Synopsis

ULONG AttachVLayerTagList(
         struct VLayerHandle * VLayerHandle,
         struct Window * Window,
         struct TagItem  * TagItems );

ULONG AttachVLayerTags(
         struct VLayerHandle * VLayerHandle,
         struct Window * Window,
         TAG tag, ... );

Function

Attaches a previously created videolayer handle to the specified window.
The video overlay should now be dynamically linked to the window.
If the window is moved or resized, the overlay is also moved or resized.

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Window - pointer to the window that the videolayer should be attached to

TagItems - pointer to an optional tag list

Result

result - 0 if videolayer could be attached to the window

Notes

Tags available are:

        VOA_LeftIndent (ULONG) - additional offset from the left window border

        VOA_RightIndent (ULONG) - additional offset from the right window border

        VOA_TopIndent (ULONG) - additional offset from the top window border

        VOA_BottomIndent (ULONG) - additional offset from the bottom window border

Bugs

Fails while the layer is locked or already attached. The indent
tags are ignored by the null backend.

See also

DetachVLayer()

Synopsis

struct VLayerHandle * CreateVLayerHandleTagList(
         struct Screen * Screen,
         struct TagItem  * TagItems );

struct VLayerHandle * CreateVLayerHandleTags(
         struct Screen * Screen,
         TAG tag, ... );

Function

Creates a video layer handle for the given screen

Inputs

Screen - Screen we wish to create a handle for

TagItems - pointer to an optional tag list

Result

VLayerHandle - pointer to the created videolayer handle or 0

Notes

Tags available are:

        VOA_SrcType (ULONG) - specifies source type that is used for video
                      overlay data

                Currently supported formats:

                        SRCFMT_YUV16 (not recommended, use YCbCr16 instead)
                        SRCFMT_YCbCr16
                        SRCFMT_RGB15PC
                        SRCFMT_RGB16PC

        VOA_SrcWidth (ULONG) - source width in pixel units

        VOA_SrcHeight (ULONG) -  source height in pixel units

        VOA_Error (ULONG *) - If you specify VOA_Error with ti_Data pointing
                      to an ULONG, you will get more detailed information
                      if the creation of the video layer handle fails

        VOA_UseColorKey (BOOL) - If you specify VOA_UseColorKey as TRUE, color
                keying is enabled for the video layer. A
                certain color key is generated then and the
                stream data is only visible where this color
                could be found.

        VOA_UseBackFill (BOOL) - If you specify VOA_UseBackFill as TRUE automatic
                backfilling for the videolayer is enabled. This
                option is only available if color keying is
                enabled.

        VOA_Modulo (ULONG) - bytes per source row (V43). Defaults to
                VOA_SrcWidth * 2.

Error codes:

        VOERR_INVSRCFMT - unknown VOA_SrcType, zero dimensions or a
                modulo shorter than a source row

        VOERR_INVSCRMODE - the screen has no video overlay

        VOERR_NOMEMORY - out of memory

Bugs

No display driver provides an overlay yet. Setting the
CGXVideoNullBackend variable selects a backend that keeps the
source in system RAM and displays nothing. It does not accept
SRCFMT_YCbCr420.

Synopsis

void DeleteVLayerHandle(
         struct VLayerHandle * VLayerHandle );

Function

Deletes a created video layer handle

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Result

none

Notes

The handle may still be locked or attached.

Synopsis

ULONG DetachVLayer(
         struct VLayerHandle * VLayerHandle );

Function

Detaches a videolayer from a given window. As a result, the video
overlay should now be unlinked from the window and the original
contents of the window are visible now.

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Result

result - 0 if videolayer could be detached from the window

Bugs

Fails while the layer is locked or not attached.

See also

AttachVLayerTagList()

Synopsis

IPTR GetVLayerAttr(
         struct VLayerHandle * VLayerHandle,
         ULONG AttrNum );

Function

Gets a certain attribute from a given video layer. You have to call
LockVLayer() to make sure that the result is valid !

