) should be specified. An io_connect_t handle is returned by IOServiceOpen(). This handle must be passed to IOFBCreateSharedCursor() to create the slice of shared memory. Then IOConnectMapMemory() may be called with a memory type of kIOFBCursorMemory to map the shared memory into the non-kernel task.

Included Headers

  • <IOKit/hidsystem/IOHIDTypes.h>

  • <IOKit/graphics/IOGraphicsTypes.h>

  • <libkern/OSAtomic.h>

Data Types

See the Overview section above for header-level documentation.

  • Cursor image for 1-bit cursor.

    Declaration

    Objective-C

    struct bm12Cursor { unsigned int image[4][16]; unsigned int mask[4][16]; unsigned int save[16]; };

    Fields

    image

    This array contains the cursor images.

    mask

    This array contains the cursor mask.

    save

    This array stores the pixel values of the region underneath the cursor in its last drawn position.

    Discussion

    This structure stores 16 pixel x 16 pixel cursors to be used with 1-bit color depth. This structure is only defined if IOFB_ARBITRARY_SIZE_CURSOR is not defined.

    Availability

    Available in OS X v10.6 and later.

  • Cursor image for 8-bit cursor.

    Declaration

    Objective-C

    struct bm18Cursor { unsigned char image[4][256]; unsigned char mask[4][256]; unsigned char save[256]; };

    Fields

    image

    This array contains cursor color values, which are converted to displayed colors through the color table. The array is two dimensional and its first index is the cursor frame and the second index is the cursor pixel.

    mask

    This array contains the cursor alpha mask. The array is two dimensional with the same indexing as the image. If an alpha mask pixel is 0 and the corresponding image pixel is set to white for the display, then this cursor pixel will invert pixels on the display.

    save

    This array stores the color values of the region underneath the cursor in its last drawn position.

    Discussion

    This structure stores 16 pixel x 16 pixel cursors to be used with 8-bit color depth. This structure is only defined if IOFB_ARBITRARY_SIZE_CURSOR is not defined.

    Availability

    Available in OS X v10.6 and later.

  • Cursor image for 15-bit cursor.

    Declaration

    Objective-C

    struct bm34Cursor { unsigned short image[4][256]; unsigned short save[256]; };

    Fields

    image

    This array defines the cursor color values and transparency. The array is two dimensional and its first index is the cursor frame and the second index is the cursor pixel. A value of 0 means the pixel is transparent. Non-zero values are stored with the red, green, blue, and alpha values encoded with the following masks:

    red mask = 0xF000

    blue mask 0x0F00

    green mask 0x00F0

    alpha mask = 0x000F

    Note, only 4 bits are allocated for each color component.

    save

    This array stores the color values of the region underneath the cursor in its last drawn position.

    Discussion

    This structure stores 16 pixel x 16 pixel cursors to be used with 15-bit color depth. This structure is only defined if IOFB_ARBITRARY_SIZE_CURSOR is not defined.

    Availability

    Available in OS X v10.6 and later.

  • Cursor image for 24-bit cursor.

    Declaration

    Objective-C

    struct bm38Cursor { unsigned int image[4][256]; unsigned int save[256]; };

    Fields

    image

    This array defines the cursor color values and transparency. The array is two dimensional and its first index is the cursor frame and the second index is the cursor pixel. The lower 24 bits of a pixel's value contain the RGB color, while the upper 8 bits contain the alpha value.

    save

    This array stores the color values of the region underneath the cursor in its last drawn position.

    Discussion

    This structure stores 16 pixel x 16 pixel cursors to be used with 24-bit color depth. This structure is only defined if IOFB_ARBITRARY_SIZE_CURSOR is not defined.

    Availability

    Available in OS X v10.6 and later.

  • Declaration

    Objective-C

    struct StdFBShmem_t { OSSpinLock cursorSema; int frame; char cursorShow; char cursorObscured; char shieldFlag; char shielded; IOGBounds saveRect; IOGBounds shieldRect; IOGPoint cursorLoc; IOGBounds cursorRect; IOGBounds oldCursorRect; IOGBounds screenBounds; int version; int structSize; AbsoluteTime vblTime; AbsoluteTime vblDelta; unsigned long long int vblCount; #if IOFB_ARBITRARY_FRAMES_CURSOR unsigned long long int vblDrift; unsigned long long int vblDeltaMeasured; unsigned int reservedC[24]; #else unsigned int reservedC[27]; unsigned char hardwareCursorFlags[kIOFBNumCursorFrames]; #endif unsigned char hardwareCursorCapable; unsigned char hardwareCursorActive; unsigned char hardwareCursorShields; unsigned char reservedB[1]; #if IOFB_ARBITRARY_FRAMES_CURSOR IOGSize cursorSize[kIOFBNumCursorIndex]; IOGPoint hotSpot[kIOFBNumCursorIndex]; #else IOGSize cursorSize[kIOFBNumCursorFrames]; IOGPoint hotSpot[kIOFBNumCursorFrames]; #endif #ifndef IOFB_ARBITRARY_SIZE_CURSOR union { struct bm12Cursor bw; struct bm18Cursor bw8; struct bm34Cursor rgb; struct bm38Cursor rgb24; } cursor; #else /* IOFB_ARBITRARY_SIZE_CURSOR */ unsigned char cursor[0]; # endif /* IOFB_ARBITRARY_SIZE_CURSOR */ };

    Fields

    cursorSema

    Semaphore lock for write access to the shared data in this structure.

    frame

    The current cursor frame index.

    cursorShow

    The cursor is displayed when cursorShow is 0.

    cursorObscured

    If this is true, the cursor has been obscured and cursorShow should not be 0. The cursor will be shown again the next time it is moved.

