DynaPDF Manual - Page 231

Previous Page 230   Index   Next Page 232

Function Reference
Page 231 of 777
Specific flags supported by combo boxes:
// Enable adding of values in Adobe's Acrobat
// Change the sort flag if necessary
// Submit the new value immediately (PDF 1.5)
ffDoNotSpellCheck // Disable spell checking (requires ffEdit)
Interactive form fields can be structured into several groups by passing a handle of a group field to
the parameter Parent. See CreateGroupField() for further information.
Return values:
If the function succeeds the return value is the handle of the combo box, a value greater or equal
zero. If the function fails the return value is a negative error code.
SI32 pdfCreateDeviceNColorSpace(
const PPDF* IPDF,
// Instance pointer
const char** Colorants,
// Array of colorant names (required)
UI32 NumColorants,
// Number of colorants in the array
const char* PostScriptFunc, // Postscript calculator function (required)
TExtColorSpace Alternate,
// Alternate color space
SI32 Handle)
// Handle of the alternate color space or -1
The function creates a DeviceN color space. DeviceN color spaces (PDF 1.3) can contain up to 32
color components. They provide greater flexibility than is possible with standard device color spaces
such as DeviceCMYK or with individual Separation color spaces. For example, it is possible to create
a DeviceN color space consisting of only the cyan, magenta, and yellow color components, with the
black component excluded.
Colors of a DeviceN color space are always treated as subtractive colors, even if the device produces
output for the designated component by an additive method. Thus, a tint value of 0 denotes the
lightest color that can be achieved with the given colorant and 255 the darkest. This convention is the
same one as for DeviceCMYK color components but opposite to the one for DeviceGray or
DeviceN was designed to represent color spaces containing multiple components that correspond to
colorants of some target device. As with Separation color spaces, PDF consumer applications must
be able to approximate the colorants if they are not available on the current output device, such as a
display. To accomplish this, the color space definition provides a tint transformation function that
can be used to convert all the components to an alternate color space.
The tint transformation function consists of a PostScript calculator function that is called with n tint
values and returns m color component values, where n is the number of components needed to

Previous topic: CreateComboBox

Next topic: Encoding of Colorant Names, DeviceN Attributes, Spot colorant attributes