GPR_$INQ_PIXEL_FORMATS GPR Calls GPR_$INQ_PIXEL_FORMATS
NAME
gpr_$inq_pixel_formats - returns the pixel formats available on the dev-
ice.
FORMAT
gpr_$inq_pixel_formats (resource_type, resource_id, max_formats,
format_size, num_formats, formats, status)
DESCRIPTION
This routine returns the pixel formats available on the device.
Input Parameters
resource_type
The display resource type, in gpr_$resource_type_t format. Possible
values for this parameter are:
gpr_$memory_bitmap
A main memory bitmap. This has no effect on the screen.
gpr_$pad_id
A display-manager window
gpr_$pad_frame_id
A display-manager frame
gpr_$screen
The entire screen
gpr_$x_window_id
An X window
resource_id
The resource identifier. This value can have the following mean-
ings:
⊕ The display unit, if the display resource type is gpr_$screen.
This is a 2-byte integer. The only valid display ID for
gpr_$screen is 1.
⊕ The stream identifier for the pad or X window, if the display
resource is gpr_$pad_id or gpr_$x_window_id. Use stream_$id_t
format. This is a 4-byte integer.
⊕ Any value, such as zero, if the display resource is
gpr_$memory_bitmap.
max_formats
The maximum number of formats requested. This is a 4-byte integer.
The maximum number of formats available is defined in
gpr_$max_formats.
format_size
The size in bytes of the format record. For example, if the buffer
is ten 16-bit words in length, the program gives 20 as the value of
this parameter. No checking is (or can be) done to verify that this
length is correct; so unpredictable results are obtained if the pro-
gram gives a size that is larger than the actual size of the buffer.
This parameter allows the calling program to request that less than
the full set of characteristics be returned. It also allows the pro-
gram to continue to function correctly if the list is extended in the
future. To get the size of the buffer, use the 'sizeof' function in C
and Pascal. In FORTRAN, use the constant gpr_$pixel_format_size,
which has been defined in gpr.ins.ftn, to get this value. This param-
eter is a 4-byte integer.
Output Parameters
num_formats
The number of formats returned in the pixel format array.
formats
An array of supported pixel formats for this device, in
gpr_$pixel_format_array_t format. This is an array of
gpr_$pixel_format_t.
status
Completion status, in status_$t format.
NOTES
Use this call to find a valid pixel format for gpr_$initialize and
gpr_$inq_pixel_characteristics.
The formats returned in gpr_$inq_pixel_formats specify the maximum allow-
able depth of each projection for each of the given formats. In addi-
tion, you may specify a format with fewer planes for a particular projec-
tion than a format returned in gpr_$inq_pixel_formats. For example, you
may specify a pseudo color pixel format with an image depth of four
planes even though eight would be available to you.
The display resource is the equivalent of the display mode used in
gpr_$init, except that it does not specify true color or pseudo color.