Inputs

VLayerHandle - pointer to a previously created videolayer handle

AttrNum - attribute that you want to get

Result

value - the value for the given attribute

Notes

Attributes available are:

VOA_BaseAddress -       if this attribute is specified the base address for
                        the source data is returned

VOA_ColorKeyPen -       returns the pen number used for color keying. If color
                        keying is not enabled, -1 is returned

VOA_ColorKey -  returns the 24 bit color value used for color keying.
                        If color keying is not enabled, -1 is returned.

VOA_Width, VOA_Height - source dimensions in pixels

VOA_Modulo -            bytes per source row

Bugs

VOA_BaseAddress returns NULL unless the layer is locked. Color
keying is not supported yet. Other attributes return 0.

See also

SetVLayerAttrTagList()

Synopsis

ULONG LockVLayer(
         struct VLayerHandle * VLayerHandle );

Function

Locks the specified video layer to allow access to source data. Make
sure that you don't keep that lock for too long. It is only allowed
to keep it for a short time.

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Result

result - TRUE if video layer could be locked, FALSE otherwise

Bugs

The lock does not nest; a second LockVLayer() fails until
UnlockVLayer() is called.

See also

UnlockVLayer()

Synopsis

ULONG QueryVLayerAttr(
         struct Screen * Screen,
         ULONG AttrID );

Function

Queries the video layer capabilities of a screen.

Inputs

Screen - screen to query

AttrID - one of:

        VSQ_SupportedFeatures - mask of VSQ_FEAT_... bits

        VSQ_SupportedFormats - mask of VSQ_FMT_... bits

        VSQ_MaxWidth - maximum source width of an overlay

        VSQ_MaxWidthSP - maximum width of a subpicture

Result

value - the value of the attribute, 0 if unsupported

Notes

Available since V50.

Bugs

Only the null backend reports any capabilities.

See also

CreateVLayerHandleTagList()

Synopsis

void SetVLayerAttrTagList(
         struct VLayerHandle * VLayerHandle,
         struct TagItem  * TagItems );

void SetVLayerAttrTags(
         struct VLayerHandle * VLayerHandle,
         TAG tag, ... );

Function

Sets certain attributes for a given video layer

Inputs

VLayerHandle - pointer to a previously created videolayer handle

TagItems - pointer to a tag list which contains attributes to be
        modified

Result

none

Notes

Tags available are:

        VOA_LeftIndent (ULONG) - additional offset from the left window
                                        border

        VOA_RightIndent (ULONG) - additional offset from the right window
                                        border

        VOA_TopIndent (ULONG) - additional offset from the top window border

        VOA_BottomIndent (ULONG) - additional offset from the bottom window
                                        border

Bugs

The null backend has no runtime attributes, so all tags are
ignored.

See also

GetVLayerAttr()

Synopsis

void SwapVLayerBuffer(
         struct VLayerHandle * VLayerHandle );

Function

Swaps the displayed and the rendering buffer of a double buffered
video layer at the next vertical blank. The next LockVLayer() may
wait for that vertical blank.

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Result

none

Notes

Available since V50.

Bugs

No backend supports double buffering yet, so this does nothing.

See also

LockVLayer() QueryVLayerAttr()

Synopsis

ULONG UnlockVLayer(
         struct VLayerHandle * VLayerHandle );

Function

Unlocks a previouly locked video layer

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Result

result - always 0

See also

LockVLayer()

Synopsis

ULONG WriteSPLine(
         struct VLayerHandle * VLayerHandle,
         UBYTE * Buffer,
         LONG X,
         LONG Y,
         LONG Width );

Function

Writes one line of subpicture data to a video layer.

Inputs

VLayerHandle - pointer to a previously created videolayer handle

Buffer - subpicture pixel data

X, Y - position of the line in the subpicture

Width - number of pixels to write

Result

result - 0

Notes

Available since V50.

Bugs

No backend supports subpictures yet, so this does nothing.

See also

QueryVLayerAttr()