    shieldFlag

    When this is set to true the cursor will not be displayed in the region specified by shieldRect.

    shielded

    True if the cursor has been hidden because it entered the shielded region.

    saveRect

    The region that is saved underneath the cursor in software cursor mode.

    shieldRect

    The region that the cursor will not be displayed in if shieldFlag is true.

    cursorLoc

    The location of the cursor hot spot.

    cursorRect

    The region that the cursor image currently occupies in software cursor mode.

    oldCursorRect

    The region that the cursor image occupied the last time the cursor was drawn in software cursor mode.

    screenBounds

    The region that the current screen occupies.

    version

    Contains kIOFBCurrentShmemVersion so that a user client can ensure it is using the same version of this structure as the kernel.

    structSize

    Contains the size of this structure.

    vblTime

    The time of the most recent vertical blanking.

    vblDelta

    The interval between the two most recent vertical blankings.

    vblCount

    A running count of vertical blank interrupts.

    reservedC

    Reserved for future use.

    hardwareCursorCapable

    True if the hardware is capable of using hardware cursor mode.

    hardwareCursorActive

    True if currently using the hardware cursor mode.

    reservedB

    Reserved for future use.

    cursorSize

    This array contains the cursor sizes indexed by frame.

    hotSpot

    This array contains the location of the cursor hot spots indexed by frame. The hot spots coordinates are given relative to the top left corner of the cursor image.

    cursor

    A union of structures that define the cursor images. The structure used depends on the framebuffer's bit depth. These structures are defined above.

    Discussion

    This structure contains cursor and window server state data and occupies a slice of shared memory between the kernel and window server. Several elements of this structure are only used in software cursor mode. Unless otherwise indicated, the coordinates in this structure are given in display space. Display space is the coordinate space that encompasses all the screens. The positions of the screens within display space indicate their location relative to each other as the cursor moves between them. If there is only one screen, the screen coordinates and display space coordinates will be the same.

    Availability

    Available in OS X v10.6 and later.

Constants

See the Overview section above for header-level documentation.

  • Declaration

    Objective-C

    #define CURSORHEIGHT 16 /* height in pixels */ #define CURSORWIDTH 16 /* width in pixels */ #define IOFB_ARBITRARY_SIZE_CURSOR #define IOFRAMEBUFFER_CONFORMSTO "IOFramebuffer"

    Constants

    • CURSORHEIGHT

      CURSORHEIGHT

      The maximum height of the cursor image in pixels. This is only defined if IOFB_ARBITRARY_SIZE_CURSOR is not defined.

      Available in OS X v10.0 and later.

    • CURSORWIDTH

      CURSORWIDTH

      The maximum width of the cursor image in pixels. This is only defined if IOFB_ARBITRARY_SIZE_CURSOR is not defined.

      Available in OS X v10.0 and later.

    • IOFB_ARBITRARY_SIZE_CURSOR

      IOFB_ARBITRARY_SIZE_CURSOR

      When IOFB_ARBITRARY_SIZE_CURSOR is not defined, the maximum cursor size is assumed to be CURSORWIDTH x CURSORHEIGHT and this header file will define a number of structures for storing cursor images accordingly. A non-kernel task may define IOFB_ARBITRARY_SIZE_CURSOR and use cursors up to the size specified when IOFBCreateSharedCursor() was called. In this case appropriate structures for storing cursor images must be defined elsewhere. In the kernel, IOFB_ARBITRARY_SIZE_CURSOR is always defined.

      Available in OS X v10.6 and later.

    • IOFRAMEBUFFER_CONFORMSTO

      IOFRAMEBUFFER_CONFORMSTO

      The class name of the framebuffer service.

      Available in OS X v10.0 and later.

  • Declaration

    Objective-C

    enum { #if IOFB_ARBITRARY_FRAMES_CURSOR kIOFBMainCursorIndex = 0, kIOFBWaitCursorIndex = 1, kIOFBNumCursorIndex = 4, #else kIOFBNumCursorFrames = 4, kIOFBNumCursorFramesShift = 2, #endif kIOFBMaxCursorDepth = 32 };

    Constants

    • kIOFBNumCursorFrames

      kIOFBNumCursorFrames

      The number of cursor images stored in the StdFBShmem_t structure.

      Available in OS X v10.0 and later.

    • kIOFBNumCursorFramesShift

      kIOFBNumCursorFramesShift

      Used with waiting cursors.

      Available in OS X v10.0 and later.

    • kIOFBMaxCursorDepth

      kIOFBMaxCursorDepth

      The maximum cursor pixel depth.

      Available in OS X v10.0 and later.

  • Declaration

    Objective-C

    enum { // version for IOFBCreateSharedCursor kIOFBShmemVersionMask = 0x000000ff, kIOFBTenPtOneShmemVersion = 2, kIOFBTenPtTwoShmemVersion = 3, kIOFBCurrentShmemVersion = 2, // number of frames in animating cursor (if > kIOFBTenPtTwoShmemVersion ) kIOFBShmemCursorNumFramesMask = 0x00ff0000, kIOFBShmemCursorNumFramesShift = 16, // memory types for IOConnectMapMemory. kIOFBCursorMemory = 100 };

    Constants

    • kIOFBCurrentShmemVersion

      kIOFBCurrentShmemVersion

      The current version of the slice of shared memory that contains the cursor and window server state data in the StdFBShmem_t structure.

      Available in OS X v10.0 and later.

    • kIOFBCursorMemory

      kIOFBCursorMemory

      The memory type for IOConnectMapMemory() to get a slice of shared memory that contains the StdFBShmem_t structure.

      Available in OS X v10.0 and later.